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Hierarchical microstructures with high spatial frequency laser induced periodic surface structures possessing different orientations created by femtosecond laser ablation of silicon in liquids 预览
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作者 Dongshi Zhang Koji Sugioka 《光电进展(英文)》 2019年第3期1-18,共18页
High spatial frequency laser induced periodic surface structures(HSFLs)on silicon substrates are often developed on flat surfaces at low fluences near ablation threshold of 0.1 J/cm2,seldom on microstructures or micro... High spatial frequency laser induced periodic surface structures(HSFLs)on silicon substrates are often developed on flat surfaces at low fluences near ablation threshold of 0.1 J/cm2,seldom on microstructures or microgrooves at relatively higher fluences above 1 J/cm^2.This work aims to enrich the variety of HSFLs-containing hierarchical microstructures,by femtosecond laser(pulse duration:457 fs,wavelength:1045 nm,and repetition rate:100 kHz)in liquids(water and acetone)at laser fluence of 1.7 J/cm^2.The period of Si-HSFLs in the range of 110–200 nm is independent of the scanning speeds(0.1,0.5,1 and 2 mm/s),line intervals(5,15 and 20μm)of scanning lines and scanning directions(perpendicular or parallel to light polarization direction).It is interestingly found that besides normal HSFLs whose orientations are perpendicular to the direction of light polarization,both clockwise or anticlockwise randomly tilted HSFLs with a maximal deviation angle of 50°as compared to those of normal HSFLSs are found on the microstructures with height gradients.Raman spectra and SEM characterization jointly clarify that surface melting and nanocapillary waves play important roles in the formation of Si-HSFLs.The fact that no HSFLs are produced by laser ablation in air indicates that moderate melting facilitated with ultrafast liquid cooling is beneficial for the formation of HSFLs by LALs.On the basis of our findings and previous reports,a synergistic formation mechanism for HSFLs at high fluence was proposed and discussed,including thermal melting with the concomitance of ultrafast cooling in liquids,transformation of the molten layers into ripples and nanotips by surface plasmon polaritons(SPP)and second-harmonic generation(SHG),and modulation of Si-HSFLs direction by both nanocapillary waves and the localized electric field coming from the excited large Si particles. 展开更多
关键词 HIGH spatial frequency LASER induced periodic SURFACE structures SILICON LASER ablation in liquids HIERARCHICAL MICROSTRUCTURES femtosecond LASER HIGH fluence formation mechanism SURFACE melting nanocapillary wave SURFACE plasmon polaritons second-harmonic generation
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Satellite-observed trends in the Arctic sea ice concentration for the period 1979–2016 预览
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作者 WANG Yunhe BI Haibo +5 位作者 HUANG Haijun LIU Yanxia LIU Yilin LIANG Xi FU Min ZHANG Zehua 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第1期18-37,共20页
Arctic sea ice cover has decreased dramatically over the last three decades.This study quantifi es the sea ice concentration(SIC)trends in the Arctic Ocean over the period of 1979–2016 and analyzes their spatial and ... Arctic sea ice cover has decreased dramatically over the last three decades.This study quantifi es the sea ice concentration(SIC)trends in the Arctic Ocean over the period of 1979–2016 and analyzes their spatial and temporal variations.During each month the SIC trends are negative over the Arctic Ocean,wherein the largest(smallest)rate of decline found in September(March)is-0.48%/a(-0.10%/a).The summer(-0.42%/a)and autumn(-0.31%/a)seasons show faster decrease rates than those of winter(-0.12%/a)and spring(-0.20%/a)seasons.Regional variability is large in the annual SIC trend.The largest SIC trends are observed for the Kara(-0.60%/a)and Barents Seas(-0.54%/a),followed by the Chukchi Sea(-0.48%/a),East Siberian Sea(-0.43%/a),Laptev Sea(-0.38%/a),and Beaufort Sea(-0.36%/a).The annual SIC trend for the whole Arctic Ocean is-0.26%/a over the same period.Furthermore,the infl uences and feedbacks between the SIC and three climate indexes and three climatic parameters,including the Arctic Oscillation(AO),North Atlantic Oscillation(NAO),Dipole anomaly(DA),sea surface temperature(SST),surface air temperature(SAT),and surface wind(SW),are investigated.Statistically,sea ice provides memory for the Arctic climate system so that changes in SIC driven by the climate indices(AO,NAO and DA)can be felt during the ensuing seasons.Positive SST trends can cause greater SIC reductions,which is observed in the Greenland and Barents Seas during the autumn and winter.In contrast,the removal of sea ice(i.e.,loss of the insulating layer)likely contributes to a colder sea surface(i.e.,decreased SST),as is observed in northern Barents Sea.Decreasing SIC trends can lead to an in-phase enhancement of SAT,while SAT variations seem to have a lagged infl uence on SIC trends.SW plays an important role in the modulating SIC trends in two ways:by transporting moist and warm air that melts sea ice in peripheral seas(typically evident inthe Barents Sea)and by exporting sea ice out of the Arctic Ocean via passages into the Greenland and Barents Seas, 展开更多
关键词 SEA ice concentration(SIC) Arctic Ocean SURFACE air temperature(SAT) SEA SURFACE temperature(SST) SURFACE wind(SW) INTERANNUAL and DECADAL oscillation
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Surface charge accumulation behavior and its influence on surface flashover performance of Al2O3-filled epoxy resin insulators under DC voltages
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作者 刘彦琴 吴广宁 +3 位作者 高国强 薛建议 康永强 石超群 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第5期132-141,共10页
Surface charge accumulation on insulator surface can have great influence on surface flashover performance.An experimental system is established to investigate surface charge accumulation and decay characteristics of ... Surface charge accumulation on insulator surface can have great influence on surface flashover performance.An experimental system is established to investigate surface charge accumulation and decay characteristics of Al2O3-filled epoxy resin insulators in 0.1 MPa SF6 under DC voltages.Surface potential is recorded by a Kelvin vibrating probe connected to an electrostatic voltmeter.By pre-depositing charges on insulator surface,the influence of surface charges on surface flashover performance is studied.The results reveal that surface charge distribution appearance is the combined effect of electrode injection,back discharge and gas ionization.Surface charge distribution has obvious polarity effect.It is concentrated near the HV electrode under positive voltages and dispersed under negative voltages.The difference in positive and negative surface flashover voltage is attributed to the difference in surface charge distribution under DC voltages of different polarities.Surface charge decay contains two stages,which satisfies the law of double exponential function.At first stage,surface charge decays fast,which corresponds to charges escaping from shallower traps.While it decays slowly at the second stage,which corresponds to charge escaping from deeper traps.Surface charge decay process is dominated by surface conductivity mechanism.The pre-deposited charges on insulation surface have great influence on surface flashover performance.The deposited positive charges can increase positive flashover voltage but decrease negative flashover voltage. 展开更多
关键词 SURFACE charge electrode injection SURFACE FLASHOVER SURFACE CONDUCTIVITY pre-deposited CHARGES
Comparisons of urban-related warming in Beijing using different methods to calculate the daily mean temperature
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作者 Deming ZHAO Jian WU 《中国科学:地球科学英文版》 SCIE EI CAS CSCD 2019年第4期693-702,共10页
To evaluate the contribution of urban surface expansion to regional warming using different methods to calculate the daily mean surface air temperature(SAT), satellite-based images displaying urban surface expansion o... To evaluate the contribution of urban surface expansion to regional warming using different methods to calculate the daily mean surface air temperature(SAT), satellite-based images displaying urban surface expansion over the past 37 years(1980–2016) across China were collected for use in nested numerical experiments using the weather research and forecasting(WRF) regional climate model. The contribution of urban surface expansion to urban-related warming was determined using the daily mean SAT averages based on four time records each day(00, 06, 12, and 18 h UTC, T4) and averages of the SAT maximum(Tmax) and minimum(Tmin)(Txn). The contribution of urban surface expansion to urban-related warming(relative value) in Beijing was 0.110°C per decade(22.8% of total warming) for T4 and 0.094°C per decade(20.2%) for Txn. The values obtained when using T4 were larger than those obtained when using Txn. Differences in the urban-related warming calculated using T4 and Txncould be attributed to the smaller changing trends in Txnin the urban-surface expansion experiment, which resulted from a large changing trend in Tminand a much smaller changing trend in Tmax. The changes in the diurnal cycle of the energy budget due to urban surface expansion induced changes in the diurnal cycle of SAT, as evidenced by the four time records each day, as well as Tmaxand Tmin. This was especially true for periods of intense urban surface expansion, although the annual mean SAT calculated using Txnwas larger than that calculated using T4. The increase in impervious area(walls, streets, etc.) due to urban surface expansion, as well as the widespread use of building materials with a large heat capacity resulted in a marked increase in ground heat flux in the daytime. This restricted the increase in SAT in the daytime, but promoted it at night. The increases in SAT due to urban surface expansion were not symmetrical, being smaller in the daytime and larger at night. 展开更多
关键词 Urban SURFACE expansion SURFACE air TEMPERATURE DAILY mean TEMPERATURE Changing trend Urban-related WARMING
Surface treatments of CdGeAs2 single crystals
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作者 Wei Huang Bei-Jun Zhao +4 位作者 Shi-Fu Zhu Zhi-Yu He Bao-Jun Chen Zhen Zhen Yun-Xiao Pu 《稀有金属:英文版》 SCIE EI CAS CSCD 2019年第7期683-688,共6页
The performances of second harmonic gen eration (SHG) and optical parametric oscillator (OPO) in CdGeAs2 crystal are strongly influenced by surface quality. In this paper, the surfaces of samples were treated by mecha... The performances of second harmonic gen eration (SHG) and optical parametric oscillator (OPO) in CdGeAs2 crystal are strongly influenced by surface quality. In this paper, the surfaces of samples were treated by mechanical polishing (MP), chemical polishing (CP), chemical-mechanical polishing (CMP) and CP following CMP closely (CMP + CP). Then, the surface state was characterized by optical microscopy (OM), scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). AFM measurements show that an ultra-smooth surface is achieved after CMP + CP treatment and the roughness value is 0.98 nm. Meanwhile, the roughness of the surfaces treated by MP, CP and CMP are 4.53, 2.83 and 1.38 nm, respectively. By XRD rocking curves, the diffraction peak which belongs to the wafer treated by CMP + CP is the highest in intensity and best symmetrical in shape. XPS analysis indicates that Ge4+ proportions of GeO2 in total Ge content of CdGeAs2 wafers' surface after MP, CP, CMP and CMP + CP treatment are 27.6%, 42.8%, 6.1% and 30.3%, respectively. 展开更多
关键词 CdGeAs2 SINGLE CRYSTAL SURFACE TREATMENTS SURFACE ROUGHNESS
Co-variation of the surface wind speed and the sea surface temperature over mesoscale eddies in the Gulf Stream region: momentum vertical mixing aspect 预览
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作者 HE Jingjing LIN Xiaopei 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第4期1154-1164,共11页
The co-variation of surface wind speed and sea surface temperature (SST) over the Gulf Stream frontal region is investigated using high-resolution satellite measurements and atmospheric reanalysis data. Results show t... The co-variation of surface wind speed and sea surface temperature (SST) over the Gulf Stream frontal region is investigated using high-resolution satellite measurements and atmospheric reanalysis data. Results show that the pattern of positive SST-surface wind speed correlations is anchored by strong SST gradient and marine atmospheric boundary layer (MABL) height front, with active warm and cold-ocean eddies around. The MABL has an obvious transitional structure along the strong SST front, with greater (lesser) heights over the north (south) side. The significant positive SST-surface wind-speed perturbation correlations are mostly found over both strong warm and cold eddies. The surface wind speed increases (decreases) about 0.32 (0.41) m/s and the MABL elevates (drops) approximate 55 (54) m per 1℃ of SST perturbation induced by warm (cold) eddies. The response of the surface wind speed to SST perturbations over the mesoscale eddies is mainly attributed to the momentum vertical mixing in the MABL, which is confirmed by the linear relationships between the downwind (crosswind) SST gradient and wind divergence (curl). 展开更多
关键词 GULF Stream positive sea SURFACE temperature (SST)-surface wind speed correlation marine atmospheric boundary layer (MABL) height MESOSCALE EDDY MOMENTUM vertical mixing
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Investigation of the factors affecting the limit of detection of laser-induced breakdown spectroscopy for surface inspection
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作者 Tadatake SATO Kenichi TASHIRO +2 位作者 Yoshizo KAWAGUCHI Hideki OHMURA Haruhisa AKIYAMA 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第3期174-181,共8页
Laser-induced breakdown spectroscopy(LIBS)was examined to detect a trace substance adhered onto Al alloys for the surface inspection of materials to be adhesively bonded.As an example of Si contamination,silicone oil ... Laser-induced breakdown spectroscopy(LIBS)was examined to detect a trace substance adhered onto Al alloys for the surface inspection of materials to be adhesively bonded.As an example of Si contamination,silicone oil was employed and sprayed onto substrates with a controlled surface concentration.LIBS measurements employing nanosecond UV pulses(λ=266 nm)and an off-axis emission collection system with different detecting heights were performed.Because surface contaminants are involved in the plasma formed by laser ablation of the substrates,the relative contribution of the surface contaminants and the substrates to the plasma emission could be changed depending on the conditions for plasma formation.The limit of detection(LOD)was evaluated under several detecting conditions for investigating the factors that affected the LOD.A significant factor was the standard deviation values of signal intensities obtained for the clean substrates.This value varied depending on the measurement conditions.For the Al alloy(A6061),the smallest LOD obtained was 0.529μg·cm^-2.Furthermore,an improved LOD(0.299μg·cm^-2)was obtained for the Al alloy with a lower Si content. 展开更多
关键词 LASER-INDUCED BREAKDOWN spectroscopy adhesive BONDING SURFACE CONTAMINATION detection pre-bond SURFACE inspection
Comparison of low.pressure oxygen plasma and chemical treatments for surface modifications of Ti6Al4V 预览
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作者 María Elena Alemán.Domínguez Zaida Ortega +4 位作者 Antonio N.Benítez Aday Romero.Pérez Ling Wang Ruymán Santana.Farré Francisco Rodríguez.Esparragón 《生物设计与制造(英文)》 CSCD 2019年第2期65-75,共11页
Different treatments were conducted over Ti6Al4V samples in order to produce a surface modification to increase cell attachment and proliferation.The surface treatments evaluated in this study were as follows:etching ... Different treatments were conducted over Ti6Al4V samples in order to produce a surface modification to increase cell attachment and proliferation.The surface treatments evaluated in this study were as follows:etching with sulfuric acid/hydrochloric acid,oxidizing with hydrogen peroxide and low-pressure oxygen plasma treatment.In contrast to other works found in the literature,this research conducts a comparison between different chemical and physical treatments in terms of different assays for surface characterization:X-ray diffraction,scanning electron microscope(SEM),energy-dispersive X-ray spectroscopy,water contact angle,release of vanadium ions and cell viability tests(MTT)of human osteoblasts(hFOB 1.19).Cell morphology over the different substrates was also studied by SEM observation.It was found that plasma and peroxide treatments increase the O/Ti ratio at the titanium surface and provide an increase in cell affinity.On the other hand,acid etching provides a superhydrophilic surface which is not able to improve the cell attachment of human osteoblasts. 展开更多
关键词 SURFACE ACTIVATION TITANIUM alloys SURFACE FUNCTIONALIZATION LOW-PRESSURE plasma
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Preliminary Findings on Distribution of Bali Sardinella (Sardinella lemuru) in Relation to Oceanographic Conditions during Southeast Monsoon in Bali Strait Using Remotely Sensed Data 预览
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作者 Achmad Fachruddin Syah Nurul Setyowati Eko Susilo 《海洋科学杂志(英文)》 2019年第1期25-30,共6页
Bali sardinella (Sardinella lemuru) is the main fishing catches in Bali Strait. The distribution of S. lemuru and its preferred oceanographic condition were investigated from remotely sensed data. The objectives of th... Bali sardinella (Sardinella lemuru) is the main fishing catches in Bali Strait. The distribution of S. lemuru and its preferred oceanographic condition were investigated from remotely sensed data. The objectives of this study were to elucidate the distribution of S. lemuru and the preferred oceanographic condition of S. lemuru in Bali Strait using remotely sensed data. Sea surface temperature (SST) and sea surface chlorophyll-a (chl-a) were downloaded from ocean colour website meanwhile the fishing location generated from daily Visible Infrared Imaging Radiometer Suite (VIIRS) boat detection (VDB), downloaded from NOAA website. The results showed that at the beginning of southeast monsoon (April), most of the fishing location appeared in the north part of Bali Strait, and moved to south part of Bali Strait at the end of the southeast monsoon (September). The results also revealed that most of fishing location of S. lemuru located in SST value of 26℃– 30℃ and chl-a value of 0.3 – 0.8 mg/m3. Integration VDB data and oceanographic condition generated from remotely sensed data could form the basis for fisheries management and information system, such as S. lemuru in Bali Strait, in the future. 展开更多
关键词 Main fishing CATCHES SEA SURFACE temperature SEA SURFACE CHLOROPHYLL-A visible infrared imaging radiometer suite boat detection
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Genetic algorithm aided density functional theory simulations unravel the kinetic nature of Au(100) in catalytic CO oxidation
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作者 Yi Fang Xueqing Gong 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第6期1346-1350,共5页
Heterogeneous catalysis is of tremendous importance to modern industries. Exposed atoms of heterogeneous catalysts are heavily involved in surface processes such as the adsorption, activation, diffusion and reaction o... Heterogeneous catalysis is of tremendous importance to modern industries. Exposed atoms of heterogeneous catalysts are heavily involved in surface processes such as the adsorption, activation, diffusion and reaction of substrate molecules. Surfaces of metal or metal oxide based catalysts are usually taken as hard templates that only undergo limited relaxation during catalytic reactions, especially in theoretical simulations. In this work, by using genetic algorithm (GA) aided density functional theory (DFT) calculations, we studied the surface processes involved in CO oxidation on the Au(100) surface. The use of GA greatly improves the capacity of DFT calculations in locating the potential energy surface (PES) of the surface reactions, and surprisingly, it has been found that the Au(100) surface can undergo drastic reconstruction under the influence of O adsorption and the adapted partially oxidized Au surface exhibits unique activities for subsequent adsorptions and reactions. This work depicts the kinetic nature of the Au (100) surface in its catalyzed reactions and also significantly expands our understanding of how surface atoms act in heterogeneous catalysis. 展开更多
关键词 Gold CATALYSTS GENETIC algorithm Density functional theory Potential energy SURFACE SURFACE reconstruction
Improving fatigue performance of Ti-6Al-4V alloy via ultrasonic surface rolling process
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作者 Chengsong Liu Daoxin Liu +4 位作者 Xiaohua Zhang Dan Liu Amin Ma Ni Ao Xingchen Xu 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第8期1555-1562,共8页
The effect of a gradient nanostructured(GNS) surface layer obtained by ultrasonic surface rolling process(USRP) on the fatigue behavior of Ti-6Al-4V alloy has been studied in this paper. Microstructure, surface topogr... The effect of a gradient nanostructured(GNS) surface layer obtained by ultrasonic surface rolling process(USRP) on the fatigue behavior of Ti-6Al-4V alloy has been studied in this paper. Microstructure, surface topography, surface roughness and residual stress measurements were performed to characterize the surface under different conditions. Rotating bending fatigue tests were carried out to evaluate the fatigue behavior of different treatments. The results present a remarkable fatigue performance enhancement for the Ti-6Al-4V alloy with a GNS surface layer obtained by application of USRP with respect to the untreated condition, notwithstanding its considerable surface roughness due to severe ultrasonic impacts and extrusions. Mechanical surface polishing treatment further enhances the beneficial effects of USRP on the fatigue performance. The significantly improved fatigue performance can mainly be ascribed to the compressive residual stress. Simultaneously, the GNS surface layer and surface work hardening have a synergistic effect that accompanies the effect of compressive residual stress. 展开更多
关键词 ULTRASONIC SURFACE rolling process Fatigue COMPRESSIVE residual stress Gradient NANOSTRUCTURED SURFACE layer Ti-6Al-4V alloy
Ln2Zr2O7 compounds (Ln=La, Pr, Sm, Y) with varied rare earth A sites for low temperature oxidative coupling of methane
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作者 Xiuzhong Fang Lianghui Xia +7 位作者 Liang Peng Yuan Luo Junwei Xu Luoji Xu Xianglan Xu Wenming Liu Renyang Zheng Xiang Wang 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第6期1141-1146,共6页
With the objective to develop catalysts having application potential for oxidative coupling of methane (OCM) at relatively lower temperature. A series of Ln2Zr2O7 compounds with varied rare earth A sites have been pre... With the objective to develop catalysts having application potential for oxidative coupling of methane (OCM) at relatively lower temperature. A series of Ln2Zr2O7 compounds with varied rare earth A sites have been prepared by a co-precipitation method. XRD and Raman have proved that pure Ln2Zr2O7 compounds have been successfully prepared for all the catalysts. By decreasing the rA/rB ratio, their crystalline structure transform from an ordered pyrochlore (La2Zr2O7) to a less ordered pyrochlore (Pr2Zr2O7 and Sm2Zr2O7) and eventually to a defective cubic fluorite phase (Y2Zr2O7). H2-TPR, O2-TPD and XPS have testified that the amount of surface active O2-species follows the order of La2Zr2O7>Pr2Zr2O7>Sm2Zr2O7 > Y2Zr2O7, which is well consistent with the reaction performance, indicating that the abundance of surface O2- sites is a critical factor influencing the reaction performance. CO2-TPD has demonstrated that a better catalyst generally possesses a larger amount of surface moderate alkaline sites, which is another factor to affect the reaction performance. It is concluded that the concerted interaction between the two types of surface active sites controls the reaction performance of the Ln2Zr2O7 catalysts. In comparison with the state-of-the art Mn/Na2WO4/SiO2, La2Zr2O7, the best catalyst, exhibits much improved reaction performance below 750 ℃. 展开更多
关键词 PYROCHLORE COMPOUNDS Low temperature OCM A site SUBSTITUTION effects SURFACE superoxide SITES SURFACE alkaline SITES
Trends of sea surface temperature and sea surface temperature fronts in the South China Sea during 2003–2017 预览
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作者 Yi Yu Hao-Ran Zhang +1 位作者 Jiangbo Jin Yuntao Wang 《海洋学报:英文版》 SCIE CAS CSCD 2019年第4期106-115,共10页
The trends of the sea surface temperature(SST)and SST fronts in the South China Sea(SCS)are analyzed during 2003–2017 using high-resolution satellite data.The linear trend of the basin averaged SST is 0.31℃per decad... The trends of the sea surface temperature(SST)and SST fronts in the South China Sea(SCS)are analyzed during 2003–2017 using high-resolution satellite data.The linear trend of the basin averaged SST is 0.31℃per decade,with the strongest warming identified in southeastern Vietnam.Although the rate of warming is comparable in summer and winter for the entire basin,the corresponding spatial patterns of the linear trend are substantially different between them.The SST trend to the west of the Luzon Strait is characterized by rapid warming in summer,exceeding approximately 0.6℃per decade,but the trend is insignificant in winter.The strongest warming trend occurs in the southeast of Vietnam in winter,with much less pronounced warming in summer.A positive trend of SST fronts is identified for the coast of China and is associated with increasing wind stress.The increasing trend of SST fronts is also found in the east of Vietnam.Large-scale circulation,such as El Nino,can influence the trends of the SST and SST fronts.A significant correlation is found between the SST anomaly and Nino3.4 index,and the ENSO signal leads by eight months.The basin averaged SST linear trends increase after the El Nino event(2009–2010),which is,at least,due to the rapid warming rate causing by the enhanced northeasterly wind.Peaks of positive anomalous SST and negatively anomalous SST fronts are found to co-occur with the strong El Nino events. 展开更多
关键词 South China SEA SEA SURFACE TEMPERATURE SEA SURFACE TEMPERATURE FRONTS WARMING trend wind stress
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Enhanced organic solar cell performance: Multiple surface plasmon resonance and incorporation of silver nanodisks into a grating‐structure electrode 预览
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作者 Thitirat Putnin Chutiparn Lertvachirapaiboon +5 位作者 Ryousuke Ishikawa Kazunari Shinbo Keizo Kato Sanong Ekgasit Kontad Ounnunkad Akira Baba 《光电进展(英文)》 2019年第7期7-20,共14页
In this study, plasmonic nanostructures were examined to enhance the light harvesting of organic thin-film solar cells (OSCs) by multiple surface plasmon resonance (SPR) phenomena originating from the grating-coupled ... In this study, plasmonic nanostructures were examined to enhance the light harvesting of organic thin-film solar cells (OSCs) by multiple surface plasmon resonance (SPR) phenomena originating from the grating-coupled configuration with a Blu-ray Disc recordable (BD-R)-imprinted aluminum (Al) grating structure and the incorporation of a series of silver nanodisks (Ag NDs). The devices with such a configuration maximize the light utilization inside OSCs via light absorption, light scattering, and trapping via multiple surface plasmon resonances. Different types and sizes of metallic nanoparticles (NPs), i.e., gold nanoparticles (Au NPs), Ag nanospheres (Ag NSs), and Ag NDs, were used, which were blended separately in a PEDOT:PSS hole transport layer (HTL). The device structure comprised of grating- imprinted-Al/P3HT:PCBM/Ag ND:PEDOT:PSS/ITO. Results obtained from the J–V curves revealed that the power conversion efficiency (PCE) of grating-structured Al/P3HT:PCBM/PEDOT:PSS/ITO is 3.16%;this value is ~6% higher than that of a flat substrate. On the other hand, devices with flat Al and incorporated Au NPs, Ag NSs, or Ag NDs in the HTL exhibited PCEs ranging from 3.15% to 3.37%. Furthermore, OSCs with an Al grating substrate were developed by the incorporation of the Ag ND series into the PEDOT:PSS layer. Compared with that of a reference device, the PCEs of the devices increased to 3.32%–3.59%(11%–20% improvement), indicating that the light absorption enhancement at the active layer corresponds to the grating-coupled surface plasmon resonance and localized surface plasmon resonance excitations with strong near-field distributions penetrating into the active layer leading to higher efficiencies and subsequent better current generation. 展开更多
关键词 grating-coupled SURFACE PLASMON RESONANCE LOCALIZED SURFACE PLASMON RESONANCE Ag NANODISKS organic solar cells imprinted GRATING
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Subwavelength negative-index waveguiding enabled by coupled spoof magnetic localized surface plasmons
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作者 Zhen Liao Guo Qing Luo +2 位作者 Ben Geng Cai Bai Cao Pan Wen Hui Cao 《光子学研究:英文版》 CSCD 2019年第3期274-282,共9页
Magnetic localized surface plasmon modes are supported on metallic spiral structures. Coupling mechanisms for these metamaterial resonators, which are the joint action of magnetic and electric coupling, are studied. B... Magnetic localized surface plasmon modes are supported on metallic spiral structures. Coupling mechanisms for these metamaterial resonators, which are the joint action of magnetic and electric coupling, are studied. Based on the strong coupling, spoof magnetic plasmon modes propagating in the backward direction are proposed along a chain of subwavelength resonators. The theoretical analysis, numerical simulations, and experiments are in good agreement. The proposed novel route for achieving negative-index waveguiding has potential applications in integrated devices and circuits. 展开更多
关键词 SUBWAVELENGTH NEGATIVE-INDEX waveguiding COUPLED spoof MAGNETIC LOCALIZED SURFACE plasmons MAGNETIC LOCALIZED SURFACE plasmon modes
Invitro Biodegradability of Silk Fibroin/Xanthan Biopolymeric Composite Scaffolds
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作者 Shailendra Singh Shera Shraddha Sahu Rathindra Mohan Banik 《仿生工程学报:英文版》 SCIE EI CSCD 2019年第2期299-310,共12页
Silk fibroin/xanthan scaffolds were prepared by blending silk fibroin and xanthan in the ratios 80SF:20Xa(SFX82),60SF:40Xa(SFX64),and 50SF:50Xa(SFX55)using freeze drying method.In-vitro degradation behavior of the pre... Silk fibroin/xanthan scaffolds were prepared by blending silk fibroin and xanthan in the ratios 80SF:20Xa(SFX82),60SF:40Xa(SFX64),and 50SF:50Xa(SFX55)using freeze drying method.In-vitro degradation behavior of the prepared scaffolds was studied for 37 days in phosphate buffer saline.The degradation rate was the function of silk fibroin,xanthan and^-crystallite contents in the silk fibroin/xanthan composites.SFX82 degraded extremely slowly whereas SFX55 showed faster degradation rate.Hydrophilic xanthan was the main contributor of weight loss.SFX82 and SFX64 exhibited surface degradation whereas SFX55 showed bulk degradation which indicated that higher silk fibroin ratios favor surface degradation.Due to bulk degradation,SFX55 showed maximum surface roughness among the composite scaffolds.The FTIR spectrum revealed total loss of xanthan from the composites after degradation.The broad and low-intensity peaks in the FTIR spectrum of composite scaffolds con finned reduction in 0-sheet crystallite content during degradation.XRD analysis also confirmed reduction in 0-sheet crystals and revealed that degraded composite scaffold had predominantly amorphous structure.The degraded scaffold showed higher porous structure than the non-degraded scaffold.The in vitro degradability testing gives a good approximation of degradation of scaffold in vivo and helps in designing a robust biopolymeric composite scaffold for tissue engineering. 展开更多
关键词 BIOPOLYMER composites SURFACE ROUGHNESS BIOPOLYMER DEGRADATION SURFACE DEGRADATION tissue engineering
Modelling of the In uence of Tool Runout on Surface Generation in Micro Milling
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作者 Wanqun Chen Yazhou Sun +1 位作者 Dehong Huo Xiangyu Teng 《中国机械工程学报:英文版》 SCIE EI CAS CSCD 2019年第1期152-160,共9页
Micro milling is a flexible and economical method to fabricate micro components with three-dimensional geometry features over a wide range of engineering materials. But the surface roughness and micro topography alway... Micro milling is a flexible and economical method to fabricate micro components with three-dimensional geometry features over a wide range of engineering materials. But the surface roughness and micro topography always limit the performance of the machined micro components. This paper presents a surface generation simulation in micro end milling considering both axial and radial tool runout. Firstly, a surface generation model is established based on the geometry of micro milling cutter. Secondly, the influence of the runout in axial and radial directions on the surface generation are investigated and the surface roughness prediction is realized. It is found that the axial runout has a significant influence on the surface topography generation. Furthermore, the influence of axial runout on the surface micro topography was studied quantitatively, and a critical axial runout is given for variable feed per tooth to generate specific surface topography. Finally, the proposed model is validated by means of experiments and a good correlation is obtained. The proposed surface generation model o ers a basis for designing and optimizing surface parameters of functional machined surfaces. 展开更多
关键词 SURFACE generation ROUGHNESS prediction SURFACE TOPOGRAPHY RUNOUT Micro MILLING
A surface parametric control and global optimization method for axial flow compressor blades
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作者 Jinxin CHENG Jiang CHEN Hang XIANG 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第7期1618-1634,共17页
An aerodynamic optimization method for axial flow compressor blades available for engineering is developed in this paper. Bezier surface is adopted as parameterization method to control the suction surface of the blad... An aerodynamic optimization method for axial flow compressor blades available for engineering is developed in this paper. Bezier surface is adopted as parameterization method to control the suction surface of the blades, which brings the following advantages:(A) significantly reducing design variables;(B) easy to ensure the mechanical strength of rotating blades;(C) better physical understanding;(D) easy to achieve smooth surface. The Improved Artificial Bee Colony(IABC) algorithm, which significantly increases the convergence speed and global optimization ability, is adopted to find the optimal result. A new engineering optimization tool is constructed by combining the surface parametric control method, the IABC algorithm, with a verified Computational Fluid Dynamics(CFD) simulation method, and it has been successfully applied in the aerodynamic optimization for a single-row transonic rotor(Rotor 37) and a single-stage transonic axialflow compressor(Stage 35). With the constraint that the relative change in the flow rate is less than0.5% and the total pressure ratio does not decrease, within the acceptable time in engineering, the adiabatic efficiency of Rotor 37 at design point increases by 1.02%, while its surge margin 0.84%,and the adiabatic efficiency of Stage 35 0.54%, while its surge margin 1.11% after optimization, to verify the effectiveness and potential in engineering of this new tool for optimization of axial compressor blade. 展开更多
关键词 Aerodynamic OPTIMIZATION BEZIER SURFACE Compressor Global OPTIMIZATION SURFACE PARAMETRIC CONTROL
Plasmon-tunable Au@Ag core-shell spiky nanoparticles for surfaceenhanced Raman scattering
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作者 Zhulin Huang Guowen Meng +5 位作者 Xiaoye Hu Qijun Pan Dexian Huo Hongjian Zhou Yan Ke Nianqiang Wu 《纳米研究:英文版》 SCIE EI CAS CSCD 2019年第2期449-455,共7页
A facile synthetic approach has been developed to prepare uniform and size-tunable spiky Au@Ag core-shell nan oparticles (NPs) to tailor the localized surface plasm on res onance (LSPR) properties. The gradual assembl... A facile synthetic approach has been developed to prepare uniform and size-tunable spiky Au@Ag core-shell nan oparticles (NPs) to tailor the localized surface plasm on res onance (LSPR) properties. The gradual assembly of small Au nano crystals allows the size of spiky Au NPs to be modulated from tens to several hundreds of nano meters by tuning the concentration of initial Au seeds and Au source;and the thick ness of the Ag shell can be adjusted with stepwise reduction of Ag(l)ions. The LSPR bands of such spiky Au@Ag core-shell NPs resemble those of pure spiky Au NP cores of similar sizes in near-infrared region, and increasing the Ag shell thickness results in a blue shift and broadening of the LSPR band in the n ear-i nfrared regi on. Additi on ally, the spiky Au@Ag core-shell NPs exhibit improved surface-e nhan ced Rama n scattering (SERS) activity as compared to the bare spiky Au NPs and spherical Ag@Au NPs. This work has offered a facile route to synthesize plasmonic metal NPs with LSPR band in 650 to 800 nm that show strong enhancement of localized electromagnetic field, which provides an effective SERS substrate for SERS imaging and detection in biological fluids and tissues. 展开更多
关键词 LOCALIZED surface PLASMON resonanee gold silver surface-enhanced RAMAN spectroscopy
High quality NbTiN films fabrication and rapid thermal annealing investigation
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作者 葛欢 金贻荣 宋小会 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第7期439-443,共5页
NbTiN thin films are good candidates for applications including single-photon detector, kinetic inductance detector, hot electron bolometer, and superconducting quantum computing circuits because of their favorable ch... NbTiN thin films are good candidates for applications including single-photon detector, kinetic inductance detector, hot electron bolometer, and superconducting quantum computing circuits because of their favorable characteristics,such as good superconducting properties and easy fabrication.In this work, we systematically investigated the growth of high-quality NbTiN films with different thicknesses on Si substrates by reactive DC-magnetron sputtering method.After optimizing the growth conditions, such as the gas pressure, Ar/N2 mixture ratio, and sputtering power, we obtained films with excellent superconducting properties.A high superconducting transition temperature of 15.5 K with narrow transition width of 0.03 K was obtained in a film of 300 nm thickness with surface roughness of less than 0.2 nm.In an ultra-thin film of 5 nm thick, we still obtained a transition temperature of 7.6 K.In addition, rapid thermal annealing(RTA) in atmosphere of nitrogen or nitrogen and hydrogen mixture was studied to improve the film quality.The results showed that Tc and crystal size of the NbTiN films were remarkably increased by RTA.For ultrathin films, the annealing in N2/H2 mixture had better effect than that in pure N2.The Tc of 10 nm films improved from 9.6 K to 10.3 K after RTA in N2/H2 mixture at 450℃. 展开更多
关键词 SUPERCONDUCTING TRANSITION temperature surface ROUGHNESS NbTiN film rapid thermal ANNEALING
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