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Predation risk affects egg mass but not egg steroid hormone concentrations in yellow-legged gulls
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作者 Cristina Daniela Possenti Alexandra Bea Bentz +5 位作者 Andrea Romano Marco Parolini Manuela Caprioli Diego Rubolini Kristen Navara Nicola Saino 《动物学报:英文版》 SCIE CAS CSCD 2019年第4期401-408,共8页
Predators have both direct, consumptive effects on their prey and non-lethal effects on physiology and behavior, including reproductive decisions, with cascading effects on prey ecology and evol tion. Here, we experim... Predators have both direct, consumptive effects on their prey and non-lethal effects on physiology and behavior, including reproductive decisions, with cascading effects on prey ecology and evol tion. Here, we experime ntally tested such non-lethal effects of exposure to in creased predati on risk on clutch size, egg mass, and the concentration of yolk steroid hormones in the yellow-legged gull Larus michahellis. We simulated increased predation risk by displaying stuffed predators (adult fox Vulpes vulpes, and adult buzzard Buteo buteo) to breeding adults before egg laying. The concentration of corticosterone, which has bee n show n to in crease un der exposure to mater nal predati on risk in other species, and of testosterone did not differ between eggs from mothers exposed to the predators and eggs from control mothers (i.e., eggs exposed to a novel object of similar size and position to the stuffed predators). The concentration of the two hormones negatively covaried. Clutch size did not vary according to experimental treatment, whereas egg mass was markedly larger in clutches from n ests exposed to predators than in clutches from control n ests. By in creasing egg mass, mothers may reduce the risk of cooling of the eggs when incubation is impeded by predators, boost energy reserves, reduce post-natal detectability caused by food solicitation, and/ or enha nee developme nt at hatchi ng, thus increasing the cha nces of offspri ng survival. In general, our results are inconsistent with most of the few previous studies on similar non-lethal predator effects and suggest that such effects may vary among species according to ecological conditions, social behavior, and developmental mode. 展开更多
关键词 CLUTCH SIZE CORTICOSTERONE EGG SIZE PREDATION effects TESTOSTERONE
Home range variation of two different-sized groups of golden snub-nosed monkeys (Rhinopithecus roxellana) in Shennongjia,China:implications for feeding competition
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作者 Peng-Lai Fan Yi-Ming Li +4 位作者 Craig B.Stanford Fang Li Ze-Tian Liu Kai-Hua Yang Xue-Cong Liu 《动物学研究》 CAS CSCD 2019年第2期121-128,共8页
Knowledge on the home range size of a species or population is important for understanding its behavioral and social ecology and improving the effectiveness of conservation strategies.We studied the home range size of... Knowledge on the home range size of a species or population is important for understanding its behavioral and social ecology and improving the effectiveness of conservation strategies.We studied the home range size of two different-sized groups of golden snub-nosed monkeys (Rhinopithecus roxellana)in Shennongjia,China.The larger group (236 individuals) had a home range of 22.5 km^2 from September 2007 to July 2008,whereas the smaller group (62 individuals)occupied a home range of 12.4 km^2 from November 2008 to July 2009.Both groups exhibited considerable seasonal variation in their home range size,which was likely due to seasonal changes in food availability and distribution.The home range in any given season (winter,spring,summer,or winter+spring+summer)of the larger group was larger than that of the smaller group.As the two groups were studied in the same area,with the confounding effects of food availability thus minimized,the positive relationship between home range size and group size suggested that scramble feeding competition increased within the larger group. 展开更多
关键词 RHINOPITHECUS ROXELLANA Home range SIZE Group SIZE FEEDING competition
Age factor affects reading acuity and reading speed in attaining text information
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作者 Ai-Hong Chen Nursyairah Mohd Khalid Noor Halilah Buari 《国际眼科杂志:英文版》 SCIE CAS 2019年第7期1170-1176,共7页
AIM: To investigate the effect of age on reading acuity and reading speed in attaining text information in healthy eyes.METHODS: Reading acuity, critical print size, reading speed and maximum reading speed were measur... AIM: To investigate the effect of age on reading acuity and reading speed in attaining text information in healthy eyes.METHODS: Reading acuity, critical print size, reading speed and maximum reading speed were measured in groups of 40 children (8 to 12 years old), 40 teenagers (13 to 19 years old), 40 young adults (20 to 39 years old), and 40 adults (40 years old and above) using the Buari-Chen Malay Reading Chart [contextual sentences (CS) set and random words (RW) set] in a cross-sectional study design.RESULTS: Reading acuity was significantly improved by 0.04 logMAR for both CS set and RW set from children to teenagers, then gradually worsened from young adults to adults (CS set: 0.06 logMAR;RW set: 0.08 logMAR). Critical print size for children showed a significant improvement in teenagers (CS set: 0.14 logMAR;RW set: 0.07 logMAR), then deteriorated from young adults to adults by 0.09 logMAR only for CS set. Reading speed significantly increased from children to teenagers,[CS set: 46.20 words per minute (wpm);RW set: 42.06 wpm], then stabilized from teenagers to young adults, and significantly reduced from young adults to adults (CS set: 28.58 wpm;RW set: 24.44 wpm). Increment and decrement in maximum reading speed measurement were revealed from children to teenagers (CS set: 39.38 wpm;RW set: 43.38 wpm) and from young adults to adults (CS set: 22.26 wpm;RW set: 26.31 wpm) respectively.CONCLUSION: The reference of age-related findings in term of acuity and speed of reading should be incorporated in clinical practice to enhance reading assessment among healthy eyes population. 展开更多
关键词 READING ACUITY critical PRINT size readingspeed MAXIMUM READING SPEED age effect
A facile synthesis of magnetite single-crystal particles by employing GO sheets as template for promising application in magnetic fluid
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作者 Zhen Qin Zhen-Hui Ma +1 位作者 Jian-Kang Zhi Yong-Ling Fu 《稀有金属:英文版》 SCIE EI CAS CSCD 2019年第8期764-769,共6页
It was reported a facile strategy to fabricate magnetite(Fe3O4)single-crystal particles with critical single-domain size by employing graphene oxide(GO)sheets as template.In this method,the small-sized Fe2 O3 nanopart... It was reported a facile strategy to fabricate magnetite(Fe3O4)single-crystal particles with critical single-domain size by employing graphene oxide(GO)sheets as template.In this method,the small-sized Fe2 O3 nanoparticles were first synthesized,and then low-temperature annealing under H2 would convert them into large-sized Fe3 O4 single-crystal particles.The synthetic particles with an average size of 100 nm exhibit high saturation magnetization(Ms)of 0.085 A·m^2·g^-1,which is very close to theoretical value,being among the highest values in ever reported for Fe3O4 made from chemical methods.On this basis,the small-sized Fe3 O4 particles(average size of 30 nm)were also fabricated by coating with Na2 CO3 shell. 展开更多
关键词 Fe3O4 Critical SINGLE-DOMAIN size SATURATION MAGNETIZATION Chemical synthesis
Effect of Particle Size on Gasification Reactivity of Different Rank Coal Chars 预览
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作者 Li Wenxiu Rong Ling Kun Jia Feng Jun 《环境科学前沿:中英文版》 2019年第1期8-12,共5页
In the current research process of coal rank char gasification reaction in China, it is found that particle size has different influence on the gasification reactivity of coal char of different ranks. Therefore, monod... In the current research process of coal rank char gasification reaction in China, it is found that particle size has different influence on the gasification reactivity of coal char of different ranks. Therefore, monodisperse pulverized coal was prepared from eight kinds of coal chars of different ranks in entrained-flow gasifier. The particle size and gasification temperature of coal char were analyzed for these samples. The degree of influence of carbon dioxide gasification reaction. Through research and analysis, the performance differences of these samples under different carbon conversion rates were compared, and the sample reaction under high carbon conversion rates was discussed. The experimental results show that the orderliness of the microcrystalline structure of coal char is directly proportional to the rank of coal, while the gasification activity of coal char is inversely proportional to the rank of coal. Therefore, for different coal ranks, the influence of coal char particle size on coal char gasification reaction is different. According to the experiments, smaller coal char size and higher gasification temperature can promote the reactivity of higher-order coal gasification. In order to clarify the correlation between particle size and gasification reactivity of coal chars with different ranks, this paper discussed this issue. 展开更多
关键词 Particle Size DIFFERENT RANKS of COAL GASIFICATION Activity of COAL CHAR
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Fatigue behavior of CoCrFeMnNi high-entropy alloy under fully reversed cyclic deformation
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作者 Y.Z.Tian S.J.Sun +1 位作者 H.R.Lin Z.F.Zhang 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第3期334-340,共7页
Bulk ultrafine-grained(UFG) CoCrFeMnNi high-entropy alloy(HEA) with fully recrystallized microstructure was processed by cold rolling and annealing treatment. The high-cycle fatigue behaviors of the UFG HEA and a coar... Bulk ultrafine-grained(UFG) CoCrFeMnNi high-entropy alloy(HEA) with fully recrystallized microstructure was processed by cold rolling and annealing treatment. The high-cycle fatigue behaviors of the UFG HEA and a coarse-grained(CG) counterpart were investigated under fully reversed cyclic deformation.The fatigue strength of the UFG HEA can be significantly enhanced by refining the grain size. However,no grain coarsening was observed in the UFG HEA during fatigue tests. Mechanisms for the superior mechanical properties of the UFG HEA were explored. 展开更多
关键词 High-entropy alloy(HEA) Ultrafine-grain(UFG) High-cycle FATIGUE RECRYSTALLIZATION GRAIN size FATIGUE strength
Big Grain3 encoding a purine permease,regulates grain size via modulating cytokinin transport in rice^FA
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作者 Yunhua Xiao Dapu Liu +7 位作者 Guoxia Zhang Shaopei Gao Linchuan Liu Fan Xu Ronghui Che Yiqin Wang Hongning Tong Chengcai Chu 《植物学报:英文版》 SCIE CAS CSCD 2019年第5期581-597,共17页
Grain size is an important agronomic trait affecting grain yield,but the underlying molecular mechanisms remain to be elucidated.Here,we isolated a dominant mutant,big grainy(bg3-D),which exhibits a remarkable increas... Grain size is an important agronomic trait affecting grain yield,but the underlying molecular mechanisms remain to be elucidated.Here,we isolated a dominant mutant,big grainy(bg3-D),which exhibits a remarkable increase of grain size caused by activation of the PURINE PERMEASE gene,OsPUP4.BC3/OSPUP4 is predominantly expressed in vascular tissues and is specifically suppressed by exogenous cytokinin application.Hormone profiling revealed that the distribution of different cytokinin forms,in roots and shoots of the bg3-D mutant,is altered.Quantitative reverse transcription-PCR(qRT-PCR)analysis indicated that expression of rice cytokinin type-A RESPONSE REGULATOR(OsRR)genes is enhanced in the roots of the bgj-D mutant.These results suggest that OSPUP4 might contribute to the long-distance transport of cytokinin,by reinforcing cytokinin loading into vascular bundle cells.Furthermore,plants overexpressing OsPUP7,the closest homolog of OsPUP4,also exhibited a similar phenotype to the bg3-D mutant.Interestingly,subcellular localization demonstrated that OSPUP4 was localized on the plasma membrane,whereas OSPUP7 was localized to the endoplasmic reticulum.Based on these findings,we propose that OSPUP4 and OSPUP7 function in a linear pathway to direct cytokinin cell-to-cell transport,affecting both its long-distance movement and local allocation. 展开更多
关键词 Grain size is an important UNDERLYING molecular local ALLOCATION
DESCENT DIRECTION STOCHASTIC APPROXIMATION ALGORITHM WITH ADAPTIVE STEP SIZES
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作者 Zorana Luzanin Irena Stojkovska Milena Kresoja 《计算数学:英文版》 SCIE CSCD 2019年第1期76-94,共19页
A stochastic approximation (SA)algorithm with new adaptive step sizes for solving unconstrained minimization problems in noisy environment is proposed.New adaptive step size scheme uses ordered statistics of fixed num... A stochastic approximation (SA)algorithm with new adaptive step sizes for solving unconstrained minimization problems in noisy environment is proposed.New adaptive step size scheme uses ordered statistics of fixed number of previous noisy function values as a criterion for accepting good and rejecting bad steps.The scheine allows the algorithm to move in bigger steps and avoid steps proportional to 1/k when it is expected that larger steps will improve the performance.An algorithin with the new adaptive scheme is defined for a general descent direction.The ahnost sure convergence is established.The performance of new algorithm is tested on a set of standard test problems and compared with relevant algorithms.Numerical results support theoretical expectations and verify efficiency of the algorithm regardless of chosen search direction and noise level.Numerical results on probleins arising in machine learning are also presented.Linear regression problem is considered using real data set.The results suggest that the proposed algorithln shows proinise. 展开更多
关键词 UNCONSTRAINED OPTIMIZATION STOCHASTIC OPTIMIZATION STOCHASTIC APPROXIMATION NOISY function Adaptive step size DESCENT direction Linear regression model
The influence of particle size and concentration combined with pH on coagulation mechanisms
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作者 Hongyan Sun Ruyuan Jiao +2 位作者 Hui Xu Guangyu An Dongsheng Wang 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第8期39-46,共8页
In order to evaluate the influence of particle size and particle concentration on the coagulation process, two kinds of particle suspensions, nanoparticles and microparticles,were employed to investigate the effect of... In order to evaluate the influence of particle size and particle concentration on the coagulation process, two kinds of particle suspensions, nanoparticles and microparticles,were employed to investigate the effect of particle size on coagulation mechanisms with varying coagulation parameters. Results showed that it is easier for nanoparticles to cause self-aggregation because of Brownian motion, while interception and sedimentation are the mainly physical processes affecting particle transport for microparticles, so they are more stable and disperse more easily. The particle size distribution and particle concentration had distinct influence on the coagulation mechanisms. Under neutral conditions, as the amount of coagulant increased, the coagulation mechanism for nanoparticles changed from charge neutralization to sweep flocculation and the nanoparticles became destabilized, re-stabilized and again destabilized. For microparticles, although the coagulation mechanism was the same as that of nanoparticles, the increased rate of aluminum hydroxide precipitation exceeded the adsorption of incipiently formed soluble alum species, resulting in the disappearance of the re-stabilization zone. Under acidic conditions, Brownian motion dominates for nanoparticles at low particle concentrations, while sweep flocculation is predominant at high particle concentrations. As for microparticles, charge neutralization and sweep flocculation are the mechanisms for low and high particle concentrations respectively.Under alkaline condition, although the mechanisms for both nano-and microparticles are the same, the morphology of flocs and the kinetics of floc formation are different. At low particle concentrations, nanoparticles have larger growth rate and final size of flocs, while at high particle concentrations, nanoparticles have higher fractal dimension and recovery factors. 展开更多
关键词 Nanoparticles MICROPARTICLES PARTICLE size distribution COAGULATION MECHANISMS ALUM
尺寸对NaYbF4纳米晶活性氧产生速率的影响 预览
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作者 张佳音 王启宇 +2 位作者 梁红 孙凯霞 张治国 《人工晶体学报》 EI CAS 北大核心 2019年第5期878-882,888共6页
本文采用热分解法制备了NaYbF4纳米晶,并通过控制反应时间调节纳米晶尺寸来增加其比表面积,进而提高活性氧产率。通过TEM图像对NaYbF4纳米晶的尺寸进行表征。利用化学探针法检验NaYbF4纳米晶分散液中活性氧的产生,并计算了活性氧产生速... 本文采用热分解法制备了NaYbF4纳米晶,并通过控制反应时间调节纳米晶尺寸来增加其比表面积,进而提高活性氧产率。通过TEM图像对NaYbF4纳米晶的尺寸进行表征。利用化学探针法检验NaYbF4纳米晶分散液中活性氧的产生,并计算了活性氧产生速率。结果表明纳米晶尺寸在影响Yb3+与O2的能量传递过程中占主导因素。同时,当生长时间较短时,晶格缺陷较多,无辐射弛豫过程增加,也影响活性氧产生速率。尺寸约8nm时,NaYbF4纳米晶活性氧产生速率最大。 展开更多
关键词 NaYbF4纳米晶 尺寸 活性氧 光动力疗法
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Microbial aerosol chemistry characteristics in highly polluted air
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作者 Ting Zhang Xinyue Li +2 位作者 Minfei Wang Haoxuan Chen Maosheng Yao 《中国科学:化学英文版》 SCIE EI CAS CSCD 2019年第8期1051-1063,共13页
Aerosol chemistry is often studied without considering microbial involvements. Here, we investigated time-and size-resolved bacterial aerosol dynamics in air. Under high particulate matter(PM) polluted episodes, bacte... Aerosol chemistry is often studied without considering microbial involvements. Here, we investigated time-and size-resolved bacterial aerosol dynamics in air. Under high particulate matter(PM) polluted episodes, bacterial aerosols exhibited a viability of up to 50%–70% in the 0.56–1 μm size range, at which elevated levels of SO42-, NO3- and NH4+ were concurrently observed.Engineered or acclimated for both industrial use, bacteria such as Psychrobacter spp., Massilia spp., Acinetobacter lwoffii,Exiguobacteriumaurantiacum and Bacillusmegaterium were shown to have experienced massive abundance shifts in polluted air on early mornings and late afternoons, on which rapid new particle formation events were widely reported. Here, Psychrobacter spp. were shown to account for >96% abundance at a corresponding PM2.5 level of 208 μg/m3. These observed bacterial aerosol changes corresponded to the PM2.5 mass peak shift from 3.2–5.6 μm to the high viability size range of 0.56–1 μm. Additionally,elevated levels of soluble Na, Ca, Mg, K, Al, Fe and P elements, required for bacterial growth, were observed to co-occur with those significant bacterial aerosol structure shifts in the air. For particular time-resolved PM2.5 pollution episodes, Acinetobacter,Psychrobacter and Massilia were shown to alternate in dominating the time-resolved aerosol community structures. The results from a HYSPLIT trajectory model simulation suggested that air mass transport played a minor role in affecting the observed bacterial aerosol structure dynamics. All the data here suggested that airborne bacteria in the size range of 0.56–1 μm could be extensively involved in aerosol chemistry in highly polluted humid air. 展开更多
关键词 BACTERIAL AEROSOL dynamics in AIR PARTICULATE matter size-and TIME-RESOLVED BACTERIAL AEROSOL AEROSOL chemistry
Grain boundary segregation and its influences on ionic conduction properties of scandia doped zirconia electrolytes
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作者 Qiannan Xue Xiaowei Huang +2 位作者 Jianxing Zhang He Zhang Zongyu Feng 《中国稀土学报:英文版》 SCIE EI CAS CSCD 2019年第6期645-651,共7页
Solid oxide fuel cell is a promising energy conversion system which converts chemical energy into electrical energy directly. Electrolyte is the key component and determines the working temperature. In this paper,ceri... Solid oxide fuel cell is a promising energy conversion system which converts chemical energy into electrical energy directly. Electrolyte is the key component and determines the working temperature. In this paper,ceria and scandia co-doped zirconia electrolytes sintered from 1300 to 1550 ℃ were chosen as research objects. Scanning electron microscopy, X-ray diffraction and transmission electron microscopy were performed to characterize the ceramic samples. The effects of grain size and grain boundary element segregation on the electrical conductivity were focused. Electrochemical impedance spectroscopy was used to calculate the bulk, grain boundary and specific grain boundary conductivity. Results show that the bulk and grain boundary ionic conductivity increases with the increasing grain size.However, the specific grain boundary conductivity decreases with the increasing grain size. This is explained by the fact that Sc3+ is segregated at the grain boundary, which leads to higher oxygen vacancy concentration when sintered at lower temperature. 展开更多
关键词 Electrolytes CO-DOPED ZIRCONIA Grain size DOPANT SEGREGATION IONIC CONDUCTIVITY Rare earths
A Correction Algorithm for Atmospheric Visibility Based on Fog Droplet Size Data Obtained on a Moving Ship During 2016 Arctic Cruise 预览
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作者 LIU Yilin ZHAO Jinping 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2019年第3期596-604,共9页
In this study, we measured the droplet size distribution(DSD) and visibility of sea fog using a fog droplet spectrometer and visibility meter, respectively, during the July 23-August 3 and August 22-September 13 perio... In this study, we measured the droplet size distribution(DSD) and visibility of sea fog using a fog droplet spectrometer and visibility meter, respectively, during the July 23-August 3 and August 22-September 13 periods of the 2016 Chinese National Arctic Research Expedition. We calculated the visibility using the Mie theory and the DSD data and then compared the calculated with the observed visibility. The comparison shows that the deviations in the calculated visibility caused by DSD data sampling errors cannot be ignored. During navigation, wind and ship speeds tended to push or pull the sampled air and cause turbulence pulsation, which influenced the sampling of the fog droplet spectrometer. This influence is weak when the liquid water content(LWC) is high but becomes stronger as the LWC decreases. Taking the sailing speed and heading into consideration, the wind speed component parallel and perpendicular to the air inlet of the fog droplet spectrometer exhibit different laws in the deviation. By performing a fitting analysis of the calculated and observed visibilities under different wind speeds and wind directions, here, we present two sets of correction coefficients for the two wind-speed components and a method for correcting the calculated visibility. This correction method shows excellent results. 展开更多
关键词 ARCTIC sea FOG FOG DROPLET size distribution liquid water content VISIBILITY MIE theory
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TiO2纳米变压器油击穿和电导特性的微观模型
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作者 王磊 牛铭康 +3 位作者 李超 吕玉珍 黄猛 李成榕 《高电压技术》 EI CAS CSCD 北大核心 2019年第10期3350-3356,共7页
变压器油中水分的存在将导致变压器油绝缘性能降低,而变压器油中添加TiO2纳米粒子可以束缚变压器油中的水分,减轻水分对变压器油的不利影响。为此,测试了40×10?6水分质量分数下变压器油和3种TiO2纳米变压器油的工频击穿电压和电阻... 变压器油中水分的存在将导致变压器油绝缘性能降低,而变压器油中添加TiO2纳米粒子可以束缚变压器油中的水分,减轻水分对变压器油的不利影响。为此,测试了40×10?6水分质量分数下变压器油和3种TiO2纳米变压器油的工频击穿电压和电阻率。结果表明,10nm球状纳米变压器油的工频击穿电压提高了111.9%,改性效果最为显著;5nm球状纳米变压器油和5nm棒状纳米变压器油分别提高了100.6%、97.9%。而3种TiO2纳米变压器油的电阻率相比于纯油却要小3个数量级。这并不符合电气绝缘材料电阻率越大,击穿电压也越高的现象。因此,利用MaterialStudio模拟了水分子与3种纳米粒子的结合方式、分布状态,基于液固界面Gouy-Chapman-Stern模型提出了TiO2纳米变压器油中改进Stern双电层微观模型,并指出纳米颗粒表面吸附油中水分子和负电荷形成水膜,减少电子碰撞油中水分子产生贯通气体小桥通道的概率。利用此模型揭示了纳米粒子尺寸与纳米粒子形貌对变压器油击穿和电导特性的影响机理。 展开更多
关键词 工频击穿 电阻率 双电层 尺寸 形貌
Improvement of proof-ultimate strength difference in laser additive manufactured Ti-6Al-2V-1.5Mo-0.5Zr-0.3Si alloy by tuning basketweave structure
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作者 Guo-chao Li Xu Cheng Hua-ming Wang 《钢铁研究学报:英文版》 SCIE EI CAS CSCD 2019年第6期631-636,共6页
After annealed at 1000 ℃, a special basket-weave structure is obtained in laser additive manufactured Ti-6Al-2V-1.5Mo- 0.5Zr-0.3Si alloy. The unit of the special basket-weave structure is a lamellas clusters, which c... After annealed at 1000 ℃, a special basket-weave structure is obtained in laser additive manufactured Ti-6Al-2V-1.5Mo- 0.5Zr-0.3Si alloy. The unit of the special basket-weave structure is a lamellas clusters, which consist of lamellar primary ot (otp), crab-like structures at the edges of otp and lamellar secondary a (as) on both sides of otp. As the units of basket-weave structures, the width of the clusters is much larger than that of a lamellas in as-deposited alloy. The formation temperature and process of the special basket-weave structure are studied, and the room temperature properties are tested and compared with the as-deposited alloy. The results show that the formation of the special basket-weave structure finishes within about 30 s and crab-like structures form earlier than lamellar as. The yield strength of the alloy is decreased by about 75 MPa compared to that of the as-deposited alloy. Besides, the proof-ultimate strength difference of the alloy is two times higher than that of the as-deposited alloy with about 34% improvement for the impact toughness. It is because ot colony size shows a positive correlation to the width of the unit forming basket-weave structure. The enhancement in proof-ultimate strengthdifference could significantly improve the toughness of the alloy, and thus effectively increase the safety of the alloy. 展开更多
关键词 Titanium ALLOY Basket-weave structure Formation process a COLONY size YIELD strength
Ni catalysts supported on nanosheet and nanoplate γ-Al2O3 for carbon dioxide methanation 预览
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作者 Jinwei Sun Yujiang Wang +2 位作者 Haikui Zou Xiaoguang Guo Zhou-jun Wang 《能源化学:英文版》 SCIE EI CAS CSCD 2019年第2期3-7,共5页
Nanosheet(S) and nanoplate(P) γ-Al2O3 were synthesized by simple hydrothermal methods and employed as supports for Ni catalysts in CO2 methanation.Both of the nanostructured Ni/Al2O3 catalysts displayed good activity... Nanosheet(S) and nanoplate(P) γ-Al2O3 were synthesized by simple hydrothermal methods and employed as supports for Ni catalysts in CO2 methanation.Both of the nanostructured Ni/Al2O3 catalysts displayed good activity.In comparison,the Ni/Al2O3-S catalyst showed higher CO2 conversion than the Ni/Al2O3-P counterpart at the reaction temperature ranging from 250 to 400 °C.The physical and chemical properties of the catalysts were systematically characterized by N2 sorption,X-ray diffraction(XRD),high resolution-transmission electron microscopy(HR-TEM),hydrogen temperature-programmed reduction(H2-TPR) and CO2 temperature-programmed desorption(CO2-TPD) techniques.Higher specific surface area and stronger metal-support interactions were confirmed on the Ni/Al2O3-S catalyst,which may lead to smaller particle size of Ni nanoparticles.Moreover,the Ni/Al2O3-S catalyst possessed more abundant weak and medium basic sites,which would benefit the activation of CO2.The smaller Ni size and more suitable basic sites may rationalize the superior activity of the Ni/Al2O3-S catalyst.Besides,the Ni/Al2O3-S catalyst exhibited excellent stability at 325 °C for 40 h. 展开更多
关键词 ALUMINA Nickel Size Nano Interaction METHANATION
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Effect of Pelleted Total Mixed Ration of Different Particle Sizes on Production Performance and Serum Biochemical Index of Fattening Hainan Black Goats 预览
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作者 Liu Quanwei Wei Limin +4 位作者 Wang Feng Tan Shuyi Sun Ruiping Huang Lili Zheng Xinli 《动物与饲料科学:英文版》 CAS 2019年第1期23-27,共5页
[Objective] The paper to investigate the effects of pelleted total mixed ration of different particle size on production performance and serum biochemical index of fattening Hainan black goats.[Method] Thirty-six fatt... [Objective] The paper to investigate the effects of pelleted total mixed ration of different particle size on production performance and serum biochemical index of fattening Hainan black goats.[Method] Thirty-six fattening Hainan black goats with the same genetic backgrounds and similar initial weight of(19.02±0.22) kg were randomly divided into three treatments. Goats were fed with Juncao+concentrate(control group), pel-leted total mixed ration I(particle size 6 mm, experimental group I) and II(particle size 5 mm, experimental group II), respectively. The trial lasted 45 d.[Result](1) The final weight and daily gain of experimental group II were significantly higher than those of control group( P<0.05), and the daily gain of experimental group II was also higher than that of experimental group I(P<0.05);the feed intake of experimental group II was markedly higher than that of control group(P<0.05), but was significantly lower than that of experimental group I(P<0.05). The feed/gain ratio of experimental group II was significantly lower than those of control group and experimental group I(P<0.05).(2) The feed gain cost of experimental group II was markedly lower than that of control group(P<0.05), but the gross profit was significantly higher than those of control group and experimental group I(P<0.05).(3) Compared with the control group, the serum total protein content of experimental group II increased markedly( P<0.05) while the urea nitrogen level decreased(P>0.05).[Conclusion] The pelleted total mixed ration with the particle size of 5 mm obtained better fattening ef-fect, and obviously improved the serum total protein level. 展开更多
关键词 FATTENING HAINAN black GOAT Pelleted total mixed RATION Particle size Production performance SERUM BIOCHEMICAL parameters
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盐度对不同规格九孔鲍耗氧量和排氨率的影响 预览
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作者 刘建勇 陈园媛 +2 位作者 曹伏君 许胜青 王崇懿 《广东海洋大学学报》 CAS 2019年第5期129-134,共6页
【目的】探讨盐度对不同规格九孔鲍(Haliotis diversicolor supertexta)耗氧量和排氨率的影响。【方法】采用实验室生态学方法,测定7种盐度下(21、24、27、30、33、36和40)3种规格[干质量(1.53±0.14)、(1.11±0.23)和(0.68... 【目的】探讨盐度对不同规格九孔鲍(Haliotis diversicolor supertexta)耗氧量和排氨率的影响。【方法】采用实验室生态学方法,测定7种盐度下(21、24、27、30、33、36和40)3种规格[干质量(1.53±0.14)、(1.11±0.23)和(0.68±0.20)g]九孔鲍的耗氧率和排氨率。【结果】(1)盐度在21~36时,耗氧率随着盐度的上升而增大;盐度为36时,3种规格九孔鲍的耗氧率均达到最大值;当盐度大于36时,耗氧率随盐度上升而下降,九孔鲍的耗氧率(RO)与软体部干质量(m)的回归关系符合幂函数:RO=a m-b,其中a的波动范围在0.412~1.216之间,平均值为0.818±0.286;b的波动范围在0.311~0.546之间,平均值为0.446±0.074;(2)排氨率在实验盐度范围内呈持续升高趋势,排氨率(RN)与软体部干质量(m)的回归关系符合幂函数:RN=c m-d,其中c的波动范围在0.174~0.621之间,平均值为0.330±0.154;d的波动范围在0.439~0.668之间,平均值为0.521±0.084;(3)相同盐度下,九孔鲍的耗氧率和排氨率随干质量的增大而显著减小(P<0.05),且耗氧率和排氨率与干质量均符合R=a m-b模型;(4)九孔鲍的规格对O/N比值影响不显著(P> 0.05),当盐度为40时,O/N值显著降低。【结论】盐度、规格及两者间的交互作用均对九孔鲍的耗氧率和排氨率有显著影响。 展开更多
关键词 九孔鲍 盐度 规格 耗氧率 排氨率
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Determination of the particle load based on detailed suspended sediment measurements at a hydropower plant 预览
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作者 Anant Kumar Rai Arun Kumar 《国际泥沙研究:英文版》 SCIE 2019年第5期409-421,共13页
Suspended sediment particles contained in inflows of water systems of hydropower plants (HPPs) cause hydro-abrasive erosion of the hydraulic turbines and structures leading to significant maintenance costs, efficiency... Suspended sediment particles contained in inflows of water systems of hydropower plants (HPPs) cause hydro-abrasive erosion of the hydraulic turbines and structures leading to significant maintenance costs, efficiency reductions, and downtime. Relevant parameters such as suspended sediment concentration (SSC), particle size distribution (PSD), shape, and mineralogical composition were measured with an online multi-frequency acoustic instrument and based on manually taken samples from the end of the sand trap of the Toss HPP in the Himalayan region, India. In the laboratory, the samples were analyzed using the gravimetric method, laser diffraction, turbidity, dynamic digital image processing, scanning electron microscope, petrography analysis, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The online instrument and the samples provided measurement results at a single point. To investigate vertical gradients in concentration and particle sizes, additional samples were collected 9 times at 7 relative water depths. The SSC, most particle sizes, and particle shape were found to be evenly distributed over depth except d90, i.e. the diameter which is not exceeded by 90% of the particle mass. d90 measured at 76% of the water depth was in the range of fine sand and was multiplied by 1.05 to obtain an average value representative for the entire depth. Improved methodologies to quantify both particle shape and size in an analytical model for hydro-abrasive erosion are proposed. Also, the PSD measuring performance of laser diffraction and dynamic imaging was studied and similar values of the median particle sizes were obtained from both instruments. Further, multi-frequency acoustic, turbidity and laser diffraction techniques were found suitable for SSC measurement at the test case HPP. 展开更多
关键词 Suspended sediment concentration Hydro-abrasive EROSION HYDROPOWER PARTICLE size distribution PARTICLE shape MINERALOGICAL composition
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Exploration of particle technology in fine bubble characterization
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作者 Renliang Xu Yaru Wang Zhaojun Li 《颗粒学报:英文版》 SCIE EI CAS CSCD 2019年第5期109-115,共7页
Fine bubble technology has been applied in many fields, including semiconductor processing, waste water treatment, and agricultural development. Fine bubble technology has the advantages of being environ-mentally beni... Fine bubble technology has been applied in many fields, including semiconductor processing, waste water treatment, and agricultural development. Fine bubble technology has the advantages of being environ-mentally benign, and ease of production and use when compared with other processes that involve chemicals or biological agents. However, the mechanisms of fine bubble applications in many aspects still require exploration. The characterization of fine bubbles is one of the essential issues for better understanding the technology. This article reviews modern particle characterization technologies, espe-cially those that can be used to characterize fine bubbles, and briefly reports on some applications of fine bubbles. 展开更多
关键词 FINE BUBBLES BUBBLE CHARACTERIZATION PARTICLE technology PARTICLE size
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