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Changes in Meteorological Information Transmission in the All-media Era 预览
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作者 Yeting GU Lu HUANG Leina CHEN 《气象与环境研究:英文版》 CAS 2020年第1期16-18,共3页
In the all-media era,in order to adapt to the transmission of different channels,the requirements for meteorological information have become increasingly high,and the display format has also undergone a huge change.To... In the all-media era,in order to adapt to the transmission of different channels,the requirements for meteorological information have become increasingly high,and the display format has also undergone a huge change.To expand the effect of communication,create public opinion and hot spots,popularize meteorological knowledge,and spread meteorological disaster prevention and mitigation knowledge,it is necessary to transform original meteorological information into video pictures or recently popular short videos,small moving pictures,etc.Transforming meteorological information into graphics,video,dynamic graphics,micro-video,etc.is collectively called the visualization process of meteorological information.Therefore,meteorological information visualization is extremely urgent,and the natural visual communication production advantages of meteorological film and television will play a huge role.In this paper,some methods of visualizing meteorological information,expanding the spread of visualized meteorological information,and enhancing the transmission rate were proposed. 展开更多
关键词 VISUALIZATION Communication rate High efficiency
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Geographical Variation and Influencing Factors of Spartina alterniflora Expansion Rate in Coastal China 预览
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作者 ZHANG Danhua HU Yuanman +2 位作者 LIU Miao CHANG Yu SUN Lishuang 《中国地理科学:英文版》 SCIE CSCD 2020年第1期127-141,共15页
Biological invasion poses a huge threat to ecological security.Spartina alterniflora was introduced into China in 1979,and its arrival corresponded with negative effects on native ecosystems.To explore geographical va... Biological invasion poses a huge threat to ecological security.Spartina alterniflora was introduced into China in 1979,and its arrival corresponded with negative effects on native ecosystems.To explore geographical variation of its expansion rate in coastal China,we selected 43 S.alterniflora sites from Tianjin Coastal New Area to Beihai.The area expansion rate,expansion rate paralleling and vertical to the shoreline were analysed based on Landsat images and field survey in 2015.Simple Ocean Data Assimilation(SODA)and climate data were collected to statistically analyse the influential factors of expansion rate.Results showed that significant difference of S.alterniflora area expansion rate among different latitude zones(P<0.01),increasing from 6.08%at southern(21°N–23°N)to 19.87% in Bohai Bay(37°N–39°N)along latitude gradient.There was a significant difference in expansion rate vertical to shoreline in different latitude zones(P<0.01)with the largest occurring in Bohai Bay(256m/yr,37°N–39°N),and showed an decreasing tendency gradually from north to south.No significant difference and latitudinal clines in expansion rate paralleling to shoreline were observed.Expansion rate had significant negative correlation with mean seawater temperature,the lowest seawater temperature,current zonal velocity and meridional velocity and presented a reducing trend as these biotic factors increased;however,they were not significantly correlated with the highest seawater temperature and mean seawater salinity.We identified significant correlations between expansion rate and annual mean temperature,the lowest temperature in January and annual precipitation,but there was little correlation with annual diurnal difference in temperature and the highest temperature in July.The rapid expansion rate in high-latitude China demonstrated a higher risk of potential invasion in the north;dynamic monitoring and control management should be established as soon as possible. 展开更多
关键词 geographical variation biological invasion Spartina alterniflora expansion rate coastal wetlands China
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Application Specified Soft-Error Failure Rate Analysis Using Sequential Equivalence Checking Techniques
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作者 Tun Li Qinhan Yu +1 位作者 Hai Wan Sikun Li 《清华大学学报自然科学版(英文版)》 EI CAS CSCD 2020年第1期103-116,共14页
Soft errors have become a critical challenge as a result of technology scaling. Existing circuit-hardening techniques are commonly associated with prohibitive overhead of performance, area, and power. However,evaluati... Soft errors have become a critical challenge as a result of technology scaling. Existing circuit-hardening techniques are commonly associated with prohibitive overhead of performance, area, and power. However,evaluating the influence of soft errors in Flip-Flops(FFs) on the failure of circuit is a difficult verification problem.Here, we proposed a novel flip-flop soft-error failure rate analysis methodology using a formal method with respect to application behaviors. Approach and optimization techniques to implement the proposed methodology based on the given formula using Sequential Equivalence Checking(SEC) are introduced. The proposed method combines the advantage of formal technique-based approaches in completeness and the advantage of application behaviors in accuracy to differentiate vulnerability of components. As a result, the FFs in a circuit are sorted by their failure rates, and designers can use this information to perform optimal hardening of selected sequential components against soft errors. Experimental results of an implementation of a SpaceWire end node and the largest ISCAS’89 benchmark sequential circuits indicate the feasibility and potential scalability of our approach. A case study on an instruction decoder of a practical 32-bit microprocessor demonstrates the applicability of our method. 展开更多
关键词 soft error failure rate ANALYSIS SEQUENTIAL EQUIVALENCE Checking(SEC) APPLICATION specified
下行NOMA系统中公平的功率分配方案 预览
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作者 田心记 张丹青 李晓静 《电子科技大学学报》 EI CAS CSCD 北大核心 2020年第1期36-41,共6页
已有的非正交多址接入(NOMA)系统中最大化公平性的功率分配方案没有考虑到用户的最低速率需求。针对此问题,该文提出了NOMA系统中公平地提高用户速率的功率分配方案。首先根据信道条件以及每个用户的最低速率需求计算每个簇所需的最低功... 已有的非正交多址接入(NOMA)系统中最大化公平性的功率分配方案没有考虑到用户的最低速率需求。针对此问题,该文提出了NOMA系统中公平地提高用户速率的功率分配方案。首先根据信道条件以及每个用户的最低速率需求计算每个簇所需的最低功率,然后以每个簇所需的最低功率以及所有簇所需的最低总功率作为约束条件,建立满足所有用户最低速率需求的情况下公平地提高每个用户速率的功率分配优化问题,最后通过多次调整部分簇的功率得到既满足用户最低速率需求又公平地提高用户速率的功率分配方案。仿真结果显示,用户的最低速率需求不同时,所提方案中用户提高的速率和中断概率均优于相同场景中已有的功率分配方案。 展开更多
关键词 最大化公平性 非正交多址接入 中断概率 功率分配 速率
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Modeling and Simulation of Packet Delivery Rate in LTE-V Network Based on Markov Chain
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作者 Mengkai Shi Yaohan Tang +2 位作者 Xiangyun Zhang Yi Zhang Jun Xu 《清华大学学报自然科学版(英文版)》 EI CAS CSCD 2020年第3期357-367,共11页
As one of the most promising communication technologies for vehicular networks, LTE-V has the advantages of wide coverage and a high transmission rate. 3 GPP released the technical specification of LTE-V in March 2017... As one of the most promising communication technologies for vehicular networks, LTE-V has the advantages of wide coverage and a high transmission rate. 3 GPP released the technical specification of LTE-V in March 2017, launching a spate of related research and industrialization. In this paper, we propose a communication model based on Markov process to evaluate the reliability of LTE-V. We derived the Packet Delivery Rate(PDR) of LTE-V based on the model. Moreover, we use Poisson process to model the distribution of vehicles on a highway,then combine the communication model with the vehicles’ distribution to derive the PDR under this scenario. To verify the correctness of the proposed model, we established a simulation program on the MATLAB platform. By comparing the simulation results and the mathematical results, we found that simulation results are a very good fit for the model. 展开更多
关键词 Vehicle-to-everything(V2X) LTE-V vehicle infrastructure cooperation system packet delivery rate
Chinese Medicine Sequential Therapy improves Pregnancy Outcomes after Surgery for Endometriosis-Associated Infertility: A Multicenter Randomized Double-blind Placebo Parallel Controlled Clinical Trial
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作者 ZHAO Rui-hua LIU Yong +12 位作者 LU Dan WU Ying WANG Xiao-yun LI Wei-li ZENG Cheng MENG Qing-wei LIAN Feng-mei ZHOU Jun SHI Yun SUN Wei-wei HAN Qian TANG Yi SHI Guang 《中国结合医学杂志:英文版》 SCIE CAS CSCD 2020年第2期92-99,共8页
Objective:To evaluate the efficacy and safety of Chinese medicine(CM)improving pregnancy outcomes after surgery for endometriosis-associated infertility.Methods:A multicenter,randomized,doubleblind placebo parallel co... Objective:To evaluate the efficacy and safety of Chinese medicine(CM)improving pregnancy outcomes after surgery for endometriosis-associated infertility.Methods:A multicenter,randomized,doubleblind placebo parallel controlled clinical trial was designed.A total of 202 patients who had laparoscopy for endometriosis-associated infertility with qi stagnation and blood stasis syndrome were included and randomly divided into the CM treatment group and placebo control group at a ratio of 1:1 using a central block randomization from May 2014 to September 2017,101 patients in each group.The two groups received continuous intervention at 1–5 days after surgery,for 6 menstrual cycles.Before ovulation,the CM group was treated Huoxue Xiaoyi Granule(活血消异颗粒);after ovulation,Bushen Zhuyun Granule(补肾助孕颗粒)was involved.The control group was treated with placebo.Transvaginal ultrasonography was performed every menstrual cycle during the treatment,and female hormone levels in the follicular and luteal phases were measured during the 1 st,3 rd and 6 th menstrual cycles.The analysis was continued until pregnancy.The primary outcomes were clinical pregnancy rate and pregnancy outcome,and the secondary outcomes were follicular development and endometrial receptivity.Safety evaluations were performed before and after treatment.Results:(1)Clinical pregnancy and live birth rates:the clinical pregnancy and live birth rates of the CM group were significantly higher than those of the placebo group[44.6%(45/101)vs.29.7%(30/101),34.7%(35/101)vs.20.8%(21/101),both P<0.05].(2)Follicle development:the incidence of dominant follicles,rate of cumulative cycle ovulation,and rate of cumulative cycle mature follicle ovulation were significantly higher in the CM group than those in the placebo group[93.8%(350/373)vs.89.5%(341/381),80.4%(275/342)vs.69.1%(253/366),65.8%(181/275)vs 56.1%(142/253),P<0.05 or P<0.01]).The incidence of cumulative cycle luteinized unruptured follicle syndrome was significantly lower in the CM group tha 展开更多
关键词 ENDOMETRIOSIS INFERTILITY Huoxue Xiaoyi Granule Bushen Zhuyun Granule pregnancy rate randomized controlled clinical trial Chinese medicine
Relay-intercropping soybean with maize maintains soil fertility and increases nitrogen recovery efficiency by reducing nitrogen input 预览
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作者 Qing Du Li Zhou +11 位作者 Ping Chen Xiaoming Liu Chun Song Feng Yang Xiaochun Wang Weiguo Liu Xin Sun Junbo Du Jiang Liu Kai Shu Wenyu Yang Taiwen Yong 《作物学报:英文版》 CAS CSCD 2020年第1期140-152,共13页
Optimized nitrogen(N)management can increase N-use efficiency in intercropping systems.Legume-nonlegume intercropping systems can reduce N input by exploiting biological N fixation by legumes.Measurement of N utilizat... Optimized nitrogen(N)management can increase N-use efficiency in intercropping systems.Legume-nonlegume intercropping systems can reduce N input by exploiting biological N fixation by legumes.Measurement of N utilization can help in dissecting the mechanisms underlying N uptake and utilization in legume-nonlegume intercropping systems.An experiment was performed with three planting patterns:monoculture maize(MM),monoculture soybean(SS),and maize-soybean relay intercropping(IMS),and three N application levels:zero N(NN),reduced N(RN),and conventional N(CN)to investigate crop N uptake and utilization characteristics.N recovery efficiency and 15N recovery rate of crops were higher under RN than under CN,and those under RN were higher under intercropping than under the corresponding monocultures.Compared with MM,IMS showed a lower soil N-dependent rate(SNDR)in 2012.However,the SNDR of MM rapidly declined from 86.8%in 2012 to 49.4%in 2014,whereas that of IMS declined slowly from 75.4%in 2012 to 69.4%in 2014.The interspecific N competition rate(NCRms)was higher under RN than under CN,and increased yearly.Soybean nodule dry weight and nitrogenase activities were respectively 34.2%and 12.5%higher under intercropping than in monoculture at the beginning seed stage.The amount(Ndfa)and ratio(%Ndfa)of soybean N2 fixation were significantly greater under IS than under SS.In conclusion,N fertilizer was more efficiently used under RN than under CN;in particular,the relay intercropping system promoted N fertilizer utilization in comparison with the corresponding monocultures.An intercropping system helps to maintain soil fertility because interspecific N competition promotes biological N fixation by soybean by reducing N input.Thus,a maize-soybean relay intercropping system with reduced N application is sustainable and environmentally friendly. 展开更多
关键词 Maize-soybean relay intercropping Reduced nitrogen Biological nitrogen fixation Nitrogen recovery efficiency Soil nitrogen dependent rate
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El Nino/Southern Oscillation during the 4.2 ka event recorded by growth rates of corals from the North South China Sea 预览
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作者 Shaohua Dang Kefu Yu +3 位作者 Shichen Tao Tao Han Huiling Zhang Wei Jiang 《海洋学报:英文版》 SCIE CAS CSCD 2020年第1期110-117,共8页
The 4.2 ka event that occurred during the period from 4 500–3 900 a BP was characterized by cold and dry climates and resulted in the collapse of civilizations around the world. The cause of this climatic event, howe... The 4.2 ka event that occurred during the period from 4 500–3 900 a BP was characterized by cold and dry climates and resulted in the collapse of civilizations around the world. The cause of this climatic event, however, has been under debate. We collected four corals(Porites lutea) from Yongxing Island, Xisha Islands, South China Sea, dated them with the U-series method, and measured the annual coral growth rates using X-ray technology. The dating results showed that the coral growth ages were from 4 500–3 900 a BP, which coincide well with the period of the4.2 ka event. We then reconstructed annual sea surface temperature anomaly(SSTA) variations based on the coral growth rates. The growth rate-based SSTA results showed that the interdecadal SSTA from 4 500–3 900 a BP was lower than that during modern times(1961–2008 AD). A spectral analysis showed that the SSTA variations from4 500–3 900 a BP were under the influence of El Nino-Southern Oscillation(ENSO) activities. From 4 500–4 100 a BP, the climate exhibited La Nina-like conditions with weak ENSO intensity and relatively stable and lower SSTA amplitudes. From 4 100–3 900 a BP, the climate underwent a complicated period of ENSO variability and showed alternating El Nino-or La Nina-like conditions at interdecadal time scales and large SSTA amplitudes. We speculate that during the early and middle stages of the 4.2 ka event, the cold climate caused by weak ENSO activities largely weakened social productivity. Then, during the end stages of the 4.2 ka event, the repeated fluctuations in the ENSO intensity caused frequent extreme weather events, resulting in the collapse of civilizations worldwide. Thus, the new evidence obtained from our coral records suggests that the 4.2 ka event as well as the related collapse of civilizations were very likely driven by ENSO variability. 展开更多
关键词 4.2 ka event ENSO variability SSTA coral growth rate Xisha Islands
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Development of an aftershock occurrence model calibrated for Turkey and the resulting likelihoods 预览
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作者 Ziya Muderrisoglu Ufuk Yazgan 《地震工程与工程振动:英文版》 SCIE EI CSCD 2020年第1期149-160,共12页
This paper presents the calibration of Omori’s aftershock occurrence rate model for Turkey and the resulting likelihoods. Aftershock occurrence rate models are used for estimating the probability of an aftershock tha... This paper presents the calibration of Omori’s aftershock occurrence rate model for Turkey and the resulting likelihoods. Aftershock occurrence rate models are used for estimating the probability of an aftershock that exceeds a specific magnitude threshold within a time interval after the mainshock. Critical decisions on the post-earthquake safety of structures directly depend on the aftershock hazard estimated using the occurrence model. It is customary to calibrate models in a region-specific manner. These models depend on rate parameters(a, b, c and p) related to the seismicity characteristics of the investigated region. In this study, the available well-recorded aftershock sequences for a set of Mw ≥ 5.9 mainshock events that were observed in Turkey until 2012 are considered to develop the aftershock occurrence model. Mean estimates of the model parameters identified for Turkey are a =-1.90, b = 1.11, c = 0.05 and p = 1.20. Based on the developed model, aftershock likelihoods are computed for a range of different time intervals and mainshock magnitudes. Also, the sensitivity of aftershock probabilities to the model parameters is investigated. Aftershock occurrence probabilities estimated using the model are expected to be useful for post-earthquake safety evaluations in Turkey. 展开更多
关键词 aftershock occurrence model aftershock likelihoods rate parameters aftershock hazard
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Mechanical characterization of Mg−B4C nanocomposite fabricated at different strain rates 预览
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作者 Gholam Hossein Majzoobi Kaveh Rahmani 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2020年第2期252-263,共12页
Magnesium has wide application in industry.The main purpose of this investigation was to improve the properties of magnesium by reinforcing it using B4C nanoparticles.The reinforced nanocomposites were fabricated usin... Magnesium has wide application in industry.The main purpose of this investigation was to improve the properties of magnesium by reinforcing it using B4C nanoparticles.The reinforced nanocomposites were fabricated using a powder compaction technique for 0,1.5vol%,3vol%,5vol%,and 10vol% of B4C.Powder compaction was conducted using a split Hopkinson bar(SHB),drop hammer(DH),and Instron to reach different compaction loading rates.The compressive stress–strain curves of the samples were captured from quasi-static and dynamic tests carried out using an Instron and split Hopkinson pressure bar,respectively.Results revealed that,to achieve the highest improvement in ultimate strength,the contents of B4C were 1.5vol%,3vol%,and 3vol% for Instron,DH,and SHB,respectively.These results also indicated that the effect of compaction type on the quasi-static strength of the samples was not as significant,although its effect on the dynamic strength of the samples was remarkable.The improvement in ultimate strength obtained from the quasi-static stress–strain curves of the samples(compared to pure Mg)varied from 9.9% for DH to 24% for SHB.The dynamic strength of the samples was improved(with respect to pure Mg)by 73%,116%,and 141%for the specimens compacted by Instron,DH,and SHB,respectively.The improvement in strength was believed to be due to strengthening mechanisms,friction,adiabatic heating,and shock waves. 展开更多
关键词 powder compaction B4C MAGNESIUM strain rate ultimate strength SINTERING
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Medium and Long Term Decomposition Process of Litter in Abies Fabri Forest 预览
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作者 LI Wei YANG Danli +1 位作者 LUO Ji HE Yongmei 《景观研究:英文版》 2020年第1期127-130,136,共5页
Litter is an important part of forest ecosystem and its decomposition process is the key link of nutrient cycling in forest ecosystem.Accurate determination of litter decomposition dynamics is very important to study ... Litter is an important part of forest ecosystem and its decomposition process is the key link of nutrient cycling in forest ecosystem.Accurate determination of litter decomposition dynamics is very important to study the pattern and process of forest ecosystem.This paper selected The Gongga Mountain Alpine Ecosystem Observation and Experiment Station at an altitude of 3000 m to observe and determine litter decomposition process of the Abies fabri forest over a long period of time.The results showed that:①The decomposition rate of litter was broadleaf>needles>dead branches,and the time required to decompose half of broadleaf,needles and dead branches was 6.8 years,10.5 years and 14.5 years respectively;the time of decompose 95%of them was 29.3 years,45.6 years and 63.1 years,respectively;②Regardless of broadleaf,needles or dead branches,the organic carbon content of them decreased with time,while the decomposition rate of organic carbon increased with time;By using the exponential decay model the decomposition coefficient of litter organic carbon calculated was broadleaf>needle>dead branches;③The organic carbon released by the annual decomposition of broadleaf,needles and dead branches in Abies fabri forest was 52.18,4.32 and 0.67 kg/hm^2,respectively.The total amount of organic carbon released by various litter was 61.13 kg/hm^2 per year,accounting for 6.58%of the total organic carbon of litter. 展开更多
关键词 Abies fabri Litter decomposition Decomposition rate HALF-LIFE Turnover period
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Square Geometrical Shaping 128QAM Based Time Domain Hybrid Modulation in Visible Light Communication System 预览
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作者 Peng Zou Yiheng Zhao +1 位作者 Fangchen Hu Nan Chi 《中国通信:英文版》 SCIE CSCD 2020年第1期163-173,共11页
We proposed two kinds of visible light communication(VLC)systems which respectively based on 64QAM/square geometrical shaping(SGS)128QAM time domain hybrid modulation scheme(SGSHY)and 64QAM/128QAM time domain hybrid m... We proposed two kinds of visible light communication(VLC)systems which respectively based on 64QAM/square geometrical shaping(SGS)128QAM time domain hybrid modulation scheme(SGSHY)and 64QAM/128QAM time domain hybrid modulation scheme(REGHY).These two systems can operate around specific forward error correction(FEC)threshold and maximize the achievable information rate(AIR)of the system.The principles of SGSHY and REGHY are proposed in detail,which has very low computation complexity compared with probabilistic shaping.The SGSHY outperforms REGHY at high peak to peak voltage(Vpp).Experimental results show that at high Vpp like 1.4V,which means the system is suffering from high nonlinear distortion,the AIR of SGSHY outperforms that of REGHY by 0.12Gb/s at the 2×10-2 FEC threshold.The AIR of the REGHY is at most 0.36Gb/s higher than that of 64QAM at 0.8V Vpp and 7%FEC threshold,while the(achievable information rate)AIR of SGSHY is at most 0.40Gb/s higher than that of 64QAM at 1.4V Vpp and 20%FEC threshold. 展开更多
关键词 SGS128QAM MPN TDHM nonlinear distortion achievable information rate
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Efficacy of cattle encephalon glycoside and ignotin in patients with acute cerebral infarction:a randomized,double-blind,parallel-group,placebo-controlled study 预览
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作者 Hui Zhang Chuan-Ling Li +11 位作者 Feng Wan Su-Juan Wang Xiu-E Wei Yan-Lei Hao Hui-Lin Leng Jia-Min Li Zhong-Rui Yan Bao-Jun Wang Ren-Shi Xu Ting-Min Yu Li-Chun Zhou Dong-Sheng Fan 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第7期1266-1273,共8页
Cattle encephalon glycoside and ignotin(CEGI)injection is a compound preparation formed by a combination of muscle extract from hea lthy rabbits and brain gangliosides from cattle,and it is generally used as a neuropr... Cattle encephalon glycoside and ignotin(CEGI)injection is a compound preparation formed by a combination of muscle extract from hea lthy rabbits and brain gangliosides from cattle,and it is generally used as a neuroprotectant in the treatment of central and peripheral nerve injuries.However,there is still a need for high-level clinical evidence from large samples to support the use of CEGI.We therefore carried out a prospective,multicenter,randomized,double-blind,parallel-group,placebo-controlled study in which we recruited 319 patients with acute cerebral infarction from 16 centers in China from October 2013 to May 2016.The patients were randomized at a 3:1 ratio into CEGI(n=239;155 male,84 female;61.2±9.2 years old)and placebo(n=80;46 male,34 female;63.2±8.28 years old)groups.All patients were given standard care once daily for 14 days,including a 200 mg aspirin enteric-coated tablet and 20 mg atorvastatin calcium,both taken orally,and intravenous infusion of 250–500 mL 0.9%sodium chloride containing 40 mg sodium tanshinone IIA sulfonate.Based on conventional treatment,patients in the CEGI and placebo groups were given 12 mL CEGI or 12 mL sterile water,respectively,in an intravenous drip of 250 mL 0.9%sodium chloride(2 mL/min)once daily for 14 days.According to baseline National Institutes of Health Stroke Scale scores,patients in the two groups were divided into mild and moderate subgroups.Based on the modified Rankin Scale results,the rate of patients with good outcomes in the CEGI group was higher than that in the placebo group,and the rate of disability in the CEGI group was lower than that in the placebo group on day 90 after treatment.In the CEGI group,neurological deficits were decreased on days 14 and 90 after treatment,as measured by the National Institutes of Health Stroke Scale and the Barthel Index.Subgroup analysis revealed that CEGI led to more significant improvements in moderate stroke patients.No drug-related adverse events occurred in the CEGI or placebo groups.In conclusion,CEGI may be a 展开更多
关键词 acute cerebral infarction Barthel Index cattle encephalon glycoside and ignotin modified Rankin Scale National Institutes of Health Stroke Scale NEUROPROTECTANTS recovery rate stroke
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Relative energy zero ratio-based approach for identifying pulse-like ground motions 预览
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作者 Liu Ping Li Ning +2 位作者 Ma Hua Xie Lili Zhou Baofeng 《地震工程与工程振动:英文版》 SCIE EI CSCD 2020年第1期1-16,共16页
Pulse-like ground motions are capable of inflicting significant damage to structures. Efficient classification of pulse-like ground motion is of great importance when performing the seismic assessment in near-fault re... Pulse-like ground motions are capable of inflicting significant damage to structures. Efficient classification of pulse-like ground motion is of great importance when performing the seismic assessment in near-fault regions. In this study, a new method for identifying the velocity pulses is proposed, based on different trends of two parameters: the short-time energy and the short-time zero crossing rate of a ground motion record. A new pulse indicator, the relative energy zero ratio(REZR), is defined to qualitatively identify pulse-like features. The threshold for pulse-like ground motions is derived and compared with two other identification methods through statistical analysis. The proposed procedure not only shows good accuracy and efficiency when identifying pulse-like ground motions but also exhibits good performance for classifying records with high-frequency noise and discontinuous pulses. The REZR method does not require a waveform formula to express and fit the potential velocity pulses;it is a purely signal-based classification method. Finally, the proposed procedure is used to evaluate the contribution of pulse-like motions to the total input energy of a seismic record, which dramatically increases the seismic damage potential. 展开更多
关键词 pulse-like ground motion velocity pulse relative energy zero-crossing ratio short-time input energy shorttime zero crossing rate
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Optimal Tariff and Endogenous Drivers for Trade Liberalization 预览
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作者 李春顶 陆菁 何传添 《中国经济学人:英文版》 2020年第2期30-40,共11页
Trade liberalization requires institutional coordination and openness,and is driven by a multitude of factors.This paper simulates endogenous optimal tariffs under different model structures to uncover the underlying ... Trade liberalization requires institutional coordination and openness,and is driven by a multitude of factors.This paper simulates endogenous optimal tariffs under different model structures to uncover the underlying drivers of trade liberalization.Parametric calibration and simulation methods based on the numeric general equilibrium model are employed to estimate the optimal tariff rates of countries with and without trade retaliation.Then,near-reality assumptions are added into the standard general equilibrium model structure,including the cross-border capital flow,multi-country assumption and trade cost,to simulate decreasing optimal tariff rates.The simulation results suggest that world economic development has increased the economic ties and interdependence among nations,making trade liberalization an endogenous optimal choice.The backlash against globalization in recent years is motivated by short-term factors,but will not persist in the long run since it goes against the law of economic growth and socio-economic development. 展开更多
关键词 optimal tariff rate general equilibrium model structure trade liberalization
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Compression analysis of the gray and white matter of the spinal cord 预览
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作者 Norihiro Nishida Fei Jiang +7 位作者 Junji Ohgi Akihiro Tanaka Yasuaki Imajo Hidenori Suzuki Masahiro Funaba Takashi Sakai Itsuo Sakuramoto Xian Chen 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第7期1344-1349,共6页
The spinal cord is composed of gray matter and white matter.It is well known that the properties of these two tissues differ considerably.Spinal diseases often present with symptoms that are caused by spinal cord comp... The spinal cord is composed of gray matter and white matter.It is well known that the properties of these two tissues differ considerably.Spinal diseases often present with symptoms that are caused by spinal cord compression.Understanding the mechanical properties of gray and white matter would allow us to gain a deep understanding of the injuries caused to the spinal cord and provide information on the pathological changes to these distinct tissues in several disorders.Previous studies have reported on the physical properties of gray and white matter,however,these were focused on longitudinal tension tests.Little is known about the differences between gray and white matter in terms of their response to compression.We therefore performed mechanical compression test of the gray and white matter of spinal cords harvested from cows and analyzed the differences between them in response to compression.We conducted compression testing of gray matter and white matter to detect possible differences in the collapse rate.We found that increased compression(especially more than 50%compression)resulted in more severe injuries to both the gray and white matter.The present results on the mechanical differences between gray and white matter in response to compression will be useful when interpreting findings from medical imaging in patients with spinal conditions. 展开更多
关键词 biomechanical study cervical spondylotic myelopathy collapse rate compression gray matter mechanical properties spinal cord injury white matter
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Research Progress and Prospect on the Effects of Abiotic Stress on Plant Photosynthesis 预览
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作者 Qing FU Jin ZHANG +6 位作者 Tongfu QIAO Ye LIU Caifeng HOU Wenbo XU Haifeng MA Bo WANG Yilong HOU 《农业生物技术:英文版》 CAS 2020年第1期45-49,共5页
Photosynthesis is the basis of plant growth and development as well as the existence of the biological world. Photosynthesis is of great theoretical and practical significance. In this paper, the effects of temperatur... Photosynthesis is the basis of plant growth and development as well as the existence of the biological world. Photosynthesis is of great theoretical and practical significance. In this paper, the effects of temperature, drought, salt, light and other abiotic stress factors on plant photosynthesis were reviewed. 展开更多
关键词 Abiotic stress PHOTOSYNTHESIS Photosynthetic rate PLANT
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Carrier frequency and symbol rate estimation based on cyclic spectrum 预览
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作者 CAO Sisi ZHANG Weiyan 《系统工程与电子技术:英文版》 SCIE EI CSCD 2020年第1期37-44,共8页
Carrier frequency and symbol rate estimation are the main contents of parameter estimation,which is the basis of modulation recognition and further processing of signals especially in non-cooperative communication.Wit... Carrier frequency and symbol rate estimation are the main contents of parameter estimation,which is the basis of modulation recognition and further processing of signals especially in non-cooperative communication.With the development of wireless communication,the signal transmission environment has become increasingly bad,causing more difficulties in parameter estimation.It is well known that the signal cycle spectrum is robust to noises and signal parameters are closely related.In practice,it is impossible to calculate the cyclic spectrum of infinite length data signals.When using finite length data to obtain a cycle spectrum,the truncation noise is induced,resulting in interference.It is necessary to overcome the influence of noises in order to improve the detection ability of discrete spectral lines.An improved method of the discrete spectral line extraction algorithm is proposed by reflecting the amplitude advantage of discrete spectral lines through salient features of continuous noises in discrete spectral line neighborhood. 展开更多
关键词 digital modulation signal carrier frequency symbol rate cyclic spectrum noise control
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Discussion on the Operation of Urban Domestic Sewage Treatment Facilities : A Case Study of Guangdong Province 预览
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作者 Du Shuntao Yang Shewei +1 位作者 Guo Qian Huang Zhihua 《气象与环境研究:英文版》 CAS 2019年第4期110-113,117共5页
Urban sewage treatment facility is an important ways to control polluted domestic water. The operation of urban sewage treatment facilities is good or not, and whether the effectiveness of pollutant emission reduction... Urban sewage treatment facility is an important ways to control polluted domestic water. The operation of urban sewage treatment facilities is good or not, and whether the effectiveness of pollutant emission reduction can be exerted play a significant role in reducing the pollution of living sources. Nowadays the operation of urban sewage treatment facilities is mainly evaluated by the load rate. However, due to the failure to fully implement the reformation of the rainwater and polluted water in Guangdong Province, the domestic sewage is mixed with rainwater during the rainy season and is included in the treatment of urban sewage treatment facilities. Therefore, it is not objective to evaluate the operation of sewage treatment facilities using only the load rate of sewage treatment. According to the situation of Guangdong Province, the load rates of COD, ammonia nitrogen and total phosphorus in domestic sewage and load rate of sewage treatment were included in the evaluation, and 20 urban sewage treatment facilities were selected as research objects. The operation situations and emission reduction benefits of urban sewage treatment facilities in different regions of Guangdong Province were roughly evaluated. 展开更多
关键词 Operation evaluation URBAN SEWAGE TREATMENT facilities LOAD RATE of SEWAGE TREATMENT LOAD RATE of COD LOAD RATE of AMMONIA nitrogen LOAD RATE of total phosphorus
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Relationship on the Head Deviation Rate and LayingLength of Porous Tubes 预览
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作者 Yameng Wang Huanfang Liu 《哈尔滨工业大学学报:英文版》 EI CAS 2019年第5期88-96,共9页
To improve the utilization efficiency of water the laying length of porous tubes was analyzed. Considering long porous tubes the irrigation uniformity of porous tubes was studied by analyzing the deviation rate of the... To improve the utilization efficiency of water the laying length of porous tubes was analyzed. Considering long porous tubes the irrigation uniformity of porous tubes was studied by analyzing the deviation rate of the working head of porous tubes and through an impact analysis of the deviation ratio of flow rate based on laying length slope pressure head and perforation spacing. Results showed that the deviation ratio of the flow rate could be reduced by decreasing the length of tubes and increasing the slope. The deviation ratio of flow rate was less influenced by pressure head and perforation spacing. A best laid slope resulted in a longer laying length of the porous tubes and they were not constant. 展开更多
关键词 flow deviation RATE POROUS TUBES deviation RATE of working HEAD LAYING length HEAD LOSS
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