检索结果-南通市图书馆

Nuclear Science and Techniques 2022年第10期33卷 22-32页

作者： Jian Chen Yong-Bin Leng Lu-Yang Yu Long-Wei Lai Ren-Xian Yuan Shanghai Advanced research institute Chinese Academy of SciencesShanghai 201204China Shanghai institute of Applied Physics Chinese Academy of SciencesShanghai 201800China

To achieve high-efficiency operation of the highgain free-electron laser(FEL),the electron beams and radiated photon beams need to be overlapped precisely and pass through the entire undulator ***,a high-resolution beam-position monitor(BPM)is required.A cavity BPM(CBPM)with a resonant cavity structure was developed and used in the Shanghai Soft X-ray FEL(SXFEL)test facility and can achieve a position resolution of<1μ*** construction and operation of the SXFEL user facility also bring about higher requirements for beamposition *** this case,the factors that affect the performance of the CBPM system were further *** included the amplitude and phase stability of the local oscillator,stability of the trigger signal,performance of the radio frequency front-end,signal processing electronics,and signal processing *** on the upgrade and optimization of the system,a beam test platform was built at the end of the linear acceleration section of the SXFEL,and the experimental results show that the position resolution of the system can reach 177 nm at a bunch charge of 500 pC,and the dynamic range is controlled within±300μm,and the relative measurement uncertainty of the bunch charge can reach 0.021%,which are significant improvements compared to the attributes of the previous system.

关键词： Cavity BPM SXFEL System optimization Position resolution Measurement uncertainty Algorithm

Performance improvement of optimization solutions by POD-based data mining

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2019年第4期32卷 826-838页

作者： Yanhui DUAN Wenhua WU Peihong ZHANG Fulin TONG Zhaolin FAN Guiyu ZHOU Jiaqi LUO Computational Aerodynamics institute China Aerodynamics Research and Development Center School of Aeronautics and Astronautics Zhejiang University

The performance of an optimized aerodynamic shape is further improved by a second-step optimization using the design knowledge discovered by a data mining technique based on Proper Orthogonal Decomposition(POD) in the present study. Data generated in the first-step optimization by using evolution algorithms is saved as the source data, among which the superior data with improved objectives and maintained constraints is chosen. Only the geometry components of the superior data are picked out and used for constructing the snapshots of POD. Geometry characteristics of the superior data illustrated by POD bases are the design knowledge, by which the second-step optimization can be rapidly achieved. The optimization methods are demonstrated by redesigning a transonic compressor rotor blade, NASA Rotor 37, in the study to maximize the peak adiabatic efficiency, while maintaining the total pressure ratio and mass flow ***, the blade is redesigned by using a particle swarm optimization method, and the adiabatic efficiency is increased by 1.29%. Then, the second-step optimization is performed by using the design knowledge, and a 0.25% gain on the adiabatic efficiency is obtained. The results are presented and addressed in detail, demonstrating that geometry variations significantly change the pattern and strength of the shock wave in the blade passage. The former reduces the separation loss,while the latter reduces the shock loss, and both favor an increase of the adiabatic efficiency.

关键词： Aerodynamic shape optimization Computational fluid dynamics Data mining Particle swarm optimization Proper Orthogonal Decomposition Transonic flow Turbomachinery

Synthesis of lathanum or La-B doped KIT-6 mesoporous materials and their application in the catalytic oxidation of styrene

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2010年第3期28卷 369-375页

作者：詹望成郭杨龙王艳芹郭耘卢冠忠 Key Laboratory for Advanced Materials Research Institute of Industrial CatalysisEast China University of Science and Technology

La-doped and La-B-doped KIT-6 mesoporous materials were prepared by direct hydrothermal synthesis with pH-adjusting method and characterized by X-ray diffractometer(XRD),nitrogen sorption,FT-IR,UV-Vis,X-ray photoelectron spectroscopy(XPS) and *** catalytic performance for the oxidation of styrene by hydrogen peroxide,tert-butyl hydroperoxide or oxygen was *** results showed that the introduction of heteroatoms did not destroy the mesostructure of KIT-6 with cubic Ia3d space *** or ...

关键词： mesoporous materials oxidation of styrene benzaldehyde styrene oxide rare earths

Effect of Ichnocarpus frutescens (L.) *** extract on preadipocytes viability and lipid accumulation in 3T3-L1 cells

在线全文

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Medicine 2013年第5期6卷 360-365页

作者： M Saravanan Savarimuthu Ignacimuthu Division of Ethnopharmacology Entomology Research InstituteLoyola CollegeChennaiTamilnadu 600 034India Entomology research institute Loyola CollegeChennaiTamilnadu 600 034India

Objective:To investigate the crude extracts of Ichnacarpus frutescens(***) for antiobesity ***:Leaves of *** were sequentially extracted with hexane,ethyl acetate, and methanol and their effect on viability of 3T3-L1 preadipocytes were *** on this the apoptosis on preadipocytes was confirmed by DMA fragmentation and LDH(Lactate dehydrogenase) leakage ***-adipogenesis was performed by oil red O(ORO) staining and free glycerol release in the medium of differentiated ***:The hexane extract of ***(IFHE) inhibited cell viability in a time- and dose-related *** increased release of *** a marker of membrane integrity,was observed at a dose of 200μg/mL The discontinuous DMA fragments on agarose gel electrophoresis showed the apoptotic effect of the *** observations of cells stained with ORG showed a decrease in cellular lipid content at the concentrations tested compared to the induced control *** the experiment of lipolytic activity,treatment with IFHE enhanced glycerol secretion with the rates of approximately 28%.55%,and 46%at the concentrations of 100,200 and 300μg/mL,***: The observed properties clearly revealed the medicinal property of *** in the treatment of obesity.

关键词： Obesity Adipocytes Apoptosis Adipogenesis

Shock wave velocity measurement in the Al_2O_3 under ultrahigh pressure

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2011年第6期20卷 307-312页

作者：王峰彭晓世刘慎业李永升蒋小华丁永坤 research Centre of Laser Fusion Chinese Academy of Engineering Physics institute of Applied Physics and Computational Mathematics

in indirect-drive experiment, the blank effect caused by X-rays from Hohlraum will show the dark area in time scale of optical streak camera （OSC）. This blank effect, which was a serious problem in indirect-drive shock wave experiments, has been explained by the semiconductor model. The X-rays cause the band to band transition and the probe laser is absorbed by the intraband transition, which leads to a dark region in time scale of the OSC image. In the experiment, the reflectivity of shock wave front was measured to be about 50% at shock wave velocity 32 km/s and was compared to the theoretical calculations with the Drude free electron model. From the experimental data, it is found that the blank effect can be avoided at radiation temperature of 170 eV if the Al layer is thicker than 60μm.

关键词： shock wave optical diagnosis interfere meter semiconductor model

Hydrothermal Uranium Deposits and Sulfur Isotopes

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 1984年第2期3卷 154-160页

作者：蔡根庆 Beijing research institute of Uranium Geology

research on sulfur isotopes in hydrothermal uranium deposits with acid alterations shedmuch light on the genetic aspects of hydrothermal uranium *** on the studies ofuranium deposits of different genesis,it is concluded that δ;S of sulfides in hydrothermaluranium deposits derived from residual magma is within the range of +2‰—2.6‰,appro-ximately the same as meteorite sulfur.δ;S of sulfides in polygenetic hydrothermal uranium de-posits is slightly lighter than meteorite sulfur and varies over a restricted range（6.7‰）,avera-ging—10.15‰.Two intervals can be recognized with respect to sulfur isotopic compositionsin palingenetic hydrothermal uranium deposits.δ;S of sulfides formed in diagenesis,autometa-morphism and hypothermal stages is similar to meteorite *** the other hand,at the stagestarting from the alteration of uranium mineralization to the formation o uranium depositsand postmineralization the average δ;S is -7.89‰,with a wider range of δ;S variation（13.7‰）,which can be attributed to the enrichment of δ;S in palingenetic hydrothermalsolutions. Sulfur isotopic characteristics of uranium deposits of various replacement-filling typesas mentioned above can be summarized as follows:*** homogeneity is maintained in the sulfur of sulfides in hydrothermal ura-nium deposits derived from residual magma,with δ;S ranging from +2.0‰ to-2.6‰,approximately the same as meteorite *** sulfur isotopic compositions are determined is sulfides from polygenetichydrothermal uranium *** may be attributed to assimilation and contaminationby the;S-rich sulfur of sedimentary origin in the wall rocks.δ;S fluctuates around-9.5‰,with a small isotopic variation （6.7‰）.*** intervals can be distinctly recognized with respect to the sulfur isotopic com-positions of palingenetic hydrothermal uranium *** sulfur isotopic compositions ofprimary sulfides are similar to meteorite sulfur,while sulfides formed at the time startingfrom the alterat

关键词： Hydrothermal Uranium Deposits and Sulfur Isotopes

Reversible addition-fragmentation chain transfer graft polymerization of acrylonitrile onto PE/PET composite fiber initiated by γ-irradiation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2015年第2期26卷 32-37页

作者：马垚虞鸣李林繁马红娟王自强李景烨 Innovation research institute of TMSR Energy System Shanghai Institute of Applied PhysicsChinese Academy of Sciences University of Chinese Academy of Sciences

Reversible addition-fragmentation chain transfer(RAFT) mediated grafting of acrylonitrile onto Polyethylene/Poly(ethylene terephthalate)(PE/PET) composite fibers was performed using γ-irradiation as the initial source at ambient temperature. Different initial concentrations of 2-cyanoprop-2-yl dithiobenzonate were used as the chain transfer agent. The kinetics of graft polymerization is in accordance with the living RAFT polymerization. The successful grafting of acrylonitrile is proved by Fourier transform infrared spectroscopy *** results of monofilament tensile test show that mechanical properties of the fibers change slightly after grafting. Scanning electronic microscopy images of the fibers show that the surface of RAFT grafted fibers is smoother than that of fibers grafted conventionally.

关键词： RAFT聚合复合纤维接枝聚合链转移剂 PET 丙烯腈傅里叶变换红外光谱分析加成

A NEW METHOD FOR DESIGNING CIRCULAR WAVEGUIDE PHASER WITH SMALL ELLIPTICITY

在线全文

学校读者我要写书评

暂无评论

Journal of Electronics(China) 1987年第3期4卷 214-224页

作者：潘宗达 Nanjing research institute of Electronic Technology

A method for calculating the phase shift of a dielectrically loaded circular waveguide with smallellipticity is *** gives an excellent result for enqineering purposes,although it is not rigorous *** maximum difference... 详细信息

关键词： mode A NEW METHOD FOR DESIGNING CIRCULAR WAVEGUIDE PHASER WITH SMALL ELLIPTICITY length

Business Cycle in China since the Lehman Crisis:Interaction among Macroeconomic Policy,Economic Growth and Inflation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

China & World Economy 2013年第5期21卷 1-19页

作者： C.H.Kwan Zhinan Zhang Nomura institute of Capital Markets research

The major objectives of China＇s macroeconomic policy are to stabilize economic growth and inflation, which, in turn, are important factors determining key prices, such as the policy interest rate, the renminbi exchange rate and stockprices. In a framework that distinguishes different phases of the business cycle based on whether the current period＇s economic growth rate and inflation rate are above or below their ＂＇normal＂ values, this paper analyzes the interaction among macroeconomic policy, economic growth and inflation in China since the Lehman crisis, and the implications for these key prices. The path of China＇s economy indicates that stimulus measures taken by the government during the recession phase and tightening measures implemented during the overheating phase have helped minimize the fluctuation over the business cycle. Our analysis shows that Chinese authorities tend to rely more on adjusting the exchange rate than the interest rate to stabilize the economy. Comparing with conditions at the time of the post-Lehman recession, the current slowpace of economie growth in China may reflect not only weakening demand, but also a lowerpotential growth rate associated with the arrival of the Lewis turning point.

关键词： business cycle inflation Lehman crisis Lewis turning point Taylor rule

Ecological niche modelling of a critically endangered species Commiphora wightii (Arn.) Bhandari using bioclimatic and non-bioclimatic variables

在线全文

学校读者我要写书评

暂无评论

Ecological Processes 2023年第1期12卷 110-139页

作者： Manish Mathur Preet Mathur Harshit Purohit ICAR-Central Arid Zone research institute Jodhpur 342003India Jodhpur institute of Engineering and Technology JodhpurIndia Neal Analytics PuneMaharashtraIndia

Background The aim of this study is to examine the effects of four different bioclimatic predictors(current,2050,2070,and 2090 under Shared Socioeconomic Pathways SSP2-4.5)and non-bioclimatic variables(soil,habitat heterogeneity index,land use,slope,and aspect)on the habitat suitability and niche dimensions of the critically endangered plant species Commiphora wightii in *** also evaluate how niche modelling affects its extent of occurrence(EOO)and area of occupancy(AOO).Results The area under the receiver operating curve(AUC)values produced by the maximum entropy(Maxent)under various bioclimatic time frames were more than 0.94,indicating excellent model ***-bioclimatic characteristics,with the exception of terrain slope and aspect,decreased the accuracy of our ***,Maxent accuracy was the lowest across all combinations of bioclimatic and non-bioclimatic variables(AUC=0.75 to 0.78).With current,2050,and 2070 bioclimatic projections,our modelling revealed the significance of water availability parameters(BC-12 to BC-19,*** and seasonal precipitation as well as precipitation of wettest,driest,and coldest months and quarters)on habitat suitability for this ***,with 2090 projection,energy variables such as mean temperature of wettest quarter(BC-8)and isothermality(BC-3)were identified as governing *** salt,rooting conditions,land use type(grassland),characteristics of the plant community,and slope were also noticed to have an impact on this *** distribution modelling of this species in both its native(west-ern India)and exotic(North-east,Central Part of India,as well as northern and eastern Ghat)habitats,we were also able to simulate both its fundamental niche and its realized *** EOO and AOO analysis reflects the possibility of many new areas in India where this species can be planted and *** According to the calculated area under the various suitability classes,we can conclude

关键词： Commiphora wightii Critically endangered Maxent Habitat heterogeneity index Niche hypervolume

同方期刊数据库