检索结果-南通市图书馆

Experimental and analytical studies on the vibration serviceability of long-span prestressed concrete floor

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

Earthquake Engineering and Engineering Vibration 2018年第2期17卷 417-428页

作者： Cao Liang Liu Jiepeng Li Jiang zhang ruizhi School of Civil Engineering Chongqing University Key Laboratory of New Technology for Construction of Cities in Mountain Area (Chongqing University) Ministry of Education

An extensive experimental and theoretical research study was undertaken to study the vibration serviceability of a long-span prestressed concrete floor system to be used in the lounge of a major ***,jumping impact tests were carried out to obtain the floor’s modal parameters,followed by an analysis of the distribution of peak *** tests were also performed to capture the acceleration *** prestressed concrete floor was found to have a low fundamental natural frequency（≈8.86 Hz）corresponding to the average modal damping ratio of≈2.17%.A coefficients plate with simply-supported *** calculated analytical results（natural frequencies and root-mean-square acceleration）agree well with the experimental *** analytical approach is thus validated.

关键词： vibration serviceability prestressed concrete floor airport lounge theoretical analysis modal superposition method

High-Performance Aqueous Zinc–Manganese Battery with Reversible Mn^(2+)/Mn^(4+) Double Redox Achieved by Carbon Coated MnO_x Nanoparticles

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2020年第9期12卷 44-55页

作者： Jingdong Huang Jing Zeng Kunjie Zhu ruizhi zhang Jun Liu School of Materials Science and Engineering Central South UniversityChangsha 410083People’s Republic of China Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) College of ChemistryNankai UniversityTianjin 300071People’s Republic of China Hunan Institute of Technology Hengyang 421002People’s Republic of China

There is an urgent need for low-cost,high-energy-density,environmentally friendly energy storage devices to fulfill the rapidly increasing need for electrical energy ***-electron redox is considerably crucial for the development of high-energy-density *** we present highperformance aqueous zinc-manganese batteries with reversible Mn2+/Mn4+ double *** active Mn4+is generated in situ from the Mn2+-containing MnOx nanoparticles and *** from the low crystallinity of the birnessite-type MnO2 as well as the electrolyte with Mn2+additive,the MnOX cathode achieves an ultrahigh energy density with a peak of845.1 Wh kg-1 and an ultralong lifespan of 1500 *** combination of electrochemical measurements and material characterization reveals the reversible Mn2+/Mn4+double redox(birnessite-type MnO2? monoclinic MnOOH and spinel ZnMn2O4 H?Mn2+ions).The reversible Mn2+/Mn4+double redox electrode reaction mechanism offers new opportunities for the design of low-cost,high-energy-density cathodes for advanced rechargeable aqueous batteries.

关键词： Aqueous zinc–manganese batteries Mn-based cathode materials High energy density Mn2+/Mn4+double redox

Experimental and numerical investigations into flow features in an intake duct for the waterjet propulsion under mooring conditions

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2021年第5期37卷 826-843,I0003页

作者： Renfang Huang ruizhi zhang Yiwei Wang Xianwu Luo Lei Zhu Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China Science and Technology on Water Jet Propulsion Laboratory Shanghai 200011China College of Engineering Science University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Hydroscience and Engineering Department of Energy and Power EngineeringTsinghua UniversityBeijing 100084China China Institute of Water Resources and Hydropower Research Beijing 100038China

The waterjet propulsion is widely applied in the marine vessels over 30 knots,and the intake duct is considered as an essential component that strongly relates to the propulsion *** paper sheds light on the flow features inside an intake duct under mooring conditions by using the particle image velocimetry(PIV)technique with three-dimensional(3D)numerical *** hydraulic loss gradually increase as the flow-rate *** to analyses via the Bernoulli equation,the hydraulic loss is composed of the frictional head loss(h_(f)~V^(1.75))and the local head loss(h_(j)~V^(2.0)).A recirculation region is observed near the duct lower wall with a high-velocity flow near the upper wall,and subsequently a shear flow presents in the horizontal straight pipe with an obvious velocity ***-dimensional simulations demonstrate that the vortex pair is very strong in the recirculation region and then it gradually decreases as the fluid flows *** the flow-rate increasing,the non-uniformity at the duct outlet firstly increases to a peak and then slightly decreases,while the perpendicularity at the duct outlet dramatically decreases to a minimum and then *** work not only reveals some physics of the waterjet propulsion under mooring conditions,but also promotes its efficient operation.

关键词： Waterjet propulsion Particle image velocimetry(PIV) Intake duct Waterjet pump Mooring conditions

A high-efficiency charge pump in BCD process for implantable medical devices

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

Journal of Semiconductors 2018年第10期39卷 82-89页

作者： Jie zhang Hong zhang ruizhi zhang School of Microelectronics Xi'an Jiaotong University

This paper presents a high-efficiency charge pump circuit composed of cascaded cross-coupled voltage doublers implemented in an isolated bipolar-CMOS-DMOS（BCD） technology for implantable medical *** advantage of the transistor structures in the isolated BCD process, the leakage currents caused by the parasitic PNP transistors in the cross-coupled PMOS serial switches are eliminated by simply connecting the inside substrate terminal to the isolation terminal of each PMOS transistor. The simple circuit structure leads to small parasitic capacitance in the voltage doubler, which in turn ensures high efficiency of the overall charge pump. The proposed charge pump with 5 cascaded voltage doublers is fabricated in a 0.35-μm isolated BCD process. Measurement results with 2-V power supply, 1-MHz driving clock frequency and 40-μA current load show that an efficiency of 72.6% is achieved, and the output voltage can be pumped to about 11.5 V at zero load current. The chip area of the charge pump is 1.6 × 0.35 mm^2.

关键词： voltage doubler charge pump high-efficiency implantable medical device

A 16-bit, ±10-V Input Range SAR ADC with a 5-V Supply Voltage and Mixed-Signal Nonlinearity Calibration

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2022年第4期31卷 690-697页

作者： LUO Hongrui ZHAO Xianlong JIAO Zihao zhang Jie WANG Xiaofei zhang ruizhi zhang Hong School of Microelectronics Xi'an Jiaotong University Beijing Smartchip Microelectronics Company Limited

This paper presents a high-precision, successive approximation register(SAR) analog-to-digital converter(ADC) with resistive analog front-end for lowvoltage and wide input range applications. To suppress the serious nonlinearity brought by the voltage coefficients of analog front-end without deteriorating differential nonlinearity performance, a mixed-signal calibration scheme based on piecewise-linear method with calibration digital-to-analog converter is proposed. A compensation current is designed to sink or source from the reference to keep it independent of input signal, which greatly improves the linearity performance. Fabricated in a 0.5-μm CMOS process, the proposed ADC achieves 88-d B signalto-noise-and-distortion ratio and 103-d B spurious free dynamic range with 5-V supply voltage and 2.5-V reference voltage, and the total power consumption is 37.5 m W.

关键词： Wide input range Resistive scaling front-end Mixed-signal nonlinearity calibration Precision Successive approximation register (SAR) Current compensation circuit

Variational Assimilation of Satellite Cloud Water/Ice Path and Microphysics Scheme Sensitivity to the Assimilation of a Rainfall Case

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2016年第10期33卷 1158-1170页

作者： Yaodeng CHEN ruizhi zhang Deming MENG Jinzhong MIN Lina zhang Key Laboratory of Meteorological Disaster of Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044China China Meteorological Administration Training Center Beijing 100081China

Hydrometeor variables （cloud water and cloud ice mixing ratios） are added into the WRF three-dimensional variational assimilation system as additional control variables to directly analyze hydrometeors by assimilating cloud observations. In addition, the background error covariance matrix of hydrometeors is modeled through a control variable transform, and its characteristics discussed in detail. A suite of experiments using four microphysics schemes （LIN, SBU-YLIN, WDM6 and WSM6） are performed with and without assimilating satellite cloud liquid/ice water path. We find analysis of hydrometeors with cloud assimilation to be significantly improved, and the increment and distribution of hydrometeors are consistent with the characteristics of background error covariance. Diagnostic results suggest that the forecast with cloud assimilation represents a significant improvement, especially the ability to forecast precipitation in the first seven hours. It is also found that the largest improvement occurs in the experiment using the WDM6 scheme, since the assimilated cloud information can sustain for longer in this scheme. The least improvement, meanwhile, appears in the experiment using the SBU-YLIN scheme.

关键词： variational data assimilation cloud microphysics scheme satellite

Analysis of lower-boundary climate factors contributing to the summer heatwave frequency over eastern Europe using a machine-learning model

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2022年第5期15卷 49-54页

作者： ruizhi zhang Xiaojing Jia Qifeng Qian Key Laboratory of Geoscience Big Data and Deep Resource of Zhejiang Province School of Earth SciencesZhejiang UniversityHangzhouChina Zhejiang Institute of Meteorological Science(Chinese Academy of Meteorological Sciences Zhejiang Branch)HangzhouChina

A machine-learning(ML)model,the light gradient boosting machine(LightGBM),was constructed to simulate the variation in the summer(June-July-August)heatwave frequency(HWF)over eastern Europe(HWFUR)and to analyze the contributions of various lower-boundary climate factors to the HWFUR *** examined lower-boundary climate factors were those that may contribute to the HWFUR variation—namely,the sea surface temperature,soil moisture,snow-cover extent,and sea-ice concentration from the simultaneous summer,preceding spring,and *** selected climate factors were significantly correlated to the summer HWFUR variation and were used to construct the ML *** the hindcast simulation of HWF EUR for the period 1981-2020 and its real-time simulation for the period 2011-2020,which used the constructed ML model,were *** evaluate the contributions of the climate factors,various model experiments using different combinations of the climate factors were examined and *** results indicated that the LightGBM model had comparatively good performance in simulating the HWFUR *** sea surface temperature made more contributions to the ML model simulation than the other climate *** examination showed that the best ML simulation was that which used the climate factors in the preceding winter,suggesting that the lower-boundary conditions in the preceding winter may be critical in forecasting the summer HWFUR variation.

关键词： Heatwave frequency Eastern Europe Summer Machine learning

Thermoelectric performance enhancement of(BiS)1.2(TiS2)2 misfit layer sulfide by chromium doping

在线全文

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2013年第1期2卷 42-48页

作者： Yulia Eka PUTRI Chunlei WAN ruizhi zhang Takao MORI Kunihito KOUMOTO Graduate School of Engineering Nagoya UniversityNagoya 464-8603Japan CREST Japan Science and Technology AgencyTokyo 102-0075Japan Department of Physics State Key Laboratory of Photoelectric Technology and Functional Materials(Culture Base)Northwest UniversityXi’an 710069China National Institute for Materials Science(NIMS) Tsukuba 305-0044Japan

A misfit layer sulfide(BiS)_(1.2)(TiS_(2))_(2) with a natural superlattice structure has been shown to be a promising thermoelectric material,but its high carrier concentration should be reduced so as to further optimize the thermoelectric ***,ordinary acceptor doping has not succeeded because of the non-parabolic band *** this paper,we have successfully doped chromium ions into the Ti sites,which can maintain or even enhance the high effective mass of electrons so as to effectively improve ZT value.X-ray diffraction analysis,coupled with X-ray photoelectron spectroscopy,shows that chromium has been substituted into titanium sites in TiS2 layers and confirms its ionic *** chromium doping has successfully reduced the carrier concentration with the subsequent reduction of electrical *** other acceptor dopants(alkaline earth metals),chromium also enhances Seebeck coefficient and the effective mass,which can possibly be attributed to the formation of additional resonant states near Fermi *** the power factor does not improve,the significant reduction in the electronic part of the thermal conductivity leads to a measurable improvement in ZT.

关键词： thermoelectric misfit layer sulfide spark plasma sintering electrical conductivity thermal conductivity

Effects of Silica Aerogel Content on Microstructural and Mechanical Properties of Poly(methyl methacrylate)/Silica Aerogel Dual-scale Cellular Foams Processed in Supercritical Carbon Dioxide

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

Journal of Wuhan University of Technology(Materials Science) 2016年第4期31卷 750-756页

作者：谷晓丽罗国强 zhang ruizhi zhang Jian LI Meijuan SHEN Qiang WANG Jin zhang Lianmeng State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China School of Chemistry Chemical Engineering and Life Science Wuhan University of Technology Wuhan 430070 China

A novel poly（methyl-methacrylate）/silica aerogel（PMMA/SA） dual-scale cellular foam was synthesized with internal mixing followed by the supercritical carbon dioxide foaming *** effects of silica aerogel content on the microstructural and mechanical performance of the foams were investigated by SEM,TEM analysis,and mechanical *** experimental results suggest that the employment of silica aerogel granule as addictive can distinctly improve the morphological feature as well as the mechanical performance in comparison to neat PMMA foam by uniformizing cell size distribution,decreasing cell size and increasing cell *** dual-scale cells including micrometric cells of 3-10 μm and nanometric cells of about 50 nm existed in the structure of foams resulting from the retained original framework structure of silica aerogel,which has not been described in other studies with the addition of various ***,the mechanical strength was significantly elevated even with a small amount of silica aerogel resulting from the unique microstructure,decreased cell size and enhanced cell *** compressive strength was 18.12 MPa and the flexural strength was 18.90 MPa by adding 5wt% and 2wt% silica aerogel,*** results demonstrate the potential to synthesize PMMA/SA dual-scale cellular foams to be used as structural materials with the advantages of low density and high strength.

关键词： silica methacrylate flexural nucleation adding compressive supercritical dioxide synthesize mixing