检索结果-南通市图书馆

Chinese Journal Of Geochemistry 2009年第1期28卷 97-104页

作者： yao zhigang Key Laboratory of Continental Dynamics Ministry of Education/Department of Geology Northwest University Xi ＇an 710069 China School of Petroleum Resources Xi＇an Shiyou University Xi＇an 710065 China

The Dongting Lake, the second biggest freshwater lake in China, consists of three wetlands of national importance, namely the East Dongting Lake, the South Dongting Lake, and the West Dongting Lake. Surface sediments were sampled from 57 locations across the lake. Nutrient concentrations [total organic carbon (TOC), total N (TN) and total P (TP)] and 16 element concentrations (Al, As, B, Ca, Cd, Cr, Cu, K, Fe, Hg, Mn, Ni, Pb, Si, Ti and Zn) in the sediments were measured to investigate the impact of industrialization along the lake’s coastline and several tributaries on the profiles of nutrients and heavy metals in the lake’s surface sediments. R-mode cluster analysis (CA) was used to integrate geochemical data. The result showed that euthophication of the Dongting Lake resulted mainly from TN and TOC. The main polluting trace metals are Hg, As, Cd, Zn, Pb and Mn, which are largely adsorbed on clay minerals or Fe/Mn oxides, or deposited as carbonates. Principal component analysis (PCA) revealed the source of micropollutants. The worst affected district by heavy metals is the East Dongting Lake, the pollution sources may originate mainly from the Xiangjiang drainage area. The results demonstrated that multivariate methods are the potentially great tools for the interpretation of the environmental data on lake sediments.

关键词：重金属沉积物多元方差分析洞庭湖地球化学

Periodic and chaotic dynamics of composite laminated piezoelectric rectangular plate with one-to-two internal resonance

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2009年第3期52卷 731-742页

作者： ZHANG Wei yao zhigang yao MingHui College of Mechanical Engineering Beijing University of TechnologyBeijing 100124China

The bifurcations and chaotic dynamics of a simply supported symmetric cross-ply composite lami- nated piezoelectric rectangular plate are studied for the first time, which are simultaneously forced by the transverse, in-plane excitations and the excitation loaded by piezoelectric layers. Based on the Reddy’s third-order shear deformation plate theory, the nonlinear governing equations of motion for the composite laminated piezoelectric rectangular plate are derived by using the Hamilton’s principle. The Galerkin’s approach is used to discretize partial differential governing equations to a two-degree- of-freedom nonlinear system under combined the parametric and external excitations. The method of multiple scales is employed to obtain the four-dimensional averaged equation. Numerical method is utilized to find the periodic and chaotic responses of the composite laminated piezoelectric rectangular plate. The numerical results indicate the existence of the periodic and chaotic responses in the aver- aged equation. The influence of the transverse, in-plane and piezoelectric excitations on the bifurca- tions and chaotic behaviors of the composite laminated piezoelectric rectangular plate is investigated numerically.

关键词： composite laminated piezoelectric rectangular plate third-order shear deformation parametric excitation bifurcation chaos

Higher-dimensional chaotic dynamics of a composite laminated piezoelectric rectangular plate

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2009年第12期52卷 1989-2000页

作者： ZHANG Wei GAO MeiJuan yao MingHui yao zhigang College of Mechanical Engineering Beijing University of TechnologyBeijing 100124China

The analysis on the chaotic dynamics of a six-dimensional nonlinear system which represents the averaged equation of a composite laminated piezoelectric rectangular plate is given for the first time. The theory of normal form and the energy-phase method are combined to investigate the higher-dimen-sional chaotic dynamics of the composite laminated piezoelectric rectangular plate. Firstly,the theory of normal form is used to reduce the six-dimensional averaged equation to the simpler normal form. Then,the energy-phase method is extended to analyze the global bifurcations and chaotic dynamics of a six-dimensional nonlinear system. The analysis results indicate that there exist the homoclinic bi-furcation and Shilnikov type multi-pulse chaos for the composite laminated piezoelectric rectangular plate. Finally,numerical simulations are also used to investigate the nonlinear dynamic characteristics of the composite laminated piezoelectric rectangular plate. The results of numerical simulations also demonstrate that there exist the chaotic motions and the multi-pulse jumping orbits of the composite laminated piezoelectric rectangular plate.

关键词： composite laminated piezoelectric rectangular plate normal form energy-phase method numerical simulation jumping orbits chaotic motion

基于基尼系数分解的城乡公共交通不平等测度:以浙江省海宁市为例

在线全文

学校读者我要写书评

暂无评论

交通运输系统工程与信息 2024年第1期24卷 282-289页

作者：姚志刚王淑洁龚林伟长安大学运输工程学院西安710061

探明城乡公共交通不平等来源及其变化特征对缩小城乡差距有重要意义,以浙江省海宁市为例,将站点可达性作为公共交通服务指标,以交通小区作为分析单元计算公共交通可达性,分别计算2011—2020年研究区域总体、城区、农村及城乡间的基尼系... 详细信息

探明城乡公共交通不平等来源及其变化特征对缩小城乡差距有重要意义,以浙江省海宁市为例,将站点可达性作为公共交通服务指标,以交通小区作为分析单元计算公共交通可达性,分别计算2011—2020年研究区域总体、城区、农村及城乡间的基尼系数,将总体基尼系数按城区和农村两个子群进行分解,分析城乡公共交通不平等来源及其演变特征。结果发现:总体基尼系数为0.7204~0.7736,城区基尼系数为0.5718~0.6058,农村基尼系数为0.5955~0.6390,城乡间基尼系数为0.8131~0.8710,研究区域公共交通严重不平等,城乡间不平等程度最大;2011—2020年间总体、城区、农村和城乡间的基尼系数分别下降了5.62%、6.88%、5.21%和6.65%,公共交通不平等不断改善;城乡间不平等对总体不平等的贡献率为63.03%~67.58%,是总体不平等的主要来源。研究表明,基尼系数分解能有效测度城乡公共交通不平等来源,缩小城乡间不平等是城乡客运均等化发展的重要任务。

关键词：交通运输经济城乡不平等基尼系数分解公共交通可达性

Synergistic Use of AIRS and MODIS for Dust Top Height Retrieval over Land

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2015年第4期32卷 470-476页

作者： yao zhigang Jun LI ZHAO Zengliang Beijing Institute of Applied Meteorology Cooperative Institute for Meteorological Satellite Studies University of Wisconsin-Madison

It is nontrivial to extract the dust top height（DTH） accurately from passive instruments over land due to the complexity of the surface conditions. The Moderate Resolution Imaging Spectroradiometer（MODIS） deep blue（DB） algorithm can be used to infer the aerosol optical depth（AOD） over high-reflective surfaces. The Atmospheric Infrared Sounder（AIRS） can simultaneously obtain the DTH and optical depth information. This study focuses on the synergistic use of AIRS observations and MODIS DB results for improving the DTH by using a stable relationship between the AIRS infrared and MODIS DB AODs. A one-dimensional variational（1DVAR） algorithm is applied to extract the DTH from AIRS. Simulation experiments indicate that when the uncertainty of the dust optical depth decreases from 50% to 20%, the improvement of the DTH retrieval accuracy from AIRS reaches 200 m for most of the assumed dust conditions. For two cases over the Taklimakan Desert, the results are compared against Cloud-Aerosol Lidar with Orthogonal Polarization（CALIOP） measurements. The results confirm that the MODIS DB product could help extract the DTH over land from AIRS.

关键词： AIRS,MODIS,dust height,Cloud-Aerosol Lidar with Orthogonal Polarization

The application of threshold empirical mode decomposition de-noising algorithm for battlefield ambient noise

在线全文

学校读者我要写书评

暂无评论

International Journal of Modeling, Simulation, and Scientific Computing 2018年第4期9卷 95-107页

作者： Zhu Shaocheng Liu Limin yao zhigang Army Engineering University ShijiazhuangHebeiP.R.China

The detection of the low-altitude acoustic target is an important way to compensate for the weakness of radar.Removing the noise mixed in acoustic signal as much as possible to retain the useful information is a challenging task.Inspired by the wavelet threshold,the de-noising method for low-altitude battlefield acoustic signal based on threshold empirical mode decomposition(EMD-T)is proposed in this paper.Firstly,the noisy signal is decomposed by empirical mode decomposition(EMD)to get the intrinsic mode functions(IMFs).Then the IMFs,whose actual energy exceeds its estimated energy,are processed by the EMD threshold.Finally,the processed IMFs are summed to reconstruct the de-noised signal.To evaluate the performance of the proposed method,extensive simulations are performed using helicopter sound corrupted with four types of typical low-altitude ambient noise under different signal-to-noise ratio(SNR)input values.The performance is evaluated in terms of SNR,root mean square error(RMSE)and smoothness index(SI).The simulations results reveal that the proposed method de-noising method has the perspective of the highest SNR,smallest RMSE and SI in de-noising low-altitude ambient noise compared to other methods,including the wavelet transform(WT)and conventional EMD.

关键词： Threshold EMD low-altitude ambient noise de-noising method acoustic target.

Mineral characteristics and their geological significance of black shales in southeastern Ordos Basin by X-ray diffraction analysis

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 Journal Of Geochemistry 2014年第1期33卷 119-124页

作者： yao zhigang YANG Yang YING Huawei DONG Yunpeng School of Earth Sciences and Engineering Xi'an Petroleum University

X-ray diffraction analysis of black shale of Upper Triassic Member Chang 7 of the Yanchang Formation in southeastern Ordos Basin showed that black shales were deposited in brackish, strongly reducing, semi-deep-deep lacustrine facies, and mainly composed of quartz, feldspar, carbonate(dolomite), clay minerals(illite and illite/smectite) and a certain amount of pyrite. The mineral composition characteristics of this set of black shales are similar to those of highly productive shale gas in North America, for example shallow burial, low clay mineral and abundant brittle mineral, so the strata are conducive to the development of cracks and fractures. Thus, this area is favorable for shale oil/gas exploration and development.

关键词：鄂尔多斯盆地黑色页岩粘土矿物 X射线衍射分析东南部地质意义特征和 X-射线衍射分析

Case analysis of water exchange between the Bohai and Yellow Seas in response to high winds in winter

在线全文

学校读者我要写书评

暂无评论

Journal of Oceanology and Limnology 2020年第1期38卷 30-41页

作者： JU Xia MA Chao yao zhigang BAO Xianwen College of Oceanic and Atmospheric Sciences Ocean University of ChinaQingdao 266100China First Institute of Oceanography Ministry of Natural Resources(MNR)Qingdao 266061China Key Laboratory of Marine Science and Numerical Modeling Ministry of Natural Resources(MNR)Qingdao 266061China Pilot National Laboratory for Marine Science and Technology Qingdao 266237China

Based on the data from a special project titled China's Offshore Marine Integrated Investigation and Evaluation as well as Regional Ocean Modeling Systems(ROMS)diagnostic numerical model,we studied the influence of high wind processes on the circulation and water exchange between the Bohai and Yellow Seas(BYS)in winter.The results show that the vertical structure of the Yellow Sea Warm Current(YSWC)is relatively uniform under condition of high winds,showing obvious barotropic features.However,this flow is not a stable mean flow,showing strong paroxysmal and reciprocating characteristics.A comparison of the changes in sea level suggests that the intensity of the northwards upwind flow is consistent with the abnormal fluctuations in the sea level.It indicates that the upwind flow is closely related to the water exchange between the BYS.The impact of high wind processes on the water exchange between the BYS is enormous.It can make the flux through the Bohai Strait,as well as that through the mouth of each constituent bay(i.e.,Liaodong Bay,Bohai Bay,and Laizhou Bay)far greater than usual,resulting in a significant increase in the water exchange rate.The exchange capacity,which is about 8%of the total volume of the Bohai Sea,can be completed in a few days.Therefore,the water exchange of the Bohai Sea may be completed by only a few occasional high wind processes in winter.

关键词： high wind Yellow Sea Warm Current (YSWC) sea level rise or drop water exchange

Application of Aircraft Observations over Beijing in Cloud Microphysical Property Retrievals from CloudSat

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2014年第4期31卷 926-937页

作者： WANG Lei LI Chengcai yao zhigang ZHAO Zengliang HAN zhigang WEI Qiang Department of Atmospheric and Oceanic Sciences School of Physics Peking University Beijing Institute of Applied Meteorology

Cloud microphysical property retrievals from the active microwave instrument on a satellite require the cloud droplet size distribution obtained from aircraft observations as a priori data in the iteration procedure.The cloud lognormal size distributions derived from 12 flights over Beijing,China,in 2008-09 were characterized to evaluate and improve regional CloudSat cloud water content retrievals.We present the distribution parameters of stratiform cloud droplet （diameter ＜500 tm and ＜1500 μm） and discuss the effect of large particles on distribution parameter fitting.Based on three retrieval schemes with different lognormal size distribution parameters,the vertical distribution of cloud liquid and ice water content were derived and then compared with the aircraft observations.The results showed that the liquid water content （LWC） retrievals from large particle size distributions were more consistent with the vertical distribution of cloud water content profiles derived from in situ data on 25 September 2006.We then applied two schemes with different a priori data derived from flight data to CloudSat overpasses in northern China during April-October in 2008 and 2009.The CloudSat cloud water path （CWP） retrievals were compared with Moderate Resolution Imaging Spectroradiometer （MODIS） liquid water path （LWP） data.The results indicated that considering a priori data including large particle size information can significantly improve the consistency between the CloudSat CWP and MODIS CWP.These results strongly suggest that it is necessary to consider particles with diameters greater than 50 tm in CloudSat LWC retrievals.

关键词： CloudSat liquid water content a priori data aircraft observations

High efficiency of heavy metal removal in mine water by limestone

在线全文

学校读者我要写书评

暂无评论

Chinese Journal Of Geochemistry 2009年第3期28卷 293-298页

作者： yao zhigang ZHOU Lifa BAO Zhengyu GAO Pu SUN Xingwang Key Laboratory of Continental Dynamics Ministry of Education/Department of Geology Northwest University Xi＇an 710069 China School of Petroleum Resources Xi＇an Shiyou University Xi＇an 710065 China State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Wuhan 430074 China Chuankou Oilfield Yanchang OilfieldAdministration Bureau Shaanxi Yan＇an 768001 China

The removal of Cd, Cu, Ni and Zn from dilute mine water by using several geological materials including pure limestone, sand, carbonaceous limestone and brecciated limestone was performed on a laboratory scale. The results showed that to add geological materials in combination with sodium carbonate injection would notably enhance the efficiency of heavy metal removal to varying degrees. Pure limestone was found the best one among the four materials mentioned above for removing heavy metals from mine water. The removal efficiencies of pure limestone when it is ground as fine as 30–60 meshes are 58.6% for Cd, 100% for Cu, 47.8% for Ni, and 36.8% for Zn at 20℃. The optimum pH is about 8.9 to 9.1. The mechanism of higher effective removal, perhaps, is primarily due to co-precipitation under the control of calcite-related pH value. According to this research, Na2CO3 injection manners, including slug dosing and drip-wise, seemed to have little impact on the efficiency of heavy metal removal.

关键词：重金属石灰石高效率矿水地质资料砾状灰岩实验室规模去除率