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Supersonic swirling characteristics of natural gas in convergent-divergent nozzles

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Petroleum Science 2011年第1期8卷 114-119页

作者： Wen Chuang Cao Xuewen yang yan zhang Jing Department of Oil and Gas Engineering China University of PetroleumQingdaoShandong 266555China

The supersonic nozzle is a new apparatus which can be used to condense and separate water and heavy hydrocarbons from natural *** swirling separation of natural gas in the convergent-divergent nozzle was numerically simulated based on a new design which incorporates a central body. Axial distribution of the main parameters of gas flow was investigated,while the basic parameters of gas flow were obtained as functions of radius at the nozzle *** effect of the nozzle geometry on the swirling separation was *** numerical results show that water and heavy hydrocarbons can be condensed and separated from natural gas under the combined effect of the low temperature（-80℃） and the centrifugal field（482,400g,g is the acceleration of gravity）.The gas dynamic parameters are uniformly distributed correspondingly in the radial central region of the channel,for example the distribution range of the static temperature and the centrifugal acceleration are from -80 to -55℃and 220,000g to 500,000g,respectively,which would create good conditions for the cyclone separation of the ***,high gradients of gas dynamic parameters near the channel walls may impair the process of *** geometry of the nozzle has a great influence on the separation performance. Increasing the nozzle convergent angle can improve the separation *** swirling natural gas can be well separated when the divergent angle takes values from 4°to 12°in the convergent-divergent nozzle.

关键词： Swirling flow convergent-divergent nozzle supersonic natural gas separation numerical calculation

The oasis expansion and eco-environment change over the last 50 years in Manas River Valley, Xinjiang

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Science China Earth Sciences 2006年第2期49卷 163-175页

作者： CHENG Weiming ZHOU Chenghu LIU Haijiang zhang yang JIANG yan zhang Yichi YAO Yonghui State Key Laboratory of Resource and Environmental Information System Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China State Key Laboratory of Resource and Environmental Information System Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China State Key Laboratory of Resource and Environmental Information System Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China State Key Laboratory of Resource and Environmental Information System Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China State Key Laboratory of Resource and Environmental Information System Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China State Key Laboratory of Resource and Environmental Information System Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China State Key Laboratory of Resource and Environmental Information System Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China

The oasis expansion and economic development of the Manas River Valley is one of the most successful examples in Xinjiang. In this paper, the oasis spatial distribution pattern and dynamic change were examined using imageries of Landsat MSS, TM and ETM, land use and topographic maps in six different periods (such as 1949, 1962, 1976, 1989, 1999 and 2001) over the last 50 years in the valley. The oasis expansion process could be divided into two stages according to the annual rate of oasis area increase, the fast oasization stage (from 1949 to 1976) when the oasis area ex-panded from 156.385 km2 in 1949 to 3,639.491 km2 in 1976 because of rapidly increased population and quickly enlarged farmland area; and the urbanization stage (from 1976 to 2001) when the ex-pansion ratio of farmland slowed down, and the urbanization process quickened, the total oasis area reached 5042.440 km2 in 2001. With the continuous expansion of oasis and farmland, a large quantity of river water was drawn into irrigation ditch and plain lakes, so only a small quantity of river water could flow into lakes, as a result, the Manas Lake dried up, salization and basification problems happened in the low-lying oasis region. The natural swamp around the lake was shrunk greatly and biodiversity decreased significantly. The driving force analysis reveals that human activities, such as reclamation and population growth, played a major role in the oasis expansion and ecological dete-rioration in the Manas River Valley. So further efforts should be made to improve the efficiency of water resource utility and adjust layout of the regional agricultural and animal husbandry to keep the sustainable development of oasis economic belt of the northern slope of Tianshan Mts.

关键词： Manas River Valley, oasization, urbanization, salinization and basification, remote sensing (RS).

Optimization of Uncertain Structures with Interval Parameters Considering Objective and Feasibility Robustness

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Chinese Journal of Mechanical Engineering 2018年第2期31卷 124-136页

作者： Jin Cheng Zhen-Yu Liu Jian-Rong Tan yang-yan zhang Ming-yang Tang Gui-Fang Duan State Key Laboratory of Fluid Power&Mechatronic Systems Zhejiang University State Key Laboratory of CAD&CG Zhejiang University Key Laboratory of Micro-systems and Micro-structures Manufacturing of Ministry of Education Harbin Institute of Technology

For the purpose of improving the mechanical performance indices of uncertain structures with interval parameters and ensure their robustness when fluctuating under interval parameters, a constrained interval robust optimization model is constructed with both the center and halfwidth of the most important mechanical performance index described as objective functions and the other requirements on the mechanical performance indices described as constraint functions. To locate the optimal solution of objective and feasibility robustness, a new concept of interval violation vector and its calculation formulae corresponding to different constraint functions are proposed. The math?ematical formulae for calculating the feasibility and objective robustness indices and the robustness?based preferential guidelines are proposed for directly ranking various design vectors, which is realized by an algorithm integrating Kriging and nested genetic algorithm. The validity of the proposed method and its superiority to present interval optimization approaches are demonstrated by a numerical example. The robust optimization of the upper beam in a high?speed press with interval material properties demonstrated the applicability and effectiveness of the proposed method in engineering.

关键词： Robust optimization Uncertain structure Interval violation vector Feasibility robustness Objective robustness Nested genetic algorithm

Hydrochloric acid-enhanced radiofrequency ablation for treating a large hepatocellular carcinoma with spontaneous rapture:a case report

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Chinese Journal of Cancer 2017年第1期36卷 44-49页

作者： Ru-Hai Zou yang-Kui Gu Fei Gao Tian-Qi zhang Wang Yao Xiong-Ying Jiang yan-yang zhang Department of Minimally Invasive Interventional Therapy Sun Yat-sen University Cancer Center State Key Laboratory of Oncology in South ChinaCollaborative Innovation Center for Cancer Medicine Department of Oncologic Interventional Therapy The First Affiliated Hospital Sun Yat-sen University Department of Radiology Intervention Sun Yat-sen Memorial Hospital Sun Yat-sen University Department of Intervention The Third Affiliated Hospital Sun Yat-sen University

Background:A ruptured hepatocellular carcinoma(HCC)is often *** addition to surgery and transarterial embo?lization,radiofrequency ablation(RFA)might be another option for treating a ruptured ***,conven?tional RFA has a limited ablation zone;as such,it is rarely used to treat ruptured *** presentation:This case was a 60?year?old man who had a large,ruptured HCC in which hydrochloric acid(HCl)?enhanced RFA successfully controlled the bleeding and made the tumor completely ***:Considering the effectiveness of HCl?enhanced RFA in achieving hemostasis and tumor ablation,it might be a new option for treating large,ruptured HCCs.

关键词： Hydrochloric acid Radiofrequency ablation Spontaneous rupture Hepatocellular carcinoma

An Approach to Integer Wavelet Transform for Medical Image Compression in PACS

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Wuhan University Journal of Natural Sciences 2000年第2期5卷 204-206页

作者： yang yan zhang Dong Wuhan University College of Electronic Information Wuhan China (GRID:grid.49470.3e) (ISNI:***)

We study an approach to integer wavelet transform for lossless compression of medical image in medical picture archiving and communication system (PACS). By lifting scheme a reversible integer wavelet transform is generated, which has the similar features with the corresponding biorthogonal wavelet transform. Experimental results of the method based on integer wavelet transform are given to show better performance and great applicable potentiality in medical image compression.

关键词： Key words integer wavelet transform lifting scheme lossless compression PACS

Current carrying states in the disordered quantum anomalous Hall effect

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Chinese Physics B 2022年第9期31卷 476-481页

作者： Yi-Ming Dai Si-Si Wang yan Yu Ji-Huan Guan Hui-Hui Wang yan-yang zhang School of Physics and Materials Science Guangzhou UniversityGuangzhou 510006China Research Center for Advanced Information Materials Guangzhou UniversityGuangzhou 510006China School of Mathematics and Information Science Guangzhou UniversityGuangzhou 510006China SKLSM Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Beijing Academy of Quantum Information Sciences Beijing 100193China Huangpu Research and Graduate School of Guangzhou University Guangzhou 510700China

In a quantum Hall effect,flat Landau levels may be broadened by ***,it has been found that in the thermodynamic limit,all extended(or current carrying)states shrink to one single energy value within each Landau *** the other hand,a quantum anomalous Hall effect consists of dispersive bands with finite *** numerically investigate the picture of current carrying states in this *** size scaling,the spectrum width of these states in each bulk band still shrinks to a single energy value in the thermodynamic limit,in a power law *** magnitude of the scaling exponent at the intermediate disorder is close to that in the quantum Hall *** number of current carrying states obeys similar scaling rules,so that the density of states of current carrying states is *** states in the bulk band are localized and may contribute to the formation of a topological Anderson insulator.

关键词： quantum anomalous Hall effect Chern number disordered system localization

Poly(meta-phenylene) Derivative with Rigid Twisted Biphenyl Units in Backbone:Synthesis,Structural Characterization,Photophysical Properties and Electroluminescence

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Chemical Research in Chinese Universities 2007年第6期23卷 720-725页

作者： ZHENG yan yang Bing zhang Hai-quan LU Ping SHEN Fang-zhong LIU Lin-lin XU Hai yang Guang-di MA Yu-guang Key Lab for Supramolecular Structure and Materials of Ministry of Education Jilin University Changchun 130012 P. R. China

A soluble poly（meta-phenylene） derivative with rigid twisted biphenyl unit was synthesized by the Yamamoto coupling reaction. The polymer is soluble in common organic solvents, and the number-average molecular weight is about 6500. The UV-Vis and quantum chemical calculation indicate that the different conformation segments named ＂conformers＂ exist in the polymer backbones; it was also further confirmed by the single crystal X-ray diffraction study of the dimeric model compound. The π-π^＊ transition of biphenyl segments of twisted and planar conformations made the polymer exhibit a strong absorption around 256 nm and a weak absorption at about 300 nm. Furthermore, the polymer exhibits a strong UV photoluminescence at 372 nm when the excitation wavelengths are longer than 300 run. The ultraviolet-emitting electroluminescence（EL） device with the single layer structure shows EL λmax of the derivative at 370 nm.

关键词： Poly(phenylene) Conformation UV light-emitting

Neurological outcomes of patients admitted to the intensive care unit for cardiac arrest

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Chinese Medical Journal 2014年第16期127卷 3024-3026页

作者： Liu Lijun Zhu Jianliang yang Lin zhang yan Department of Emergency and Critical Care Medicine Second Affiliated Hospital of Soochow University Suzhou Jiangsu 215004China

Cardiac arrest （CA） is a major cause of death, with an estimated 300 000 cases of out-of-hospital CA reported in Europe and the United States each year. Advances in resuscitation techniques have improved survival such that approximately one-third of patients achieve return of spontaneous circulation （ROSC）. Nonetheless, only between half and one-third of patients who have achieved ROSC survive until discharge.

关键词： cardiac arrest neurological outcome risk factors multivariate analysis

On Fault Diagnosis of Rotating Machinery Using Wavelet Time-division Scale Level Moment

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International Journal of Plant Engineering and Management 2008年第2期13卷 61-69页

作者： yang Tao zhang yan-ping GAO Wei HUANG Shu-hong zhang Pin-ting School of Energy and Power Engineering Huazhong University of Science and Technology Wuhan 430074 P. R. China

Based on an in-depth study of wavelet gray moment, we proposed a concept of a time-division scale level moment and gave the specific definition; ulteriorly, we discussed the factors which affected the fault diagnosis ability of a time-division scale level moment. The analysis results in the caculation of six typical fault signals show that the time-division scale level moment can be used to display the detailed information of a wavelet gray level image, extract the signal＇s characteristics effectively, and distinguish the vibration fault. Compared to the method of a wave gray moment vector, the method mentioned in this paper can provide higher calculation speed and higher capacity of fault identification, so it is more suitable for online fault diagnosis for rotating machinery.

关键词： fault diagnosis wavelet transform wavelet gray moment wavelet gray moment vector time-division scale level moment rotating machinery