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Mechanical Properties and Transformation Behavior of NiTiNb Shape Memory Alloys

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Chinese Journal of Aeronautics 2009年第5期22卷 540-543页

作者： liu wei zhao Xinqing School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics Beijing 100191 China

NiTiNb shape memory alloys have attracted much attention in pipe coupling or sealing system because of their large transformation hysteresis upon a proper pre-deformation. In order to clarify the effects of adding Nb on the mechanical properties as well as the transformation behavior of NiTiNb shape memory alloys, Ni47Ti44Nb9 and Ni49.8Ti45.2Nb5 alloys with different microstructures but with similar martensitic transformation start temperature, are prepared. Comparative studies on the microstructures, mechanical proPerties and transformation characteristics are conducted by means of scanning electron microscopy （SEM）, phase transformation measurements and mechanical property tests. It is found that Nia7Ti44Nb9 and Ni49.8Ti45.2Nb5 alloys possess similar transformation hysteresis in the as-annealed state. However, the presence of Nb and its status exerts important effects on the mechanical properties, especially the yield strength and the yield behavior of the alloys. Ni49.8Ti45.2Nb5 alloy exhibits remarkable increase in the yield strength than the Ni47Ti44Nb9 alloy. The transformation hysteresis of both alloys under pre-deformation is characterized and the relative mechanism is discussed.

关键词： NiTiNb martensitic transformation mechanical properties transformation hysteresis microstructure

SIGMA-COORDINATE NUMERICAL MODEL FOR SIDE-DISCHARGE INTO NATURAL RIVERS

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Journal of Hydrodynamics 2009年第3期21卷 333-340页

作者： liu zhao-wei CHEN Yong-can LI Ling ZHENG Jing-yun State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing 100084 China Wenzhou Oujiangkou Development and Construction Headquarters Wenzhou 325027 China

Due to large topography slopes in natural rivers, pollutant concentration embodies a property of three-dimensional distribution when wastewater is discharged from effluents along the bank. With the sigma coordinate along the vertical dimension fitted to both the moving free surface and the bed topography, a three-dimensional numerical model was developed in the present work to address pollutant transport processes in the above-mentioned cases. To avoid the reduction in accuracy caused by spurious diffusion in the case of steep bottom slopes, a formula for horizontal diffusion in the sigma coordinate system was derived. A case study for the side discharge into a straight open-channel flow shows that numerical results are verified well by experimental data. Furthermore, the present model is also verified by the simulation of discharging wastewater from Fuling Phosphorus Factory effluent into the Three Gorges Reservoir and the agreement between the numerical simulation results and field observation data is satisfactory. The change of the mixing zone scope in the water surface versus the layers along the vertical dimension was also discussed in detail. The study shows that a more realistic calculation for pollutant discharge has been provided by the present model than by the depth-average model which predicts an unrealistically smaller mixing zone.

关键词： sigma-coordinate three-dimensional model side-discharge natural rivers

Transmission spectrum method to measure the photonic bandgap of hollow-core photonic crystal fiber

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Optoelectronics Letters 2007年第1期3卷 22-24页

作者： wei Hong-yan HOU Lan-tian zhao Xing-tao liu zhao-lun WANG wei MA Jing-rui Institute of Infrared Optical Fibers and Sensors Yanshan University Qinhuangdao 066004 China

A full-vector plane-wave method is introduced, particularly in calculating the photonic crystal in-plane photonic bandgap of a 2D triangular structure. Using numerical simulation, we can obtain the in-plane bandgap structure of a hollow-core photonic crystal fiber. In the experiments, we measured the transmission spectra of a hollow-core photonic crystal fiber and a silica rod. And using the numerical calculation we can get the relative transmission spectrum of a hollow-core photonic crystal fiber. Compared with the result of theoretical simulation, we found that they are in accordance with each other, i.e. they have the same bandgap in about the same normalized frequency.

关键词：空芯光子晶体光纤光子带隙测量透射谱法

城陵矶穿越长江水下软硬不均地层隧道修建技术

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中国铁道科学 2006年第3期27卷 139-144页

作者：刘招伟北京交通大学土木建筑工程学院

城陵矶穿越长江隧道全长2 756.379 m,根据地层不均匀的地质条件,为节省投资并确保水下施工的安全,在长江南岸以及长江主河道以下地质条件复杂、断层破碎带密集的地段采用盾构法施工,施工长度2 011.379 m;在长江北岸隧道穿越地质条件较... 详细信息

城陵矶穿越长江隧道全长2 756.379 m,根据地层不均匀的地质条件,为节省投资并确保水下施工的安全,在长江南岸以及长江主河道以下地质条件复杂、断层破碎带密集的地段采用盾构法施工,施工长度2 011.379 m;在长江北岸隧道穿越地质条件较好、埋深较大的河床段采用矿山法施工,施工长度745 m;竖井上部软弱地层采用沉井法施工、下部硬岩采用钻爆法施工。盾构法施工中,选择泥水加压复合式盾构机,并选择复合式刀盘。在低水压地段采用泥水平衡模式,在高水压地段采用加气模式掘进,并根据地质条件变化及时调整掘进参数。施工中通过同步注浆、二次注浆及堵水注浆等不同注浆方法充填衬砌背后空隙保证防水效果。矿山法施工中,采用红外探水和超前钻探等方法进行超前地质预报、全断面帷幕注浆及小导管注浆加固围岩、微震动爆破开挖减小对围岩的扰动等防突涌水施工技术。在施工全过程中,运用监测与信息反馈技术进行信息化施工,确保了优质、安全、快速施工。

关键词：长江隧道盾构法矿山法施工技术

Red and Blue Light Generation in an LiTaO_(3) Crystal with a Double Grating Domain Structure

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Chinese Physics Letters 2001年第4期18卷 539-540页

作者： liu zhao-wei ZHU Shi-Ning ZHU Yong-Yuan WANG Hui-Tian LUO Guo-Zhen liu Hui MIN Nai-Ben LIANG Xiao-Yan XU Zu-Yan National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093 Institute of Physics and Center for condensed Matter Physics Chinese Academy of SciencesBeijing 100080

Simultaneous red and blue light generation in an LiTaO_(3) crystal with a double grating structure is first *** double grating consists of two separate domain reversal sequences(superlattices)in series and is fabricated by field poling technique at room *** a picosecond 532 nm laser as a pump source,the red light at 631 nm and blue light at 460 nm are generated at the same time.A possible application of the superlattice crystal is presented.

关键词： temperature pump Crystal

Cultural Trials Launched in Shanghai Free Trade Zone

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China & The World Cultural Exchange 2014年第5期80卷 24-26页

作者： He Hongwei liu wei zhao Xiaohui

Professionals from the sector of cultural industries note that in a short term, open policies for cultural service will bring new opportunities for the performing and entertainment indus- tries of Shanghai Free Trade Zone （SFTZ） and the city of Shanghai as a whole; in a long run, SFTZ＇s practices and experiences will have extensive impacts on the country＇s performing and entertainment industries. What is the scenario of SFTZ~ cultural industries and what trend will they embrace？

关键词：保税区栽培试验上海文化产业娱乐行业专业人士表演

Private Capital Encouraged to Invest in Popular Theatres

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China & The World Cultural Exchange 2014年第5期80卷 22-23页

作者： He Hongwei liu wei zhao Xiaohui

Comparing with the prosperous film market, China＇s theatre industry has yet to see robust growth. Many theatres have been built and opened, but cultural clusters with market dynamics have not been developed around these theatres. This reality is largely owed to insufficient inter- action between theatres and performing arts agencies, lack of diversified modes of theatre man- agement, and diffcult access to the theatre industry by private capital. Zhai Zhihai, chairman of Jingying Group, a leading corporation in education and culture, elaborated his insights and proposals on how to encourage private capital to invest in and operate theatres.

关键词：民间资本投资民营资本电影市场市场动态管理模式龙头企业剧院多元化

基于黎曼不变量守恒的轴流压气机反问题设计方法

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推进技术 2017年第7期38卷 1491-1498页

作者：刘昭威吴虎西北工业大学动力与能源学院陕西西安710072

基于一种全新的轴流压气机叶片反问题设计边界条件,发展了一种全新的三维粘性反问题设计方法。该方法以叶片表面静压分布作为输入的气动性能参数,叶片吸、压力面型线为设计对象。全新的反问题边界条件采用壁面边界处黎曼不变量守恒建立... 详细信息

基于一种全新的轴流压气机叶片反问题设计边界条件,发展了一种全新的三维粘性反问题设计方法。该方法以叶片表面静压分布作为输入的气动性能参数,叶片吸、压力面型线为设计对象。全新的反问题边界条件采用壁面边界处黎曼不变量守恒建立起给定的气动参数分布与叶片几何变化量之间的关系。由于计算过程中叶片几何构型不断发生变化,采用动网格技术对计算网格进行更新。为了验证方法的有效性,采用NASA Rotor 37作为算例,进行叶片返回试验,对叶片表面静压分布进行合理修改,通过反问题设计计算,设计出新的叶片几何构型。计算结果显示,反问题设计很好地满足了给定的叶片表面静压分布,正确地反映了设计意图。改型后的叶片吸力面逆压梯度有所降低,气流分离得到抑制,压气机流量、总压比以及效率分别提高了0.7%,2.2%和1.0%,验证了方法的有效性和正确性。

关键词：反问题设计方法轴流压气机反问题边界条件静压分布

Factors influencing outcomes of intra-aortic balloon counterpulsation in elderly patients

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Chinese Medical Journal 2013年第14期126卷 2632-2635页

作者： WU Xue-ping liu Hong-wei zhao Xiao-ning CAO Jian ZHU Ping First Division of Geriatric Cardiology General Hospital of Chinese People's Liberation Army Medical School of Chinese People's Liberation Army Beijing 100853 China

Background Intra-aortic balloon counterpulsation （IABP） is a mechanical cardiac-assist device that is used for cardiac support. There are no published reports about the use of IABP in elderly Chinese patients, especially for those over 80 years old. The aim of this study was to describe the clinical outcomes, influencing factors, and complications in patients 〉80 years old and requiring IABP. Methods We performed a retrospective study of 134 consecutive patients who received IABP therapy. Based on age, we defined two groups; those 〉80 years old and those 〈80 years old. Results The overall mortality was 41.8%. Patients -〉80 years old had higher mortality rates than those 〈80 years old （47.9% vs. 30.2%）. Patients 〉80 years old had fewer successful revascularizations （45.8%） and more pulmonary infections （47.9%） than patients 〈80 years old （60.3% and 30.2%, respectively）; these differences were statistically significant. The most common non-cardiac complication was pulmonary infection. Cardiogenic shock and pulmonary infection were risk factors for all-cause, in-hospital mortality, whereas revascularization success was a negative risk factor for the -〉80 years old patients. Conclusions IABP may be successfully and safely employed in patients 〉80 years old, having severe heart disease, with few complications. Patients 〉80 years old who need IABP therapy are less likely to have a successful revascularization and are more likely to develop pulmonary infections than patients 〈80 years old.

关键词： intra-aortic balloon counterpulsation elderly outcome complication