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Optimizing the Qusai-static Folding and Deploying of Thin-Walled Tube Flexure Hinges with Double Slots

Chinese Journal of Mechanical Engineering 2014年第2期27卷 279-286页

作者： YANG Hui DENG Zongquan LIU Rongqiang WANG Yan GUO Hongwei State Key Laboratory of Robotics and System Harbin Institute of Technology

The thin-walled tube flexure（TWTF） hinges have important potential application value in the deployment mechanisms of satellite and solar array, but the optimal design of the TWTF hinges haven＇t been completely solved, which restricts their applications. An optimal design method for the qusai-static folding and deploying of TWTF hinges with double slots is presented based on the response surface theory. Firstly, the full factorial method is employed to design of the experiments. Then, the finite element models of the TWTF hinges with double slots are constructed to simulate the qusai-static folding and deploying non-linear analysis. What＇s more, the mathematical model of the TWTF flexure hinge quasi-static folding and deploying properties are derived by the response surface method. Considering of small mass and high stability, the peak moment of quasi-static folding and deploying as well as the lightless are set as the objectives to get the optimal performances. The relative errors of the objectives between the optimal design results and the FE analysis results are less than 7%, which demonstrates the precision of the surrogate models. Lastly, the parameter study shows that both the slots length and the slots width both have significant effects to the peak moment of quasi-static folding and deploying of TWTF hinges with double slots. However, the maximum Mises stress of quasi-static folding is more sensitive to the slots length than the slots width. The proposed research can be applied to optimize other thin-walled flexure hinges under quasi-static folding and deploying, which is of great importance to design of flexure hinges with high stability and low stress.

关键词： design optimization quasi-static folding and deploying flexure hinges thin-walled tube response surface method,numerical simulation

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Antioxidative effect of propofol during cardiopulmonary bypass in adults

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Acta Pharmacologica Sinica 2004年第3期25卷 80-86页

作者： Shi-hai ZHANG2,Shou-yong WANG,Shang-long YAO Department of Anesthesiology,Union Hospital,Tongji MedicalCollege,Huazhong Universityof Science & Technology,Wuhan 430022,China Department of Anesthesiology Union Hospital Tongji Medical College Huazhong University of Science & Technology Wuhan 430022

AIM: To investigate the antioxidative potential of propofol (an intravenous anesthetic with a chemical structure similarto phenol-basedfree radicalscavengers suchas vitaminE) during cardiopulmonary bypass(CPB). METHODS: Thirty adult patients referred for elective cardiac procedure with CPB were included and randomly allocated to a propofol group or a control group. Patients in the propofol group received propofol (0.1 mg·kg-1·min-1) intrave- nously for anesthesia maintenance, whereas those allocated to the control group received fentanyl 10 μg/kg intrave- nously and inhaled enflurane (1 %-1.5 %). Blood samples were collected at 7 time points: before the start of CPB, at 30 and 60 min of CPB, at the conclusion of CPB, 10 min after the administration of protamine, and 12 and 24 h after the cessation of CPB. Plasma levels of free F2-isoprostanes (sensitive markers of free radicals production) and complement C5a were determined by mass-spectrometricassay and enzyme immunoassay, respectively. Neu- trophil adhesion to endothelial cells was observed at ×200 magnificationunder a light microscope. RESULTS: Levels of F2-isoprostanes, complement C5a and neutrophil adhesion rate increased significantly during and after CPB in both groups. There were significantly higher levels of F2-isoprostanes, C5a, and more neutrophils adhering to endothelial cells in the control group than those in the propofol group, respectively. CONCLUSION: Cardio- pulmonary bypass is associated with a great production of damaging free radicals. Propofol may be beneficial both as an anesthetic and as a potent free radical scavenger in patients presenting pathologies associated with free radical reactions during CPB.

关键词： propofol cardiopulmonary bypass free radicals F2-isoprostanes complement 5a

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Experiment and Numerical Simulation of Free Water Jet by a Central-body Nozzle

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Chinese Journal of Mechanical Engineering 2010年第6期23卷 797-804页

作者： YANG Minguan ZHANG Feng KANG Can GAO Bo School of Energy and Power Engineering Jiangsu University Zhenjiang 212013 China

The recent research about cavitation jet mainly focuses on the organ-pipe nozzle and triangular nozzle. The research content mainly includes the optimized design about the structure of nozzles, the observation and flow analysis about the cavitation jet in the water, and the theory of rock attacked by the cavitation jet, while the energy characteristic of the free jet is not studied yet. In China, the research about the central-body nozzle is almost empty. For the purpose of studying the energy characteristic and the structure of free water jet discharged from central-body nozzle, an experiment with phase Doppler particle anemometry（PDPA） technology is carried out to measure the free water jet flow, which is produced by a central-body nozzle under the jet pressure of 15 MPa. While five sections with different axial distances from the nozzle outlet are selected for data process and analysis, the axial and radial velocity and the droplets of the particle size are studied. Meanwhile, numerical calculation of corresponding flow field is conducted by using volume of fluid（VOF） multiphase model, and the jet flow feature is discussed. The experimental and calculating results show that the axial velocity of high speed jet flow dissipates slowly in the air, and the core area and diffused area are discovered. The diameter of droplet in the core area is small, and jet energy is concentrated, while in the diffusion area, water is mingled with ambient air and radial velocity is relatively large. Obvious low-pressure area exists behind the central body and potential cavitation may occur in that area. The proposed research reveals the energy characteristic of free jet discharged from central-body nozzle, provides the theoretical basis for preestimating erosion feature of the central-body nozzle and also the theoretical foundation for revealing the mechanism of erosion.

关键词： central-body nozzle free water jet phase Doppler particle anemometry(PDPA) energy characteristic VOF model

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Effect of Manufacturing Errors on Static Characteristics of Externally Pressurized Spherical Air Bearings

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Chinese Journal of Mechanical Engineering 2009年第6期22卷 896-902页

作者： REN Di WANG Zuwen YANG Qingjun BAO Gang School of Mechanical and Electrical Engineering Harbin Institute of Technology Harbin 150001 China Transportation and Logistics Engineering College Dalian Maritime University Dalian 116026 China

Externally pressurized spherical air bearings are the key component of the three-axis air bearing table, and the manufacturing errors of the bearing affects the performance of the air bearing table. However, the manufacturing errors are unavoidable, and the pursuit to enhance the manufacturing accuracy will increase the cost greatly. In order to provide some theoretical guideline for the tolerance choice in the design of the externally pressurized spherical air bearings with inherent compensation, the effects of several manufacturing errors on the static characteristics of the air bearing are studied. Due to the complex geometry of the computational domain, an unstructured meshing technology is used for mesh generation. A finite-volume method is adopted to discretize the three-dimensional steady-state compressible Navier-Stokes equations. A modified SIMPLE algorithm which is suitable for compressible flows is applied to solve the discretized governing equations. The effects of the dimension error and the roundness error of the ball head and the ball socket on the static characteristics are investigated. The investigation result shows that the positive dimension error and the oblate spheroid-type roundness error of the ball head as well as the negative dimension error and the prolate spheroid-type roundness error of the ball socket can improve the bearing capacity and static stiffness of the air bearings by reducing the mass flow. The calculation method proposed in this paper fits well for the general principle, which can be extended to the characteristics analysis of other air bearings.

关键词： externally pressurized spherical air bearings manufacturing errors bearing capacity static stiffness mass flow

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Temperature detection circuit on the low-temperature superconducting coils

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Nuclear Science and Techniques 2013年第2期24卷 53-58页

作者： SHEN Jie LUO Jiarong Zhenshan CHEN Longwei QIAN Jing MENG Yuedong Institute of Plasma Physics Chinese Academy of Scineces College of Science Donghua University

Experimental Advanced Superconducting Tokamak(EAST) is the fully superconducting *** EAST magnet system comprises 16 D-shaped toroidal field coils and 14 poloidal field coils which are cooled by supercritical helium at 4.2 K and 3.8 *** temperature of superconducting coils is measured by Cernox as a new type low-temperature sensor,and monitored during the cooling and *** helium temperature can offer reference for quench *** this paper,a technique for the weak temperature signal measurement of superconducting coils is introduced,and its weak voltage is extracted from the intrinsic noise of the amplifier by the low-noise instrumentation amplifier,filter circuit,and high-linearity analog *** temperature detection circuit works accurately and safely whether in cooling or operating *** technique is an effective for the temperature detection on the low-temperature superconducting coils.

关键词：温度检测电路超导线圈低温超导托卡马克冷却过程信号测量技术引进操作过程

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Evaluation of Two Absolute Radiometric Normalization Algorithms for Pre-processing of Landsat Imagery

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Journal of China University of Geosciences 2006年第2期17卷 146-150,157页

作者：徐涵秋 College of Environment and Resources Fuzhou University

In order to evaluate radiometric normalization techniques, two image normalization algorithms for absolute radiometric correction of Landsat imagery were quantitatively compared in this paper, which are the Illumination Correction Model proposed by Markham and Irish and the Illumination and Atmospheric Correction Model developed by the Remote Sensing and GIS Laboratory of the Utah State University. Relative noise, correlation coefficient and slope value were used as the criteria for the evaluation and comparison, which were derived from pseudo-invarlant features identified from multitemporal Landsat image pairs of Xiamen （厦门） and Fuzhou （福州） areas, both located in the eastern Fujian （福建） Province of China. Compared with the unnormalized image, the radiometric differences between the normalized multitemporal images were significantly reduced when the seasons of multitemporal images were different. However, there was no significant difference between the normalized and unnorrealized images with a similar seasonal condition. Furthermore, the correction results of two algorithms are similar when the images are relatively clear with a uniform atmospheric condition. Therefore, the radiometric normalization procedures should be carried out if the multitemporal images have a significant seasonal difference.

关键词： Landsat radiometrie correction data normalization pseudo-invariant features image processing.

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Notch3 regulates the activation of hepatic stellate cells

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World Journal of Gastroenterology 2012年第12期18卷 1397-1403页

作者： Yi-Xiong Chen Zhi-Hong Weng Shu-Ling Zhang Depart-ment of Hepatology and Infectious Disease Union HospitalTongji Medical College Huazhong University of Science andTechnology Wuhan 430022 Hubei Province China

AIM： To investigate whether Notch signaling is involved in liver fibrosis by regulating the activation of hepatic stellate cells （HSCs）.METHODS： Immunohistochemistry was used to detect the expression of Notch3 in fibrotic liver tissues of patients with chronic active hepatitis. The expression of Notch3 in HSC-T6 cells treated or not with transforming growth factor （TGF）-β1 was analyzed by iramunofluorescence staining, The expression of Notch3 and myofibroblastic marker （z-smooth muscle actin （（z-SMA） and collagen 1 in HSC-T6 cells transfected with pcDNA3. I-N3ICD or control vector were detected by Western blotting and immunofluorescence staining. Moreover, effects of Notch3 knockdown in HSC-T6 by Notch3 siRNA were investigated by Western blotting and immunofluorescence staining.RESULTS： The expression of Notch3 was significantly up-regulated in fibrotic liver tissues of patients withchronic active hepatitis, but not detected in normal liver tissues. Active Notch signaling was found in HSC-T6 cells. TGF-β1 treatment led to up-regulation of Notch3 expression in HSC-T6 cells, and over-expression of Notch3 increased the expression of α-SMA and collagen I in HSC-T6 without TGF-β1 treatment. Interestingly, transient knockdown of Notch3 decreased the expression of myofibroblastic marker and antagonized TGF-β1 induced expression of α-SMA and collagen I in HSC-T6.CONCLUSION： Notch3 may regulate the activation of HSCs, and the selective interruption of Notch3 may provide an anti -fibrotic strategy in hepatic fibrosis.

关键词： Notch signaling Myofibroblast Liver fibrosis Hepatic stellate cells siRNA

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Further Study on Geochemical Characteristics and Genesis of the Boninitic Rocks from Bikou Group, Northern Yangtze Plate

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Journal of China University of Geosciences 2006年第2期17卷 126-131页

作者：李永飞赖绍聪秦江锋 State Key Laboratory of Continental Dynamics Department of Geology Northwest University

Compared with the major and trace elements of typical boninite, the metabasalts collected from the Nanfanba （南范坝）-Miaowanli （庙湾里） region in the Bikou （碧口） block could be treated as boninite characterized by low-Si, low-Ti, low-P, high-Mg^2 and high Al2O3/TiO2, consistent with geochemical features of boninite. The normal mid-ocean ridge basalt （N-MORB） normalized spider diagram displays fairly depleted high field strong elements （HFSE）（Zr, Y, Ti）. Enriched refractory elements （Cr, Co, Ni） as well as light rare earth elements （LREE）-depleted chondrite-normalized REE distribution patterns suggest the boninitic magmas are derived from an extremely depleted mantle wedge in the presence of a hydrous fluid, meanwhile signifying the source region had previously undergone a high degree partial melting process yielding primary magmas with enriched large ion lithophile elements （LILE）. In addition, almost all the samples in the Nb-Zr-Y and Ti-Zr-Y discrimination diagrams were plotted in the island arc basalt （IAB） field. Coupled with the island arc tholeiitic （IAT） basalt in the study region, therefore, the geochemical characteristics of the studied rocks indicate the meta-basalts probably occurred in a fore-arc subduction setting. This conclusion may be of great significance for the further study of the tectonic background of the Bikou volcanism.

关键词： boninitic rock geochemistry metabasalts Bikou Group.

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Synthesis and host-guest properties of pillar[6]arenes

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Science China Chemistry 2012年第2期55卷 223-228页

作者： TAO HongQi CAO DeRong LIU LuZhi KOU YuHui WANG LingYun MEIER Herbert School of Chemistry and Chemical Engineering South China University of Technology Guangzhou 510640 China State Key Laboratory of Luminescent Materials and Devices South China University of Technology Guangzhou 510640 China Institute of Organic Chemistry University of Mainz 55099 Mainz Germany

A facile method for the synthesis of pillar[6]arenes was developed. A series of pillar[6]arenes were prepared with FeC13 as catalyst and chloroform as solvent at room temperature in moderate yields （30%-40%）. Their host-guest properties with n-cetyltrimethyl ammonium bromide were investigated by 1 HNMR. The results showed that high selectivity in the host-guest relationship became apparent between pillar[6]arenes and pillar[5]arenes based on the different size of the inner cavity.

关键词： calixarene pillararene FeCl3 supramolecular chemistry host-guest property

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Modeling the 3D Terrain Effect on MT by the Boundary Element Method

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Journal of China University of Geosciences 2006年第2期17卷 163-167页

作者：阮百尧徐世浙徐志锋 Department of Resources &Environmental Engineering Guilin University ofTechnology Department of Geosciences Zhejiang University Department of Resources &Environmental Engineering Guilin University of Technology

A numerical method is put forward in this paper, using the boundary element method （BEM） to model 3D terrain effects on magnetotelluric （MT） surveys, Using vector integral theory and electromagnetic field boundary conditions, the boundary problem of two electromagnetic fields in the upper half space （air） and lower half space （earth medium） was transformed into two vector integral equations just related to the topography ： one magnetic equation for computing the magnetic field and the other electrical equation for computing the electrical field. The topography integral is decomposed into a series of integrals in a triangle element. For the integral in a triangle element, we suppose that the electromagnetic field in it is the stack of the electromagnetic field in the homogeneous earth and the topography response which is a constant; so the computation becomes simple, convenient and highly accurate. By decomposition and computation, each vector integral equation can be calculated by solving three linear equations that are related to the three Cartesian directions. The matrix of these linear equations is diagonally dominant and can be solved using the Symmetric Successive Over-Relaxation （SSOR） method. The apparent resistivity curve of MT on two 3D terrains calculated by BEM is shown in this paper.

关键词： 3D terrain MT boundary element method numerical modeling.

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