Application of scan pitot-pressure rake in hypersonic propulsion wind tunnel flow field measurement

在风洞实验中,为了保证实验结果的可靠性,首先需要了解流场的品质.笔者自行设计研制了用于高超声速推进风洞流场测量的带有水冷装置的可移动式扫描总压耙.对于出口截面为300mm×187mm的风洞喷管,通过计算机程序控制,可在3s时间内实现全截面间歇式或连续式扫描,最大移动速度可达250mm/s,而且定位准确.通过扫描结果,分析了流场压力均匀性、稳定性以及实验结果的可重复性,同时还给出了风洞喷管出口截面的总压与马赫数等值线图.从而为超燃冲压模型发动机实验提供参考数据

PDE/Scramjet组合循环发动机实验研究

本文对一种新概念的PDE/Scramjet 组合循环发动机在自由射流推进风洞中进行了实验研究。着重研究了点火、凹腔对发动机性能的影响。实验发现, 由爆轰管尾部带来的大扩张结构需要强制点火才能保证超燃发动机的稳定燃烧。此外发动机侧面凹腔的引入，对性能有利也有弊，需要进一步权衡。本文还开展了PDE/Scramjet 的联合实验，由于PDE 燃料流量只有超燃发动机的1%左右，导致PDE 对整体发动机性能贡献很小。最后，本文还采用总压恢复模型对组合循环发动机的推力阻力进行了分析

髓磷脂抑制因子Nogo-A及其受体在缺血性脑卒中中的作用及机制研究进展

作为临床常见的中枢神经系统血管性疾病,缺血性脑卒中具有发病率高、死亡率高、致残率高的\"三高\"特点[1]。从临床资料来看,脑卒中具有非常复杂的病理生理过程,其中一个重要原因是由于脑缺血再灌注后发生大脑局部缺血缺氧,造成组织细胞损伤,比如神经元损伤、轴突生长抑制等,导致运动、感觉、学习和记忆等神经功能障碍[2]。现有研究成果证明,髓磷脂抑制因子Nogo-A及其受体广泛存在于哺国家自然科学基金(81501207,81471265,31570845);;陕西省专项科研计划项目(16JK1645);;陕西省自然科学基金重大基础研究项目(2016ZDJC-16

中国国际科学合作中的”华人现象“

将8 个国家的合作论文分成五种类型，重点考察了中国在与8 个国家的合作中所呈现的“华人现 象”。分析表明，海外华人（包括短期在外的科研人员）在现阶段正在发挥桥梁作用，在中国国际合作中表 现得非常活跃。分析了导致“华人现象”的社会基础和政策效应

Performance of the fuel injector in supersonic combustor

Enhancing the fuel-air mixing is critical for scramjet combustor performance. The performance of four different aerodynamic ramp injectors was reported in this paper. The experiments were conducted in a direct-connected scramjet test facility. The concentration profiles were obtained by gas sampling and chromatogram analysis. The pictures of the flow field were obtained by using laser scatter. It would be used to analyze the flow field generated by the aerodynamic ramp, then optimize the layout of the injectors. The results would offer some useful information for engine design. Copyright © 2009 by the American Institute of Aeronautics and Astronautics, Inc

Measurement of temperature, velocity and water vapor concentration in a scramjet combustor based on nearinfrared diode laser absorption

A multi-channel Tunable Diode Laser Absorption Spectroscopy (TDLAS) system was designed and constructed for flow parameters diagnostics in a scramjet combustor. Two fiber coupled distributed feedback (DFB) lasers with narrow line width were used to probe two H2O absorption features (7185.597cm-1,7444.35cm-1+7444.37cm-1(c ombined)) by using direct absorption Time-Division-Multiplexing (TDM) strategy at a 4-kHz repetition rate. Laser light was split into five beams and transmitted across the test region. Two motorized precision translation stages were used to move the collimators during the test, so that the three beams located near the cavity and at the exit of the combustor can scan the cross sections respectively. Flow parameters could be obtained simultaneous which included average temperature, water vapor concentration and velocity at the entrance of the combustor, the distribution of temperature, water vapor concentration at a cross section near the cavity, the distribution of temperature, water vapor concentration and velocity at the exit cross section of the combustor. The parameters of the flow entering and exiting the combustor could be used to evaluate the performance of the direct-connected scramjet facility and the combustion efficiency of the combustor. The parameters at the cross section in the combustor could also be used to analysis combustion characteristics in the combustor

妊娠期及产褥期合并深静脉血栓 5例报告

【目的】探讨妊娠期和产褥期深静脉血栓的病因、高危因素、诊断和治疗。【方法】回顾性总结分析 10年来我院收治的 5 例妊娠期和 产褥期深静脉血栓患者的临床资料,对其病因、临床表现、诊断治疗等进行分析。【结果】4 例发生在产褥期,1 例发生在妊娠晚期; 症状以患肢肿 痛乏力为主,部分症状不明显; 经过治疗后, 4例均预后良好。【结论】妊娠晚期及产褥期易发生深静脉血栓; 高龄、手术产是其高危因素; 一旦确 诊,应尽早治疗,防止发生肺栓塞

HYDRODYNAMIC CHARACTERISTICS IN THE ARTIFICIAL REEFING CONSTRUCTION AREA IN LAIZHOU BAY： BASED ON： A CONTINUOUS LONG-TERM OBSERVATION

为了研究人工鱼礁区基本水动力特征，本文利用人工鱼礁投放区的座底海床基获取半年以上的水动力观测资料，通过谱分析、调和分析、滤波等方法分析了该海区潮汐、潮流特征，并讨论了余流特征。结果表明，该海域属于不规则半日潮，具有显著的全日潮周期和半日潮周期，潮汐性质指数为0．98，平均潮差为0．95m，最大可能潮差为2．25m。潮流为典型的往复潮，潮流主向为NNE．SSw，优势分潮为M2分潮。垂向上，流速大小随深度增加显著降低，海底lm的流速较表层降低约30％，流向向沿鱼礁布设方向偏转。该海域余流较小，欧拉余流与斯托克斯余流大小相当，分别为1．35cm／s，1．41cm／s，均为向岸输运，欧拉余流表层受风影响较大，拉格朗日余流为2．76cm／s，方向SEE。该海域流场垂向结构与人工鱼礁投放后底摩擦增加、鱼礁对近底层水流的阻滞作用有关。底层温度具有显著的季节变化与日变化特征，短期高频变化存在显著的全日周期与半日周期，冬春季由于垂向混合加强，全日信号更为显著。底层浊度的升高主要由大风过程加强垂向混合的引起

支板凹腔一体化超燃冲压发动机实验研究

本文针对以凹腔支板一体化燃烧室为基本结构的超燃冲压模型发动机在自由射流风洞中的性能，主要研究了燃料在不同位置喷入时，燃烧室几何结构/气动性能/燃料混合及燃烧特性的相互耦合，以及对发动机推力性能的影响．结果表明支板与凹腔的一体化在合理配置燃料分布情况下可以获得较好的发动机性能