负压磁头气动力静态特性

该文用有限差分法离散Reynolds润滑方程,采用交替方向隐式格式(ADI)求解离散得到的代数方程组,计算出了负压滑块的静态气动力特性

Distribution and Activity of Marine Bacterioplankton at Frequent HAB Area of East China Sea

作者简介: 王新( 1979~ ), 男, 博士研究生, 主要研究方向为资源与环境微生物学, E-mail :wxxmu@ 163. com 通讯联系人, E-mail:microzh@ xmu. edu. cn[中文文摘]于2006年4~5月对东海近海28°~30.7°N之间的赤潮高发区浮游细菌的分布、活性和群落结构特征进行了调查.采用荧光显微计数法测定细菌丰度,荧光模拟底物法测定细菌胞外酶活性,PCR-DGGE分析该区域的细菌群落结构特征.结果表明,东海赤潮高发区的浮游细菌丰度在5.85×104~9.26×105cells.mL-1之间,其中舟山外海区域较高,在整个调查区域北部海域高于南部海域.β-葡萄糖苷酶的平均活性为0.023μmol.(L.h)-1,氨肽酶的平均活性约为其3.6倍,在5μm以上颗粒中的胞外酶活性平均占总活性分别为47.4%和44.24%.细菌胞外酶活性的分布与细菌丰度的分布无相关性,在整个调查区域南部海域高于北部海域.细菌群落结构和多样性差异较大,南部海域的细菌多样性低于北部海域.人类活动和陆源输入是影响浮游细菌分布的决定性因素,台湾暖流对细菌胞外酶活性及其分布有着决定性的影响,复杂的环境条件是细菌群落结构和多样性差异的主要原因之一.海洋细菌在东海赤潮高发区的生态作用有待进一步研究. [英文文摘]The distribution, activity and community structure of bacterioplankton in surface waterwere investigated at frequent harm fulalgae blooms (HABs) a rea in East China Sea (28b23017bN ) from April to May, 2006. The abundance of bacte riop lankton was determ ined by using the DAPI (4, 62d iamidino222phenylindole) direct count (DDC) method. The B2glucosidase and am inopeptidase activityweremeasured with fluorogenicmodel substra tes. And the bacterial community structure was analyzed by PCR2DGGE. Results showed that bacterial abundance in northern of the sampling area wasmuch more than that in southern of the sampling area. It ranged from 5185@104 ce lls# mL- 1 to 9126@105 ce lls# mL- 1. And there was the highest vaue area outer the costa l of Zhou Shan Island.The average aminopeptidase activity was 316 times of B2glucosidase activity which was 01023 Lmol# ( L# h) - 1 in th is area. The B2 glucosidase ac tivity in > 5Lm fraction contr ibuted 4714% of the tota,l and that of the aminopep tidase activity was 441 24% of the tota .l Bacteria l extracellular enzyme activity had a higher average value in southern of the sampling area. This indica ted that the bacterial activity had no direct relationship with bacteria l abundance. Bac terial diversity and community structure differed from each sampling station. Thereweremore divers in northern sampling area. The results suggested that the human being activity and continental inputting organic matte rsplayed a key role on the distribution of bacterial abundance. The d istribution of bacterial extrace llular enzyme activity wasmainly a ffected by the Taiwan warm current. And it was the complicated unknown factors that caused the difference of the bacterial community structure and diversity from each sampling station. Obviously, it needed furtherwork to enhance the knowledge of the ecological function of the bacte riop lankton at frequentHABs area of the coastal water in East Ch ina Sea.国家高技术研究发展计划(863)项目(2008AA09Z408);国家自然科学基金项目(40876061,40930847,30940002,30800033);国家海洋局海洋生态系统与生物地球化学重点实验室开放基金项目(LMEB200601);长江学者和创新团队发展计划项目(40821063

The Application Of Traditional Architecture Elements In Contemporary Architecture In Chongqing

重庆作为一个典型的山地城市,其传统建筑形式深受当地文化和自然条件的影响。但由于部分建筑师对传统建筑语汇的理解不足,造成部分重庆当代建筑设计的地域性缺失。本文试图通过一系列的案例分析和深度研究,寻找将重庆地区传统建筑元素应用在当代建筑设计中的新思路。As a typical mountain city,its traditional architectural forms influenced by the local culture and natural conditions in Chongqing.However,due to the lack of understanding of traditional architectural vocabulary that can lead to the lack of regional contemporary architectural design in Chongqing.Through a series of case studies and in-depth research,this article attempts to look for the traditional architectural elements in Chongqing which is used into the new ideas of the modern architecture design

Changes And Thoughts Of The Concept Of Protection Of Historic Architectures In Xiamen

厦门近现代遗留了众多历史建筑,对其保护大致分为两个阶段,主要包括第一阶段对集美学村的保护以及第二阶段对鼓浪屿的保护。本文试图通过对两个保护阶段的对比与思考,对厦门当下历史建筑保护提出新的观念。The protection of historic architectures in Xiamen can be divided into two stages. This paper attempts to compare this two stages to make summary about the change of the concept of protecting historic architectures in Xiamen

凝胶推进剂模拟液静电雾化行为规律研究

针对凝胶推进剂雾化困难的问题,引入静电喷射技术雾化凝胶推进剂。以水凝胶模拟液为介质,探究静电雾化技术的可行性及试验条件,当收集距离2~5 cm、供液速率10~30μL/h时,凝胶模拟液可实现稳定雾化,收集液滴直径小于100μm,散射角分布在8°~36°之间,收集液滴直径和散射角均随收集距离的增大和针管直径的减小而减小;同样条件下,凝胶粘度越小,散射角和雾化液滴直径越小。在此基础上,针对单针管推力小的问题,分析使用多针管喷头进行凝胶推进剂静电雾化的可行性及其雾化区域分布,结果表明2号凝胶模拟液用于多喷头雾化可得到良好的雾化区域分布,适用于凝胶推进系统之中。国防科技重点实验室基金项目(61427040203162704004

双压电驱动高频喷射点胶阀的设计与实验

为了满足电子封装产业对胶体高速、微量分配的需求,设计了一种基于圆弧柔性铰链放大机构的双压电陶瓷驱动喷射点胶阀。首先,利用有限元分析软件对放大机构输出位移和模态进行了计算与分析。针对其高频需求,讨论了结构参数对其影响因素。基于微元法并结合喷嘴内胶体动力学分析,建立了喷嘴内胶体喷射的流体力学模型。结合阀杆与阀座配合的仿真模型,利用FLOW-3D的流固耦合仿真,揭示了喷射点胶时胶点的成型过程。在此基础上探究了胶体喷射时喷嘴处压力的变化与流速的关系,为点胶阀参数的控制和优化奠定了基础。最后,搭建了喷射系统实验平台,选用黏度为180cps的胶体进行点胶性能测试,得出了供料压力和驱动方波频率对胶点尺寸的影响规律。实验结果显示,在供料压力为6bar,驱动方波幅值频率360Hz等参数下,获得胶点最小直径为525μm。同时,在380～400Hz的频率区间内进行高频喷射实验,能够获得均匀微小的圆形胶点。实验结果验证了该圆弧柔性铰链放大机构的双压电驱动点胶阀的高频、微量喷射性能,为压电高频喷射点胶的应用和研究提供了参考。深圳市科技计划资助项目(No.JCYJ20170818141912229);;\n航空科学基金资助项目(No.20160868004

Luminescence of Strain Compensated Si/Si_(0.62)Ge_(0.38) Quantum Well Grown on Si_(0.75)Ge_(0.25) Virtual Substrate

由于SI/SIgE异质结构的带阶差主要发生在价带,为实现高效率的发光,本文从理论上设计了在硅基SI1-XgEX虚衬底上外延应变补偿的SI/S1-ygEy(y>X)量子阱的能带结构,将量子阱对电子的限制势垒提高到100MEV以上。在实验上,采用300℃生长的gE量子点插入层,制备出薄的SIgE驰豫缓冲层(虚衬底),表面gE组份达到0.25,表面粗糙度小于2nM,驰豫度接近100%。在我们制备的SIgE缓冲层上外延了应变补偿SIgE/SI多量子阱结构,并初步研究了其发光特性。In this paper,band structures of strain compensated Si/S_(1-y)Ge_y(y>x) quantum well grown on Si_(1-x)Ge_x virtual substrate was design to enlarge the conduction band offset up to 100meV for improving luminescence.The fully strain-relaxed Si_(0.75)Ge_(0.25) virtual substrate was prepared by inserting a low-temperature Ge islands layer in ultra-high vacuum chemical deposition.The root-mean-square surface roughness of the virtual substrate is less than 2nm.The luminescence of the strain compensated Si/SiGe quantum well on the virtual substrate was investigated.国家重点基础研究发展计划资助项目2007CB613400;国家自然科学基金资助项目(60676027;50672079

低温胁迫对长苞铁杉幼苗的生理影响

经模拟低温(-12、-8、-4、0、4℃)胁迫处理后,长苞铁杉幼苗叶片和根系相关生理指标均发生明显变化.随着温度降低,叶片光合色素含量增加,但反映光合活性强弱的Chla/Chlb降低;叶片中渗透调节物质脯氨酸和可溶性糖含量增加,呈极显著正相关(r=0.804,p<0.01),根系中可溶性糖含量的减少说明根对低温胁迫的渗透调节更依赖于脯氨酸的累积.幼苗在-4℃及更低温度胁迫下受到严重的冻害使SOD活性持续下降,叶片中POD活性与SOD活性变化呈极显著负相关(r=-0.908,p<0.01),但根系中POD活性与SOD活性没有相关性,说明长苞铁杉幼苗对抗外界胁迫机理的复杂性.叶片MDA含量比根系低可能与叶片中Car能缓解1O2对细胞的伤害有关

Electrospinning of aligned PVDF nanofibers with piezoelectricity and its application in pressure sensors

针对传统静电纺丝法制备聚偏二氟乙烯(PVDF)压电纤维工艺复杂和效率低等问题,提出了采用滚筒收集方式制备PVDF有序纳米纤维的方法。通过改变滚筒转速收集纤维,得到了有序程度不同的PVDF纤维膜。用傅立叶变换红外光谱(FTIR)分析了有序纤维膜β晶相的含量,并利用NI数据采集卡在相同条件下测试了纤维膜的压电特性。结果表明:随着滚筒转速提高,纤维有序度增强,β相的含量提高,压电电压输出也明显增大,由此得知滚筒转速变化对β晶相的含量及压电输出电压的影响规律基本一致。基于得到的结果,设计制作了利用该有序PVDF纤维膜的压力传感器,并在不同气压下进行了动态响应测试。结果显示:所制备的PVDF有序纤维压力传感器在0.145~0.165 MPa下的电压输出随气压的增加呈线性增大,表现出了良好的线性度,其灵敏度达179mV/kPa。采用该种方法制备PVDF纤维对研制动态压力传感器极有意义。It has complex process and lower efficiency when traditional electrospinning preparation method is used to prepare the poly(vinylidene fluoride)(PVDF)piezoelectric fibers,so this paper proposes a new method for the PVDFs by using a rotation drum to collect aligned PVDF nanofibers.Aligned fiber membranes with different alignment degrees were collected by changing the rotating speed.Then,the Fourier Transform Infrared(FTIR)spectroscopy was used to analyze the content ofβphase of the fiber membranes and a data acquisition card of National Instrument(NI)was used to research the piezoelectric property of piezoelectric fiber membrane under the same pressing force.The results show that the order of fiber alignment and the content ofβphase are both improved as the rotating speed increasing,and the output voltage of piezoelectric also increases,which indicates that the change of rotating speed has the same influence on the content ofβphase and the output voltage.Based on the aligned PVDF fiber membrane,apressure sensor was designed and its dynamic responses under different air pressures were obtained with a lab-made testing system.In the pressure range of0.145-0.165 MPa,the piezoelectric output of the sensor increases linearly with the increment of air pressure,showing excellent linearity and high sensitivity up to 179mV/kPa.The preparing method for PVDF nanofibers has wide application prospects,especially in the field of high accuracy dynamic pressure tests.国家自然科学基金青年基金资助项目(No.51105320