Effects of wall temperature on boundary layer stability over a blunt cone at Mach 7.99

Effects of wall temperature on stabilities of hypersonic boundary layer over a 7-degree half-cone-angle blunt cone are studied by using both direct numerical simulation (DNS) and linear stability theory (LST) analysis. Four isothermal wall cases with Tw/T0= 0.5, 0.7, 0.8 and 0.9, as well as an adiabatic wall case are considered. Results of both DNS and LST indicate that wall temperature has significant effects on the growth of disturbance waves. Cooling the surface accelerates unstable Mack II mode waves and decelerates the first mode (Tollmien–Schlichting mode) waves. LST results show that growth rate of the most unstable Mack II mode waves for the cases of cold wall Tw/T0=0.5 and 0.7 are about 45% and 25% larger than that for the adiabatic wall, respectively. Numerical results show that surface cooling modifies the profiles of rdut/dyn and temperature in the boundary layers, and thus changes the stability haracteristic of the boundary layers, and then effects on the growth of unstable waves. The results of DNS indicate that the disturbances with the frequency range from about 119.4 to 179.1 kHz, including the most unstable Mack modes, produce strong mode competition in the downstream region from about 11 to 100 nose radii. And adiabatic wall enhances the amplitudes of disturbance according to the results of DNS, although the LST indicates that the growth rate of the disturbance of cold wall is larger. That because the growth of the disturbance does not only depend on the development of the second unstable mode

分辨率优化的混合WENO格式

为提高有限差分格式的分辨率,利用傅里叶分析对WENO格式进行色散及耗散优化,并给出优化的线性权重.用优化后的WENO格式与保单调格式（MP）进行加权混合,得到新的加权混合WENO格式（H-WENO）.通过一维激波管问题、Shu-Osher问题及二维双Mach反射问题及R-T不稳定性问题对格式进行数值测试.结果显示,新格式具有强健的激波捕捉能力和对小尺度波结构的高分辨率,与原WENO格式相比改进明显

Delay-Constrained Mobile Energy Charging in Wireless Sensor Networks

为了延长无线传感网的生存期,基于可充电的移动设备,研究设计了一种无线传感网中移动式能量补充的方法,移动节点可以在为传感器节点补充能量的同时收集数; 据.首先,通过将无线传感器网络监测区域分割为大小相同的子区域,该子区域内的节点组成一个簇;其次,以一个簇内的总能量为计算依据,设计移动节点的路径; 生成算法以确定能量高效的移动路线;最后,使用10种不同的随机网络拓扑图进行了仿真实验,以节点移动速度和时延为限制条件分别得到了对比数据.结果表明; ,本文提出的算法与NJNP( nearest-job-next with preemption)算法相比在时延相同的条件下( 800; s),生存期提升了6 000 s左右,在节点速度5 m/s条件下生存期提升了将近14 000; s.证明本文所提方法有效地提高了充电效率,延长了网络的生存期,可用于大规模的无线传感器网络.In order to prolong the lifetime of wireless sensor networks by using; energy-rechargeable mobile devices,this paper designs a mobile energy; replenishment method wherein a mobile element gathers data and recharges; sensors simultaneously. Firstly,the whole sensor network is divided into; several sub-regions equally and the sensors in each sub-region are; formed into a cluster. Secondly, considering the energy in a whole; cluster,the mobility path is designed to find the energy-efficient; mobile trace of the mobile element. Finally,in the simulation; experiment,we used ten different random network topologies to show the; comparisons with extensive simulation experiments under different; velocities and deadlines. The results indicate that the proposed; algorithm increases lifetime by approximately 6 000 s compared with; Nearest-Job-Next with Pre-emption( NJNP) under the deadline of 800 s.; Moreover,the proposed algorithm increases lifetime by approximately 14; 000 s compared with NJNP at velocity of 5 m/s. Thus,the proposed; algorithm can improve recharging efficiency and prolong the lifetime of; wireless sensor networks,which can be used in large-scale sensor; networks.国家自然科学基金资助项目; 福建省高等学校杰出青年科研人才培育计划资助项

从生态自然观看细菌的耐药

伴随抗菌药物强大的抗感染疗效的同时,细菌等病原体对抗菌药物的耐药性问题日渐显露出来。运用生态自然观辨证地对细菌进行剖析,旨在突破传统思维认识细菌耐药性产生本质,从而更加有效,更加科学地控制细菌耐药的发生

乳化剂OP/水-氯化银体系光散射光谱应用研究

研究了乳化剂ＯＰ／ 水－ 氯化银乳浊体系的共振光散射光谱及其应用， 与其它体系相比， 微乳液体系的增溶能力、增稳效果显著提高． 用共振光散射光谱法测定微量氯离子， 与比浊法等相比， 具有更好的线性关系， 更宽的线性范围， 更高的灵敏度

Nonlinear spectral-like schemes for hybrid schemes

In spectral-like resolution-WENO hybrid schemes, if the switch function takes more grid points as discontinuity points, the WENO scheme is often turned on, and the numerical solutions may be too dissipative. Conversely, if the switch function takes less grid points as discontinuity points, the hybrid schemes usually are found to produce oscillatory solutions or just to be unstable. Even if the switch function takes less grid points as discontinuity points, the final hybrid scheme is inclined to be more stable, provided the spectral-like resolution scheme in the hybrid scheme has moderate shock-capturing capability. Following this idea, we propose nonlinear spectral-like schemes named weighted group velocity control (WGVC) schemes. These schemes show not only high-resolution for short waves but also moderate shock capturing capability. Then a new class of hybrid schemes is designed in which the WGVC scheme is used in smooth regions and the WENO scheme is used to capture discontinuities. These hybrid schemes show good resolution for small-scales structures and fine shock-capturing capabilities while the switch function takes less grid points as discontinuity points. The seven-order WGVC-WENO scheme has also been applied successfully to the direct numerical simulation of oblique shock wave-turbulent boundary layer interaction

汕尾市100kW波力电站空气透平与气室匹配设计

根据用1／15模型，在造波水槽中进行试验获得气室的△P↑-i-Q↑-、ηA-Q↑-、N↑A-Q↑-特性，以及用Ф300mm透平模型，在Ф1000mm活塞式往复流透平试验台进行试验获得的对称翼透平、双向固定导叶冲动透平和双向自调节导叶冲动透平的Cp-Ф、ητ-Ф特性，进行了气室与三种空气透平的匹配设计。表明在设计波况下，采用Ф1．025m的双向自调节导叶冲动透平时，ητ·ηA达50．43％；采用Ф0．975m的双向自调节导叶冲动透平时，ητ·ηA达46．66％；采用Ф0．975m的双向固定导叶冲动透平时，ητ·ηA达33．66％；采用Ф1．45m对称翼透平时，ητ·ηA仅为29．9％。并对四种不同匹配方案进行了对比分析

超/高超声速平板湍流边界层的 DNS 和特征分析

本文给出了马赫数为2.25,5,6 和8 的平板可压缩边界层湍流空间发展的直接数值模拟(DNS)结果，通过分析受马赫数与壁面温度共同作用影响下的可压缩边界层湍流的特征，检验了压缩性效应和Morkovin 假设成立的范围.本文重点讨论了温度－速度关系，分析了强雷诺比拟受马赫数和壁温影响的规律.结果表明，当壁面温度取近似恢复温度时，来流马赫数（最大等于8）的变化对近壁湍流的压缩性效应的影响并不显著，Morkovin 假设依然有效；当马赫数达到8 时，压缩性效应受壁温影响显著，强冷壁条件（Tw/T∞=1.9）会大幅增加压缩性，导致Morkovin 假设不再严格成立

廉洁教育面向政治生活的价值意蕴与实现路径

廉洁教育的生活化特质决定它应当面向生活。廉洁教育面向生活的一个逻辑基点,是面向政治生活。廉洁教育面向政治生活的价值意蕴在于,廉洁教育是预防政治生活变质的"防腐剂",是冲刷政治生活污垢的"洗涤剂",是营造风清气正良好政治生态的"净化剂"。廉洁教育面向政治生活的路径是:将核心价值观融入政治生活,以引导人们在政治生活中树立廉洁价值观;通过制度建设来规范政治生活,以促使人们在政治生活中自觉遵守廉洁规范;通过榜样教育和警示教育相结合来净化政治生活,以推动人们在政治生活中涵养廉洁正直的品质。国家社科基金一般项目“执政党廉洁政治生态涵养机制研究”(项目编号:16BZZ012)； 广西哲学社会科学规划一般项目“廉洁教育面向生活研究”(项目编号:13DZX002)阶段性成