横流均匀环境中三维线源型正负浮力射流特性研究

本文利用混合有限分析法及交错网格。对横流均匀环境中三维线源型正负浮力射流及负浮力射流的特性进行研究，分析了不同工况下流速，温度和湍动能在断面上的分布及影响射流轨迹线的因素，讨论了轨迹线上温度的变化及浮力射流的贴壁现象。对三维长线源型负浮力射流，分析了流速比，喷口弗汝德数对负浮力射流的影响。     

液氮温区同轴脉冲管制冷机的实验研究

脉冲管制冷机冷头朝上布置可以使制冷机与超导器件的耦合更方便 ,但对G -M型脉冲管制冷机 ,重力会对这种布置方式产生不利影响。对双向进气型脉冲管制冷机 ,直流和耦合传热会共同影响脉冲管制冷机的性能。介绍了液氮温区G -M型同轴脉冲管制冷机的实验结果 ,主要研究了蓄冷器温度分布和重力对脉冲管制冷机性能的影响     

超声变幅杆解析法设计的可靠性研究

本文提出了用有限元法验证变幅杆解析法设计的可靠性，对三种类型的变幅杆先作解析法设计；然后利用有限元分析软件ANSYS进行模态分析，确定了变幅杆的固有频率，计算了固有频率与工作频率之间的相对误差，以此来评价解析法设计的可靠性；并分析了影响解析法设计可靠性的两个基本因素。     

The effect of pack-aluminisation on the microstructure of MCrAlY and the performance of thermal barrier coatings

Plasma spraying and pack-aluminising processes were combined and applied to the nickel-base superalloy Mar-M247 to improve its cyclic oxidation resistance. The performance tests of duplex ZrO₂-8 wt.%Y₂O₃/MCrAlY thermal barrier coatings (TBCs) were conducted at 1050 °C, 1075 °C, 1100 °C, 1150 °C and 1200 °C. The results of the experiments in this study showed that TBC specimens with the aluminised MCrAlY bond coat exhibited higher cyclic lives (except for the Ni-22Cr-10Al-1Y bond coat), at all the temperatures tested, than specimens on which the bond coat was not aluminised. The microstructures of the Co-29Cr-6Al-1Y, Co-32Ni-21Cr-8Al-0.5Y and Ni-22Cr-10Al-1Y bond coats with or without aluminising treatment were examined in detail using a scanning electron microscope equipped with an electron probe microanalyzer.     

铅酸蓄电池的清洁生产

就中国铅酸蓄电池工业的可持续性发展与清洁生产问题进行了初步探讨,并就蓄电池正负极板水洗的清洁生产实例进行了介绍。     

An efficient approach for calculating the dispersions of photonic-crystal fibers: design of the nearly zero ultra-flattened dispersion

A novel and efficient approach is proposed to calculate the dispersions of the guided modes of the photonic-crystal fibers (PCFs). Based on the vector boundary-element method (VBEM), the surface integral equations for the first and second derivatives of the propagation constants with respect to the wavelength are explicitly derived. Compared with the three-point finite-difference approach, which needs to solve and search three effective indexes near the interested wavelength, this approach can determine the dispersions of the PCFs by only solving one effective index at this wavelength based on the derived formulations. This novel approach saves over 60% computing time without losing the accuracy. Based on this approach, a novel four-ring PCF is designed by optimizing only three geometrical parameters to achieve the nearly zero ultra-flattened dispersion property. Compared with previously presented dispersion-flattened PCFs, the design procedure for the four-ring structure could be more efficient and easier because relatively lesser parameters need to be optimized.     

60Co辐照预处理对苹果片脱水特性和品质的影响

进行了不同辐照剂量、热风温度、切片厚度对苹果脱水速率及品质的影响试验,结果表明该三因子影响苹果片的脱水速率和外观质量.辐照剂量增加,热风温度增高,脱水速率高,VC含量和复水比下降.辐照剂量、热风温度、切片厚度三因素对脱水速率和干制品的外观质量、VC含量、复水比等四指标大都呈显著影响.     

A Study of AlN Films Prepared by Arc Ion Plating

Hexagonal AlN films have been obtained by arc ion plating at different negative biases ,X-ray diffraction and scanning electron microscopy results show that AlN films with smooth surfaces and (002) preferred orientation are obtained at low biases ,whereas those with coarse surfaces and (100) preferred orientation are obtained at high biases,The formation mechanism of AlN is analyzed and the experiment results are discussed,The effect of bias on adhesion strength has also been examined.     

PetaStar: a petabit photonic packet switch

This paper presents a new petabit photonic packet switch architecture, called PetaStar. Using a new multidimensional photonic multiplexing scheme that includes space, time, wavelength, and subcarrier domains, PetaStar is based on a three-stage Clos-network photonic switch fabric to provide scalable large-dimension switch interconnections with nanosecond reconfiguration speed. Packet buffering is implemented electronically at the input and output port controllers, allowing the central photonic switch fabric to transport high-speed optical signals without electrical-to-optical conversion. Optical time-division multiplexing technology further scales port speed beyond electronic speed up to 160 Gb/s to minimize the fiber connections. To solve output port contention and internal blocking in the three-stage Clos-network switch, we present a new matching scheme, called c-MAC, a concurrent matching algorithm for Clos-network switches. It is highly distributed such that the input-output matching and routing-path finding are concurrently performed by scheduling modules. One feasible architecture for the c-MAC scheme, where a crosspoint switch is used to provide the interconnections between the arbitration modules, is also proposed. With the c-MAC scheme, and an internal speedup of 1.5, PetaStar with a switch size of 6400 /spl times/ 6400 and total capacity of 1.024 petabit/s can be achieved at a throughput close to 100% under various traffic conditions.     

利用UTD修正的MoM-PO混合算法研究

介绍了利用矩量法(MoM)和物理光学(PO)混合方法处理复杂线体结构的电磁散射问题，提出利用pulse基函数对线电流进行展开，使得处理复杂线体结构问题变得简化，并推导出一般的矩阵方程。然后针对PO在阴影区域失效等问题，利用UTD(一致性几何绕射)对该简化模型结构下的PO区域电流进行了修正，使得其应用范围得到扩展、计算精度得到提高。文中的实例结果与传统的MoM很好的一致，从而说明了该方法的有效性和精确性。