C_（60）－AALB膜光学累积和记录效应的研究

Ｃ＿（６０）是碳的第三种同素异构体。本文将Ｃ＿（６０）和花生酸混合制得高质量的Ｃ＿（６０）－花生酸复合ＬＢ多层膜，在对其光学非线性特性的研究中首次发现这种ＬＢ膜具有光学累积和记录效应。采用布居光栅模型，分析了这种ＬＢ膜中的光学累积和记录效应的机制。     

C_（60）－AALB膜光学三次非线性特性及机理的研究

本文将新发现的、具有很强的非线性光学效应的全碳有机材料Ｃ＿（６０）作为成膜单体制各成ＬＢ膜。对其三次非线性性质进行了研究。在Ｃ＿（６０）－ＡＡＬＢ膜的立体简并四波混频实验中实现多空前向相位共轭输出，采用相对测量法测得其三次极化率Ｘ￣（３）＝（１．８　　０．４）×１０￣（－８）ｅｓｕ．并对Ｃ＿（６０）－ＡＡＬＢ膜中的光学非线性机理进行分析。研究表明：ＬＢ膜中的三次非线性主要源于Ｃ＿（６０）的吸收效应，该效应产生的三次极化率与实验测试值具有同一量级。     

AES(RFA)谱形分析及其在Mo-Si多层膜界面研究中的应用

应用减速场分析器（RFA）俄歇能谱仪得到直接谱N（E）－E，经计算机程序处理保存谱形方面的信息，并应用于软X射线光学Mo-Si多层膜介面的研究中。并说明经H＋离子轰击的界面谱形。     

一类新型的聚氨酯类二阶非线性光学材料

报道了一类新型的含对硝基苯偶氮苯烷基胺发色团的热交联型二阶非线性光学聚合物的合成和极化工艺。将分散红－１９、甲苯二异氰酸酯和三乙醇胺预反应生成的溶胶－凝胶液旋转涂膜后在１６０℃电晕极化１ｈ可制得光学性质良好的极化膜。采用可见光谱测定了极化膜取向发色团的序参数及其取向的热稳定性。用一维刚性取向气体模型计算极化膜的二阶非线性光学极化系数ｘ＾（２）达１０＾－７ｅｓｕ量级。该极化膜有良好的取向稳定性，在１     

巨磁电阻多层结构——从多层膜到多层纳米线

综述了巨磁电阻多层膜（包括连续多层膜,不连续多层膜,颗粒膜,非匀相合金膜及层状与粒状混合型多层膜）研究的一些结论,着重评述了巨磁电阻多层纳米线的研究进展,包括其制备,表征,传输性能的测定方法,电流垂直于膜面的巨磁电阻（CPP－GMR）,及如何利用多层纳米线的CPP－GMR测定材料的自旋扩散长度和自旋散射不对称因子等材料常数。简要介绍了开发前景。     

C60—AALB膜光学累识和记录效应的研究

Ｃ６０是碳的第三种同素异构体。本文将Ｃ６０和花生酸混合制得高质量的Ｃ６０－花生酸复合ＬＢ多层膜，在对其光学非线性特性的研究中首次发现这种ＬＢ膜具有光学累记和记录效应，采用布居光栅模型，分析了这种ＬＢ膜中的光学累积和记录效应的机制。     

类金刚石碳膜的结构及其微动磨损行为

采用非平衡磁控溅射与等离子源离子注入(PSII)的混合技术，在1Crl8Ni9Ti不锈钢上制备N／Ti，N／TiN／C／DLC多层膜，研究其结构和微动磨损性能，并与N注入层比较。结果表明，N注入层内形成了CrN和Fe3N等氮化物相；多层膜内形成了TiN，Ti2N和CrN等化舍物相。PSII技术能够提高1Crl8Ni9Ti不锈钢的表面硬度，N注入层的硬度约为基体硬度的2．5倍，DLC多层膜的硬度约为基体硬度的4倍。N注入层和DLC多层膜都能够提高1Crl8Ni9Ti的抗微动磨损性，虽然DLC多层膜比N注入层薄，但其抗微动磨损性能更好。     

偶氮苯功能化聚酯的合成与二阶非线性光学特性

合成了３种含偶氮苯侧基的聚酯并研究了其二阶非线性光学（ＮＬＯ）的特性。这类聚酯具有较好的成膜性能，聚合物的极性、链结构、生色团含量以及生色团不同聚集状态膜的吸民光谱和极化膜的二次谐波产生，其中以４－（Ｎ，Ｎ－二羟 在）－胺基－４－硝基偶氮苯与丁二酸酐合成的聚酯具有较强的ＮＬＯ效应，且在玻璃化温度以上极化膜的极化膜的二次谐波衰减较慢，以４－（Ｎ，Ｎ－二羟乙基）胺基－４－硝基偶氮苯与己二酰氯合成的聚酯     

PZT多层薄膜物性的研究

对磁控溅射PZT铁电多层薄膜进行了分析，结果表明：通过对多层薄膜合理的设计和厚度控制，可以改善薄膜的性能，为进一步的器件应用提供了可能性。通过研究发现。制备多层膜较理想的溅射条件是衬底温度Ts＝650℃，薄膜子层厚度约为300um，衬底则以MgO（100）单晶、SiO2（100）单晶为佳。结构分析的结果显示出：PZT多层铁电膜中的晶粒排列整齐，颗粒大小均匀，基本上和衬底成定向织构，膜的电畴呈180°。通过比较可以发现，子层厚度及总厚度超薄，膜的介电常数越大，弛豫频率也越高。但薄膜总厚度对多层膜的绝缘性能影响不大，这说明薄膜的绝缘性质主要是由金属－铁电薄膜的界面决定的。在不同的电压下，多层膜的传导性能影响肖特基势垒的穿透和Fowler－Nordheim隧穿。     

全氟羧酸离子交换膜内硫化铅超微粒的光学非线性研究

在全氟羧酸阳离子交换膜中制备出不同颗粒尺寸的ＰｂＳ超微粒，并由吸收光谱及电镜测量结果获得证实。用飞秒激光脉冲对ＰｂＳ超微粒复合膜进行了时间分辨光克尔效应测定，发现ＰｂＳ超微粒具有三阶光学非线性，三阶光学非线性极化率Ｘ（３）约为１０（－１２）ｅｓｕ，光克尔效应响应时间小于１６５ｆｓ，并且发现ＰｂＳ超微粒的光学非线性随着超微粒颗粒尺寸的减小而增大，显示出量子限域效应对于超微粒子光学非线性的贡献。     

Real gas choked flow conditions at low reduced-temperatures

Real gas choked mass flux is calculated for a frictionless stream expanding isentropically until it reaches the speed of sound and without phase changes. The other parameters associated with the choked state are the pressure, density, temperature ratios, and the speed of sound. Departure of the choked mass flux from the ideal gas model is discussed first in absolute terms and then in relative terms, using the Principle of Corresponding States, for gases with boiling points in the low temperature range. Reduced-stagnation pressures are examined up to values of 30 for hydrogen, neon, nitrogen, argon, methane, krypton, xenon, and R-14 and up to 100 for ⁴He. The corresponding reduced-stagnation temperatures go down to 1.4 and in some cases down to 1.2 for nitrogen and argon. Also discussed are the limiting values of stagnation parameters for which no phase change occurs in the choked state. Compared to the ideal gas, the mass flux may almost double and the critical pressure ratio may decrease by an order of magnitude. The relevance of results is discussed qualitatively and quantitatively for Joule-Thomson cryocooling.     

As-cast microstructures and behavior at high temperature of chromium-rich cobalt-based alloys containing hafnium carbides

Hafnium is often used to improve the high temperature oxidation resistance of superalloys but not to form carbides for strengthen them against creep. In this work hafnium was added in cobalt-based alloys for verifying that HfC can be obtained in cobalt-based alloys and for characterizing their behavior at a very temperature. Three Co–25Cr–0.25 and 0.50C alloys containing 3.7 and 7.4 Hf to promote HfC carbides, and four Co–25Cr– 0 to 1C alloys for comparison (all contents in wt.%), were cast and exposed at 1200 °C for 50 h in synthetic air. The HfC carbides formed instead chromium carbides during solidification, in eutectic with matrix and as dispersed compact particles. During the stage at 1200 °C the HfC carbides did not significantly evolve, even near the oxidation front despite oxidation early become very fast and generalized. At the same time the chromium carbides present in the Co–Cr–C alloys totally disappeared in the same conditions. Such HfC-alloys potentially bring efficient and sustainable mechanical strengthening at high temperature, but their hot oxidation resistance must be significantly improved.     

Chitosan-collagen/organomontmorillonite scaffold for bone tissue engineering

A novel composite scaffold based on chitosan-collagen/organomontmo-rillonite (CS-COL/OMMT) was prepared to improve swelling ratio, biodegradation ratio, biomineralization and mechanical properties for use in tissue engineering applications. In order to expend the basal spacing, montmorillonite (MMT) was modified with sodium dodecyl sulfate (SDS) and was characterized by XRD, TGA and FTIR. The results indicated that the anionic surfactants entered into interlayer of MMT and the basal spacing of MMT was expanded to 3.85 nm. The prepared composite scaffolds were characterized by FTIR, XRD and SEM. The swelling ratio, biodegradation ratio and mechanical properties of composite scaffolds were also studied. The results demonstrated that the scaffold decreased swelling ratio, degradation ratio and improved mechanical and biomineralization properties because of OMMT.     

Capacitance based mass metering for cryogenic fluids

This paper describes a method for measuring the mass of cryogenic fluids in on-board rocket propellant tanks or ground storage tanks. Linear approximations to the Clausius-Mossotti relationship serve as the foundation for a capacitance based mass sensor, regardless of fluid density stratification or tank shape. Sensor design considerations are presented along with the experimental results for a capacitance based mass gage tested in liquid nitrogen. This test data is shown to be consistent with theory resulting in a demonstrated mass measurement accuracy of ±0.75% and a deviation from linearity of less than ±0.30% of full scale mass. Theoretical accuracies are also shown to be ±0.73% for hydrogen and ±1.39% for oxygen for a select range of pressures and temperatures.     

Equipment using a “static-analytic” method for solubility measurements in potentially hazardous binary mixtures under cryogenic temperatures

A new apparatus designed to study, at cryogenic temperatures, thermodynamic equilibria of potentially explosive binary systems such as hydrocarbon-oxygen mixtures is described herein. This equipment has an equilibrium cell which was especially designed to minimize hazards while allowing accurate phase equilibrium measurements. Reliability of results, obtained with this equipment has been verified by working on the nitrogen-propane system, for which data are already available in literature, over a large range of compositions and at various temperatures. Four isothermal curves describing liquid phase compositions at 109.98, 113.77, 119.75 and 125.63 K have been determined. Our experimental data are represented within 2% in compositions and in pressures through the Peng-Robinson equation of state implying Mathias-Copeman alpha function and Huron-Vidal mixing rule. Comparisons to literature allow pointing out: good agreement is observed with Kremer and Knapp data (1983) while the three sets of Poon and Lu data (1974) presenting systematic positive deviation are consequently judged as suspicious.     

Gas gap thermal switches using neon or hydrogen and sorption pump

The very low pressure obtained thanks to adsorption phenomenon at low temperature can be used to build cryogenic heat switches, which offer the possibility to make or break thermal contact between two parts of a cryogenic system. The ON (conducting) and OFF (insulating) states of the switch are obtained by varying the gas pressure between two copper blocks separated by a gap of 100 μm. This pressure is controlled by acting upon the temperature of a small sorption pump (activated charcoal) connected to the gap space. For a “high” sorption pump temperature, the gas previously adsorbed in the sorption pump is released to the gap between the two blocks, allowing a good thermal conduction through the gas (ON state). On the opposite, cooling the sorption pump allows a very good vacuum between the copper blocks, which efficiently break the thermal contact (OFF state). Experimental thermal characteristics (Conductance in the ON and OFF state, ON-OFF switching temperature) of such a “Gas Gap Heat Switch” are described using hydrogen or neon as exchange gas and are compared with theoretical calculations.     

Development of No-Vent™ liquid hydrogen storage system for space applications

A number of technological advances required to store and maintain normal-boiling-point and densified cryogenic liquids, including liquid hydrogen, under zero boil-off conditions in-space, for long periods of time, have been developed. These technologies include (1) thermally optimized compact cryogen storage systems that reduce environmental heat leak to the lowest-temperature cryogen, which minimizes cryocooler size and input power, and (2) actively-cooled shields that surround the storage systems and intercept heat leak. The processes and tools used to develop these technologies are discussed. A zero boil-off liquid hydrogen storage system technology demonstrator for validating the actively-cooled shield technology is presented.     

Development of a miniature cryogenic fluid circuit and a cryogenic micropump

This article presents the development of a miniaturized cryogenic fluid circuit for distributed cooling of low-temperature tracking detectors in high-energy physics (HEP). The heart of the circuit is a prototype cryogenic micropump. This volumetric pump is compatible with cooling powers of about 10-100 W, and capable of producing pressure heads of up to around 0.3 MPa. Besides detector and electronics cooling in HEP, potential applications are found in the field of superconductor technology.     

Integrated Resonant Self-Pumped Loop and pulse tube cryocooler for cryogenic cooling distribution

Cooling distribution is a vital technology concerning cryogenic thermal management systems for many future space applications, such as in-space, zero boil-off, long-term propellant storage, cooling infrared sensors at multiple locations or at a distance from the cryocooler, and focal-plane arrays in telescopes. These applications require a cooling distribution technology that is able to efficiently and reliably deliver cooling power (generated by a cryocooler) to remote locations and uniformly distribute it over a large-surface area. On-going efforts by others under this technology development area have not shown any promising results.This paper introduces the concept of using a Resonant Self-Pumped Loop (RSPL) integrated with the proven, highly efficient pulse tube cryocooler. The RSPL and pulse tube cryocooler combination generates cooling power and provides a distributive cooling loop that can be extended long distances, has no moving parts, and is driven by a single linear compressor. The RSPL is fully coupled with the oscillating flow of the pulse tube working fluid and utilizes gas diodes to convert the oscillating flow to one-directional (DC) steady flow that circulates through the cooling loop. The proposed RSPL is extremely simple, lightweight, reliable, and flexible for packaging. There are several requirements for the RSPL to operate efficiently. These requirements will be presented in this paper. Compared to other distributive cooling technologies currently under development, the RSPL technology is unique.     

Helium liquefaction with a commercial 4 K Gifford-McMahon cryocooler

This paper describes helium liquefaction using a commercial cryocooler with 1.5 W cooling power at 4.2 K (Sumitomo model RDK415D with compressor CSW-71D, consuming 6.5 kW electrical power), equipped with heat exchangers for precooling the incoming gas. No additional cooling power of cryoliquids or additional Joule-Thomson stages were utilized. Measurements of the pressure dependence of the liquefaction rate were performed. A maximum value of 83.9 g/h was obtained for 2.25 bar stabilized input pressure. Including the time needed to cool the liquefied helium to 4.2 K at 1 bar after filling the bottle connected to the cold head, and correcting for heat screen influences, this results in a net liquefaction rate of 67.7 g/h. Maintaining a pressure close to 1 bar above the bath during liquefaction, a rate of 55.7 g/h was obtained. The simple design enables many applications of the apparatus.