Description of the Sounding Rocket Experiment—SOURCE

A SOUnding Rocket Compere Experiment (SOURCE) is prepared for launch in spring 2008 and shall deliver approximately 360 s of microgravity time. The experiment is intended to partially fulfill the scientific objectives of the European Space Agency Microgravity Applications Program project AO-2004-111 (Convective boiling and condensation). One of the tasks of this experiment is the investigation of capillary dominated flow at a heated wall. The SOURCE experiment will also serve the needs of the COMPERE research group whose mandate is to investigate the behavior of propellant in spacecraft tanks. SOURCE is a benchmark type of experiment on fluid behavior in tanks to test hypotheses and numerical predictions (quantitative results on a tank scale). Several work packages have been distributed to the Center of Applied Space Technology and Microgravity (ZARM) to manage a part of the preparation of this experiment. Since ZARM acts also as a principal investigator, the subject of surface tension driven flows is one of the main topics. It includes the design of the experimental setup to study free surface behavior as well as the numerical predictions to quantify the heat transfer at a non-isothermal boundary condition in the absence of gravity.     

Drop Tower Experiments on Non-isothermal Reorientation of Cryogenic Liquids

Capillary driven surface oscillations of liquid argon (T_sat = 87.3 K at 1,013 hPa) have been investigated in a partly filled right circular cylinder under non-isothermal boundary conditions. The oscillations take place during the reorientation from the normal gravity surface position towards a new position upon step reduction of gravity. The situation is similar to the end of thrust in a rocket tank when the cold propellant moves along the warmer tank wall driven by capillary forces. The aim was to investigate the influence of the temperature difference between the slightly subcooled cryogenic liquid and the superheated cylinder wall on the oscillations and their characteristics in a single-component, two-phase system. Axial wall temperature gradients of averaged 0.15 K/mm ? 1.93 K/mm above the normal gravity surface position were implemented. A general dependence of the reorientation behavior on the gradient value was observed, concerning the apparent contact line behavior, the frequency and damping of the oscillations of the free surface center point, and the apparent contact angle. The behavior of the ullage pressure was found to follow the behavior of the contact line.     

Application of a chromium‐free photoresist to CRT screen processing

In 1998, Toyo Gosei Co. published a paper on the development of a new water‐soluble photopolymer of high sensitivity, PVA‐ARBB. In close co‐operation with LG. Philips Displays, the new material was further developed to be applicable in patterning the phosphor layer of a CRT screen. The new material shows about 3 times higher light sensitivity, gives 4–5% higher luminance, has no dark reaction, and is chromium‐free. It is the first chromium‐free photoresist used for phosphor patterning in CRT mass production. A comparison is presented between the conventional resist and the new resist. A survey is given of the most important process conditions.     

A fast numerical procedure for steady capillary flow in open channels

The surface evolver (SE) algorithm is a valued numerical tool for computations of complex equilibrium interfacial phenomena. In this work, an iterative procedure is implemented such that SE can be employed to predict steady-state flows along capillary channels of arbitrary cross-section. As a demonstration, a one-dimensional stream filament flow model is solved that approximates the pressure changes inside the channel. Despite its simplicity, the precision, stability, and speed of the method affirm it as an efficient and unique design tool for a variety of capillary flow problems. The procedure is ideally suited for slender column flows such as open wedge channel flows, several of which are validated herein via parabolic flight and drop tower experiments.     

热湿存储环境下须状晶体的生长机理与影响因素

纯哑锡表面的晶须特性已经成为IC封装中无铅焊接工艺实施的主要影响因素之一。由于其它替代方法,例如预先在引脚上镀Ni/Pd/Au层,会导致成本无法预估以及可靠性下降等问题,因此,目前的关注点是进一步减少纯锡表面须状晶体的生长。     

一种用于实时体绘制系统的自适应采样算法

本文讨论了一种用于体绘制的、支持基于空间跳跃和自适应光线终止等优化算法的高效硬件结构及一种加速半透明物体绘制的新技术.这种硬件结构用于绘制规模为256³体元的数据时可达到70Hz的帧频,但这样的帧频只是在体元的透明度都被置为0(完全透明)或1(完全不透明)的情况下才能取得.引入新的加速技术后,绘制半透明物体的帧频也可接近上述数值.新的加速技术采用自适应采样步长减少体绘制过程中冗余的体元重采样,从而使算法的复杂度和对存储器的带宽要求大大减小.新的加速技术对半透明体数据可取得高达4.7倍的加速比.采用新的加速技术需要在开始交互绘制前对体数据进行距离编码.优化后的距离编码对有8兆体元的体数据的预处理时间仅需要8~30秒.     

质量上的最高水准与操作上的方便性--RSB-D 35并条工艺

全球范围内的纺纱厂一直面对着以下挑战和要求: ·为了保持竞争力,必须一直有稳定的纱线质量; ·国际性的竞争要求生产成本不断降低;     

Reconfigurable optoelectronic wavelength translation based on anintegrated electroabsorption modulated laser array

Reconfigurable optoelectronic wavelength conversion to 11 100-GHz spaced wavelengths is achieved using a wavelength selectable laser array with an integrated electroabsorption (EA) modulator at a bit rate of 2.5 Gb/s. Wide dynamic range at the input from -24.2 to -6.5 dBm is achieved and uniform back-to-back transmission performance is measured for all wavelengths     

Neutron detection by measuring capture gammas in a calorimetric approach

The neutron capture detector (NCD) is introduced as a novel detection scheme for thermal and epithermal neutrons that could provide large-area neutron counters by using common detector materials and proven technologies. The NCD is based on the fact that neutron captures are usually followed by prompt gamma cascades, where the sum energy of the gammas equals to the total excitation energy of typically 6-9 MeV. This large sum energy is measured in a calorimetric approach and taken as the signature of a neutron capture event. An NCD consists of a neutron converter, comprising of constituents with large elemental neutron capture cross-section like cadmium or gadolinium, which is embedded in common scintillator material. The scintillator must be large and dense enough to absorb with reasonable probability a portion of the sum energy that exceeds the energy of gammas emitted by common (natural, medical, industrial) radiation sources. An energy window, advantageously complemented with a multiplicity filter, then discriminates neutron capture signals against background. The paper presents experimental results obtained at the cold-neutron beam of the BER II research reactor, Helmholtz-Zentrum Berlin, and at other neutron sources with a prototype NCD, consisting of four BGO crystals with embedded cadmium sheets, and with a benchmark configuration consisting of two separate NaI(Tl) detectors. The detector responses are in excellent agreement with predictions of a simulation model developed for optimizing NCD configurations. NCDs could be deployed as neutron detectors in radiation portal monitors (RPMs). Advanced modular scintillation detector systems could even combine neutron and gamma sensitivity with excellent background suppression at minimum overall expense.