牛奶加工过程中的清洗(二)

五．牛奶厂的清洗。目前，牛奶厂采用的清洗方式主要是CIP清洗(Cleaning in place)，原地清洗或称定置清洗，即在基本不拆卸或挪动机械装置和管线的情况下对生产过程中能与牛奶发生接触的设备表面进行的清洗。其冲刷、清洗、灭菌的整个过程全部实现了自动化因此大大降低了劳动强度。而有一些不     

半导体硅片清洗工艺发展方向

对半导体硅片传统的RCA清洗办法中各种清洗液的清洗原理、清洗特点、清洗局限以及清洗对硅片表面微观状态的影响进行了详细的论述,同时在此基础上,对新的清洗办法(改进的RCA清洗办法)进行了一定的说明,指出了硅片清洗工艺的发展方向。     

高密度印制板组件离心清洗工艺技术研究

针对低架空高度、高密度封装BGA和CSP底部难以清洗干净的难题,将离心清洗工艺技术应用于PCBA的清洗中.探讨清洗溶剂选择原则,研究离心清洗工艺原理,设计和优化了离心清洗工艺流程,设置了离心清洗工艺参数,分析以上因素对高密度印制板组件清洗效果的影响规律.清洁度检测结果表明:清洗溶剂选择正确,清洗工艺流程合理,离心清洗工...     

CBGA封装植球清洗影响因素分析

清洗是CBGA封装中的一道重要工序,它对电子产品的质量和可靠性起着极为重要的作用。对于CBGA电子产品,植球后都需要进行严格有效的清洗,以去除残留助焊剂和污染物。主要介绍了CBGA植球回流焊后助焊剂清洗的基本原理,分析了清洗温度和清洗剂浓度对陶瓷基板上残留的助焊剂清洗效果的影响,并对其影响机理进行了深入剖析。结果表明,清洗温度为55℃～65℃、清洗剂浓度为8%~12%时,残留助焊剂的清洗效果最佳。     

免清洗焊剂真的无需清洗？

使用免清洗焊剂意味着没有清洗的必要吗？一般而言，如果遵循规则进行焊接，免清洗残余是无害的，不需要清洗。但是，有些情况下，免清洗焊剂可能有害，应该从印刷电路组件(PCA)上清除掉。不知怎么回事，我们这个行业似乎已然将免清洗焊剂残余在任何情况下都无需清洗这种说法当成事实接受了。这种说法，与其说是事实，不如说是神话。它会带来一些长期性的问题。     

半水清洗替代ODS清洗PCB的技术探讨

本文主要叙述了ODS清洗剂对大气臭氧层的破坏，从而导致对人类生存环境的危害，介绍了目前替代ODS清洗剂的几种方法。其中半水清洗替代ODS清洗PCB的技术是一种比较好的工艺方法。本文着重对我公司在实施这种方法过程中，设备的选型、清洗荆的选择、清洗技术参数的设定、清洗效果等进行了探讨。     

多功能清洗平台

化学清洗是工业清洗中的重要手段，成套清洗装置是必要的装备。本文详细介绍了多功能清洗平台这种清洗装置，它可以方便地完成多种设备的清洗工作。     

激光清洗阈值和损伤阈值的研究

讨论了采用波长为３０８ｎｍ，脉冲宽度为２８ｎｓ的准分子激光清洗基片的实验研究，分析了激光清洗过程中清洗阈值和损伤阈值存在的原因，并对它们进行了定量性推导。     

宇航用PCB组件的半水清洗工艺研究

PCB组件的清洗是宇航电子产品装联中的重要工序,清洗的质量对PCB组件的可靠性影响极大。针对焊丝手工焊接和免清洗焊膏的再流焊接两种焊接方式进行了全自动半水清洗工艺研究。结果显示随着清洗剂浓度增加清洗效果越好,对清洗后的PCB组件进行了表面离子污染测试,离子污染量仅为0.14μg/cm2;同时还对清洗过程对元器件的标识影响进行了分析,研制了新型的固定工装,防止在清洗过程中PCB组件移动,探索出采用聚酰亚胺胶带保护电连接器腔体,防止多余物进入。     

化学清洗时机的确定

为了解决工厂常遇到的对设备进行化学清洗时机难以确定的问题，从设备安全、正常生产和节能的角度考虑，提出包括新装设备的清洗，定期清洗，根据结垢量决定清洗时机，根据运行参数决定清洗时机，从经济上考虑等确定清洗时机的方法及其依据，推导出有关的计算公式。据此，工厂可从化学清洗获得更大效益。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.