金刚石薄膜的形核研究

本文介绍了当前金刚石薄膜形核的现状及用热丝化学气相沉积法在不同的衬底上沉积金刚石膜，对Si、Ni、Cu三种衬底生长的金刚石膜进行研究如何增大形核密度、提高形核质量。得到了制备高密度和高质量的金刚石膜的方法。     

基片预处理对CVD金刚石薄膜形核的影响

微波辅助等离子体化学气相沉积法是目前低压气相合成金刚石薄膜方法中应用最普遍、工艺最成熟的方法,形核是CVD金刚石沉积的第一步．利用微波辅助等离子体化学气相沉积装置,研究了硅基片预处理方式对金刚石薄膜形核密度的影响．在工作气压为5-8kPa,微波功率为2500—5000W,甲烷流量为4-8cm^3／min,氢气流量为200em3／min,沉积温度为500℃-850℃的条件下,在单晶Si基片上沉积金刚石薄膜．通过扫描电子显微镜形貌观察表明,基片预处理能够显著提高金刚石形核密度,同时用拉曼光谱表征了金刚石薄膜的质量,     

偏流对金刚石膜生长的影响

采用电子辅助热灯丝化学气相沉积(EA-CVD)方法沉积大面积金刚石膜,在金刚石膜的沉积过程中,偏流对金刚石膜沉积的影响会直接影响着金刚石膜的生长和质量。用Raman、SEM等手段对金刚石膜的生长特性进行了表征。     

涂石墨粉增强金刚石薄膜形核密度的研究

涂石墨粉增强金刚石薄膜形核密度的研究张贵锋，耿东生，李兴无，郑修麟关键词ＣＶＤ（化学气相沉积），预涂层，石墨粉，金刚石膜中图分类号ＴＢ４３微电子学等领域的应用往往要求金刚石选择性生长；而作为耐磨硬质涂层，要求最大限度地提高形核密度，以便获得连续、均匀...     

关于非均质形核问题的探讨

对金属结晶中非均质形核的热力学模型进行了深入研究，指出了此模型的弊端，提出了新的与均质形核基本一致的模型，使非均质形核的热力学模型更完善与切合实际。     

脉冲电流对形核率影响机制的研究

根据经典的形核理论及脉冲电流对凝固组织的作用机理,从电磁场理论出发研究了脉冲电流作用下晶粒细化的作用机制。通过讨论过冷度的变化对形核率的影响,研究了电流产生的电磁力效应及焦耳热效应对过冷度的影响,建立了电流与过冷度的关系式。研究结果表明了电流对形核率的影响主要是由于电流改变了过冷度,电流能否细化凝固组织由电磁力和焦耳热效应引起的过冷度的变化决定,并与脉冲宽度有关。     

关于非均质形核问题的探讨

对金属结晶中非均质形核的热力学模型进行了深入研究．指出了此模型的弊端．提出了新的与均质形核基本一致的模型．使非均质形核的热力学模型更完善与切合实际．     

外调制器直流偏压与输出光功率特性分析

根据铌酸锂晶体的电光调制特性,采用折射率椭球方法分析了x切y传马赫-曾德强度调制器的调制原理.讨论了直流偏置电压对调制器输出相位的影响,给出直流偏压与调制器输出光功率之间的非线性特性关系式.当调制器工作在最佳的直流偏置点Vπ/2附近时为近线性工作区;当直流偏压偏离Vπ/2过多,则造成较大幅度的输出光功率变化,并导致微波光纤链路中所传输的电信号失真.实验表明,测试结果与理论分析相符.     

THE EFFECT OF DIAMOND FILM NUCLEATION AND GROWTH IN DIFFERENT SUBSTRATE PRETREATMENT METHODS

The diamond film on single crystal silicon substrate in three kinds of substrate is deposited by pretreatment method using microwave plasma, the diamond film is analyzed using SEM and Raman, the reasons why substrate pretreatment affects nucleation and growth are probed. The results show that substrate pretreatment directly affects nucleation and growth of diamond film, homogeneous nucleation and growth can be formed only in suitable pretreatment method.     

STUDY ON SURFACE OF DIAMOND PARTICLE BY CHEMICAL CU-CLADDING AND ITS APPLICATION IN DIAMOND WHEEL

In this paper,a method that a layer of Cuwas cladded on the surface of diamond particle by an apprro-priate chemically Cu-cladded process was put forward.Themethod can adjust the thickness of cladding by one step ormultiple steps.The composition and structure of Cu-claddeddiamond were analyzed with help of XRD,SEM and EP-MA.The results show that copper was homogeneously dis-persed on the surface of diamond particle by this method,thedeposited copper is loosely dispersed by one step cladding pro-cess,and the copper is tightly organized by multiple stepscladding process.Copper presents crystalline,and a smallamount of oxygen and iron exits in copper layer.Wearing testshows that the wear-resisting property of Cu-cladded dia-mond wheel is superior to that of general diamona wheel,andthat of diamond of which Cu-cladded thickness is depositedmore thickly by multi-steps cladding process is better.     

超声场对碳酸钙反应结晶成核影响的研究

研究了超声场作用对反应结晶过程中成核诱导期的影响.以碳酸钙为实验对象,在不同频率和超声作用时间下观察了成核诱导期的变化,结果表明,结晶诱导期随着超声作用时间的增加而缩短.机理分析认为超声场对成核过程的主要影响有两个方面:溶液表面张力的下降和扩散系数的上升.超声场作用可降低成核诱导期.     

常压MOCVD法制备ZnTe单晶膜

本文叙述了常压MOCVD法制备ZnTe单晶膜的方法.通过x-ray衍射和光政发光的测量,表明已生长出高质量的ZnTe单晶膜.为生长ZnSxTel-x固溶体,获得从绿色到紫色的发光材料准备了条件.     

射频辅助脉冲激光沉积镀膜技术的特点

介绍了脉冲激光沉积（PLD）制备薄膜的原理，讨论了射频辅助脉冲激光沉积镀膜技术的特点，通过分析比较证实了射频辅助脉冲激光沉积比无射频辅助脉冲激光沉积具有更突出的优点。     

离子轰击在玻璃蒸发镀膜中的应用

提出了在蒸发镀膜玻璃中引入离子轰击的方法，阐述了蒸发镀膜过程中离子轰击的工作原理，并运用断面电子描描显微观察，评价了离子轰击对薄膜附着性能的影响。     

EFFECT OF NaOH ON HYDRATES OF SILICATE CONCRETE IN ANTOCLAVE SYSTEM

In this paper,the macro properties and hy-dration phases of lime-sand silicate concrete which NaOH ofvarious contents are added are studied by means of XRD、SEM etc.The results reveal that the addition of NaOHgreatly increases the alkalinity of the concrete and have littleinfluence on compressive strength of the concrete,the results also show that the addition of NaOH promotes the for-mation of low alkaline hydrous calcium silicates but inhibitsthe formation of high-alkaline hydrous calcium silcates inthe concrete.     

CHEMICAL DURABILITY OF WINDOW GLASS IN TALL BUILDING AND ITS EFFECT ON STRENGTH

The window glasses in tall buildings areexposed to rain,polluted air and sunshine,etc.In thispaper the variance of the surface chemical durabilityand bending strength of float glass under the influenceof acid,alkali,CO_2,ultra-violet ray are investigated byelectron probe X-ray microanalyser,atomic absorptionspectrophotometer,FT-IR spectrometer and Materialstesting machine.It is found that the concentration ofNa ion at glass surface changes after the glass reactswith the media mentioned above and the bending strengthof glass is increased with the exception of the glass ex-posed to UV ray.If the micro-crack at glass surfacecan be treated properly,the bending strength will be im-proved.     

氟化电热蒸发ICP—AES直接测定茶叶中痕量元素

以聚四氟乙烯悬浮体为氟化剂,对悬浮体制样电热蒸发电感耦合等离子体原子发射光谱法(ETV—ICP—AES)直接测定茶叶中的痕量元素La、Yb、Y、Cu、Cr的蒸发行为及主要影响因素进行了研究。在优化实验条件下,方法的检出限为2．0～15．3ng／ml,相对标准偏差(RSD)为2．3％～4．0％。本法用于茶叶标样(GBW 07605)中痕量元素直接测定,结果与参考值基本一致。