线光栅扫描实现衍射图形的矢量化直写

在双光束激光直写系统中,衍射光变图像的光刻是逐像素点进行的.本文提出在该系统中采用狭缝获得光栅线来进行衍射图形的直写,利用一种改进的矢量文件格式,使平台沿着垂直光栅线的方向运动,获得连续的多光点同时直写,直写后的衍射光栅线是连续的,系统的运行效率是逐点光刻的几十倍.编写了与DXF文件的接口直写控制程序,给出了实验结果.     

DXDK-70型包装机常见故障分析处理

我公司使用天津华特DXDK-70型包装机4台，在生产中出现的主要问题及解决方法作了详尽阐述，以供同行探讨。     

Preparation and properties of nano-sized SnO2 powder

1　INTRODUCTIONSnO2isoneofthemainmaterialsusedingassensor.Becauseofthehumidityandgassensingfunction,itattractsmoreandmoreattentions.Butthepresentproblemishowtoimprovethestabilityandsensibilityofgassensor.Researchershavetakenmanymeasurestoresolvethisproble…     

GaN and AlGaN high-voltage rectifiers grown by metal-organic chemical-vapor deposition

In this paper, we report the study of the electrical characteristics of GaN and AlGaN vertical p-i-n junctions and Schottky rectifiers grown on both sapphire and SiC substrates by metal-organic chemical-vapor deposition. For GaN p-i-n rectifiers grown on SiC with a relatively thin “i” region of 2 μm, a breakdown voltage over 400 V, and forward voltage as low as 4.5 V at 100 A/cm² are exhibited for a 60-μm-diameter device. A GaN Schottky diode with a 2-μm-thick undoped layer exhibits a blocking voltage in excess of ∼230 V at a reverse-leakage current density below 1 mA/cm², and a forward-voltage drop of 3.5 V at a current density of 100 A/cm². It has been found that with the same device structure and process approach, the leakage current of a device grown on a SiC substrate is much lower than a device grown on a sapphire substrate. The use of Mg ion implantation for p-guard rings as planar-edge terminations in mesageometry GaN Schottky rectifiers has also been studied.     

电子束和接触式曝光机的混合曝光技术

Ⅰ线光致抗蚀剂可以同时实用电子束和光学系统曝光，在50kV加速电压下，其曝光剂量为50-100μC/cm^2，曝光后在0.7%NaOH溶液内显影1分钟。其灵敏度比PMMA快5倍，分辩率为0.5μm。采用两方法制备CaAsPHEMT：一种用Ⅰ线光致抗蚀剂，对源、漏及栅全部都采用电子束曝光，制备了0.5μm栅长的GaAs PHEMT；另一种将源、漏及栅分割成两部分，其中精细部分由电子束曝光，其余部分由光学系统曝光，用这种方法制备了0.25μm栅长的GaAs PHEMT。Ⅰ     

具有除草活性的双膦酸衍生物的研究动态

许多含双膦酸结构单元的化合物都显示了良好的除草活性,本文对这类化合物的结构特点、生物活性以及相关的研究动态进行了归纳和概述。     

千米桥潜山构造特征及其在油气成藏中的作用

千米桥潜山是黄骅坳陷最典型的新生古储型油气藏，恢复潜山古构造是认识其油气藏特征的重点和难点之一，运用地质力学方法研究潜山内幕构造之后认为，该潜山的形成基础是古生界印支期宽缓复背斜，在燕山期挤压构造作用下形成由逆冲叠瓦扇和反冲断层构成的三角带内幕构造，抬升受侵蚀形成潜山主体，喜马拉雅的两次古旋拉张使潜山掀斜定型。晚第三纪以来发生整体热沉降，潜山两侧凹陷沙三段生成油气向潜山侧向运移成藏。     

α-蒎烯催化加氢反应的研究

以FYX - 2G型高压搅拌釜为加氢反应器 ,测定了在不同搅拌器型式和搅拌转速下高压釜的持气量和反应效果 ,认识到α 蒎烯催化加氢是外扩散控制的反应 ,当搅拌转速为 6 0 0r/min时 ,基本上能消除外扩散的影响。考察了Raney镍和Pd/C催化剂、反应温度在 35 3～ 499K ,压力在 4 0～ 10MPa的条件下对α 蒎烯加氢转化率和选择性的影响 ,结果表明Raney镍更适宜于α 蒎烯催化加氢 ,其转化率随温度、压力增加而提高 ,但选择性下降。采用温度 35 3～ 433K、压力 4 0～ 7 0MPa的操作序列 ,克服了α 蒎烯加氢转化率与选择性互为逆向的缺点 ,缩短了反应时间 ,制得了顺反比高达 18 2∶1的蒎烷 ,并且发现加氢反应从温度 433K开始有副产物对烷生成 ,当温度超过 45 6K时 ,加氢过程还出现飞温现象。     

微晶合金在电流互感器中的应用

从微晶合金的性能特点出发，分析了其在电流互感器中的应用前景。     

Automatic conversion from lexical words to prosodic words for mandarin text-to-speech system

In real speech, not like lexical words (LWs), prosodic words (PWs) are basic rhythmic units. The naturalness of a Text-to-Speech (TTS) system is directly influenced by the segmentation of the PWs. Most of the PWs are the combination of several LWs. In this paper, three Lexical Combination Models are proposed to combine LWs into PWs, including a Directed Acyclic Graph Model, a Segmentation Model and a Markov Model (MM). To cope with the situation where some long LWs should be segmented into two or more PWs, a Lexical Split Model (LSM) is applied to the long LWs. Experimental results prove that relatively constant results with various training data can be obtained from a MM. The Transformation-Based Error Driven Learning (TBED) algorithm, for its high performance of individual property, is applied in combination with the MM to improve the precision of PW segmentation. Experiments show that among the three proposed models, the MM combined with TBED and LSM, leads to the best performance, in which a precision of 93.00% and a recall of 93.23% are achieved. The perception test indicates that by using PWs as the lowest prosodic units a speech sounds more natural and acceptable than by using LWs. This paper is supported by NSFC Project (60503071); 973 Natural Basic Research Program of China (2004CB318102); Postdoctor Science Foundation of P. R. China (20070420275).