ERP的发展、现状及展望

企业资源计划ERP已成为近期的热门话题，越来越多的企业已经开始采用MRPⅡ/ERP产品。本文作者就ERP发展历程，技术特点进行总结，对其发展进行展望，预示着未来随着ERP的完善，一种基于网络的全球化企业合作与虚拟企业运营的集成化企业管理系统必然产生。     

中国陶瓷业如何与国际市场对接——访中国建筑卫生陶瓷协会秘书长缪斌

我国是陶瓷生产大国,近几年发展速度很快.2001年,我国的建筑陶瓷产量约20亿平方米,卫生瓷5000万件以上,全年全行业出口额超过2亿美元,创历史最好水平.加入WTO给我国陶瓷行业带来了很多机遇和挑战,但我们究竟与意大利、西班牙等陶瓷强国差距在哪里呢?记者最近走访了中国建筑陶瓷协会秘书长缪斌先生.恰逢秘书长刚从欧洲考察回来,便聊起这次欧洲之行……     

Set－up of a Pure Electron Plasma Device

An electron Penning-Malmberg trap,which can confine an electron column and provide a good platform to investigate the cross-filed transportation of strongly magnetized electron plasma ,has been set up.With the device,an electron plasma with a density of 10^7 cm^-3 can be confined for a relatively long time.The structure of the trap,electron source,as well as the way how th measure electron plasma density profile and velocity distrbustion are introduced in detail.     

单晶凝固组织的样品尺寸效应

通过对不同直径的单晶样品的凝固实验，研究了样品尺寸对单晶凝固组织的影响规律，研究发现，随样品尺寸减小，单晶凝固组织被细化，尤其一次枝晶间距λ1和枝晶间γ′相尺寸对样品尺寸的依赖性更为明显；样品尺寸影响的要质在于此表面积的变化，进而对凝固过程温度梯度产生影响，最终作用于凝固组织和力学性能，一次枝晶间距λ1和枝晶间γ′尺寸与样品的比表面积近拟呈线性关系，样品尺寸变化，明显改变了单晶生长过程的温度梯度和合金的高温持久寿命。     

基于混沌电路的一种混合噪声调制雷达引信

提出了一种基于混沌电路的随机脉位调制（RPPM）和随机二相码调相（RBCPM）混合调制的雷达引信系统。介绍了该引信波形的数学模型，平均模型函数及引信的实现框图和工作原理，研究了基于混沌电路的混合调制信号的产生方法，这种引信波形不仅具有结构简单和易于处理等特点，而且具有良好的测距和测速性能，以及极低的截获概率和很强的抗干扰特性。     

Synthesis and Characterization of Poly （L-lactide-co-ε-caprolactone） Copolymers

A series of random and block poly（ L-lactide-co-e-caprolactone ） （ PCLA ） copolymers whh different composition are prepared using stannous octaoate as catalyst.The effects of the amount of initiator on the intrinsic viscosity have been investigated. The structure of the PCLA copolymers is characterized by means of nuclear magnetic resonance（ NMR ）, Fourier transform infrared spectrum （ FTIR ）, differential scanning calorimetry （ DSC ） and X- ray diffraction （ XRD ） methods. It is shown that the synthesis condition and the composition of copolymers obrious influence on the structure of PCLA copolymers. Hydrolytic degradation of the copolymers in a PBS solution of pH 7.4 at 37.0℃ shows that the copolymers of different composhions degrade at different rates.     

驱蚊酯的合成及应用研究

本文合成了一种高效低毒驱蚊剂-驱蚊酯[(insectifuge ester)[1],3-(Acetyl-butyl-amino)-propionic acid ethyl ester],并对其结构进行了全面鉴定,同时对其合成过程中所产生的副产物进行了分析测定。用驱蚊酯配成含2.3%驱蚊酯的花露水,并测试了其驱蚊效果,有效驱蚊时间可达5小时以上。     

超临界CO2流体萃取莪术挥发油的工艺研究

利用超临界CO2流体萃取技术,以榄香烯为目标物,研究了萃取压力、温度、时间、原料粒度和CO2流量对莪术挥发油萃取率的影响,建立了获得莪术挥发油的最佳工艺条件.实验结果表明,莪术粉粒度40目,萃取压力18 MPa,温度50℃,萃取时间120 min,流量20～30 kg/h条件下,挥发油中榄香烯含量最高,相对含量为2.8%,为以后精馏研究奠定了基础.     

公钥密码探源

如何能够在利用网络速度的同时,保护我们的信息安全,这给密码学家提出了一个难题。 公钥密码系统的诞生解决了这个难题。本文在研究了公钥密码学的教学基础上,以椭圆曲线加密 (ECC)为例,把椭圆曲线信息编码成二进制数,把明文加密成密文,把密文还原为明文,完整地研究 了公钥密码系统。     

Tile-boundary artifact reduction using odd tile size and the low-pass first convention.

It is well known that tile-boundary artifacts occur in wavelet-based lossy image coding. However, until now, their cause has not been understood well. In this paper, we show that boundary artifacts are an inescapable consequence of the usual methods used to choose tile size and the type of symmetric extension employed in a wavelet-based image decomposition system. This paper presents a novel method for reducing these tile-boundary artifacts. The method employs odd tile sizes (2N + 1 samples) rather than the conventional even tile sizes (2N samples). It is shown that, for the same bit rate, an image compressed using an odd tile length low-pass first (OTLPF) convention has significantly less boundary artifacts than an image compressed using even tile sizes. The OTLPF convention can also be incorporated into the JPEG 2000 image compression algorithm using extensions defined in Part 2 of this standard.