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.     

Parameters evaluation of SOLA algorithm for time scale modification

Successful operation of the Synchronous Overlap and Add (SOLA) algorithm for Time Scale Modification (TSM) of speech is closely tied to the proper choice of parameters. This paper investigates the quality of time scale modified speech under different values of primary parameters. Based on Mean Opinion Score (MOS) tests and Bark Spectral Distortion (BSD) measure, the proper choices of synthesis shift (Ss) and the duration of the shift search interval (K _max?) are given experimentally. The conclusions can be helpful for operating the SOLA algorithm for time scale modification of speech.     

Template-assisted synthesis of lamellar mesostructured hydroxyapatites

Novel lamellar mesostructured hydroxyapatites have firstly been synthesized by template-assisted technique. The mild and nontoxic surfactant, phosphoric acid monododecyl ester (MAP), is used to act as a structure-directing template. The structure of sample was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Scanning electron microscope and Transmission electron microscopy. The results indicate that the obtained sample is a well-organized lamellar mesostructured hydroxyapatite with a uniform layer spacing of 3.64 nm.     

宝钢2号高炉4号热风炉凉炉实践

对宝钢2号高炉4号热风炉凉炉的原因、凉炉的前期族备工作、凉炉的设备和方法以及凉炉的实际效果进行了总结。通过这次凉炉实践，取得了一些有价值的经验，这些经验对今后宝钢砖硅热风炉的凉炉具有重要的参考意义。     

Trellis and convolutional precoding for transmitter-based interference presubtraction

This paper studies the combination of practical trellis and convolution codes with Tomlinson-Harashima precoding (THP) for the presubtraction of multiuser interference that is known at the transmitter but not known at the receiver. It is well known that a straightforward application of THP suffers power, modulo, and shaping losses. This paper proposes generalizations of THP that recover some of these losses. At a high signal-to-noise ratio (SNR), the precoding loss is dominated by the shaping loss, which is about 1.53 dB. To recover shaping loss, a trellis-shaping technique is developed that takes into account the knowledge of a noncausal interfering sequence, rather than just the instantaneous interference. At rates of 2 and 3 bits per transmission, trellis shaping is shown to be able to recover almost all of the 1.53-dB shaping loss. At a low SNR, the precoding loss is dominated by power and modulo losses, which can be as large as 3-4 dB. To recover these losses, a technique that incorporates partial interference presubtraction (PIP) within convolutional decoding is developed. At rates of 0.5 and 0.25 bits per transmission, PIP is able to recover 1-1.5 dB of the power loss. For intermediate SNR channels, a combination of the two schemes is shown to recover both power and shaping losses.     

N,N''-取代邻苯二胺的合成

通过2-取代苯并咪唑盐的还原开环反应制备了8个N,N′-不同取代的邻苯二胺,并经1HNMR、IR、MS及元素分析表征,其中5个未见文献报道.这是一条由邻苯二胺和羧酸经2.取代苯并咪唑制取该类化合物的简洁合成路线.     

一个用户接口管理系统

本文介绍了一个用户接口管理系统NUUIMS的设计和实现.重点叙述了该系统基于规范化目标用户接口模型的设计思想,系统组成及描述方法.文章也讨论了使用NUUIMS设计而成的用户接口的特点.     

基于ARIMA和支撑矢量机组合预测的惯性器件故障预报

文中提出一种基于ARIMA和支撑矢量机进行组合预测的方法,该方法综合运用ARIMA良好的线性拟合能力和支撑矢量机强大的非线性映射功能,将两种预测模型有机地组合在一起,综合各自优点,以期有效改善模型的拟合能力,获得最优预测效果.文中将该方法应用于某飞行器惯性器件的故障预报当中并进行了仿真实验.结果表明,这种方法相对于单项模型的预测具有更高的精度,对于复杂时间序列的分析和预测有很好的应用价值,在故障预报中具有广泛的应用前景.     

中国铜冶炼企业的竞争趋势及对策建议

文章分析了我国大型及中小型铜冶炼企业所面临竞争环境,提出了我国铜冶炼企业应采取的对策建议,即:联合进口原料;走大型企业联合之路,组建中国铜业集团;开发利用海外资源;加大国内资源勘探;继续进行技改、挖潜,提高企业竞争力等。     

Preparation and photochromism of nanocomposite thin film based on polyoxometalate and polyethyleneglycol

A photochromic nanocomposite based on Keggin structure phosphomolybdic acid (PMoA) well dispersed in polyethyleneglycol (PEG) was fabricated. TEM image showed that PMoA nanoparticles with narrow size distribution were finely dispersed in polymer matrix. FT-IR results showed that the Keggin geometry of polyoxometalates was still preserved inside the composites and strong coulombic interaction was built between PMoA and polymer matrix. Under UV irradiation, the film was reduced photochemically to yield a blue species, which was in accordance with a charge-transfer mechanism.