Spectrum efficient region-based resource allocation with fractional loading for FH-OFDMA cellular systems

A practical resource management method that can significantly reduce cochannel interference (CCI) and improve spectrum utilisation in FH-OFDMA packet-based cellular networks is presented. The proposed method seeks an effective combination of dynamic resource allocation with fractional coding and bit loading to respectively minimise CCI and maximise system throughput for a desired performance.     

2/spl times/4 optical add-drop module with no difference in propagation length

We developed a micromachined X-type 2/spl times/4 optical add-drop module (OADM) featuring no difference in propagation length. Four pairs of lensed fibers are aligned in "X" position, and four micromirrors are located between the pairs of optical fibers. The OADM was fabricated utilizing a silicon-on-insulator process. Electrostatic comb actuators can be driven up to 90 /spl mu/m to change the light path within 1 ms. The insertion loss and the on-off ratio were less than 3 and 70 dB, respectively. The loss uniformity in every channel was 1.5 dB.     

三圆弧形叶片型线理论及其泵的性能测试

介绍了三圆弧形叶片型线理论，叙述了采用该理论制造的150XA—520泵的叶轮、测量方法及结果。     

浅谈专业数字化图书馆建设

数字图书馆是图书馆发展的主要方向。在我国，数字图书馆建设存在一些问题。探索解决问题的方法和途径，是摆在我们面前的一项任务。     

Production and structural features of a water-soluble polysaccharide from a mutant strain of Agrobacterium sp.

We have developed a mutant strain derived from Agrobacterium sp. ATCC 31750, which produces a water-soluble polysaccharide having potential utility to the food, feed, pharmaceutical and cosmetic industries. A high concentration of product (15 g/L) is obtained by 48 h cultivation of the mutant strain under optimized fermentation conditions. The water-soluble polysaccharide obtained from cultures of the mutant strain beta82 has Glc:Man:Gal in approximate molar ratios of 5.8:6.7:1.0. The molecular weight of the polysaccharide was determined to be approximately 1000 kDa by HPSEC analysis. Linkage analysis contained 3-Glcp, 3-Manp, terminal Glcp and terminal Manp, as well as a small proportion of 3- and 3,4-Galp, and 4,6-Manp residues. Based on analyses using FT-IR and ¹³C NMR spectrometers, most glycosidic bonds joining these sugar residues are of the α-type, and acetyl groups are apparently attached to the polymer chain at random.     

生态平衡的伦理学意蕴解读

20世纪以来，人类采用技术工程治理、法律制裁和经济惩罚等措施，一定意义上改善了局部的生态环境，但是未能遏制住全球环境问题的恶化态势。生态危机的根本解决，关键在于人类自身必须进行深刻的利益观念和价值观念的变革。重新审视人与自然界的关系，对自然进行伦理关怀，寻求和建立以保护地球环境和人类生存与可持续发展的生态平衡理念。     

Simultaneous degradation of nitroaromatic compounds TNT,RDX, atrazine,and simazine by Pseudomonas putida HK‐6 in bench‐scale bioreactors

BACKGROUND: Environmental contamination by nitroaromatic compounds such as 2,4,6‐trinitrotoluene (TNT), hexahydro‐1,3,5‐trinitro‐1,3,5‐s‐triazine (RDX), atrazine, and/or simazine (TRAS) generated as waste from military and agricultural activities is a serious worldwide problem. Microbiological treatment of these compounds is an attractive method because many explosives and herbicides are biodegradable and the process can be made cost‐effective. We explored the feasibility of using cultures of Pseudomonas putida HK‐6 for simultaneous degradation of TRAS with the aim of microbial application in wastewater treatment in bench‐scale bioreactors. RESULTS: Experiments were conducted to study the effects of supplemental carbons, nitrogens, and Tween‐80 on the degradation of Ps. putida HK‐6 in media containing TRAS as target substrate(s). The most effective TRAS degradation was shown in the presence of molasses. Addition of nitrogen sources produced a delayed effect for the target substrate(s). Tween‐80 enhanced the degradation of target substrate(s). Simultaneous degradation of these compounds proceeded to completion within the given period. CONCLUSIONS: Ps. putida HK‐6 was capable of growth with TRAS, and the effects of supplements on TRAS degradation and simultaneous TRAS degradation were evaluated in bench‐scale bioreactors. The results of this study have practical applications in the processes of industrial waste stream treatment where the disposal of TRAS may be problematic. Copyright © 2008 Society of Chemical Industry     

真空相变锅炉低排烟温度设计与低温腐蚀

真空相变锅炉是否会明显发生烟气低温腐蚀，一直众说不一。文章从锅炉发生低温腐蚀的机理人手，通过理论分析计算并通过实践检验，提出了真空相变锅炉虽然不能完全避免低温腐蚀问题，但不论排烟温度是否高于烟气露点，低温腐蚀的程度都很弱的观点；给出了真空相变锅炉沿烟气流程金属壁面的腐蚀速度与壁面温度的关系曲线，和烟气温度低于酸露点时金属壁面的腐蚀速度与壁面温度的关系曲线；同时，文章推荐真空相变锅炉的设计排烟温度取130℃左右的低排烟温度。根据上述观点设计的数百台产品已经过多年实际运行，未发现明显     

长液信息化建设项目情况简介

1项目背景1.1公司面临的内外形势一方面,市场竞争加剧,客户对时间、价格、质量及个性化服务的要求越来越苛刻,市场瞬息万变,定单忽多忽少;另一方面,企业生产计划不准确,订单无法及时交付,库存积压严重。企业粗放式的管理造成产品成本居高不下,效率降低,越来越不能适应市场的需要,企业在行业中的排名也逐年下滑。