Optimal resource allocation for wireless video over CDMA networks

We present a multiple-channel video transmission scheme in wireless CDMA networks over multipath fading channels. We map an embedded video bitstream, which is encoded into multiple independently decodable layers by 3D-ESCOT video coding technique, to multiple CDMA channels. One video source layer is transmitted over one CDMA channel. Each video source layer is protected by a product channel code structure. A product channel code is obtained by the combination of a row code based on rate compatible punctured convolutional code (RCPC) with cyclic redundancy check (CRC) error detection and a source-channel column code, i.e., systematic rate-compatible Reed-Solomon (RS) style erasure code. For a given budget on the available bandwidth and total transmit power, the transmitter determines the optimal power allocations and the optimal transmission rates among multiple CDMA channels, as well as the optimal product channel code rate allocation, i.e., the optimal unequal Reed-Solomon code source/parity rate allocations and the optimal RCPC rate protection for each channel. In formulating such an optimization problem, we make use of results on the large-system CDMA performance for various multiuser receivers in multipath fading channels. The channel is modeled as the concatenation of wireless BER channel and a wireline packet erasure channel with a fixed packet loss probability. By solving the optimization problem, we obtain the optimal power level allocation and the optimal transmission rate allocation over multiple CDMA channels. For each CDMA channel, we also employ a fast joint source-channel coding algorithm to obtain the optimal product channel code structure. Simulation results show that the proposed framework allows the video quality to degrade gracefully as the fading worsens or the bandwidth decreases, and it offers improved video quality at the receiver.     

Al_(10)Zn_(2.9)Mg_(1.7)Cu超高强铝合金的喷射成形制备研究

采用喷射成形技术制备了Al1 0 Zn2 .9Mg1 .7Cu高强高韧铝合金沉积坯件 ,研究了喷射成形制备过程中各工艺参数对沉积坯件的成形性、显微组织、致密度的影响 ,确定了适当的工艺参数 ,研究了沉积坯件的热挤压及热处理工艺 ,对材料的组织进行了分析并对不同状态的材料性能进行了比较。研究结果表明 :当喷射成形工艺参数合理时 ,沉积坯件具有良好的成形性与致密度 ,在随后的热挤压过程中 ,通过较低的挤压比即可使材料达到全致密 ;通过对合金进行适当的热处理 ,材料的极限抗拉强度达到 810MPa ,同时延伸率保持在 8%～ 11% ,该材料是一种理想的轻质高强结构材料。     

GM300电台的调试原理及方法

GM300电台是一种性能优良的电台，目前在我国的地震勘探领域广泛应用。与其它类型的电台相比，GM300电台的调试方法完全不同。掌握其调试原理及方法是对该类电台进行正确维护的基础。本文从分析GM300电台调试原理入手，总结了该电台的调试方法。     

The Bisphosphonate Clodronate Modifying Hydroxyapatite Bioceramics for Bone Scaffold

To investigate the efficiency of clodronate modifying HA bioceramics,and to evaluate the effect of clodronate modifying HA bioceramics on the cells in vitro,clodronate modified the porous HA bioceramics for bone scaffold by chelation .The outermost layer of the specimens was analyzd by XPS and FI-IR ,The depth profile was investigated by the argon-ion sputtering method.The cell culture test was conducted using MC3T3-E1 osteoblastic cells,The cells were inoculated and cultured on the scaffolds.Morphological observation of the cells,MTT test and ALP activity test evaluated the cell attachment ,proliferation and activity on the scaffolds.The cell culture test in cell quantity and morphology indicated active proliferation of the cells on the scaffolds.The ALP activity of the cells cultured for 3d and 7d on clodronate-HA bioceramics was slightly higher than that on HA bioceramics ,but the difference was not signifcant,This result indicated that clodronate-HA bioeramics had favorable cytocompatibility to be used as bone scaffold with potential ability to improve asteogensis.     

水轮机过流部件磨蚀问题的研究与防护

针对我国高含沙水流中运行的水轮机组的过流部件的磨蚀这个长期存在的疑难问题，开展研究工作，在分析水轮机过流部件泥沙磨损、空化破坏各自的磨损机理、特点、影响因素、预测模型等的基础上，总结出水轮机过流部件的磨蚀主要是泥沙磨损、空化破坏及它们的联合作用，提出水轮机过流部件磨蚀的主要防护措施，为最终解决水轮机过流部件磨蚀问题提供了理论依据。图6幅，表1个。     

用Simadyn-D改造宝钢150t电弧炉整流器控制系统

宝钢炼钢厂150 t电弧炉是我国目前最大的直流电弧炉,2003年对其整流器控制系统进行了改造。新系统采用的硬件是西门子公司的Simadyn-D系统,采用CFC编程环境。由于新系统可以与冶炼弧流模型紧密结合,因此保证了在各冶炼阶段调节器性能的最优。     

模糊环境的表示及机器人轨迹规划

本文利用模糊集理论，提出一种非确定环境的描述方法，并且针对机器人在该类环境中的避障轨迹规划，建立了相应的决策函数和规划策略，最后，给出在ＰＣ－３８６计算机上的仿真试验结果。     

ATP-Dependent inhibition of Ca2+-activated K+ channels in vascular smooth muscle cells by neuropeptide Y

Neuropeptide Y(NPY) inhibits Ca2+-activated K+ channels reversibly in vascular smooth muscle cells from the rat tail artery. NPY (200 microM) had no effect in the absence of intracellular adenosine 5'-triphosphate (ATP) and when the metabolic poison cyanide-M-chlorophenyl hydrozone (10 microM) was included in the intracellular pipette solution. NPY was also not effective when ATP was substituted by the non-hydrolysable ATP analogue adenosine 5'-[beta gamma-methylene]-triphosphate (AMP-PCP). NPY inhibited Ca2+-activated K+ channel activity when ATP was replaced by adenosine 5'-O-(3-thiotriphosphate) (ATP [gamma-S]) and the inhibition was not readily reversed upon washing. Protein kinase inhibitor (1 microM), a specific inhibitor of adenosine 3', 5'-cyclic monophosphate-dependent protein kinase, had no significant effect on the inhibitory action of NPY. The effect of NPY on single-channel activity was inhibited by the tyrosine kinase inhibitor genistein (10 microM) but not by daidzein, an inactive analogue of genistein. These observations suggest that the inhibition by NPY of Ca2+-activated K+ channels is mediated by ATP-dependent phosphorylation. The inhibitory effect of NPY was antagonized by the tyrosine kinase inhibitor genistein.     

小型水电站联网改造应注意的几个问题

针对铜鼓县小水电站联网时存在的问题及其不利影响进行了分析，井提出了改进途径，指出小水电站的联网改造应立足安全，争取效益。     

PET／PC共混物的辐射效应研究

研究了经溶液共混制备的聚对苯二甲酸乙二醇酯／聚碳酸酯（ＰＥＴ／ＰＣ）共混物的辐射效应。结果表明：ＰＥＴ／ＰＣ共混物在辐照过程中未发生酯交换反应和交联反应，但有降解反应发生。在研究的剂量范围内，辐照对ＰＥＴ／ＰＣ共混物中ＰＥＴ和ＰＣ的晶体形态影响不明显。