Emergy account for biomass resource exploitation by agriculture in China

On the basis of Odum's ecological economic measure of emergy as embodied solar energy, a system account of biomass resource exploitation by agriculture in China 2004 is developed in this paper, which supplements a former study on corresponding long-term historical trends during 1978 to 2000 (Chen et al., 2006. Emergy-based analysis of the Chinese agriculture. Agriculture, Ecosystems and Environment 115, 161–173). The aggregate fluxes and indicators for biomass resource exploitation in China 2004 are calculated and illustrated when compared with those for 2000 to elucidate the latest status of the Chinese agriculture as the exploitation sector for biomass resource. Data sources and algorithm are presented in detail as basic references for related analysis involving the ecological economy of biomass exploitation in agriculture.     

Electrical properties and positron annihilation study of (Ba<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>Ho<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>)TiO<Subscript>3</Subscript> ceramics

DC resistivity, dielectric constant, dielectric loss and positron annihilation spectra of (Ba_1−x Ho _x )TiO₃ ceramics have been measured as a function of holmium concentration x. It has been found that the DC resistivity of (Ba_1−x Ho _x )TiO₃ is strongly dependent on the Ho content: it decreases three orders of magnitude and reaches a minimum at x = 0.4%. Doping with 0.6% holmium increases the permittivity of BaTiO₃ by approximately three times (from ∼1,300 to ∼4,000), with only a slight increase in the corresponding dielectric loss. The local electron density and defect concentration estimated using positron annihilation technique conforms well to the features found in the dielectric and resistivity measurements. The results have been discussed in terms of a mixed compensation model.     

Reliability Analysis on the δ-Shock Model of Complex Systems

We investigate the delta-shock model of complex systems consisting of n i.i.d. components. We first obtain a general lifetime distribution for the delta-shock model of a general complex system by reducing the system to a linear combination of parallel systems. We then consider coherent system structures including series, parallel, and k-out-of-n, then derive some useful results including reliability bounds, bounds on the mean lifetime, limiting distributions, and Laplace-Stieltes transforms     

BOPP薄膜生产中的功能母料

简述了BOPP薄膜生产过程中所需要的抗静电母料、防粘连母料和爽滑母料等功能母料，并分析了它们的作用、机理以及在生产中的应用特点。     

南渡江海口段防洪工程设计的关键问题

在建的南渡江河口段防洪工程具有海岸堤防工程的特点。本文对原堤防存在的问题、设计洪（潮）水面线的确定、不同条件下的堤防断面的设计、水土保持的设计以及环境保护设计等关键的技术问题，进行阐述，以供与一般江河堤防比较和类似海岸堤防工程参考。     

基于IR1167的智能同步整流控制

引言 随着近年来数字处理电路电压的不断降低，电源功率密度的不断提高，对于电源次级整流的要求越来越高。整流器件已从最初的肖特基二极管整流，发展到用同步整流开关管替代二极管，以降低功耗。目前，控制同步整流开关管的方法主要有分立式和基于锁相环的控制芯片两种。用分立元件实现同步整流的缺点是响应过慢，系统可靠性相对差。单芯片同步整流是基于锁相环技术的，从初级取信号同步控制次级整流开关管，这种方法的缺点是不能保证在间隔模式（轻载或空载时发生）下可靠操作。     

岩溶地区设计洪水计算的探讨

岩溶地区溶洞形状千姿百态，对洪水的影响程度各不相同，如何考虑其影响，在目前的水利水电工程设计规范中没有明确规定。贵州省是世界上典型的岩溶地貌地区之一，根据在贵州省水利水电工程设计的实践，总结摸索出针对不同溶洞状况、集水状况和水文站布设情况的设计洪水计算方法。在可确定岩溶集水面积条件下的方法有调洪演算法、溶洞削减法、叠加合成法和统一处理法；不能确定岩溶集水面积条件下的方法有流量法、地区综合法、统一处理法等。     

Blind channel estimation and equalization in wireless sensor networks based on correlations among sensors

In densely deployed wireless sensor networks, signals of adjacent sensors can be highly cross-correlated. This paper proposes to utilize such a property to develop efficient and robust blind channel identification and equalization algorithms. Blind equalization can be performed with complexity as low as O(N/spl tilde/), where N/spl tilde/ is the length of equalizers. Transmissions can be more power and bandwidth efficient in multipath propagation environment, which is especially important for wideband sensor networks such as those for acoustic location or video surveillance. The cross-correlation property of sensor signals and the finite sample effect are analyzed quantitatively to guide the design of low duty-cycle sensor networks. Simulations demonstrate the superior performance of the proposed method.     

Network traffic prediction based on a new time series model

Fast and accurate methods for predicting traffic properties and trend are essential for dynamic network resource management and congestion control. With the aim of performing online and feasible prediction of network traffic, this paper proposes a novel time series model, named adaptive autoregressive (AAR). This model is built upon an adaptive memory‐shortening technique and an adaptive‐order selection method originally developed by this study. Compared to the conventional one‐step ahead prediction using traditional Box–Jenkins time series models (e.g. AR, MA, ARMA, ARIMA and ARFIMA), performance results obtained from actual Internet traffic traces have demonstrated that the proposed AAR model is able to support online prediction of dynamic network traffic with reasonable accuracy and relatively low computation complexity. Copyright © 2005 John Wiley & Sons, Ltd.     

China＇s Electric Power Reform：Different Economics and Challenges

China＇s electric power reform has followed the western reform format, however, it doest not seem to have endorsed the liberalization ideology underlying the reform model. This raises the concern of whether and how a competitive power market may be established and reform objectives reached. The new market competition model is easy to build in theory. The experience of many countries suggests that the market reform is extremely difficult because of the interruptions by different interest groups. To transform a centrally planned power sector into a competitive power market is a daunting task. Policy makers need to take into consideration the transitional nature of the economy and power industry as they implement the competitive power market model.