The role of forest and bioenergy strategies in the global carbon cycle

Forest and bioenergy strategies offer the prospect of reduced CO₂ emissions to the atmosphere. Such strategies can affect the net flux of carbon to the atmosphere through 4 mechanisms: storage of C in the biosphere; storage of C in forest products; use of biofuels to displace fossil-fuel use; use of wood products which often displaces other products that require more fossil fuel for their production. We use the mathematical model GORCAM (Graz/Oak Ridge Carbon Accounting Model) to examine these mechanisms for 16 land-use scenarios. Over long time intervals the amount of C stored in the biosphere and in forest products reaches a steady state and continuing mitigation of C emissions depends on the extent to which fossil fuel use is displaced by the use of bioenergy and wood products. The relative effectiveness of alternative forest and bioenergy strategies and their impact on net C emissions strongly depend, for example, on the productivity of the site, its current usage, and the efficiency with which the harvest is used. When growth rates are high and harvest is used efficiently, the dominant opportunity for net reduction in C emissions is seen to be fossil-fuel displacement. At the growth rates and efficiencies of harvest utilization adopted in many of our base scenarios, the net C balance at the end of 100 years is very similar whether trees are harvested and used for energy and traditional forest products, or reforestation and forest protection strategies are implemented. The C balance on a plantation system that provides a constant output of biomass products can look different than the balance of a single parcel of land.     

MIM隧道结的电子输运特性和发光研究

论述作为一种新型发光器件的ＭＩＭ隧道结的发光机理，报告了该器件的发光现象和Ｉ－Ｖ特性曲线中负阻现象的实验观察。数据显示，结中表面等离极化激元（ＳＰＰ）与粗糙度的耦合是引起光发射的主要方面，ＳＰＰ对隧穿电子的阻塞作用导致了电子输运中的负阻现象。此外，还观察到了直接辐射的紫外峰。     

Method of increasing the output signal-to-noise ratio in passive multi-element antenna arrays

A method of processing complex signals in passive multi-element antenna arrays based on an analysis of the natural values of the correlation matrix of the signal is considered. By means of the method it is possible to substantially increase the output signal-to-noise ratio. An iterational process by means of which optimal estimators of both the signal and the amplitude-phase distribution may be obtained, is proposed. Theoretical estimators of the efficiency of the method are given. It is proved that, in terms of the efficiency, the approach considered in the article comes close to the technique of matched filtration. Results of statistical modeling that confirm the statistical results are presented.     

PLANTSCAPE系统在长庆银川配气站的应用

银川配气站是长庆油田公司采气一厂下属配气站之一,地处宁夏银川市长庆石油基地,肩负着向近10家天然气用户供气的任务,供气量也逐年增大,旧的生产模式(如双波纹管流量计量)已不能满足生产的需求。所以我们引进了HONEYWELL公司的PLANTSCAPE工业控制系统,该系统达到国际先进水平,在国内属于领先地位。伴随着气田的大规模开发,外供气量的逐年增加,此系统必将发挥更大的作用,对长庆气田的可持续发展具有十分重要的意义。     

Kinetics of phenol oxidation in a trickle bed reactor over active carbon catalyst

The wet air oxidation of phenol over a commercial active carbon catalyst was studied in a trickle bed reactor (TBR) in the temperature and oxygen partial pressure ranges of 120–160 °C and 0.1–0.2 MPa, respectively. The performance of the active carbon was compared in terms of phenol and COD destruction. The weight change of active carbon due to reaction was also measured. Finally, oxic phenol adsorption isotherms were assessed in batch conditions at 25, 125 and 160 °C. In order to use the conversion data obtained from the TBR for a kinetic study, special care was taken to check the kinetic control in the TBR experiments. Several kinetic models including power law or Langmuir–Hinshelwood expressions were considered to describe the catalytic oxidation of phenol over active carbon. The simple power law model with first order dependence on both phenol and oxygen concentration predicted satisfactorily the experimental data not only over the entire range of operating conditions studied, but also outside its validity range. Copyright © 2005 Society of Chemical Industry     

试谈我国紫菜资源的工业利用

介绍了我国紫菜工业在工艺改进、资源开发、综合利用和深度加工等方面的情况,提出了提高产率、降低物耗、增进效益和增加品种的途径。     

真空微电子三极管几何参数的设计考虑

真空微电子三极管是近年来兴起与发展的真空微电子学中的一类重要器件。本文从真空微三极管的工作特性出发,分析了这类器件中所需考虑的几何参数和工作特性的关系,并给出了一些理论和实验公式,为今后的设计提供一些参考。     

提高16Mn连铸坯控轧合格率

１６Ｍｎ连涛坯进行控轧时，按铸坯碳当量的上限和下限，分别采用两种不同的控轧制度。在邯钢中板分厂试轧的结果，轧材合格率均达到９６％以上，投产后轧材合格率达到９８％以上。     

论工业设计中产品造型设计之特征

本文系统地论述了工业设计中产品造型设计所具有的特征，双重性，时代性，民族性，协调性，独创性，经济性和模糊性，为企业开发新产品提供了科学的依据。     

石化行业污水回用途径的可行性分析

随着石化行业污水回用技术的成熟,污水回用途径成了制约污水回用的瓶颈。通过对各种回用水途径的可操作性比较,筛选出最佳途径,并通过现场试验,从技术、经济、可操作性方面论证,认为石化污水回用于工业循环冷却水场作为补充水确实可行。