Emissions of volatile organic compounds originating from UK livestock agriculture

In this paper we estimate the quantity of non‐methane volatile organic compounds (NMVOCs) emitted from UK livestock. The final estimate is derived from published values and from direct measurements of NMVOC emissions from dairy cattle slurry and laying hen manure. Emission rates of NMVOCs were determined for fresh dairy cattle slurry and laying hen manure using a 40 m³ emissions chamber. Dimethyl sulphides dominated emissions from laying hen manure at 753 ± 263 g m^?3 day^?1. Emissions from dairy cattle slurry were dominated by volatile fatty acids (C₂? C₅, 6.3 ± 3.1 g m^?3 day^?1) and phenols (2.4 ± 1.2 g m^?3 day^?1). Many of these NMVOCs are decomposition products from protein sources from which ammonia is also a by‐product. There is a close association between ammonia and NMVOC production from manure, and on this basis we estimated the annual NMVOC emissions from UK livestock as 165 ± 56 kt for 2002. These emissions compare to those from the larger industrial and transport sectors and exceed the 50–100 kt C year^?1 currently determined as originating from biogenic sources including agriculture. These findings have implications for air quality, and these NMVOCs may affect the cleansing capacity of the troposphere. Copyright © 2004 Society of Chemical Industry     

小麦热激蛋白基因sHSP16.9植物表达载体构建

以小麦中国春热激蛋白基因sHSP1 6.9为材料,用PCR扩增的方法于目的基因片段5和3上分别添加Xba Ⅰ和Kpn Ⅰ的酶切位点,然后与植物表达载体pCAMBIA Super-1300连接.用Xba Ⅰ和Kpn Ⅰ进行双酶切验证,确定已将热激蛋白基因sHSP16.9连接到植物表达载体上,表达载体pCAMBIA Super-1300-TasHSP16.9构建成功.为验证小麦热激蛋白基因sHSP16.9的功能及转基因植物表达奠定基础.     

Kronig–Penney model simulation with equivalent circuit method

The Kronig–Penney model is quite useful for illustrating many important features of the quantum behaviour of electrons in periodic lattice. Although the Kronig–Penney model is well‐known and has been discussed in solid state textbooks, we try to use a simple and accessible way without the extremely laborious and tedious algebra evaluation to solve Kronig–Penney model. This paper presents a simple method without solving the difficult eigen‐problem to solve the Kronig–Penney model, and the important energy band characteristics can be easily obtained with circuit concepts. The simulation results are presented to demonstrate the accuracy and superiority of the model. Copyright © 2006 John Wiley & Sons, Ltd.     

Uplink channel assignment with balanced load for code division multiple access cellular systems

In a code division multiple access (CDMA) wireless communication system, each mobile handset must be power controlled such that the power received at the base station is roughly the same. Otherwise, the interferences between mobile handsets will degrade the performance and increase the error rate. When a mobile handset uses channels from the neighbouring cells, it will raise its power to meet the threshold of signal strength. This will also increase the interference in the home cell. Therefore, we do not want a mobile handset to use channels from other cells blindly. In this paper, we propose an uplink channel assignment method based on the directed retry concept for CDMA cellular systems. The purpose is to achieve load balancing between neighbouring cells and at the same time controlling the interference levels at the base stations such that it will not affect the performance. Furthermore, priorities are given to handoff calls when assigning channels. Copyright © 2002 John Wiley & Sons, Ltd.