试论会计电算化系统的内部控制

阐述了会计电算化系统产生和发展对内产控制的影响，以及内部控制的实施方法。     

中国石油未来油气勘探重点领域分析

根据近几年来的研究认识与勘探成果分析,未来几年中国石油油气勘探主要集中于如下五大重点领域:大面积低渗透岩性油气藏、成熟区复杂隐蔽油气藏、前陆盆地复杂构造油气藏、海相碳酸盐岩油气藏和渤海湾滩海第三系油气藏。     

太阳热水器:解决我国百姓生活热水的唯一有效途径

提起小康水平，人们往往想到人均收入、人均住房面积、人均受教育程度等，往往忽视了更能体现人们生活品质的另一项重要指标：人均生活热水消耗量。目前，发达国家家庭热水能源消耗占总能耗的比例为２５％～３０％。我国是一个能耗大国，人均常规能源占有量极低，２１世纪面临着经济的可持续发展与节能环保的双重课题。用可再生清洁能源解决全部或部分家用热水，节能环保意义重大，推广普及太阳热水器决不是无关紧要的，而是唯一有效途径。就现状而言，解决普通百姓生活热水的途径主要有使用电热水器、燃气热水器和太阳热水器三种。我们从能…     

ADS7822及其在CO气体浓度监测仪中的应用

在介绍TI公司的12位串行、高速、微功耗A/D转换器ADS7822工作原理的基础上,以ADS7822在CO气体浓度监测仪的前向通道设计中的应用为例,讨论了它与AT2051单片机的硬件接口问题,给出了利用ADS7822进行A/D转换的51汇编语言程序,并做了详细注释.串行、微功耗及小型封装使ADS7822非常适合电池供电的智能便携式仪器采用.     

尿素解吸废液及甲醇残液联合处理工艺的应用

安阳化学工业集团公司(以下简称安化集团)现有2套200 kt/a尿素装置及1套60 kt/a甲醇装置.尿素及甲醇装置在生产过程中会产生大量的尿素解吸废液和甲醇残液,废液中的氨氮(NH3-N)含量和化学需氧量(CODCr)较高,给该公司废水的达标排放带来很大压力.     

黄土丘陵沟壑区王家沟流域水文特征分析

王家沟流域属暖温带大陆性季风气候,冬季严寒少雪,春季干燥多风,夏季酷热多雨,秋季温凉适中,雨热同季,当地常见暴雨历时大多在2h以下,这种短历时、大强度的暴雨最易引起水土流失。分析了流域治理前后径流泥沙的来源情况,为同类型小流域综合治理提供科学依据。     

Study of specific absorption rate (SAR) induced in two child head models and in adult heads using mobile phones

This paper gives a first comparison of specific absorption rate (SAR) induced in a child-sized (CS) head and an adult head using a dual-band mobile phone. In the second study, the visible human head is considered and comparison of SAR induced in a CS or child-like (CL) head and an adult head using a dual-band mobile phone is given. All the peaks of average SAR over a mass of 10 and 1 g in the head and the power budget are determined in the two comparisons using the finite-difference time-domain method. The differences between the results for adult and CS or CL heads are given at 900 and 1800 MHz. No important differences are noted for the peak SAR averaged over 10 g (SAR10 g), between the two adult head models, as well as between the two child head models. The peak SAR10 g in the brain of the CS or CL head is slightly more significant than that for the adult one.     

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.     

Peracetic acid pretreatment of sugarcane bagasse for enzymatic hydrolysis: a continued work

Previous work has shown that the enzymatic hydrolysis of sugarcane bagasse could be greatly enhanced by peracetic acid (PAA) pretreatment. There are several factors affecting the enzymatic digestibility of the biomass, including lignin and hemicelluloses content, cellulose crystallinity, acetyl group content, accessible surface area and so on. The objective of this work is to analyze the mechanism of the enhancement of enzymatic digestibility caused by PAA pretreatment. Delignification resulted in an increase of the surface area and reduction of the irreversible absorption of cellulase, which helped to increase the enzymatic digestibility. The Fourier transform infrared (FTIR) spectrum showed that the absorption peaks of aromatic skeletal vibrations were weakened or disappeared after PAA pretreatment. However, the infrared crystallization index (N.O'KI) was increased. X‐ray diffraction (XRD) analysis indicated that the crystallinity of PAA‐treated samples was increased owing to the partial removal of amorphous lignin and hemicelluloses and probable physical change of cellulose. The effect of acetyl group content on enzymatic digestibility is negligible compared with the degree of delignification and crystallinity. The results indicate that enhancement of enzymatic digestibility of sugarcane bagasse by PAA pretreatment is achieved mainly by delignification and an increase in the surface area and exposure of cellulose fibers. Copyright © 2008 Society of Chemical Industry