厚板双曲率模冲压过程的数值模拟与分析

使用有限元方法研究了在制造某特大型真空容器时厚板料的双曲率模冲压过程.对双曲率模冲压后板料的回弹规律进行了模拟,得出了不同的板宽和板厚对板料冲压后回弹量的影响规律,从而为确定冲模修正量的大小提供了依据.同时,也得出了厚板料双曲率模冲压的变形的发生和发展过程,从而为采取措施,避免方板冲压时的屈曲和起皱,使变形过程按照合理的路线进行提供了理论根据.所得结果具有普遍的规律.     

二维无压稳定渗流分析的改进方法

人类发展演变过程中,经历了各种各样的地质作用所造成的灾害,其中大部分地质灾害的形成都有地下水的参与,因而确定地质体稳定性时不能忽略地下水。无压渗流是比较复杂的非线性问题,难点在于如何求自由面, 尤其是对溢出点的求解一直没有很好的解决。本文提出了求解无压渗流自由面的一种新方法,在采用等效渗透系数法搜索到自由面后,通过反复移动溢出点再次搜索自由面,最终达到准确求解自由面的目的。实例证明该方法是简单准确有效的。本方法对解决工程问题具有一定的实际意义。     

碱性条件下化学法处理大同齿轮厂混合电镀废水

针对大同齿轮厂电镀车间外排废水中既含CN- 离子 ,又含Cr6+及Ni2 +、Zn2 +、Cu2 +等重金属离子的现状 ,在碱性条件下 ,采用先氧化破氰 ,再还原六价铬至三价铬 ,最后混凝沉淀的处理工艺 ,使处理后出水达标排放     

浅谈推行清洁生产的必要性及技术方法

清洁生产是世界各国推进可持续发展所采用的一项基本策略，是《中国21世纪议程》提出的工业、交通、能源等实现可持续发展的核心战略措施。本文简要论述了清洁生产的内涵、大力推行清洁生产的必要性、实现清洁生产的技术方法。     

Quantification of human amniotic fluid constituents by high resolution proton nuclear magnetic resonance (NMR) spectroscopy

We have investigated the ability of high-resolution proton NMR spectroscopy to provide a biochemical constituent screening of human amniotic fluid (AF). Proton NMR spectra were obtained at 300 MHz on AF from patients undergoing amniocentesis in the mid-trimester. Only AF from normal pregnancies (normal fetal karyotype, normal a-fetoprotein levels, normal birth outcome) was used in this study. The AF supernatant was lyophilized and resuspended in deuterated water containing 0.1 mm phosphate buffer and 6.02 mm disodium maleate. Identification of low molecular weight compounds was confirmed by two-dimensional NMR spectra (primarily correlated spectroscopy, or COSY) and standard addition techniques. A broad profile of compounds were ‘NMR visible’ in a single proton spectrum, including creatinine, glucose, organic acids (acetate, citrate, and lactate) and several amino acids (alanine, histidine, leucine, phenylalanine, tyrosine and valine). The proton spectrum was unaffected by prior freezing/thawing of AF samples. We were able to quantify compounds by comparison with an added concentration standard (maleate) at concentrations as low as 30 μm. Good agreement with literature values based on other analytical techniques was obtained.     

十六位DAC转换器的研制

十六位DAC转换器是为MAT系列同位素质谱仪磁场控制关键部件DAC73K模块进行国产化而设计的,它能够与八位、或十六位微机相兼容,具有精度高、准确度好、温飘小等特点,它的研制成功不仅加速了MAT系列质谱仪国产化进程,而且在其它自动控制系统中得到广泛应用.     

颗粒物悬浮体系中聚合铝凝聚絮凝形态表征 (Ⅰ):Al-Feron法的应用研究

应用Ａｌ－Ｆｅｒｒｏｎ法于悬浮体系中聚合铝的形态分布表征，对其中的主要影响因素进行探讨，就不同碱化度聚合铝的形态分析进行实例研究．结果表明，混合方式对Ａｌ－Ｆｅｒｏｎ法的应用具有一定的影响作用．比色管混合测得Ａｌａ为２１．５４％，低于磁力搅拌方式结果（２４．５２％，２５．２２％，２５．０６％）．应用磁力搅拌方式可以获取较好的重复性与更多初期反应信息．颗粒物的存在对反应的影响主要取决于其浓度与粒度分布，成一定线性关系，可以从中加以扣除．在本实验范围内因其溶解所产生的影响可以忽略不计．对多个碱化度聚合铝的实例研究表明，Ａｌ－Ｆｅｒｏｎ法完全适用于颗粒物悬浮体系中的形态分布表征     

Eco-environmental susceptibility in Shangyi County,Northern Hebei Province,China

In this paper,the eco-environmental susceptibility of Shangyi County,Northern Hebei Province of China has been calculated by using the weighted-addition method based on expert's giving a mark to each influencing factor according to their knowledge on the influence of all the factors on eco-environmental susceptibility.The eco-environmental classification and distribution map were reached based on the above results,its difference is mainly result from the physical conditions and human activity,however the value of eco-environmental susceptibility is only a relative index which can not completely reflect the quality of eco-environment.This work provided a basis for controlling the further development of desertification.     

在磁场中活性炭吸附有机物的研究

将磁化技术引入吸附过程中，考察了磁场处理对活性炭吸附苯、硝基苯、苯甲酸、氯苯和苯酚的影响．结果表明，预磁处理能使非极性物质苯和极性较小的氯苯、苯酚在活性炭上的吸附容量减小，而使极性较大的苯甲酸和有NO2基团的硝基苯的吸附容量增大．增大磁场强度能加强苯和苯甲酸的磁处理效果。     

汉江水华的影响因素分析及控制方法初探

从分析汉江水华的状况、影响因素及其水华发生的参数阈值着手,初步探讨了汉江水华的控制方法。