Polybrominated Diphenyl Ethers in Surface Sediment from Songhua River Basin, Northeast of China

Sixty sediment samples were collected from the main Songhua River in three years. Twelve polybrominated diphenyl ether ( PBDE) congeners ( BDE17, 28, 47, 66, 99, 100, 153, 154, 138, 183, and BDE?209) w...     

从复杂硫化精矿中浸取金和银 1.氰化浸取动力学的研究

报导了从含铜硫化金精矿中氰化浸取金和银的动力学。实验考察了室温下氰化过程中精矿粒度、矿浆搅拌强度、初始氰浓度和氧分压等过程参量对金和银溶解动力学的影响。其实验数据以末反应核收缩模型进行数学处理,得到一个关联初始氰浓度和氧分压的溶解速度常数表达式。速率模型和贵金属氧化溶解的电化学机理相符,并表明氰离子和溶解氧分子扩散通过金粒表面的多孔层是速率控制步骤。     

电热流态床渗碳动力学

在石墨流态粒子炉中,在直接电阻加热的影响下,强化了表面过程和加速了碳在奥氏体中的扩散,因而渗碳速度比在常规的气体炉中快得多,作者利用一台在设计时消除了第二影响因素的流态床炉探讨了前一因素对阿姆柯铁试样渗碳动力学的影响。     

Al—Zn—Mg三元合金的晶界偏析

使用俄歇电子光谱仪对合金添加剂在新淬火,未充分时效、峰值时效和过时效状态的三元Al—5.5％Zn—2.5％Mg合金晶界处的含量分布情况进行了测量。AES深度分布图示出了Mg和Zn在晶界处的明显偏析,它与以前对相同合金的测量结果完全不同。还发现,这种明显的矛盾,可通过AES光谱的等离子损失特点来阐明晶界偏析情况面得到解决。用AES等离子损耗测量方法,即可测定Mg和Zn在晶界处的偏析,又能测定合金添加剂周围的冶金环境。还指出,过时效的Al合金试样,仅有部分Mg(占晶界处总Mg含量的一部分)进入了MgZn_2沉淀相,余者则集中分布在界面处的几个原子层内。     

离子渗氮在曲轴增强上的应用

或为在实现提高车辆装载的限制,或为在汽油机和柴油机上应用增压器,曲轴的增强问题总是会被提出的。功率的增加必然会导致要使用更加合理的材料和热处理,以及这种工件的更小的尺寸公差。在《MTZ》杂志上已提出过这个问题的几个方面,而我     

日本高纯铝的生产

1 生产现状高纯铝的应用包括铝制电解电容器与磁盘基片。霍尔-埃鲁法生产的铝的纯度为99.5～99.9％,必须经过进一步的精炼,才能获得高纯铝。日本采用的主要铝精炼法是三层液电解     

Note: Simultaneous electrical and optical detection of expanding dense partially ionized vapour clouds

The scheme and construction of an electro-optical probe able to collect charge and detect optical emission from expanding dense partially ionized vapour clouds are reported. The instrument can be applied to phenomena such as dust impact ionization and solid target laser ablation. First, results of measurements of expanding plasma cloud formed upon ablating W target are presented. Use of the instrument in different experimental facilities, including tokamak, is discussed.     

Pressure waves in the aorta during isolated abdominal belt loading: the magnitude, phasing, and attenuation

While rupture of the aorta is a leading cause of sudden death following motor vehicle crashes, the specific mechanism that causes this injury is not currently well understood. Aortic ruptures occurring in the field are likely due to a complex combination of contributing factors such as acceleration, compression of the chest, and increased pressure within the aorta. The objective of the current study was to investigate one of these factors in more detail than has been done previously; specifically, to investigate the in situ intra-aortic pressure generated during isolated belt loading to the abdomen. Ten juvenile swine were subjected to dynamic belt loads applied to the abdomen. Intraaortic pressure was measured at multiple locations to assess the magnitude and propagation of the resulting blood pressure wave. The greatest average peak pressure (113.6 +/- 43.5 kPa) was measured in the abdominal aorta. Pressures measured in the thoracic aorta and aortic arch were 70 per cent and 50 per cent, respectively, that measured in the abdominal aorta. No macroscopic aortic trauma was observed. To the authors' knowledge the present study is the first one to document the presence, propagation, and attenuation of a transient pressure wave in the aorta generated by abdominal belt loading. The superiorly moving wave is sufficient to generate hydrostatic and intimal shear stress in the aorta, possibly contributing to the hypothesized mechanisms of traumatic aortic rupture.     

Sensitivity analysis for the SimpleTreat model to simulate fate of chemicals in sewage treatment plants

SimpleTreat 3.1 predicts the distribution and elimination of chemicals by sewage treatment. The model is used as the default calculation in EUSES 2.0 to estimate exposure concentration in the receiving water, soil and air. A sensitivity analysis was performed to rank input parameters according to their influence on model predictions. Triclosan was selected for the base case. The sewage flow, degradation rates and parameters describing the raw sewage were shown to be the most sensitive inputs. The pH and dissociation constant are very sensitive parameters when working with ionisable compounds. Variation in certain input parameters was propagated through the model to yield greater variation in output parameters with a maximum ratio of 4.0. SimpleTreat 3.1 is a steady state model describing a highly non-steady system. A large variability in the most sensitive parameters is expected within a single sewage plant and parameters should therefore be selected to cover this variability.