潜孔锤冲击作用下土体变形的有限元分析

潜孔锤冲击挤密钻进过程中周围土体的变形机理是一个高度非线性问题。针对潜孔锤在土中的面-面接触问题,运用Drucker-Prager屈服准则为判据,将土体视为DP材料,通过钻具与土之间的接触及施加冲击载荷来模拟钻进过程,从而建立了潜孔锤在土中冲击挤密钻进的有限元模型。利用非线性瞬态动力学有限元分析手段,对钻进过程中冲击力对土的作用加以研究,分析了钻具周围土体的应力、应变以及钻具与土体的摩擦情况。结果表明,在冲击载荷作用下,锥形钻头前端土体应力集中,并形成应力泡,冲击功主要用于竖向压缩土体,而水平方向的挤压作用相对较小,摩擦应力在钻头锥面附近出现峰值,是影响钻进速度的主要原因之一。     

三维精细积分法地震正演及边界条件

 将任意差分精细积分法用于三维波动方程地震正演，关键在于如何消除数值计算中有限波场区域边界引起的边界反射。文中采用Berenger给出的电磁波完全匹配层吸收边界条件，推导出三维波动方程任意差分精细积分法地震正演的完全匹配层吸收边界条件计算公式，并给出了完全匹配层吸收边界条件算例。计算结果表明，此方法压制边界反射效果明显。三维波动方程地震正演模拟实例表明，完全匹配层吸收边界条件的任意差分精细积分法为复杂区地震波传播规律研究提供了一种实用的正演模拟工具     

胜科1井钻井事故的预防与处理

胜科1井设计井深7 000 m,完钻井深7 026 m。在该井钻井过程中,针对上部大尺寸钻头破岩效率低、大井眼井壁稳定性差、大段盐膏层、膏岩层的塑性蠕变和塑性流动造成井眼复杂、超深井高温高压给钻井液性能的控制和水泥浆调控等带来的一系列技术难题,制定了一整套预防井下事故和复杂情况的技术措施,从而确保了该井的钻探成功。该井在钻井过程发生了2次断钻具事故和1次卡钻事故,根据超深井的特点,采取了较为稳妥的处理措施,同时,有针对性地研制了高效铣环和PDC钻头专用打捞器,3次事故处理均获得了成功,共耗时38.5 d。详细介绍了该井所采取的预防和处理钻井事故的技术措施,可为其他超深井的钻井施工提供一定的借鉴。     

吸入短寿命氡子体动物肺组织剂量与体重关系的探讨

本文介绍吸入短寿命氡子体的不同种动物肺组织吸收剂量与体重的关系。实验结果表明,吸收剂量随体重的增加而减小。     

巯基棉预浓集—中子活化法测定水泥及其浸出水中的微量汞

在不同酸度下巯基棉可以从溶液中富集和分离Au、As、Ag、Br、Cu、Ca Co、InHg、Ni、Se、Sb、Sn、Pb、W、Fe和In等30多种元素。由于用巯基棉吸附待测元素后不必洗脱,因此大大提高了富集能力,可用于海水、地下水、地表水及工业废水中一些元素的测量。本文用巯基棉富集后进行中子活化分析测定水泥及其浸出水中的汞。     

秦岭造山带（陕西部分）中新生代陆内造山及与矿产关系

印支运动后的秦岭造山带受古亚洲构造域、环太平洋构造域和特题斯三大构造域联合作用，发生了强烈的陆内造山，奠定了该区条块相间构造岩片系统的基本构造格架，控制了本区斑岩型钼矿和众多热液型多金属矿产的最终成矿作用和矿带展布。     

辊涂花纹厚铝板浅谈

在1.0mm～3.0mm厚的铝板上辊涂花纹,是涂装领域的新课题,是亟待研发的新产品.对此,本文以行业扫描的眼光,蜻蜓点水,略谈几点个人浅见.     

Effects of home preparation on pesticide residues in cabbage

Experiment was carried out to evaluate the pesticides (chlorpyrifos, p,p-DDT, cypermethrin, chlorothalonil) residue levels in cabbage in the process of home preparation by washing with different concentrations of acetic acid and sodium chlorine, and tap water, preserving in refrigerator, and stir-frying for different time. Results showed that washing by tap water and/or detergent solution for cooking are necessary to decrease the concentration of pesticide residues in cabbage. Washing with acetic acid solutions (at 10% concentration for 20 min) caused 79.8%, 65.8%, 74.0% and 75.0% loss of the above pesticides, respectively. Washing with NaCl solutions (at 10% concentration for 20 min) produced 67.2%, 65.0%, 73.3% and 74.1% loss, respectively, and washing by tap water (for 20 min) were 17.6%, 17.1%, 19.1% and 15.2% loss, respectively. The reductions due to the refrigeration (for 48 h) were 3.4%, 2.6%, 3.1% and 3.6%, respectively, and those due to the stir-frying (for 5 min) were 86.6%, 67.5%, 84.7% and 84.8%, respectively. The data indicated that washing by detergent solutions and stir-frying of cabbage are the most effective home preparations for the elimination of pesticide residues.     

浅谈火灾调查的边缘化趋势

从火灾调查实际工作状态出发,提出火灾调查存在地位边缘化的趋势,并在分析边缘化趋势原因的基础上提出了相应的对策,供火灾调查同仁探讨。     

Optical Endless Polarization Stabilization at 9 krad/s With FPGA-Based Controller

We demonstrate endless polarization stabilization with a control speed of up to 9 krad/s, over random Poincare sphere trajectories. These are in total >35 Mrad long, are composed in particular of difficult-to-track circles with all radii and orientations, and thereby include all possible worst cases. The maximum polarization mismatch and relative intensity errors are 0.13 rad and 0.43%, respectively. The controller runs on a field-programmable gate array and uses a commercial multistage LiNbO₃ polarization transformer as the control device.