Spatial distribution of hexachlorocyclohexanes in agricultural soils in Zhejiang province, China, and correlations with elevation and temperature

Large quantities of hexachlorocyclohexanes (HCHs) were historically applied to soils in Zhejiang, a hilly province of eastern China, yet very limited information is publicly available for the present levels and residue characteristics of HCHs in the region. In this work, concentrations of HCHs and enantiomeric fractions (EFs) of α-isomer were analyzed in 58 agricultural soil samples (0-20 cm) collected in Zhejiang province. On the basis of the ratio of α-HCH/β-HCH and the fact that HCHs were banned in 1983 for agricultural use in China, fresh application of technical HCHs in a large quantity was unlikely in this province. Significant correlation was found between soil concentrations and elevation (R = 0.52, P < 0.001) and temperature (R = -0.55, P < 0.0001), but not between soil concentrations and total technical usage (R = -0.24, P = 0.1), suggesting a typical secondary distribution pattern. The soil residue inventories of HCHs derived from the relationship between concentration and elevation indicated 14.2 tons of HCHs left in agricultural soils in plain areas with the average elevation less than 100 m, and 61.6 tons of HCHs left in mountain soils with the average elevation higher than 100 m. It was also found that EFs of α-HCH were significantly negatively correlated with carbon biomass (C(bio)) in soils. This implies that C(bio) might have important impact on orientation and extent of enantioselective degradation of α-HCH in the region, which is, according to our knowledge, the first report of this kind.     

粘结层对不同形状叠层压电振子发电性能影响

针对悬臂梁叠层压电振子,利用ANSYS软件仿真分析了其自由端尺寸的改变对于压电振子的输出电压及其固有频率的影响,并得到了叠层压电振子在结合面上的切应力的变化关系。研究表明,在相同条件下,随着自由端尺寸的减小,压电振子的开路电压、基频均有不同程度的增加,但其结合面上的切应力却有较大程度的增幅(最大为74%),这种变化易使叠层结构发生抗剪强度不足的破坏。     

尼日尔三角洲里奥-德雷盆地泥底辟变形与形成演化特征

尼日尔三角洲东北部的里奥-德雷盆地发育多条阿卡塔组泥底辟构造带,对油气成藏产生了重要影响。根据泥岩隆升幅度及其与周围地层的接触关系,可将泥底辟划分为复杂形态刺穿型和简单形态隐伏型两类。平面上,泥底辟主要呈近SN向的条带状和圆点状展布,并影响上覆地层的发育,形成3类正断层。泥底辟主要经历了中渐新世之前的初始沉积-微弱活动期、晚渐新世-中新世的强烈隆升活动期以及上新世至今的微弱活动-整体埋藏期等3个形成演化阶段。泥底辟的发育除受到重力滑动作用及上覆地层的差异负载作用影响外,还受到盆地东南部大西洋转换断层及泥下基底断裂的影响。对里奥-德雷盆地泥底辟构造发育特征的研究,有助于分析泥底辟对圈闭、储层发育以及油气运移的影响。     

福州东区热电厂贮煤场结构设计

本文介绍了福州东区热电厂贮煤场结构设计，论证该设计的可行性、实用性和经济性。     

含对羟基苯甲酸、对苯二甲酸、间苯二酚、4,4′-二羟二苯酮共聚酯的流变行为研究

采用锥板流变仪研究了本实验室合成的含对羟基苯甲酸、对苯二甲酸、间苯二酚、４，４′－二羟二苯酮共聚酯的流变行为，结果表明，该共聚物具有典型的热致液晶性聚合物的流变特性。     

高韧性管线钢工艺优化研究

研究了高韧性管线用钢热变形过程中的变形奥氏体再结晶规律，轧后冷却过程中的相变规律，优化出实验用钢的合理控轧控冷工艺，采用该工艺，宝钢生产的Ｘ６０￣Ｘ６５级管线钢板的冲击韧性值提高了１倍以上，其综合力学性能达到甚至超过日本进口钢板的实物水平。     

HVA—10A型维氏硬度计压痕位置的调整

重点介绍压痕在视场内或不在视场内的调整方法以及调整过程中对同轴度的影响。     

浅谈芳烃装置改造检修中的安全管理

论述了天津石化芳烃联合装置在2004年改造检修中,针对各项环节制定切实可行的安全措施,有效地保证了现场作业的安全进行,为同类装置的检修提供依据。     

一种DC-DC芯片内建可测性设计

DC-DC芯片设计中有许多内部参数需要检测和控制，有限的引脚数目使得直接测试内部参数比较困难. 文中提出一种通用性很强的内建可测性设计方法，在芯片内部设计时只需要增加规模较小的测试电路，就可以在芯片外引脚上测量芯片内部众多的参数.     

相移数字散斑干涉术测量振动模态

数字散斑干涉技术是一种非接触，全场测试的光学测试方法。用数字散斑干涉术时间平均法测得的物体表面稳态振动，可描述为受高频分量调制的零阶Ｂｅｓｓｅｌ函数。文章提供一种在数字散斑时间平均法测振中使用的相移方案，以消除条纹图中的背景分量，使条纹仅与振幅有关，阐述了此方案的原理，并给出实验的结构和结果。