A comparable study of image approximations to the reaction field

The recently developed high-order accurate multiple image approximation to the reaction field for a charge inside a dielectric sphere [J. Comput. Phys. 223 (2007) 846-864] is compared favorably to other commonly employed reaction field schemes. These methods are of particular interest because they are useful in the study of biological macromolecules by the Monte Carlo and Molecular Dynamics methods.     

塑料合金高弹性联轴器试验台的开发研究

对塑料合金高弹性联轴器的综合性能试验台进行了设计，阐述试验台的设计要求、设计思想和结构特点，并介绍试验台的总体布局和组成部分；液压系统是试验台的核心部分，重点对液压系统进行设计及说明。     

应力腐蚀试验机数据处理系统

本文介绍了ＧＹＦ－３０低应变速率腐蚀试验机数据处理系统的原理及系统设计。     

钢结构的防火及防火涂料的涂装

详细了介绍了锦州石化公司体育馆及附属设施钢架结构的防火及防火涂料涂装;讨论了钢架结构的防火,并且制定涂层的设计方案、施工工艺及质量验收标准等。     

利用抽余碳五馏份制备TAME

探索了以抽余Ｃ５为原料经与甲醇醚化制ＴＡＭＥ的过程。试验表明，在国产催化剂Ｄ５４型大孔阳离子交换树脂存在下，在反应温度６０℃、ＬＨＳＶ２．４ｈ－１、甲醇／异戊烯物质的量比１．００、反应压力０．２ＭＰａ的条件下，抽余Ｃ５中的异戊烯可与甲醇反应生成醚，异戊烯的转化率达６３．２６％，ＴＡＭＥ的选择性可达９９．６１％。     

条形药包爆炸应力场试验研究

应用动态光弹性模型试验方法研究了条形药包的爆炸应力场分布特性。研究结果表明：起爆方式和位置影响着条形药包爆炸应力场的分布形态，并首次成功地记录了条形药包瞬间爆炸应力场的动光弹条纹，得到了理想成力场的分布形式。     

横观各向同性土介质与结构物共同作用的有限元与边界元耦合分析

本文采用有限元与边界元耦合方法对上与结构物进行共同作用的分析．其中上部结构采用有限元子结构法，地基上考虑为横观各向同性特性，应用边界元法，通过基础界面上位移连续、面力平衡的条件进行耦合分析．编制了相应的计算程序，对某高层空间剪力培与地基的共同作用进行了计算，与有限元法和实测结果进行了对比分析，得到了满意的结果．说明：有限元和边界元的耦合方法能充分发挥两者的优越性，不失为共同作用分析的一种有效途径．     

钢筋混凝土矩形截面双向偏心受压构件配筋的计算

本文在综合、分析有关文献的基础上寻求一种新的途径,以解决钢筋混凝土双向偏心受压配筋计算中存在的若干实际问题。文中采用了最优布筋因子的概念,确定最合理的布筋形式,直接求得一组最优的或逼近最优的配筋量。在计算过程中,引进了迭代模式,同时直接引用规范(TJ 10-74)公式(65),不附加任何条件。本计算方法已编制成程序,可在PC-1500机上计算。     

Negative chronotropic and inotropic effects exerted by diadenosine hexaphosphate (AP6A) via A1-adenosine receptors

1. Diadenosine hexaphosphate (AP6A) exerts vasoconstrictive effects. The purpose of this study was to investigate whether AP6A has any effect on cardiac function. 2. The effects of AP6A (0.1-100 microM) on cardiac contractility and frequency were studied in guinea-pig and human isolated cardiac preparations. Furthermore, the effects of AP6A on the amplitude of the L-type calcium current, on the adenosine 3':5'-cyclic monophosphate (cyclic AMP) content and on the phosphorylation of regulatory phosphoproteins, i.e. phospholamban and troponin inhibitor, were investigated in guinea-pig isolated ventricular myocytes. 3. In isolated spontaneously beating right atria of the guinea-pig AP6A exerted a negative chronotropic effect and reduced the rate of contraction maximally by 35% (IC20 = 35 microM). 4. In isolated electrically driven left atria of the guinea-pig AP6A exerted a negative inotropic effect and reduced force of contraction maximally by 23% (IC20 = 70 microM). 5. In isolated electrically driven papillary muscles of the guinea-pig AP6A alone was ineffective, but attenuated isoprenaline-stimulated force of contraction maximally by 23% (IC20 = 60 microM). Furthermore, AP6A attenuated the relaxant effect of isoprenaline. 6. In human isolated electrically driven ventricular preparations AP6A alone was ineffective, but attenuated isoprenaline-stimulated force of contraction by maximally 42% (IC20 = 18 microM). Moreover, AP6A attenuated the relaxant effect of isoprenaline. 7. All these effects of AP6A were abolished by the selective A1-adenosine receptor antagonist 1,3-dipropyl-cyclopentyl-xanthine (DPCPX, 0.3 microM), whereas the M-cholinoceptor antagonist atropine (10 microM) and the P2-purinoceptor antagonist suramin (300 microM) failed to abolish the effects of AP6A. 8. AP6A 100 microM had no effect on the amplitude of the L-type calcium current, but attenuated isoprenaline-stimulated L-type calcium current. The maximum of the current-voltage relationship (I-V curve) was shifted to the left by isoprenaline and additional application of AP6A shifted the I-V curve back to the right to the control value. The phosphorylation state of phospholamban and the troponin inhibitor was unchanged by AP6A alone, but was markedly attenuated by AP6A in the presence of isoprenaline. Cyclic AMP levels remained unchanged by AP6A, even after stimulation with isoprenaline. 9. In summary, AP6A exerts negative chronotropic and inotropic effects in guinea-pig and human cardiac preparations. These effects are mediated via A1-adenosine receptors as all effects were sensitive to the selective A1-adenosine receptor antagonist DPCPX. Furthermore, the effects of AP6A on cyclic AMP levels, protein phosphorylation and the L-type calcium current are in accordance with stimulation of A1-adenosine receptors.