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.     

Incompressible flow calculations with a consistent physical interpolation finite volume approach

The computation of incompressible three-dimensional viscous flow is discussed. A new physically consistent method is presented for the reconstruction for velocity fluxes which arise from the mass and momentum balance discrete equations. This closure method for fluxes allows the use of a cell-centered grid in which velocity and pressure unknowns share the same location, while circumventing the occurrence of spurious pressure modes. The method is validated on several benchmark problems which include steady laminar flow predictions on a two-dimensional cartesian (lid driven 2D cavity) or curvilinear grid (circular cylinder problem at Re = 40), unsteady three-dimensional laminar flow predictions on a cartesian grid (parallelopipedic lid driven cavity) and unsteady two-dimensional turbulent flow predictions on a curvilinear grid (vortex shedding past a square cylinder at Re = 22,000).     

Immunohistochemical localization of estradiol and progesterone receptors in human uterus throughout pregnancy: expression in endometrial blood vessels

Although progesterone and estrogens are essential to maintain human pregnancy after implantation, the localization of their specific receptors in different uterine cell types during pregnancy has not been investigated. We studied uteri (n = 40) obtained during the first 3 months of pregnancy (n = 21) and in late pregnancy (n = 9) as well as from women 5-14 weeks pregnant (n = 10) who had received the antiprogestagen RU 38486 (Roussel-UCLAF) to induce cervical dilation. Frozen tissues were processed for indirect immunocytochemical staining with specific monoclonal antibodies against estrogen receptors (ER; Abbott Laboratories) and progesterone receptors (PR; Li 417). Specific staining for steroid receptors was only detected in the nucleus. In the endometrium, PR staining remained fairly constant throughout pregnancy, whereas ER staining was initially weak and then undetectable. PR was widely expressed in stromal cells and in spiral arterial wall cells, whereas ER was expressed in scattered stromal cells and arterial cells. Both PR and ER were absent from glandular epithelium, contrasting with the secretory activity during the first trimester. Spiral arteries of the endometrium and myometrial smooth muscle cells showed intense PR and moderate ER staining in early pregnancy. The progesterone antagonist RU 38486 (mifepristone), given in early pregnancy at a dose of 200 mg, caused a marked increase in ER staining and a smaller increase in PR staining in stromal cells, whereas the glandular epithelium remained negative for both ER and PR (except for one and two specimens, respectively). We conclude the following. 1) Stromal cells retain PR despite the high progesterone levels during pregnancy, in keeping with the role of progesterone in stromal decidualization. The absence of PR from the secretory glandular epithelium suggests a paracrine link between decidualized stromal cells and epithelial cells. 2) Significant PR down-regulation by progesterone during pregnancy occurs only in epithelial cells of the endometrium. 3) In contrast, the absence or low level of ER staining in the various cell types of the endometrium during gestation concurs with the known effect (down-regulation) of steroid hormones on ER mRNA or protein levels. The increase in ER in human decidua after RU 38486 treatment indicates that the main cause of the low ER levels is progesterone secretion. 4) The intense PR staining in smooth muscle cells of spiral arteries during early pregnancy suggests that progesterone is essential for modulating blood flow during pregnancy.     

PD275kg／m全长热处理钢轨研制

以高碳低锰碳素热轧钢轨为热处理原料轨，采用双频电感应加热、压缩空气欠速淬火热处理技术研制的ＰＤ２７５ｋｇ／ｍ热处理钢轨，硬化层深度≥１５ｍｍ、组织为细珠光体；力学性能：σ０．２８１５￣９８０ＭＰａ、σｂ１１８５￣１３４０ＭＰａ、δ５１０％￣１５％，常温冲击韧性ａＫ１４￣３３Ｊ／ｃｍ＾２，断裂韧性ＫＩｃ平均值４５．５ＭＰａ·ｍ＾１／２。具有强度高，塑韧性好的综合性能。使用性能优良，寿命比同曲线的Ｕ７     

Synthesis and characterization of block copolymers from D,L-lactide and poly(tetramethylene ether glycol)

The copolymer from D ,L -lactide and poly(tetramethyene ether glycol) (PTMG) was prepared in bulk with an isotributyl aluminum–water–phosphoric acid complex catalyst as the initiator and characterized by H-NMR, GPC, and DSC. The effects of the temperature and the amount of PTMG on the polymerization rate and the molecular weight of copolymers were studied. The behavior of the degradation and delivery rate of Levonorgestrel microspheres in vitro was observed. The results show that the degradation and the delivery rate can be controlled by adjusting the molar rate of hydrophilic and hydrophobic segments of the copolymer © 1995 John Wiley & Sons, Inc.     

聚乙二醇-硫酸钠-硫氰酸钾体系中Co(Ⅱ)、 Ni(Ⅱ)、 Mo(Ⅵ)的萃取分离研究

用硫氰酸钾作萃取剂，探讨了在聚乙二醇（ＰＥＧ）２０００硫酸钠硫氰酸钾双水相体系中Ｃｏ（Ⅱ）、Ｎｉ（Ⅱ）、Ｍｏ（Ⅵ）等金属离子的萃取行为。控制一定条件，实现了Ｃｏ（Ⅱ）与Ｎｉ（Ⅱ）、Ｃｏ（Ⅱ）与Ｍｏ（Ⅵ）及Ｃｏ（Ⅱ）与Ｎｉ（Ⅱ）、Ｍｏ（Ⅵ）混合离子的定量分离，并研究了不同类型的表面活性剂对ＰＥＧ相萃取行为的影响。