中兴宽带线路测试技术及功能介绍

宽带线路测试是中兴通讯ZXDSL综合宽带运维系统的核心功能，在DSL业务提供过程中主要应用在开通前的预测试、线路测试、开通后的例测试以及故障时的在线测试。对其测试技术和功能作了介绍。     

真空冷冻干燥技术在三七加工中的应用

介绍了真空冷冻干燥的基本原理，并据三七的特点，探讨三七真空冷冻干燥的工艺流程及特点，简要分析了三七冷冻干燥的前景。     

高层建筑地下室人防及通风设计

该文结合工程实例介绍了地下室人防及通风设计的方法及实际运用中的注意事项．     

40kg试验焦炉的研制

文章介绍了40kg试验焦炉，分析和比较了试验焦炉与生产焦炉的差异，指出它们之间的模拟条件是炭化室宽度、煤料堆密度、炼焦速度和单向传热。     

点状屏彩色显示管校正透镜优化设计

本文在条状屏彩色显象管校正透镜设计的基础上，提出了蹼状屏彩色显示管校正透镜的优化设计方法并给出了设计实例，通过计算机模拟电子束轨迹和光线追迹，分析了校正透镜面型修正程序的精度。     

Dopamine D2 receptor signaling via the arachidonic acid cascade: modulation by cAMP-dependent protein kinase A and prostaglandin E2

Recent studies have shown that, in Chinese hamster ovary cells transfected with D2-receptor cDNA, CHO(D2) cells, D2 agonists are potent in enhancing the release of [3H]arachidonic acid (AA) induced by stimulation of constitutive purinergic receptors or by application of Ca2+ ionophores. This facilitatory action is further amplified by the concomitant activation of D1 receptors, which per se have no effect on evoked [3H]AA release. Here, we review a series of experiments aimed at examining the molecular mechanism of this synergistic interaction. The results show that, in CHO(D2) cells: (a) application of 8-Br-cAMP or stimulation of constitutive prostaglandin (PG)E2 receptors augment the AA response produced by D2 agonists; (b) in CHO(D2) cells transfected with human beta 2-receptor cDNA, the beta-agonist, isoproterenol, produces a similar effect; (c) the potentiation of [3H]AA release produced by PGE2 and 8-Br-cAMP is prevented by overexpressing either a protein inhibitor of cAMP-dependent protein kinase (PKA) or a mutated form of pKA regulatory subunit incapable of binding cAMP; (d) mock-synergism is obtained in CHO(D2) cells overexpressing the catalytic subunit of PKA; (e) PGE2 is a major AA metabolite in stimulated CHO(D2) cells and its formation may contribute to the effect of D2 agonists on AA release. The results indicate that cAMP-induced activation of PKA represents a likely molecular basis for D1/D2 receptor synergism on AA release. They also suggest that additional membrane receptors, colocalized with D2 and positively linked to adenylyl cyclase, may exert a similar action. Furthermore, stimulation of PGE2 receptors by endogenously produced prostaglandin may participate in AA signaling at the D2 receptor, by providing a paracrine positive feedback loop.     

Novel diterpenoid diacylglycerols from marine molluscs: potent morphogens and protein kinase C activators

Five novel 1,2-sn-diacylglycerols with diterpenoid acyl moieties in the sn-1 position were isolated and characterized, together with the corresponding 1,3-sn-diacylglycerols, from three species of dorid nudibranchs molluscs. Their potent activity as morphogens in vivo in the Hydra tentacle regeneration assay and their parallel activity as activators of rat brain protein kinase C (PKC) in vitro are reported here. Our findings promote the use of these compounds as useful molecular probes for both in vivo and in vitro studies on the participation of PKC in cell development.     

Modeling electromigration lifetime under bidirectional currentstress

Electromigration reliability of interconnect under bidirectional current stress has been studied in a wide frequency range (mHz to 200 MHz). Experimental results show that the AC lifetime rises with the stress current frequency. The current density exponent and the activation energy of AC lifetime are found to be twice that of DC lifetime. Pure AC current stress failure at extremely high current density is believed to result from thermal migration of metal at hot/cold transition points