几种天南星科植物受芋花叶病毒感染后的叶片组织病变研究

对自然感染芋花叶病毒（ＤＭＶ）的几种天南星科植物的叶片超微结构进行电镜观察的结果表明：ＤＭＶ感染天南星科植物同时形成风轮状（Ｐｉｎｗｈｅｅｌ）、卷筒状（Ｓｃｒｏｌｌ－ｌｉｋｅ）和片层状聚集体（ｌａｍｉｎａｔｅｄａｇｒｅｇｇａｔｅｓ）结构的细胞质内含体（即柱状内含体，ＣｙｌｉｎｄｅｒｉｃａｌＩｎｃｌｕｓｉｏｎ，ＣＩ）。ＤＭＶ所产生的细胞质内合体与Ｅｄｗａｒｄｓｏｎ等所划分的Ⅱ型ＣＩｓ相符。在叶肉细胞质中还观察到分散的病毒粒子、大量紧密聚集的病毒粒子以及主要由病毒粒子组成的类似病毒包含体（Ｖｉｒｏｐｌａｓｍａ）的结构。同时，不同寄主来源对ＤＭＶ细胞质内含体的形状有明显影响：来源于自然感病的马蹄莲细胞中ＣＩｓ横切面上主要是风轮状结构组成；在芋、广东万年青的感病细胞中亦是以风轮状结构占优势，但具有一定数量的片层状结构和卷筒状结构；在魔芋、半夏和海芋的细胞中则以卷简状结构为主，具有一定数量的片层状结构，有的甚至完全不形成风轮状．     

AcMNPV诱导sf9细胞核内产生海绵状基质

ＡｃＭＮＰＶ诱导ｓｆ９细胞核内产生海绵状基质陈建国滕俊琳翟中和（北京大学生命科学学院，北京１００８７１）苜蓿银纹夜蛾核型多角体病毒（Ａｕｔｏｇｒａｐｈａｃａｌｉｆｏｒｎｉｃａｎｕｃｌｅａｒｐｏｌｙｈｅｄｒｏｓｉｓｖｉｒｕｓ，ＡｃＭＮＰＶ）属于杆状病毒...     

实时MPEG编码视频处理器

描述Ｃ－Ｃｕｂｅ公司实时ＭＰＥＧ编码芯片ＶｉｄｅｏＲＩＳＣ（ＴＭ）Ｐｒｏｃｅｓｓｏｒ（ＶＲＰ）的结构特点和操作方式，介绍了Ｃ－Ｃｕｂｅ公司用ＶＲＰ开发的ＭＰＥＧ编码板。     

实时MPEG编码频处理器

描述Ｃ－Ｃｕｂｅ公司实时ＭＰＥＧ编码芯片ＶｉｄｅｏＲＩＳＣ＾ＴＭＰｒｏｃｅｓｓｏｒ（ＶＲＰ）的结构特点和操作方式，介绍了Ｃ－Ｃｕｂｅ公司用ＶＲＰ开发的ＭＰＥＧ编码板。     

A Virtual Private Local PCN Ring Network Based on ATM VP Cross—Connection

ＡＶｉｒｔｕａｌＰｒｉｖａｔｅＬｏｃａｌＰＣＮＲｉｎｇＮｅｔｗｏｒｋＢａｓｅｄｏｎＡＴＭＶＰＣｒｏｓｓ－ＣｏｎｎｅｃｔｉｏｎＬｉｕＢｉｎ；ＭａＹｉｎｇｊｕｎ；ＭｅｎｇＬｕｏｍｉｎｇ（ＢｅｉｊｉｎｇＵｎｉｖｅｒｓｉｔｙｏｆＰｏｓｔｓａｎｄＴｅｌｅｃｏｍ...     

Simulation of Power Control and Diversity of Cellular CDMA

ＳｉｍｕｌａｔｉｏｎｏｆＰｏｗｅｒＣｏｎｔｒｏｌａｎｄＤｉｖｅｒｓｉｔｙｏｆＣｅｌｌｕｌａｒＣＤＭＡＲｏｍａｎＰｉｃｈｎａ；ＱｉａｎｇＷａｎｇ；ＶｉｊａｙＫ．Ｂｈａｒｇａｖａ；ＪｉａｌｉｎＺｏｕ；ＲｏｎＫｅｒｒ（ＵｎｉｖｅｒｓｉｔｙｏｆＶｉｃｔｏｒｉ...     

DVD的调制方式EFM plus（8／16调制）

ＤＶＤ的调制方式ＥＦＭｐｌｕｓ（８／１６调制）张绍高ＤＶＤ（ＤｉｇｉｔａｌＶｉｄｅｏｄｉｓｃ，数字视频光盘，或ＤｉｇｉｔａｌＶｅｒｓａｔｉｌｅＤｉｓｃ，数字通用光盘）的调制方式ＥＦＭｐｌｕｓ（８／１６调制）是在ＣＤ的ＥＦＭ（Ｅｉｇｈｔ－Ｆｏｕｒｔｅｅ...     

猪瘟病毒的形态结构与形态发生的电子显微镜研究

猪瘟病毒的形态结构与形态发生的电子显微镜研究王镇闵光伟李明义藤俊琳丁明孝翟中和（北京大学生命科学学院，北京１００８７１）猪瘟病毒（Ｃｌａｓｓｉｃａｌｓｗｉｎｅｆｅｖｅｒｖｉｒｕｓ，ＣＳＦＶ）属瘟病毒属（Ｐｅｓｔｉｖｉｒｕｓ）、黄病毒科（Ｆｌａｖｉｖｉ...     

复值多状态双向联想记忆神经网络

离散但非二值状态将提供一种更好的信息表达方式。本论文中,我们将复符号操作子（ｃｏｍｐｌｅｘ－ｓｉｇｎｕｍ ｏｐｅｒａｔｉｏｎ）和双向联想记忆（Ｂｉｄｉｒｅｃｔｉｏｎａｌ Ａｓｓｏｃｉａｔｉｖｅ Ｍｅｍｏｒｙ,ＢＡＭ）结合起来并提出了一种非二值ＢＡＭ,即复值多状态双向联想记忆神经网络（Ｃｏｍｐｌｅｘ－Ｖａｌｕｅｄ Ｍｕｌｔｉｓｔａｔｅ Ｂｉｄｉｒｅｃｔｉｏｎａｌ Ａｓｏｃｉａｔｉｖｅ Ｍａｍｏｒｙ,     

九种Potyviruses柱状内含体结构的比较研究

通过寄主叶肉细胞超薄切片的透射电镜观察，对马铃薯Ｙ病毒（ＰＶＹ），芋花叶病毒（ＤＭＶ），大蒜黄条病毒（ＧＹＳＶ），大豆花叶病毒（ＳＭＶ），蚕豆叶卷花叶病毒（ＰＬＲＭＶ），芜菁花叶病毒（ＴｕＭＶ），大丽菊上的马铃薯Ｙ组病毒（Ｐｏｔｙｖｉｒｕｓ－Ｄｈ），莴苣花叶病毒（ＬＭＶ）和大麦黄花叶病毒（ＢＹＭＶ）九种病毒共１２个病毒分离物所产生的柱状内含体的结构进行了比较研究，结果表明同一病毒的不同分离物所产生     

Primary solidification phases of the Sn-rich Sn-Ag-Cu-Ni quaternary system

The eutectic and near-eutectic Sn-Ag-Cu solders are the most promising lead-free solders, and nickel is frequently used as the barrier layer material. Nickel dissolves into the molten Sn-Ag-Ni alloy during the soldering process, and the ternary solder becomes a Sn-Ag-Cu-Ni quaternary melt near the nickel substrate. Liquidus projection is the projection of the liquidus trough and it delineates the boundaries of various primary solidification phases. Information of liquidus projection is helpful for understanding the alloys’ solidification behavior. This study prepared the Sn-Ag-Cu-Ni alloys of various compositions at the Sn-rich corner. The alloys were melted at higher temperatures and solidified in air. The solidified alloys were metallographically examined to determine the phases formed, especially the primary solidification phases. No ternary or quaternary compounds were found. The knowledge of the primary solidification phases, phase formation sequences, and reaction temperatures determined in this study were put together with all of the available liquidus projections of the constituent ternary systems to determine the primary solidification phases of the quaternary Sn-Ag-Cu-Ni system at the Sn-rich corner.     

百合小孢子母细胞形成和发育过程中细胞间连接形态和结构的变化

超显微结构水平观察发现造孢时期细胞的壁较厚，由中间层，初生和次生壁组成，细胞间的连接为典型的细胞间连丝，减数分裂前间期的细胞壁主要由中间和初生壁组成，典型的胞间连丝消失，但局部位置上的中间层和初生壁组分缺失，构成约２００～８００ｎｍ，宽的“豁口”，进入分裂期后，次生壁组分急剧增加，当整个细胞壁加厚到２４０－５００ｎｍ时，细胞壁出现穿孔，穿孔过程似乎有下列两种方式：１）在细胞壁的一侧或两侧出现电子致     

Effective permittivity of dielectric mixtures

General mixing formulas are derived for discrete scatterers immersed in a host medium. The inclusion particles are assumed to be ellipsoidal. The electric field inside the scatterers is determined by quasi-static analysis, assuming the diameter of the inclusion particles to be much smaller than one wavelength. The results are applicable to general multiphase mixtures, and the scattering ellipsoids of the different phases can have different sizes and arbitrary ellipticity distribution and axis orientation, i.e. the mixture may be isotropic or anisotropic. The resulting mixing formula is nonlinear and is suitable for iterative solutions. The formula contains a quantity called the apparent permittivity, and with different choices of this quantity, the result leads to the generalized Lorentz-Lorenz formula, the generalized Polder-van Santen formula, and the generalized coherent potential-quasicrystalline approximation formula. The results are applied to calculating the complex effective permittivity of dry and wet snow, and sea ice     

弹道导弹在飞行过程中的表面温度研究进展

弹道导弹在飞行过程中的表面温度是导弹攻击方和导弹防御方关注 的重点。综述了弹道导弹在助推段、中段和再入段的表面温度以及红外辐射源,重点 给出了弹道导弹中段弹头和诱饵的平衡温度。弹头热惯量大,几乎保持初始温度;气 球诱饵热惯量小,很快就会达到平衡温度。最后指出实际飞行试验中的动态热辐射测量是表面温 度理论研究的重要方向。     

大鼠第三脑室室管膜上巨噬细胞迁移过程的电镜观察

对第三脑室室管膜上巨噬细胞迁移过程进行不同时相的扫描电镜观察，结合透射电镜分析其细胞类型及相应功能。结果示第三脑室内存在室管膜上巨噬细胞，此类细胞胞体呈卵圆形或椭圆形，伸出多个舌状和指状伪足，其迁移的全过程是首先在室管膜表面形成穹窿样隆起，继而推开室管膜上皮细胞间隙，露出胞体，继续向外游走，最后完全游离在脑室腔内。透射电镜下该细胞呈长卵圆形，核大，异染色质多，细胞器较少，具有单核吞噬细胞的形态特征。本文在超微结构水平清晰地观察到第三脑室室管膜上巨噬细胞迁移过程的不同时相，并为进一步探讨其功能提供了超微形态学基础。     

彩虹明樱蛤精子发生的超微结构

应用透射电镜观察彩虹明樱蛤的精子发生过程,描述了从精原细胞发育成为成熟精子过程中的超微结构变化。主要表现在染色质以颗粒状形式浓缩和分散;高尔基体分泌的前顶体颗粒逐渐融合形成前顶体囊、前顶体最终发育成为顶体;线粒体逐渐融合形成精子中段;细胞核的拉伸和旋转以及中心体和鞭毛的形成等。在初级精母细胞阶段,同源染色体经历了联会复合体形成和解体的变化。前顶体颗粒和中心粒结构在精原细胞期就已经存在。根据染色质和顶体发育的变化特点将精细胞分为6个时期,并描述了各期精细胞的超微结构特点。彩虹明樱蛤成熟精子属于原生型,由头部、中段和尾部组成。     

Electron microscopic observation of recombinant Escherichia coli cells overproducing human tumor necrosis factor-alpha mutant as inclusion bodies.

Escherichia coli C600 r-m- carrying plasmid pTNF483 (E. coli [pTNF483]) produces a tumor necrosis factor-alpha (TNF-alpha) mutant protein in an insoluble form. A swollen region was observed in the SEM images to encircle the outside of most of the E. coli [pTNF483] cells just like a bandage. On the other hand, inclusion bodies of the TNF-alpha mutant as large as the short axis of the cell were observed in TEM images. This position was regarded as coinciding with the swollen region of SEM images. The inclusion bodies revealed in the swollen region of the cell envelopes were clearly observed in SEM images of isolated insoluble structures obtained by centrifugal sedimentation of a sonicated cell suspension.     

Over-phase control of inverter multiphase AC linear drives

The over-phase control method of inverter multiphase (i.e. having number of phases more than four) AC linear drives is developed by the authors of this paper. Its application allows to improve considerably a number of the drive technical-and-economic characteristics (speed of response, reliability, mass-and-overall dimensions, etc.). This control method can be used not only in the field of electrical AC drives, but also in the systems for electromagnetic stirring of molten metals. In these systems the application of one of versions of the over-phase-control for multiphase inverter-fed linear stators allows to increase the intensity of electromagnetic stirring of molten metals by providing with continuous change of the quantity, space location, and configuration of the vortex areas in the metal mass during the process of the above-mentioned stirring.     

Electric-field-induced volume and membrane ionic permeabilitychanges of red blood cells

When an external electric field (EF) is applied to red blood cells (RBCs), the RBCs are observed to undergo a swelling action. The swelling may or may not lead to hemolysis, depending on the EF strength. An objective verification of this swelling is by measuring the RBC mean corpuscular volume (MCV). In this study, the RBC's were exposed to the appropriate EF strength to induce swelling, but caused minimal hemolysis. The MCV was measured. The change in the erythrocyte membrane ionic permeability as a result of the EF exposure was also determined, as an objective verification of presumed membrane conductance change concomitant with the swelling. The fluxes of cations K⁺, Na ⁺, and Ca⁺⁺ and anion Cl^- were measured. The results showed that red cell MCV was indeed increased after EF application. The EF also altered the membrane ionic conductance to allow ions to flow down their respective concentration gradient across the membrane. Without a counterbalancing ionic pressure gradient, hemoglobin colloidal pressure inevitably drew H₂O in, thus producing the observed swelling     

Ni(85)Al(15)系掺杂钨精矿粉不同激光功率引燃烧结合金组织及性能研究

在Ni(85)Al(15)粉末中掺杂1%(质量分数)的钨精矿粉末并压制成坯,对压坯进行激光点燃自蔓延烧结。利用XRD、SEM、硬度、磨损以及腐蚀测试等手段对烧结合金进行组织结构及性能表征。结果表明,在烧结过程中,压坯实现了自蔓延烧结。合金组织为α-Ni基体上弥散分布相,物相为NiAl、Ni3Al、WO3以及Al2O3;当功率为1100 W时,烧结合金硬度较大,达到30.7 HRC;合金的单位面积磨损量较小,为0.89×10-3g/mm2;当功率为900 W时,合金的维钝电流密度为1.15 mA/mm2,自腐蚀电位为-400 mV,钝化区间为-600~-1450 mV,在浓度为1 mol/L的H2SO4溶液中腐蚀性较佳。