NT855C系列发动机喷油嘴调整方法探讨

简述NT—855C系列发动机喷油嘴的气门间隙调整方法。本文主要就NT—855C系列发动机喷油嘴的调整方法进一步说明,用百分表等调整法的不方便、不快捷,有时也不准确。本人通过多年集累的修理经验和查阅多方资料,经过重复试验,证明手工调整的方法更快捷、准确。同样的方法也可应用在TY220推土机中。     

康明斯K38发动机气缸组故障快速诊断法

发动机的汽缸套、缸盖、活塞、活塞环、进排气门等组合起来,称为汽缸组,是发动机的心脏。发动机汽缸组故障快速诊断法最终实现了把用肉眼无法观测到的汽缸组工作情况,通过气体这个介质很直观的体现出来的目标。有效的把检测汽缸组故障率提高到90%以上。     

康明斯K2000E发动机电控系统故障诊断及处理

康明斯K2000E发动机采用电子系统进行控制,发动机出现机械故障时,可直接读取故障代码发现故障原因,进行处理。当发动机出现电控系统故障时,修理人员会出现故障判断失误,因此进行故障处理时要采用正确的思路和方法。     

1998～2009年美国MPIF获奖粉末冶金汽车零件介绍(连载) (一)粉末冶金发动机零件

进入21世纪以来,中国的汽车产量从2000年的207万辆跃到了2009年的1379.10万辆,销售1364.48万辆。因此,汽车产业的节材、节能、减排、降低生产成本就变成了头等大事;恰恰在这些方面,粉末冶金汽车零件的开发与应用,对于汽车产业具有无法替代的作用。据最新资料报告,美国生产的汽车中使用的粉末冶金零件已达300种,750件。美国MPIF(金属粉末工业联合会)从1995年开始,每年举行粉末冶金设计竞赛,设大奖与优秀奖。1998～2009年获奖零件共计156个,粉末冶金汽车零件有50个,其中发动机零件16个、变速器零件19个、其他零件15个;显示出粉末冶金零件正在向高密度、高强度、形状复杂的零件、组合零件及成组零件的方向发展。为供相关业者参考,本刊将陆续介绍这50种获奖零件。     

为新发动机新气门可变动作角与升程(VVEL)机构开发的新粉末冶金零件

这2个粉末冶金零件是日产汽车公司藤木章教授等新近研发的用于V6发动机的重要零件。曾荣获日本粉体粉末冶金协会第二次(2009年度)新技术新制品奖,承蒙日本粉体粉末冶金协会准予本刊译为中文刊载,特向日本粉体粉末冶金协会致谢,并向相关业者予以介绍。     

直喷汽油(DIG)汽车发动机无声链条系统用温压-高温烧结粉末冶金链轮的开发

作者们以前报导过非直喷汽油 (一般MPI汽油 )发动机滚子链条系统用温压 -常规温度 ( 114 0℃ )烧结的粉末冶金链轮。在这个新开发的项目中 ,研究了几种温压 -高温烧结的粉末冶金钢的力学性能。为测定这些材料的耐磨性 ,用虚拟发动机进行了磨耗试验。最终开发出了可承受严酷磨耗条件的DIG发动机无声链条系统的链轮。使用的基础粉末是混合粉 (DistaloyDC1)。其含 2 %Ni(质量分数 ) ,Ni粉是通过扩散粘结在Fe - 1 5 %Mo(质量分数 )粉末颗粒上的 ,温压是在 130℃下 ,用这种粉末、阴模及模具进行的。烧结温度为 1190℃。链轮还进行了热处理     

同步电动机过电流故障原因分析

针对济钢烧结主抽风机同步电机运行过程中,在工艺参数及相关设备均正常的情况下出现的过电流故障,进行了电能质量分析及励磁系统检测。结果表明,只有母线基波平均电压偏差（9.6%）超出国标限值（7.0%）,其他基本正常;故障时,励磁电流突升46%,由于励磁方式设置为恒励磁电流,因此故障原因是励磁系统晶闸管脉冲控制的问题。改造采用可靠性高的励磁控制系统的升级换代产品,避免了电流突升现象。     

高压同步电动机定子绕组故障分析及修理

通过对高压同步电机定子绕组匝间故障的修复,对同步电机定子绕组匝间短路故障进行了简单的分析,并采用甩掉故障线圈的局部修理方法进行修复,减少了故障停机时间,取得了良好的效果.     

Evidence suggesting that galanin (GAL), melanin-concentrating hormone (MCH), neurotensin (NT), proopiomelanocortin (POMC) and neuropeptide Y (NPY) are targets of leptin signaling in the hypothalamus

Leptin (OB protein) reduces food intake by acting at the hypothalamic level. The purpose of the present study was to identify potential targets of leptin signaling in the hypothalamus in ad-lib fed rats. Central administration of leptin (5 microg) for 3 days decreased food intake and body weight gain in association with a decrease in hypothalamic galanin (GAL), melanin-concentrating hormone (MCH), proopiomelanocortin (POMC) and neuropeptide Y (NPY) gene expression and with an increase in neurotensin (NT) gene expression. In pair-fed rats, NPY gene expression was increased and there was no change in either MCH, GAL, POMC or NT gene expression. This study identifies GAL, MCH, POMC and NT as non-NPY targets of leptin signaling and suggests that leptin's action on food intake and body weight is most likely mediated by inhibiting excitatory (e.g. NPY, MCH, GAL, POMC) and stimulating inhibitory (e.g., NT) signals in the feeding circuitry.     

Immune recognition of botulinum neurotoxin type A: regions recognized by T cells and antibodies against the protective H(C) fragment (residues 855-1296) of the toxin

Botulism toxicity is caused by botulinum neurotoxins (BoNTs), a group of protein neurotoxins produced by Clostridium botulinum. Recent studies have shown that immunization with a C-terminal fragment [H(C), residues 855-1296] of BoNT type A (BoNT/A) affords excellent protection against BoNT/A toxicity. The present work was carried out in order to map the molecular and cellular immunological recognition of H(C). We have previously described the synthesis of 31 overlapping peptides encompassing the entire H(C)-fragment of BoNT/A. These peptides were employed in this study to localize the continuous regions recognized by T cells and by antibodies (Abs) generated in two mouse strains against H(C). T cells from SJL that had been primed with H(C) gave a strong proliferative response to challenge in vitro with each of the six peptides spanning residues 897-985 and a lower response to peptide 1051- 1069. While H(C)-primed T cells of BALB/c recognized three regions residing within residues 939-957, 1009-1027 and 1135-1153 (strong). Recognition regions by Abs in SJL or BALB/c anti-H(C) antisera essentially overlapped. However, the level of Abs bound to each region differed between the two strains. These common or similar recognition regions by the two strains were: 855-915 (SJL) or 855-901 (BALB/c); 939-957; 967-1013 (BALB/c) or 981-1013 (SJL); 1051-1069; 1079-1111 (BALB/c) or 1093-1125 (SJL); 1177-1195; and 1275-1296. In addition, BALB/c recognized region 1135-1153. Some of these regions show considerable sequence similarity in BoNT types B and E and, therefore, H(C) of these two BoNTs might offer protection against the correlate clostridial toxins.     

Inhibition of entry of HIV into cells by poly(A).poly(U)

Polyadenylic-polyuridylic acid referred to as poly(A).poly(U), is a synthetic double-stranded RNA that has been shown to manifest both antitumoral and immunodulatory activities. Previously, we have reported that poly(A).poly(U) inhibits HIV infection in cell cultures. Here we provide direct evidence to demonstrate that the inhibitory action of poly(A).poly(U) is through its capacity to prevent entry of HIV particles into CD4-positive T lymphocytes. Such inhibition of HIV entry is also observed in the case of other polyanions such as heparin, dextran sulfate, and poly(I).poly(C). The mechanism of inhibition appears to occur postbinding of HIV particles to the CD4 receptor molecules, because the binding of the external envelope glycoprotein of HIV-1 (gp120) is not affected significantly in the presence of poly(A).poly(U) or other polyanions. These results confirm the potential of poly(A).poly(U) as an antiviral drug against HIV infection.     

Novel insights into structure and function of MRP8 (S100A8) and MRP14 (S100A9)

Primate lentiviruses encode for an unique nef gene with an essential function in both viral replication and pathogenicity in the host. The molecular basis for this function remains however poorly defined. Several Nef-binding cellular proteins are thought to be instrumental in its function. Indeed, Nef contains a proline-rich motif implicated in the binding to the Src-like tyrosine kinase Hck and also to a Ser/Thr kinase of molecular weight 62 kDa. The disruption of this motif affects the binding to both these kinases as well as viral replication. Whereas Hck is expressed in the myeloid lineage and hence may account for the nef function in infected monocytes, we and others have reported previously that Nef also interacts with the T-lymphocyte Src-kinase Lck, leading to specific cell signaling impairment. This interaction occurs through the binding of Nef to both Lck SH2 and SH3 domains. Both the proline motif and phosphorylation of Nef on tyrosine residue were proposed to account for these interactions. Here, we investigate the mechanism of Lck SH2 binding by HIV-1 Nef. Using recombinant fusion proteins to precipitate lysates, we show that although SH2 binding is dependent on phosphorylation events, it occurs in a tyrosine independent manner because it requires neither tyrosine residues in Nef nor the phosphotyrosine binding pocket from the Lck SH2 domain, hence suggesting a role for a phosphoserine or a phosphothreonine residue. Further, we show that Hck SH2 does not interact with Nef, indicating that Hck SH3 binding is sufficient for Nef binding, whereas Lck SH2 cooperate together with SH3 to allow Nef binding to a level similar to Hck SH3. Together, our results establish different mechanisms for Hck and Lck binding by HIV-1 Nef protein, and identify a novel mechanism for Src-like tyrosine kinase targeting by a viral protein.     

(1+4)热连轧生产线的主电机与传动系统方案选择

针对中铝西南铝引进的（1＋4）热连轧生产线安装调试问题,重点对该生产线主传动电机及主传动控制系统的方案选择进行介绍。     

Three-sublattice model that takes into account the spin density anisotropy,short-range order,and dimensioned factor for the binary Fe-Cr(V,Mo) systems

The diffusion properties of the elements entering into the composition of austenitic and ferritic steels are analyzed as functions of the temperature and the time evolution of induced radioactivity. As compared to austenitic steels, ferritic steels are shown to have better diffusion properties and swelling resistance during operation at temperatures up to 650°C under irradiation conditions and can be used as structural materials in the core of a fast neutron reactor. Experimental and calculated (Calphad method) data on the Fe-Cr phase diagram and the thermodynamic properties and the experimental data on the short-range order in Fe-Cr alloys are analyzed, and it is concluded that they are conflicting and that models taking into account the short-range order should be developed. The results of quantum-mechanical calculations of the average magnetic moment for ferromagnetic (FM) iron as a function of the volume are analyzed and used to introduce a concept of partial magnetic moments of the iron atoms located in the first four coordination spheres (1–4 CS). The values of these moments are calculated. The concept of the partial magnetic moments of iron atoms agrees qualitatively with the experimental data on the spin-density anisotropy of the bcc lattice of pure iron. This concept is used to formulate a three-sublattice model for binary FM alloys of Fe-M systems (M is an alloying paramagnetic element). An extended cell whose sites contain 8 bcc cells and 16 atoms per cell and that is isomorphic to a DO₃-type crystal lattice is considered. A functional is constructed for the internal energy on the extended 16-atom cell. The dimensioned factor is taken into account in a self-consistent manner, by the expansion of the interaction energies of atoms of both components located in different CSs in the atom displacement with respect to ideal lattice sites. The dimensioned factor is taken into account in the three-sublattice model to obtain a set of equations of state for bcc FM binary iron-rich alloys in a 1–3 CS approximation. The obtained estimates demonstrate that the anisotropy of the distribution of magnetic moments in the bcc iron lattice is responsible for the appearance of a short-range order in bcc FM iron-rich Fe-Cr (V, Mo) binary alloys.