磨矿分级自动控制系统在选矿厂的运用

介绍了磨矿分级自动控制系统的控制原理、功能，以及在实际生产中的应用效果，以期推动磨矿自动系统在矿山中的应用。     

媒体服务中流式拷贝性能分析

随着网络带宽的进一步提高,视频点播的瓶颈基本卡在视频服务器端。文章提供的服务器端的流式拷贝,能进一步提高整个系统的服务能力。文章对流式拷贝的过程进行描述,对其中的数学模型进行分析,并与没有流式拷贝的系统进行比较分析。     

盐和水蒸气协同作用下TiAl合金腐蚀性能研究及其防护

研究了在700℃盐和水蒸气协同作用下TiAlNb合金的腐蚀行为以及溅射涂层对TiAlNb合金的防护作用。结果表明，在盐和水蒸气协同作用下，溅射TiAlCrAg涂层对TiAlNb合金具有一定的保护作用。盐和水蒸气协同作用加速了合金以及涂层的腐蚀。挥发性气体氯化物对α2相的循环作用是TiALNb合金腐蚀的主要原因。涂层中较少的α2相以及Laves相中较高的Cr含量是腐蚀有所减缓的主要原因。     

关于影响面条食用品质相关因素的探讨

从小麦生产概况、面条发展历史和工艺、国内外对面条食用品质的研究3个方面,分析了我国面条工业发展缓慢的原因,提出了小麦育种-面粉工业-制面工业,3个环节紧密配合,协调发展,才能形成良性循环的新思路。     

Phenotypic analysis of antigen-specific T lymphocytes

Identification and characterization of antigen-specific T lymphocytes during the course of an immune response is tedious and indirect. To address this problem, the peptide-major histocompatability complex (MHC) ligand for a given population of T cells was multimerized to make soluble peptide-MHC tetramers. Tetramers of human lymphocyte antigen A2 that were complexed with two different human immunodeficiency virus (HIV)-derived peptides or with a peptide derived from influenza A matrix protein bound to peptide-specific cytotoxic T cells in vitro and to T cells from the blood of HIV-infected individuals. In general, tetramer binding correlated well with cytotoxicity assays. This approach should be useful in the analysis of T cells specific for infectious agents, tumors, and autoantigens.     

Antibody- and cell-mediated immune responses of Actinobacillus pleuropneumoniae-infected and bacterin-vaccinated pigs

The number involved in and the rate of migration of donor leucocytes into the following recipient organs (spleen, thymus, bone marrow, lung and mesenteric lymph nodes) were measured in two rat models of orthotopic liver transplantation (OLT) using donor-specific MHC class I antibodies. The first OLT model is one that does not require immunosuppression in order to achieve tolerance and involved the transplantation of DA (MHC haplotype, RT1a) livers into PVG (RT1c) recipients. The second model was one that required a 7-day (10 mg/kg) treatment with cyclosporin A (CsA) to achieve tolerance and used DA donors into Lewis (RT1(1)) recipients. Recipient organs were biopsied on days 3, 20 and 87 following OLT and donor leucocyte migration was quantified by immunohistochemistry and computer densitometry of immunoblots of detergent-solublized tissues in order to resolve both membrane-bound and soluble donor MHC class I antigen. In a separate experiment, spleen biopsies were taken following OLT on days 3 and 15 from the naturally tolerizing OLT model (DA into PVG), treated with and without CsA for 7 days and compared with the (DA into Lewis) model. The initial rate of leucocyte migration between days 3 and 21 following OLT was found to be the most rapid into the spleen, followed by the bone marrow and mesenteric lymph nodes in the naturally tolerant (DA into PVG) model when compared with the (DA into Lewis) model. The number of donor leucocytes in the spleen and mesenteric lymph nodes in both models was, however, approximately the same by 87 days. No real difference in the rate of leucocyte migration was seen in the thymus or the lung for both transplant models over the time course assayed. CsA was found to lower the rate of donor leucocyte migration only over the period it was administered. The rate of donor leucocyte migration into the spleen was still much lower 15 days after OLT in the (DA into Lewis) model compared with the (DA into PVG) model treated with and without CsA. Thus the differences in the rate of donor leucocyte migration into the spleen, bone marrow and mesenteric lymph nodes immediately following OLT may offer an explanation as to why the (DA into PVG) combination is able to accept a transplanted liver without immunosuppressive therapy.     

耐热钢主蒸汽管的焊接

1前言我厂动力区三期锅炉项目为2台75 t/h和1台130 t/h锅炉,与之配套的主蒸汽管道大量使用不同规格的15CrMo耐热管材,其主要规格为D273mm×11mm、D219mm×10mm、D159mm×9mm、D76mm×6mm、D36mm×4mm,管内蒸汽工作温度为450℃,工作压力为3.82 MPa,根据DL5007—92《电力建设施工及验收技术规范(》火力发电厂焊接篇)的要求,50%探伤,焊后24 h进行X射线探伤,评定标准为SD143—85,Ⅱ级合格。为保证质量,对15CrMo钢的焊接工艺特点进行了分析,评定了焊接工艺。2焊接工艺特点2、1 15CrMo属耐热钢,一般在热处理状态下焊接,其热处理状态为900…     

基于Web Services的水调自动化系统

在阐述水调自动化系统主要应用功能及介绍Web Services技术的基础上,结合WebServices的原理及实现机制提出了面向网络服务的水调自动化系统设计方案.介绍了该系统的总体结构、实现思路及其技术优势和不足,为水调自动化系统的研制与开发提供了一个新型、可靠的设计方案.     

A role for Rev in the association of HIV-1 gag mRNA with cytoskeletal beta-actin and viral protein expression

Human immunodeficiency virus type-1 (HIV-1) Rev acts by inducing the specific nucleocytoplasmic transport of a class of incompletely spliced RNAs that encodes the viral structural proteins. The transfection of HeLa cells with a rev-defective HIV-1 expression plasmid, however, resulted in the export of overexpressed, intron-containing species of viral RNAs, possibly through a default process of nuclear retention. Thus, this system enabled us to directly compare Rev+ and Rev+ cells as to the usage of RRE-containing mRNAs by the cellular translational machinery. Biochemical examination of the transfected cells revealed that although significant levels of gag and env mRNAs were detected in both the presence and absence of Rev, efficient production of viral proteins was strictly dependent on the presence of Rev. A fluorescence in situ hybridisation assay confirmed these findings and provided further evidence that even in the presence of Rev, not all of the viral mRNA was equally translated. At the early phase of RNA export in Rev+ cells, gag mRNA was observed throughout both the cytoplasm and nucleoplasm as uniform fine stippling. In addition, the mRNA formed clusters mainly in the perinuclear region, which were not observed in Rev+ cells. In the presence of Rev, expression of the gag protein was limited to these perinuclear sites where the mRNA accumulated. Subsequent staining of the cytoskeletal proteins demonstrated that in Rev+ cells gag mRNA is colocalized with beta-actin in the sites where the RNA formed clusters. In the absence of Rev, in contrast, the gag mRNA failed to associate with the cytoskeletal proteins. These results suggest that in addition to promoting the emergence of intron-containing RNA from the nucleus, Rev plays an important role in the compartmentation of translation by directing RRE-containing mRNAs to the beta-actin to form the perinuclear clusters at which the synthesis of viral structural proteins begins.