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61.
The CLAS forward electromagnetic calorimeter 总被引:1,自引:0,他引:1
M. Amarian G. Asryan K. Beard W. Brooks V. Burkert T. Carstens A. Coleman R. Demirchyan Yu. Efremenko H. Egiyan K. Egiyan H. Funsten V. Gavrilov K. Giovanetti R. M. Marshall B. Mecking R. C. Minehart H. Mkrtchan M. Ohandjanyan Yu. Sharabian L. C. Smith S. Stepanyan W. A. Stephens T. Y. Tung C. Zorn 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2001,460(2-3):239-265
The CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab utilizes six iron-free superconducting coils to provide an approximately toroidal magnetic field. The six sectors are instrumented individually to form six independent spectrometers. The forward region (8°<θ<45°) of each sector is equipped with a lead–scintillator electromagnetic sampling calorimeter (EC), 16 radiation lengths thick, using a novel triangular geometry with stereo readout. With its good energy and position resolution, the EC is used to provide the primary electron trigger for CLAS. It is also used to reject pions, reconstruct π° and η decays and detect neutrons. This paper treats the design, construction and performance of the calorimeter. 相似文献
62.
AG Brooks F Borrego PE Posch A Patamawenu CJ Scorzelli M Ulbrecht EH Weiss JE Coligan 《Canadian Metallurgical Quarterly》1999,162(1):305-313
The CD94/NKG2 receptors expressed by subpopulations of NK cells and T cells have been implicated as receptors for a broad range of both classical and nonclassical HLA class I molecules. To examine the ligand specificity of CD94/NKG2 proteins, a soluble heterodimeric form of the receptor was produced and used in direct binding studies with cells expressing defined HLA class I/peptide complexes. We confirm that CD94/NKG2A specifically interacts with HLA-E and demonstrate that this interaction is dependent on the association of HLA-E with peptide. Moreover, no interaction between CD94/NKG2A and classical HLA class I molecules was observed, as assayed by direct binding of the soluble receptor or by functional assays using CD94/NKG2A+ NK cells. The role of the peptide associated with HLA-E in the interaction between HLA-E and CD94/NKG2A was also assessed. All class I leader sequence peptides tested bound to HLA-E and were recognized by CD94/NKG2A. However, amino acid variations in class I leader sequences affected the stability of HLA-E. Additionally, not all HLA-E/peptide complexes examined were recognized by CD94/NKG2A. Thus CD94/NKG2A recognition of HLA-E is controlled by peptide at two levels; first, peptide must stabilize HLA-E and promote cell surface expression, and second, the HLA-E/peptide complex must form the ligand for CD94/NKG2A. 相似文献
63.
The influence of the sulphur content of nickel on its dissolution in 10N HCl has been investigated between 45 and 75°C. The rate of dissolution increases with both increasing temperature and sulphur content. The activation energies for commercial and electrodeposited nickel having sulphur contents of 0·006–1·345 were between 11·0 and 16·7 kcal g at?1. The results are in agreement with the conclusion of Schorr and Yahalom that the activation energies for metal dissolution in acids should be below 25 kcal g at?1. A brief discussion of the results is given. 相似文献
64.
Ecosplit3系列的样机现代化表示的重要特征是不改变原来整个设计原理而能大大改进变速器的转矩能力、档平顺性和噪音状况。斜齿行星齿轮装置可使变速 降低10分贝、在车辆变速败露首次采用了“锥形止推垫圈”技术,可使该行呈齿轮传动中的斜齿轮的轴向力自身消除。 相似文献
65.
Marshall B. Elam Matthew A. von Wronski Lauren Cagen Fayanne Thorngate Poonam Kumar Murray Heimberg Henry G. Wilcox 《Lipids》1999,34(8):809-816
We previously demonstrated increased apolipoprotein B (apoB) mRNA editing, elevated levels of mRNA for the catalytic component
of the apoB mRNA editing complex, apobec-1, and increased secretion of the product of the edited mRNA, apoB48, in very low
density lipoproteins (VLDL) in primary cultures of Sprague-Dawley rat hepatocytes following insulin treatment. In order to
determine the effect of in vivo hyperinsulinemia on these processes, we determined apoB mRNA editing, apobec-1 expression, hepatic expression of mRNA for
apoB and other VLDL apoproteins, and the quantity and composition of plasma VLDL in the hyperinsulinemic fatty Zucker rat.
Total apoB mRNA content of the livers of the fatty rats and lean littermates did not differ, however, edited apoB message
coding for hepatic apo B48, and abundance of mRNA for the catalytic subunit of the apoB mRNA editing complex, apobec-1, was
increased by 1.7-and 3.3-fold, respectively, in fatty rats. ApoCIII mRNA abundance was increased in livers of fatty rats as
well, but the abundance of hepatic apoE mRNA in the fatty animal was not different from that of the lean rat. Hepatic apoAI
mRNA abundance was also increased in the fatty rats. Associated with increased apoB mRNA editing, was the 1.7-fold increase
in the fraction of apoB in plasma as apoB48 in fatty rats. VLDL-triglyceride and-apoB in plasma were 15-and 3-fold higher,
respectively, in fatty Zucker rats compared to lean littermates, indicating both enrichment of VLDL with triglycerides and
increased accumulation of VLDL particles. Increased hepatic expression of mRNA for apoCIII and apoAI was associated with increased
content of apoC (and relative depletion of apoE) in VLDL of fatty rats, and plasma apoAI was increased in fatty Zucker rats,
primarily in the HDL fraction. The current study provides further evidence that chronic exposure to high levels of insulin
influences both the quantity of and lipid/apoprotein composition of VLDL in plasma. The increased apoC and decreased apoE
(as well as increased triglyceride) content of VLDL in the fatty Zucker rat observed in the current study may affect VLDL
clearance and therefore may be a factor in the observed accumulation of VLDL in the plasma of the fatty hyperinsulinemic Zucker
rats. 相似文献
66.
双重图形需要更新更苛刻的刻蚀能力,要求低于1.5nm CD均匀性、图形收缩和原位多层刻蚀。 相似文献
67.
Arthur H. Heuer Manfred Ruhle David B. Marshall 《Journal of the American Ceramic Society》1990,73(4):1084-1093
Recent evidence is summarized showing that the tetragonal ( t ) → monoclinic ( m ) martensitic transformation in ZrO2 can occur thermoelastically in certain ZrO2 -containing ceramics, and that microcracking accompanying the transformation is more common than had previously been recognized. The implications of these new data for the conditions under which the stress-induced transformation is irreversible, and for the particle size dependence of the transformation start ( M s ), temperature, are discussed. 相似文献
68.
69.
70.
An integrated energy supply and demand model for the state of Illinois is described. This equilibrium model is an important tool for integrating information from a variety of planning studies and data bases. A wide range of energy issues affecting diverse areas of the energy system, such as Illinois coal production under alternate oil price assumptions, renewable energy resource potential, and conservation options, can be analyzed by using the model. 相似文献