340 resultados para 350
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根据重离子在CR39中能量损失率公式,建立了一个鉴别空间重离子的数学模型LET=cZdRb.通过传能线密度与剩余射程之间的关系曲线,获得了该模型的系数.在实验中发现的CR39蚀刻率与离子有限传能线密度的关系VT=A·(REL)BE<350,被用来与该数学模型相关联,并得到一等式R=A0.0455Z3.18V-1T.最终,借助于标定实验得到了离子鉴别公式Z3.18=64541.08+2.53(dR/dV-1T).
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IEECAS SKLLQG
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简要介绍一种新的输入信号时序鉴别方法与电路。该电路的主要功能是对输入信号的时序进行鉴别和分拣,它可以鉴别出一个输入信号串中包含的各个脉冲的序号,并且产生与各个序号相对应的输出信号。可以鉴别的输人信号的序号为N=1,2,3,…,8。适用于多路时间幅度转换器(TAC)和多路时间数字转换器(TDC)系统,其输出信号可作TAC和TDC的停止信号。该电路输出信号的前沿tr≤3.2ns,传输延迟tpd≤20ns.
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IEECAS SKLLQG
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描述了一个用于热核同位旋效应研究的高质量分辨带电粒子望远镜探测器。望远镜由三叠层探测器组成 ,其中前两片是全耗尽硅半导体 ΔE探测器 ,后一片是锂漂移硅探测器。其厚度分别为 :350、50 0、350 0μm。此探测器的主要特点是 :具有高能量分辨、高质量分辨 (对1 6 OΔA/ A =3.1 % )、大能量范围 (例如 ,对于氧粒子为 1 2~ 60 Me V/ amu) ,可对直到硫的粒子进行同位素鉴别 ,能较好地用于热核同位旋效应研究。
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L-shell X-ray spectra of Mo surface induced by Xe25+ and Xe29+ were measured. The X-ray intensity was obtained in the kinetic energy range of the incident ions from 350 to 600 keV. The relationship of X-ray intensity with kinetic energy of the projectile and its charge state were studied, and the simple explanation was given.
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Large-sized CsI (Tl) single crystals, similar to phi 100 mm x 350 mm, have been grown successfully, and this CsI(Tl) coupled with PD has been successfully utilized at RIBLL (the Radioactive Ion Beam Line in Lanzhou) to measure the energy of heavy ions as a stopping detector. The performances of CsI(Tl) detector coupled with PD and APD have been tested and compared, including the temperature dependence of scintillating light yield
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The reduced velocity correlation functions of the Intermediate Mass Fragments (IMFs) were measured in the reactions of Ar-36+ Sn-112,Sn-124 at 35MeV/u. The anti-correlation at small reduced velocities is more pronounced in Ar-36+ Sn-124 system than that in Ar-36+ Sn-112 system. The difference of the correlation functions between the two reactions is mainly contributed by the particle pairs with high momenta. A three-body Coulomb repulsive trajectory code (MENEKA) is employed to calculate the emission time scale of IMFs for-the both systems. The time scale is 150fm/c in the Ar-36+ Sn-112 system and 120fm/c in the Ar-36+ Sn-124 system, respectively. A calculation based on an Isospin dependence Quantum Molecular Dynamics code (IQMD) reveals that the emission time spectrum of IMFs is shifted slightly leftwards in Ar-36+ Sn-124 compared with that in the Ar-16+ Sn-112 system, indicating a shorter emission time scale. Correspondingly, the central density of the hot nuclei decreases faster in Ar-36+ Sn-124 than in Ar-36+ Sn-112
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Spectra of the ionized oxygen atom were researched with the Pro-500i monochromator equipped with CCD. The beam foil method was used at energy of 2 MeV in a 2 x 1.7 Tandem accelerator. In this work, we report 201 spectral lines determined in the region 250-350 nm, and most spectral lines were attributed to n, l energy level transitions from O II to O IV atoms. Our experimental results are in good agreement with existing theoretical calculations. Many lines reported in this paper have not been measured in past experiments, and a majority of them are week transitional lines.
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Magnesium aluminate spinel crystals (MgAl2O4 (1 1 0)) deposited with 30 nm Cu film on surface were implanted with 110 key Ar-ions to a fluence of 1.0 x 10(17) ions/cm(2) at 350 degrees C, and then annealed in vacuum condition at the temperature of 500, 600, 700, 800 and 900 degrees C for 1 h, respectively. Ultraviolet-visible spectrometry (UV-VIS), scanning electron microscopy (SEM), Rutherford backscattering (RBS) and transmission electron microscopy (TEM) were adopted to analyze the specimens. After implantation, the appearance of surface plasmon resonance (SPR) absorbance peak in the UV-VIS spectrum indicated the formation of Cu nanoparticles, and the TEM results for 500 degrees C also confirmed the formation of Cu nanoparticles at near-surface region. In annealing process, The SPR absorbance intensity increased at 500 and 700 degrees C, decreased with a blue shift of the peak position at 600 and 800 degrees C, and the peak disappeared at 900 degrees C. The SPR absorbance intensity evolution with temperature was discussed combined with other measurement results (RBS, SEM and TEM). (C) 2010 Elsevier B.V. All rights reserved.
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ZnO:Al thin films with c-axis preferred orientation were deposited on glass and Si substrates using RF magnetron sputtering technique. The effect of substrate on the structural and optical properties of ZnO:Al films were investigated. The results showed a strong blue peak from glass-substrate ZnO:Al film whose intensity became weak when deposited on Si substrate. However, the full width at half maxima (FWHM) of the Si-substrate ZnO:Al (0 0 2) peaks decreased evidently and the grain size increased. Finally, we discussed the influence of annealing temperature on the structural and optical properties of Si-substrate ZnO:Al films. After annealing, the crystal quality of Si-substrate ZnO:Al thin films was markedly improved and the intensity of blue peak (similar to 445 nm) increased noticeably. This observation may indicate that the visible emission properties of the ZnO:Al films are dependent more on the film crystallinity than on the film stoichiometry. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.
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利用100MeV/u的12C6+离子束辐照酵母Saccharomyces cerevsiea YY,选育出一株高产突变菌株C03A,考察C03A发酵过程中不同温度、pH、糖汁浓度对发酵的影响。通过正交实验确定最佳发酵条件为:糖汁浓度24%、温度35℃、pH5.0。在10L发酵罐实验中,C03A发酵速率相对原始菌株高,36h发酵完全,比原始菌株缩短12h;发酵产酒率达到13.2%(V/V),比原始菌株高1.6%(V/V)。
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本文研究在不同注入温度(50 ℃ - 350 ℃)下的~+N离子注入GCr15 (1at%C, 1.5at%Cr, 0.3at%Mn, 0.2at%Si)轴承刚和纯铁(99.99at%Fe),注入剂量:5 * 10~(17) N~+·cm~(-2)。运用~(14)N(d,d_1)~(12)C带电粒子核反应(NRA)测量氮的总保留量及深度公布;内转换电子穆斯堡乐谱(CEMS)测定铁的化学态,并用x射线衍射分析进一步加以验证;最后用磨损实验检验磨损效果,寻找对研究的两种材料的一个最佳注入温度。对GCr15钢,低温(小于100 ℃)注入比350 ℃注入更有利于提高钢的耐磨性,这是由于50 ℃注入,氮间隙原子浓度高,且形成了Fe_2N相。高于150 ℃注入时,N~+离子前移,N~+离子保留量下降,Fe_2N相消失,而Fe_2N相的产生对提高耐磨性起重要作用。对纯铁,50 ℃注入时也形成了ε-Fe_2N相,在高于150 ℃注入时,此相消失,半生新相γ-Fe_4N。但在350 ℃时,GCr15钢与纯铁都形成了Fe_3O_4相,这对改性是极为不利的,所以建议,对GCr15钢和纯铁,不宜在350 ℃时注入
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A series of Pt/Mg-Al-O catalysts with different Mg/Al atomic ratios were prepared. The NOx storage capacities of these catalysts were measured by isothermal storage at 350 degreesC. It was found that the NOx storage capacity increased with increasing Mg/Al atomic ratios. The catalytic behaviors of Pt/Mg-Al-O and Pt/MgO were studied with storage-reduction cycles at 400 degreesC. Under oxidizing conditions, NOx concentration in the outlet gas gradually increased with time, which indicated the catalysts could store NOx effectively. After a switch from oxidizing conditions to reducing conditions, NOx desorption peak emerged immediately due to the incomplete reduction of stored NOx, which lowered the total NOx conversion. With increasing Mg/Al atomic ratio in the catalysts, NOx conversion increases. Pt/MgO has the highest NOx conversion because of its best activity in the reduction of NOx by C3H6. It seems that with an increasing amount of MgO in the catalysts, the self-poisoning of Pt-sites by adsorbed species during the reaction of NOx with C3H6 may be inhibited effectively.
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以生长在沈阳市区内的银杏为试材,使用开顶箱模拟法对倍增CO2浓度(700μmolmol-1)和正常空气CO2浓度(≈350μmolmol-1)条件下银杏生长参数,超氧阴离子自由基(O2-.)产生速率,丙二醛(MDA)含量,抗坏血酸(ASA)含量,超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)及谷胱甘肽还原酶(GR)活性动态变化进行分析,探讨高浓度CO2对银杏膜脂过氧化与抗氧化酶活性的影响。结果表明,在短期(60d)内CO2浓度倍增使银杏细胞内O2-.产生速率与H2O2含量减少,而ASA含量与SOD、APX、GR活性升高。与对照相比,大多数测定显示出显著差别。但较长期(70d以上)CO2浓度倍增处理则使试验结果发生逆转,活性氧O2-.产生速率略有升高,SOD、APX、GR活性略有下降,ASA含量仍略高于对照(但与对照相比差异并不显著),长期CO2浓度倍增处理可能使试验结果发生逆转。