矩形高速流场的材料去除特性

为了提高射流抛光的加工效率,设计了一种矩形喷嘴结构,基于并行去除方式来提高工件的去除效率。根据流体力学基本理论,分析了矩形喷嘴冲击射流流场的结构特性,并对其流场分布进行了定量计算。基于射流去除理论,建立了矩形喷嘴的材料去除理论模型,并对去除量分布进行了计算与比较。详细分析了矩形喷嘴结构参数与去除量之间的关系,在此基础上对矩形喷嘴进行了优化,结果表明,矩形喷嘴长宽比控制在10左右能够得到很好的去除效果。     

L∞(A,μ)到L∞(B,ν)的最小内同构

证明如果T是L∞(Ω1,A,μ)到L∞(Ω2,B,ν)内的同构且满足‖T‖·‖T-1‖≤1+ε,ε∈(0,1-5)则在一定条件下(T-‖T‖)接近于一个等距,其误差小于6ε.     

线性扫描极谱法测定青霉素

青霉素（Penicillin）又名盘尼西林，青霉素G的化学式为C16H18N2O4S，是一种高效、低毒、临床应用广泛的重要抗生素。它对革兰阳性细菌及某些革兰阴性细菌有较强的抗生作用，金黄色葡萄球菌、肺炎球菌、淋球菌及链球菌等对其高度敏感；脑膜炎双球菌、白喉杆菌、破伤风杆菌及梅毒螺旋体也很敏感。临床用于敏感菌引起的各种包急性感染，如肺炎、支气管炎、脑膜炎、心内膜炎、腹膜炎、败血症等。     

A Novel Synthesis of Alkaline Earth Silicate Phosphor Sr3MgSi2O8： Eu^2＋, Dy^3＋

A novel method for synthesizing long afterglow silicate phosphor Sr3MgSi2O8：Eu^2＋,Dy^3＋using TEOS and inorganic powders as reactants was reported. Acetic acid as a catalyzer controlled the hydrolysis of TEOS by adjusting pH value of the system. The morphologies of precursor were characterized by transmission electron microscope （TEM）. The structure and optical properties of the phosphor powders were systematically investigated by means of X-ray diffraction and spectrofluorometry. TEM images have reflected the core-shell structure and quasi-spherical morphology of the precursor particles. It was found that the single-phase Sr3MgSi2O8 crystalline structures were obtained at 1050 and 1250 ℃ for the samples prepared with the nano-coating method and the solid state reaction, respectively. The emission intensities of the phosphors prepared by the present method were higher than those by the conventional process. Also, the afterglow characteristic was better than that prepared by solid-state reaction in the comparable condition.     

ON ALMOST ISOMETRIES FROM L~1 (μ) INTO L~∞(v) OR C_b (△)

Let μ,ν be measures with diem L~1(μ) =dim L~∞(ν)=∞ and ⊿ be a "subinterval" of the real line. Let E=L~∞(ν) or C_b(⊿), in this paper it turns out that the IAP for the space B(L~1(μ)→E) has a negative answer.     

“慢肾康”对慢性肾衰大鼠血清锌铜的影响

观察了慢性肾功能衰竭大鼠经中药“慢肾康”治疗后血清锌铜的变化，研究发现“慢肾康”能明显改善肾衰动物低血锌状况，并且慢性肾衰动物低血锌与血浆白蛋白呈正相关，而与尿蛋白呈负相关。研究提示，“慢肾康”通过改善肾功能，减轻蛋白尿和升高血浆白蛋白而使血清锌升高，同时药物本身所含的锌元素也有一定的补充作用。“慢肾康”的治疗，对肾衰动物的血清铜无明显影响。     

Performance test of the low-pressure thin window multi-wire chamber

A flow gas low-pressure multi-wire proportional chamber(LPMWPC)with an active area of 180 mm×80 mm has been developed for the flying time test of the recoil nuclei on super heavy nuclear experiments.The LPMWPC detector can be operated in single as well as double step operational modes.In the case of double step operational mode with a high gas amplification factor,signals fromα-particles reside well above the electronic noise.The gas leakage rate and time resolution obtained from theα239Pu source are shown and discussed at the condition of 3 mbar Isobutane gas.It was shown that the time resolution was better than 2.9 ns at the best work condition,and the detecting efciency was larger than 98%at the low energyαparticles.So the LPMWPC is fit to measure the flying time in the super heavy nuclear fragments experiment.     

对宇称算符显式的几点评注

指出本刊近年发表的宇称算符的显式几十年前即已见于文献.对该结果作了几点补充讨论,包括推导的改进、经典极限以及对狄拉克方程的推广.