正弦平方势与正电子面沟道辐射的一般特征

引入正弦平方势，在经典力学框架内，将面沟道粒子的运动方程化为标准的摆方程，并用Jacobian椭圆函数和椭圆积分解析地给出系统的解和粒子运动周期，导出了正电子面沟道辐射的瞬时辐射强度、平均辐射强度和辐射谱特征.结果表明，沟道辐射频率己进入γ-能区，并指出了利用它作为短波长激光的可能性. 关键词： 沟道辐射 非线性 正弦平方势     

Optical travelator: transport and dynamic sorting of colloidal microspheres with an asymmetrical line optical tweezers

We report the transport, funnelling and dynamic sorting of colloidal microspheres in an aqueous suspension using line optical tweezers with asymmetrical intensity profiles. The line tweezers readily trapped and propelled the microspheres along the length of the line tweezers. Using this simple technique, transporting and funnelling of microspheres within a microscopic region were demonstrated. To illustrate the dynamic particle-sorting capability of the line tweezers, a binary colloidal system comprising of microspheres with diameters of 1.1 μm and 3.2 μm were driven past the line tweezers by electrophoresis. As the optical trapping force is dependent on the size of the microspheres, the line tweezers was able to change the path of the larger spheres while exerting little influence on the smaller spheres thus sorting the two types of microspheres. At optimized laser power and flow rate of microspheres, sorting efficiency greater than 90% has been achieved. PACS 42.15.Eq; 87.80.Cc; 87.80.Fe; 82.70.Dd     

Small ball probabilities for Gaussian processes with stationary increments under Hölder norms

Small ball probabilities are estimated for Gaussian processes with stationary increments when the small balls are given by various Hölder norms. As an application we establish results related to Chung's functional law of the iterated logarithm for fractional Brownian motion under Hölder norms. In particular, we identify the points approached slowest in the functional law of the iterated logarithm.Supported in part by NSF Grant DMS-9024961.     

Mass deposition in tyrosine irradiated by a N ion

Based on the measured UV-, IR-, laser-Raman, and mass spectra, and analyzed with the quantum theory, the reaction pattern of an implanted N + ion with tyrosine molecule (Tyr) was deduced. It was found that a substitute reaction of the slow down N⁺ with the group =C(5)H- of Tyr's benzene ring had taken place. In addition, a new carbonyl group was measured in the irradiated Tyr sample. Hence, a N-heterocyclic compound was formed.     

Improvement of the hydrothermal stability of MCM-48 mesoporous molecular sieves

This is a review of our recent reports about improving the hydrothermal stability of MCM-48 mesoporous molecular sieves and the related works done by other groups. It presents the different effects of direct addition of various anions, including F^?, SO₄ ^2?, NO₃ ^? and Cl^?, on the improvement of the hydrothermal stability of MCM-48. The different effects of anions on the improvement of the hydrothermal stability and the critical factors influencing the formation of hydrothermally stable MCM-48 are also explained by careful analysis and discussion.     

用[LiCI、TiO_2/Al_2O_3]催化剂进行甲烷氧化偶联反应

本文报导了用机械混合法调制的 LiCl/TiO_2及 LiCl·TiO_2/Al_2O_3催化剂在甲烷氧化偶联反应过程中的活性和选择性、以及 C_2收率等。同时,还详细地测定了温度、甲烷分压等各种反应条件对催化剂活性和选择性的影响。实验结果表明,当 LiCl 含量为20%(mol 此).在 T=750℃,P_(CH4)=0.2atm.P_(CH4):Po_2=3:2的条件下进行甲烷氧化偶联反应时,用这两种催化剂,可使乙烯的选择性提高到85%,乙烯的收率分别达到27%和29%。     

广州市偏头痛调查及初步分析

本文首次报导1983年在广州地区调查的偏头痛流行病学资料。本区偏头痛发病率为13.1/10万。患病率为306/10万。14岁以下,尚未记录到有患者。广州地区偏头痛发病率和患病率明显低于国内六大城市以及国外资料。女性患者为男性的三倍,此一比例高于国外报导。家族偏头痛史及个人过敏史有一定意义。     

On a conjecture about the exponent set of primitive matrices

M. Lewin and Y. Vitek conjecture [7] that every integer $\text{?[}\text{(n>}{}^2\text{?2n+2)}\text{2}\text{]+1}$ is an exponent of some n×n primitive matrix. In this paper, we prove three results related to Lewin and Vitek's conjecture: (1) Every integer $\text{?[}\text{(n}{}^2\text{?2n+2)}\text{4}\text{]+1}$ is an exponent of some n×n primitive matrix. (2) The conjecture is true when n is sufficiently large. (3) We give a counterexample to show that the conjecture is not true in the case when n=11.     

42CrMo钢混合组织与单一回火索氏体组织接触疲劳性能的研究

研究了42CrMo 钢得到混合组织(M+B+P_细+F)的热处理工艺及在相同硬度条件下混合组织与单一回火索氏体组织的接触疲劳性能。结果表明,混合组织的接触疲劳寿命(N_o、N_f)高于单一回火索氏体组织。     

键槽对称度误差的检测与评定

本文提供了生产中实用的键槽对称度误差检测方法和数据处理公式.