ARCH(0,1)系数中位无偏估计分布的渐近展开(英文)

This paper is concerned with the distributional properties of a median unbiased estimator of ARCH(0,1)coefficient.The exact distribution of the estimator can be easily derived,however its practical calculations are too heavy to implement, even though the middle range of sample sizes.Since the estimator is shown to have asymptotic normality,asymptotic expansions for the distribution and the percentiles of the estimator are derived as the refinements.Accuracies of expansion formulas are evaluated numerically,and the results of which show that we can effectively use the expansion as a fine approximation of the distribution with rapid calculations.Derived expansion are applied to testing hypothesis of stationarity,and an implementation for a real data set is illustrated.     

Compensating large PMD by a fiber grating

In this paper, the first- and second-order polarization mode dispersion (PMD) with the amount of 132.994-ps differential group-delay (DGD) and maximum 476.129-ps/nm second-order PMD can be compensated by a two-stages PMD compensator at a 40-Gb/s optical fiber communication system. The first stage has one free degree that is used for first order and high orders PMD compensations by rotating the state of     

激光技术及强激光与物质相互作用实验

利用科研成果，开设激光技术及强激光与物质相互作用实验，让学生了解强激光与物质相互作用时的2个典型效应：二次非线性光学效应，高压冲击波（光力学）效应，实现了科研与实验教学的紧密结合。     

Lifetimes of Excited Levels in ^131Ce

The fusion-evaporation reaction ^116Sn (^19F, p3n)^131 Ce at projectile energy of 95 MeV is used to populate high spin states in ^131Ce. The de-exciting γ-rays are detected in γ-γ coincidence measurement with Compton-suppressed BGO-HPGe detectors. Level lifetimes of ^131 Ce were determined by using the Doppler shift attenuation method.The experimental results indicate that collectivity of ^131 Ce is reduced relative to that of ^130Ce and it follows that deformation decreases with increase of the neutron number on the basis of systematic comparison of transition quadrupole moments for the light cerium isotopes.     

水热处理的HZS M-5催化剂择形催化合成4 ,4′-二甲基联苯(英文)

Theshape selectivealkylationofpolycyclichy drocarbonsisusedtosynthesizesymmetricintermedi atessuchas 4 ,4′ dialkylbiphenyl (4 ,4′ DABP)and2 ,6 dialkylnaphthalene (2 ,6 DAN)whichareimpor tantprecursorsofadvancedpolymermaterials[1] .Thealkylationtoprepare4 ,4′ DABPcanbecarriedoutusingeitheralarge grouplikeisopropylorasmallgroupsuchasethylormethyl.However ,itisdiffi culttoselectivelyobtain 4 ,4′ dimethylbiphenyl(4 ,4′ DMBP)throughthemethylationofbiphenyl(BP )anditsderivatives[2 ,3] .…     

高密度聚乙烯（HDPE）在静高压下的强度研究

 高密度聚乙烯（HDPE）在1~2 GPa的静高压下发生熔体结晶。用压缩的方法对经过高压处理后的样品进行了杨氏模量的测量。测量结果表明：样品的杨氏模量随压力和结晶度的增加而增大，最大值达到1.46 GPa。伸直链晶体的形成是杨氏模量增加的重要因素。     

THE RELATIONSHIP BETWEEN ENVIRONMENT CHANGE AND SE MONSOON STRENGTH, DAIHAI LAKE, INNER MONGOLIA

Daihai Lake, located in NW margin of SE monsoon region, belongs to the sensitive area for climatic fluctuation. The analysis of continuous sedimentary column with an age of 100 ka indicates that there exists the different quasiperiodicity in time scales for monsoon shift. The climatic fluctuation in the Daihai Basin shows all along the alternation of cold and dry with a warm and wet climatic pattern, suggesting that the strength and drift of SE monsoon play a controllable role in the climatic change.