费密共振和甲烷的振动能谱

用局域模模型来解释甲烷的伸展和弯曲振动能谱，其中伸展振动和弯曲振动间的相互作用用费密共振项来描写，它由一个伸展振子的玻色产生（或湮没）算子和两个弯曲振子的玻色湮没（或产生）算子乘积的T_d不变组合构成．这模型包含10个参数，与已发表的甲烷振动能谱的实验数据比较，得到能量的方均根偏差为12.38cm^－1． 关键词：     

硒的原子吸收分析进展

本文对1985年以来硒的原子吸收分析,从石墨炉法、氢化物法、氢化物-石墨炉法和火焰法四个方面的分析进展进行综合评述。     

不协调目标信息系统知识约简的比较研究

研究不协调目标信息系统的各种知识约简之间的关系。证明分布约简既是β上分布约简，也是β下分布约简，并且在一定条件下,β上、下分布约简与不协调目标信息系统的分配约简和最大分布约简等价。     

Dynamical Model of QCD Vacuum and Color Thaw at Finite Temperatures

In terms of the Nambu-Jona-Lasinio (NJL) mechanism, the dynamical symmetry breaking of a simple localgauge model is investigated. An important relation between the vacuum expectation value of gauge fields and scalarfields is derived by solving the Euler equation for the gauge fields. Based on this relation the SU(3) gauge potential isgiven which can be used to explain the asymptotic freedom and confinement of quarks in a hadron. The confinementbehavior at finite temperatures is also investigated and it is shown that color confinement at zero temperature can bemelted away under high temperatures.     

磁场中简并四波混频的偏振旋转效应

本文讨论了磁场中简并四波混频的偏振旋转效应。计算了J_g=0→J_e=1跃迁的三阶非线性极化率X_yxx⁽³⁾。它包括两个部分:一部分是由于布居差的饱和效应产生的;另一部分是由于原子与光场的相互作用中,感生出来的塞曼相干所造成的。 关键词：     

The kernel of the wreath product of semigroups

All wreath products, in the general sense, of two semigroups with completely simple kernels have completely simple kernels. Presented here are computational characterizations of the primitive idempotents of such a wreath and of the identities and inverses in subgroups of its kernel. Research sponsored by the Air Force Office of Scientific Research, Office of Aerospace Research, United States Air Force, under Grant AF AFOSR 924-67.     

Kinetics of the esterification of maleic anhydride with octyl, decyl or dodecyl alcohol over dowex catalyst

Summary Esterification of maleic anhydride over acid ion exchange resin catalyst has been investigated in an isothermal semi batch reactor. Although this is a bimolecular reaction, first order kinetics with respect to acid has been observed.     

简并四波混频中的能级交叉效应

我们用微扰方法计算了近简并准二能级系统的三阶非线性极化率x⁽³⁾(-ω;ω,ω,-ω)。研究了简并四波混频的能级交叉效应,并与共振荧光的能级交叉效应比较。指出简并四波混频的能级交叉效应可用来测量上能级及下能级的弛豫速率。 关键词：     

Blood oxygen level-dependent and perfusion magnetic resonance imaging: detecting differences in oxygen bioavailability and blood flow in transplanted kidneys

Functional magnetic resonance imaging (fMRI) is a powerful tool for examining kidney function, including organ blood flow and oxygen bioavailability. We have used contrast enhanced perfusion and blood oxygen level-dependent (BOLD) MRI to assess kidney transplants with normal function, acute tubular necrosis (ATN) and acute rejection. BOLD and MR-perfusion imaging were performed on 17 subjects with recently transplanted kidneys. There was a significant difference between medullary R2? values in the group with acute rejection (R2?=16.2/s) compared to allografts with ATN (R2?=19.8/s; P=.047) and normal-functioning allografts (R2?=24.3/s;P=.0003). There was a significant difference between medullary perfusion measurements in the group with acute rejection (124.4±41.1 ml/100 g per minute) compared to those in patients with ATN (246.9±123.5 ml/100 g per minute; P=.02) and normal-functioning allografts (220.8±95.8 ml/100 g per minute; P=.02). This study highlights the utility of combining perfusion and BOLD MRI to assess renal function. We have demonstrated a decrease in medullary R2? (decrease deoxyhemoglobin) on BOLD MRI and a decrease in medullary blood flow by MR perfusion imaging in those allografts with acute rejection, which indicates an increase in medullary oxygen bioavailability in allografts with rejection, despite a decrease in blood flow.