特征X射线能谱法测定Fe^＋注入小麦种子的深度

用１１０ｋｅＶ Ｆｅ＾＋离子束垂直注入小麦种胚后，在扫描电子显微镜上沿种子纵沟剖面，在不同深度上测量Ｆｅ元素被激发出的特征Ｘ射线强度分布，结果表明分布呈指数衰减，与晶体中的热扩散分布相类似，并对此进行了讨论。     

HHD型核子秤电离室物理性能检测

HHD型核子秤电离室已成功地使用于HCS型核子秤.对它的各种物理性能指标进行了检测,各项性能指标都达到了设计要求。     

全封离式低,中功率CO2激光器

本文回顾了过去十年来封离CO_2激光器使用射频(RF)激发技术方面的进展,并讨论了这一技术现状以及技术与市场的挑战。     

辐射制备缓释抗癌药阿糖胞苷的研究

报告了甲基丙烯酸酯类在室温下进行辐射聚合制备缓释抗癌药阿糖胞苷（Ａｒａ－Ｃ）的研究结果。结果表明，不仅亲水性单体，而且疏水性单体（包括ＭＭＡ、ＥＭＡ和ＢＭＡ等）都可用于辐射固化。加入到亲水性基质中的疏水性单体可以延缓药物的离体释放，其顺序是ＭＭＡ＜ＥＭＡ＜ＢＭＡ，央ＭＭＡ－ＨＥＭＡ共聚物中，Ａｒａ－Ｃ释放率随着基质中的ＭＭＡ含量增加而降低。药物的离体释放还受许多困素的控制，结果显示：药物释放量随着     

Effect of quercetin on chemiluminescence of human platelets induced by arachidonic acid

Arachidonic acid (AA)-induced platelet chemiluminescence (CL) was measured with a lumiphotometer. Quercetin remarkably inhibited the CL, the IC50 of quercetin was 3 mumol.L-1. When quercetin plus aspirin, which inhibits only cyclooxygenase, was added, the inhibitory rate of platelet-CL obviously increased (P < 0.01). On the other hand, the quercetin had a scavenging effect on superoxide anion radical using alkaline sodium dithionite solution generation. The IC50 was 20.9 mumol.L-1. In addition, superoxide dismutase of 0.1 mg.ml-1 inhibited the platelet-CL by 97.8%, while mannitol, a hydroxyl radical scavenger, only by 43.3% at a concentration of 80 mg.ml-1. These results suggest that the mechanism of the inhibiting AA-induced platelet-CL by quercetin was associated with scavenging the superoxide anion radical directly and with inhibiting the cyclooxygenase.     

交联型聚醚聚氨酯的表征、力学性能及其碱金属盐络合物的导电性能

采用三羟甲基丙烷（ＴＭＰ）作交联剂与聚乙二醇（ＰＥＯ－１５４０）和甲苯二异氰酸酯（ＴＤＩ）反应，得到了具有较好力学性能的交联型聚醚聚氨酯（ＰＥＵ），该聚合物与ＬｉＣｌＯ４的结合物具有较高的室温电导率（σ３０℃＝１．８７×１０￣（－４）Ｓ／ｃｍ）。采用全反射红外光谱（ＡＴＲ－ＩＲ）对聚合物的结构进行了表征。对聚合物的组成、不同ＴＤＩ类型及络合盐浓度对聚合物力学性能及其络合物电导率的影响进行了探讨。低度交联聚合物的络合物，其电导率与温度的关系符合建立在自由体积理论上的ＶＴＦ方程，表明络合物中离子的传导主要是在无定形区域进行，与自由体积有关。     

A truncated poisson regression model with applications to occurrence of adenomatous polyps

Adenomatous polyps are considered as the dominant precursor lesion of colorectal cancer. A phase III colorectal cancer prevention trial, conducted by the Arizona Cancer Center, concerns the ability of wheat bran fibre supplement to reduce the recurrence of adenomatous polyps. All participants in the study are to have had colorectal polyps detected and removed during a baseline (qualifying) colonoscopy within three months prior to enrolment. In this paper, our interest focuses on occurrence of adenomatous polyps at the baseline colonoscopy. We use a truncated Poisson model to fit these types of data. We develop a regression model to assess the effects of explanatory factors on the positive counting variable. We fit truncated Poisson parameters by a log-linear regression model and estimate regression parameters by the maximum likelihood procedure. Finally, we apply it to the baseline colonoscopy data from the Wheat Bran Fiber study.     

STRUCTURE REPRESENTATION OF THE SPECIFIC FRACTIONS FROM PINGSHUO COAL

Basic data of four fractions, PM₁, PM₆, PM₇and PM₈, derived from Pingshuo bituminous coal were obtained by ultimate analyses, mean molecular weight measure, GC/MS, ¹³C-NM R, ¹H-NM R and FTIR technigues. A method of calculating the average molecular parameters of the fractions is introduced. Based on the calculated parameters, the molecular structure models of the fractions of PM₆, PM;and PM₈are constructed. Significant structural information about the saturated hydrocarbon and aromatic hydrocarbon with heteroatom groups is given also.