X_0(2900) and its heavy quark spin partners in molecular picture

The X₀(2900),recently observed by the LHCb Collaboration in the D-K+invariant mass of the B+→D+D-K+process,is the first exotic candidate with four different flavors,beginning a new era for the hadron community.Under the assumption that the Xo(2900)is a I(J^P)=0(0+)D*K* hadronic molecule,we extracted the whole heavy-quark symmetry multiplet formed by the(D,D*)doublet and the K*meson.For the bound state case,there would be two additional I(J^P)=0(1+)hadronic molecules associated with the DK*and D*K*channels,as well as one additional I(J^P)=0(2+)D*K*molecule.In the light quark limit,they are 36.66 MeV and 34.22 MeV below the DK*and D*K*thresholds,respectively,which are unambiguously fixed by the mass position of the Xo(2900).For the virtual state case,there would be one additional I(J^P)=0(1+)hadronic molecule,strongly coupled to the DK*channel,and one additional I(J^P)=0(2+)D*K*molecule.Searching for these heavy quark spin partners will help shed light on the nature of the X₀(2900).     

AlN在AlN/VN纳米多层膜中的相转变及其对薄膜力学性能的影响

采用反应磁控溅射制备了AlN/VN纳米多层膜.研究了多层膜调制周期对AlN生长结构的影响以 及纳米多层膜的力学性能.结果表明：小周期多层膜中的AlN以亚稳的立方相(c-AlN)存在并 与VN形成共格外延生长的超晶格.薄膜产生硬度和弹性模量升高的超硬效应.大调制周期下， AlN从立方结构转变为稳定的六方相（h-AlN），并使多层膜形成纳米晶的“砖墙”型结构. 讨论认为VN的模板作用有利于c-AlN的生长，但不能显著提高其临界厚度. 关键词： 薄膜的力学性能 外延生长 亚稳相     

北京水环境中主要阴离子污染物的监测

针对北京水环境的特点，选定了适宜的色谱条件，用离子色谱法对水环境中常见的阴离子污染物F^-、Cl^-、NO3^-－N和SO4^2-，进行了定量监测，并确定了主要的定量分析掺数。该方法用于实际样品的分析，取得了满意的结果。     

华佗豆碱甲氢溴酸盐晶体结构和绝对构型

(+)华佗豆碱甲已经从中草药华佗豆(Ipomoea hardwickii Hemsl.)中分离到。它的氢溴酸盐晶体属正交晶系,空间群P 2_12_12_1。晶胞参数:a=10.078(2)(?),b=17.303(3)(?),c=9.022(1)(?),Z=4。用四圆衍射仪收集强度数据,得到独立可观察点共1248个。用重原子法确定结构,经块对角矩阵最小二乘法修正结构参数,最终的偏离因子R为0.051。根据Br的反常散射确定华佗豆碱甲阳离子的绝对构型为S型,命名为S-1,2,3,5,8,9-六氢-6-对苯酚基-7-甲基吲嗪。晶胞内四个分子两两一对,通过氢键NH…Br…HOH…OHAr形成在晶体内沿b方向无限伸展的分子链。     

人红细胞摄入 Eu(Cit)23-阴离子通道机制的研究

研究了Eu(Cit)2^3-进入人红细胞的机制。在人红细胞与含不同浓度的Eu(Cit)2^3-的等渗缓冲液温育后。用ICP－MS测定胞浆及膜中Eu的含量，并考察了阴离子通道抑制剂DIDS，温度及pH的影响，制备了人红细胞膜正面向外囊泡（ROV）和内翻包囊泡（IOV）并研究了它们对Eu(Cit)2^3-的摄取及DIDS的影响。结果表明，Eu(Cit)2^3-可以与细胞膜结合并进入红细胞内，DIDS强烈抑制红细胞对Eu(Cit)2^3-的摄入；温度，pH对细胞摄入有显著影响，ROV和IOV可以摄入Eu(Cit)2^3-，但DIDS只抑制ROV的摄入，对IOV的摄入无影响。Eu(Cit)2^3-进入人红细胞具有阴离子通道机制的各种特征。阴离子通道是稀土柠檬酸络合物Eu(Cit)2^3-进入红细胞的途径之地。     

Variables affecting simulated use determination of residual ethylene oxide in medical devices

In autumn 1993, AAMI/ST/WG 63, Sterilization Residuals Working Group undertook the task of studying factors involved in determining the amount of residual ethylene oxide in medical devices after sterilization and developing a protocol for controlling the relevant variables. The protocol was evaluated by conducting a round robin study consisting of 8 participating laboratories from around the country. Results of this round robin study demonstrated the range over which results may vary despite controls placed on the time and temperature at which determinations were conducted. The data from the study suggest that small, random variations in technique during short sample extraction times can lead to variability in the results. Variables such as initial water temperature, oven temperature, weighing of sample, and length of extraction should be carefully controlled. Inherent variations in the material composition of similar devices are possible contributing factors. The efforts of this working group and the subsequent evaluation and discussion of its findings are presented.     

Two new triterpenoid saponins from Aralia subcapitata

Two new oleanane-type saponins, subcapitatoside B and C were isolated from the roots of Aralia subcapitata. On the basis of chemical and spectral evidences, subcapitatoside B and C were established as oleanolic acid 3-O-beta-D-glucopyranosyl-(l-->3)-[beta-D-galactopyranosyl- (1-->2)]-beta-D3--galactopyranoside, and 3-O-beta-D-glucopyranosyl- (1-->3)-[beta-D-galactopyranosyl-(1-->2)]-beta-D-glucopyranosyl oleanolic acid 28-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside, respectively.     

Ag|kCl|六氢吡啶体系表面增强喇曼散射效应的猝灭和恢复

在简述近年来电化学体系中表面增强喇曼散射(SERS)活性位置研究的实验结果和有关论述后, 着重报道作者在Ag/KCl/六氢吡啶体系中, Ag-Cl振动峰和六氢吡啶诸振动峰的强度, 在一定电位范围内电极被施加负脉冲电位后的同步下降, 以及采用氧化还原循环(ORC)处理得到同步恢复等新的实验结果, 并对上述体系中表面络合物的构成及其在SERS中的作用作了进一步的论证。