Access to functionalised silver(I) and gold(I) N-heterocyclic carbenes by [2 + 3] dipolar cycloadditions

A new strategy was developed for the modification of silver(I) and gold(I) N-heterocyclic carbenes. Azido groups were grafted and used either by copper-catalysed azide-alkyne cycloaddition before metallation or by thermal and "strain-promoted" 1,3-dipolar cycloaddition after metallation to functionalise the metal-NHCs.     

Systematics of exclusive diffraction dissociation modes inK ± p interactions at 32 GeV/c

We present results of an investigation of diffraction dissociation in exclusive channels inK ^± p interactions at 32 GeV/c. Total cross sections are determined forK ^±→K ^±π⁺π^?,K ^±2π⁺2π^?,K ⁰π^±π^± K ^±2π⁺π^?,K ^± K ⁺ K ^?,K ^±p \(\bar p\) , \(\bar \Lambda \) p, andp→pπ ⁺π^?,p2π⁺2π^?,pK ⁺K^?,ΛK ⁺,ΛK ⁺π⁺π^? dissociation modes, ranging from a high of ? 300 μb to ～ 3 μb. Thedσ/dt′ differential cross sections of most of the systems studied exhibit structure, with breaks of slope att′ ～ 0.2 to 0.5 GeV²; some modes have a sharp forward spike with a slope exceeding 10 GeV^?2. A systematic investigation of two-body dissociation modesK→A+B andp→A′+B′ shows that these cross sections decrease with increasing threshold massM _A+M _B, that they are comparable for kaon and proton dissociations at similar diffractive excitation masses and are systematically suppressed by a factor 3–4 for dissociations requiring an \(s\bar s\) quark pair creation when compared to \(u\bar u\) pair creation indicating a breakdown ofSU ₃ symmetry for the \(q\bar q\) sea.     

Inclusive production of neutral kaons inK − p interactions at 32 GeV/c

The inclusive production of neutral kaons inK ^? p interactions at 32 GeV/c is studied in final states with one, two and three strange particles (K ⁿ or Λ). Inclusive and topological cross sections are obtained and their energy dependence discussed by comparison with lower energy data. The invariant differential cross sections of neutral kaons are studied as a function of Feynmanx, the c.m. rapidity and the transverse momentum, and a comparison is made with data at 14.3 GeV/c. Invariantx-distributions are obtained separately for “indirect” neutral kaons from \(\bar K*(890)\) decays and for “prompt” kaons. We also discuss the possibility of connecting quark structure functions with hadron fragmentation spectra at this c.m. energy \(\sqrt s \simeq 8 GeV\) .     

大鼠急性缺血心肌31P磁共振波谱的基础研究

利用³¹P磁共振波谱（MRS）检测了急性缺血心肌组织提取物中高能磷酸化合物的变化. 方法：成年SD大鼠在心肌梗塞后0、5、 20、45 min后进行取材,梗塞区、边缘区及正常区的心肌组织经高氯酸萃取后进行高分辨MRS检测. 结果：梗塞区,缺血5 min PCr/Pi比值下降到对照组的12 ％;20 min ATP/Pi 比值下降至0.05,Pi/EPP比值上升至0.8;45 min 梗塞区PDE/ATP上升至1.93,与45 min心肌的不可逆损伤超微结构相吻合. 边缘区各代谢产物出现改变的程度要小于梗塞区,大于正常区. 正常区也有能量代谢的改变. 结论：心肌组织的³¹P MRS能够反映心肌缺血后心肌不同部位的动态能量代谢改变. PDE/ATP是判断心肌不可拟性损伤的可靠指标.     

A New Dihydroflavone Glycoside from Glycyrrhiza uralensis

A new dihydroflavone glycoside was isolated from the underground parts of Glycyrrhiza uralensis. Its structure was elucidated as 7-hydroxyl-4′-O-]3-D-(6″-O-α-hydroxylpropionyl) glucopyranosyl dihydroflavone by spectral methods.     

高频离子源参数研究

从自由电子在高频电场中的运动方程出发，研究了高频离子源的工作原理。由边界条件和电离条件推导出截止条件和最低点火电压的关系式。在此基础上编出了适于在各种气压下计算各种气体的Ｕｂ－ｆ曲线程序，作出了大量的计算结果。由计算结果讨论了高频离子源工作时各种参数之间的制约关系。所得结果将为利用高频离子源产生Ｈ＋ｎ离子团簇的实验提供重要的依据。     

高含硼金刚石合成的原子分子过程及其特点的初步探讨

在５．８ＧＰａ和１４８０℃条件下，首次用Ｂ４Ｃ作碳源，通过触媒合金（Ｎｉ７０Ｍｎ２５ＣＯ５及Ｆｅ５５Ｎｉ２９ＣＯ１６）的作用，合成出粒度为２０～２５μｍ，含硼量高于１ｗｔ％的黑色金刚石，晶体中存在大量针形体。最近艹勾清泉教授提出了这种金刚石形成的原子分子过程模型。用模型预言可能形成具有某些优异特性的针形硼皮及硼氮皮金刚石     

CALCULATION FOR STRETCHING VIBRATIONAL SPECTRUM OF CH_4

ＣＡＬＣＵＬＡＴＩＯＮＦＯＲＳＴＲＥＴＣＨＩＮＧＶＩＢＲＡＴＩＯＮＡＬＳＰＥＣＴＲＵＭＯＦＣＨ４ＣｈｅｎＸｉａｎｇｒｏｎｇＧｏｕＱｉｎｇｑｕａｎＰａｎｇＸｉａｏｆｅｎｇＩｎｓｔｉｔｕｔｅｏｆＡｔｏｍｉｃａｎｄＭｏｌｅｃｕｌａｒＳｃｉｅｎｃｅａｔＨｉｇ...     

He,Ne,Ar与N2分子碰撞转动激发截面理论计算

利用ＩｎｆｉｎｉｔｅＯｒｄｅｒＳｕｄｄｅｎＡｐｐｒｏｘｉｍａｔｉｏｎ（ＩＯＳ）［１］计算了Ｈｅ、Ｎｅ、Ａｒ与Ｎ２分子碰撞的总微分散射截面、弹性微分散射截面和积分散射截面。当入射能量Ｅ＝０．０２７３ｅＶ时，计算Ｈｅ－Ｎ２的碰撞总微分散射截面结果与ＣｌｏｓｅＣｏｕｐｌｉｎｇ（ＣＣ）［２］计算结果符合很好，说明ＩＯＳ对所研究的Ｈｅ、Ｎｅ、Ａｒ－Ｎ２碰撞体系是一种简捷可用的方法。     

B4C与合金触媒体系合成金刚石的反应机理探讨

在总结由Ｂ４Ｃ加合金触媒体系中合成金刚石的有关实验的基础上，从Ｂ４Ｃ和合金触媒的结构入手，探讨了其形成金刚石的宏观（化学反应）和微观（原子分子）的机理过程，为Ｂ４Ｃ合成金刚石的继续研究提供了一个有益的尝试。