10MeV 25KW industrial electron LINAC

A 10MeV 25KW plus class electron LINAC was developed for sterilisation of medical devices. The LINAC composed of a standing wave type single cavity prebuncher and a 2m electro-plated travelling wave guide uses a 5MW 2856MHz pulse klystron as an RF source and provides 25KW beam power at the Ti alloy beam window stably after the energy analysing magnet with 10MeV plus-minus 1 MeV energy slit. The practical maximum beam power reached 29 KW and this demonstrated the LINAC as one of the most powerful S-band electron LINACs in the world. The control of the LINAC is fully automated and the “One-Button Operation” is realised, which is valuable for easy operation as a plant system. 2 systems have been delivered and are being operated stably.     

Second-order Green's function calculations of the ionization potential of a (H2)7 chain embedded in a homogeneous electric field

Summary The vertical ionization potential and the related pole strength of a model alternant chain of 14 hydrogen atoms subject to a homogeneous electric field, parallel to the chain and of increasing intensity are calculated, in the framework of a 6–31G** basis set, at the second-order level of the many-body Green's function theory. Trends observed with orbital relaxation, pair removal and pair relaxation effects are interpreted in terms of deformations of the electron density.     

合成产物PEPAMP及其副产物的电喷雾串联质谱分析

PEPAMP是应用于工业循环水中的新一代高效阻垢剂.采用电喷雾电离质谱和质谱/质谱技术分析了合成产物,注射泵直接进样,正离子方式检测,方法简便、快速.通过EI-MS技术获得了目标产物PEPAMP及主要副产物的准分子离子峰,通过ESI-MS-MS技术获得了其碎片信息,并对目标化合物及主要副产物进行了精确质量测定,确定了目标化合物及主要副产物的结构.     

A Structural Basis of Light Energy and Electron Transfer in Biology (Nobel Lecture)

Aspects of intramolecular light energy and electron transfer are discussed for three protein cofactor complexes whose three-dimensional structures have been elucidated by X-ray crystallography: the light harvesting phycobilisomes of cyanobacteria, the reaction center of purple bacteria, and the blue multi-copper oxidases. A wealth of functional data is available for these systems which allows specific correlations to be made between structure and function and general conclusions to be drawn about light energy and electron transfer in biological materials.     

Electron capture detector performance parameters in view of the response presentation forms

Summary Four most frequently used presentation forms of the ECD response are described. Equations describing the dependence of the sensitivity, linearity and minimum detectable concentration of the ECD working under constant frequency mode of operation on the pulse period are derived from Wenthworth’s kinetic model for all four forms mentioned above. The forms presented are compared on the basis of equations derived. Results of the calculations are given and some predictions are experimentally tested for sulphur hexafluoride. Good agreement was found between the predicted and observed relationships. Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984     

Molar excess heat capacities and volumes for mixtures of alkanoates with cyclohexane at 25°C

Molar excess volumes V ^E at 25°C have been determined by vibrating-tube densimetry, as a function of mole fraction x for different series of an alkanoate (H _2m+1 C _m COOC _n H _2n+1 )+cyclohexane. Three types of alkanoates were investigated, i.e., methanoates (m=0, with n=3 and 4), ethanoates (m=1, with n=2, 3, and 4) and propanoates (m=2, with n=1, 2, and 3). In addition, a Picker flow calorimeter was used to obtain molar excess heat capacities C _p ^E at constant pressure at the same temperature. V ^E is positive for all systems and rather symmetric, with V ^E (x=0.5) amounting to almost identical values in a series of mixtures containing an alkanoate isomer of same formula (say C₄H₈O₂, C₅H₁₀O₂, or C₆H₁₂O₂). The composition dependence of C _p ^E is rather unusual in that two more or less marked minima are observed for most of the mixtures, especially when the alkanoate is a methanoate or an ethanoate. These results are discussed in terms of possible changes in conformation of both the ester and cyclohexane.     

The Many Measures of Molecular Dimensions

In contrast to the high precision with which masses of atoms and molecules can be specified, their external dimensions remain intrinsically fuzzy. Attention is directed to the difference between measurements of interatomic separations within molecules, that in many instances are cited with error bars of +/– 0.002 Å, and the available approximate magnitudes of over-all sizes, needed for estimating packing densities (in solids or liquids). The following account, is a critical examination of the underlying concepts and of the diversity of data in the literature, regarding internal dimensions (bond lengths), overall extensions, cross-sectional areas, and volumes of molecules that may be derived from a variety of experiments. Historical markers of the evolution of the underlying theories and experiments are included.     

飞行时间型质量分析器(TOFMS)的研制及应用

自行研制了电子碰撞离子化的飞行时间型质量分析器（ＴＯＦＭＳ），用于物质的化学分析。用研制的ＴＯＦＭＳ测量了Ａｒ离子化的飞行时间谱和离子的部分电离截面积比与碰撞电子能量的依赖关系，将它与Ｓｔｅｐｓｈａｎ等人的实验结果进行了比较。     

On the theoretical determination of the electron affinity of ozone

Summary Multiconfigurational electron correlation methods have been analyzed in order to theoretically compute the electron affinity (EA) of ozone. The near-degeneracy correlation effects, which are so important in O₃ and O ₃ ^– , have been described using complete active space (CAS) SCF wave functions. Remaining dynamic correlation effects are computed using second-order perturbation theory (the CASPT2 method). The best calculated adiabatic value (including zero-point energy corrections), 2.19 eV, is about 0.09 eV larger than the experimental value. Comparative studies using size-consistent coupled pair functional approaches (CPF and ACPF) have also been performed. The harmonic frequencies in O ₃ ^– have been determined to be: ₁=992, ₂=572, and ₃=879 cm^–1, which gives a zero-point energy of 0.151 eV.     

How anomalous are the anomalous properties of fluorine? Ionization energy and electron affinity revisited

It is well established that atomic fluorine has a miserly high ionization energy and avariciously high electron affinity. Yet, as was shown some 30 years ago, the latter value is anomalously low-linear extrapolation shows the value to be some 110 kJ/mol less than expected by comparison to the heavier halogens. Related literature investigation extended this anomaly to nitrogen and oxygen and their (valence) isoelectronic congeners. We extend it to related cationic species and thereby the noble gases and alkali metals, and the aforementioned species are better understood. We thus ask if the ionization energy/electron affinity anomaly of fluorine remains an anomaly.