Infrared Observation of the Effects of Aqueous Oxidizing Agents on the Functional Groups on Carbon Surfaces

FTIR photothermal beam deflection spectroscopy (PBDS) was used to record infrared spectra of medium-temperature carbons before and after they had been subjected to treatments with aqueous HNO₃ or H₂O₂ solution. Changes in the functional groups present on the carbon surfaces can be clearly observed.     

REVIEW: High pressure NMR study of proteins – seeking roots for function,evolution, disease and food applications

NMR experiments at variable pressure reveal a wide range of conformation of a globular protein spanning from within the folded ensemble to the fully unfolded ensemble, herewith collectively called “high-energy conformers”. The observation of “high-energy conformers” in a wide variety of globular proteins has led to the “volume theorem”: the partial molar volume of a protein decreases with the decrease in its conformational order. Since “high-energy conformers” are intrinsically more reactive than the basic folded conformer, they could play decisive roles in all phenomena of proteins, namely function, environmental adaptation and misfolding. Based on the information on high-energy conformers and the rules on their partial volume in its monomeric state and amyloidosis, one may have a general view on what is happening on proteins under pressure. Moreover, one may even choose a high-energy conformer of a protein with pressure as variable for a particular purpose. Bridging “high-energy conformers” to macroscopic pressure effects could be a key to success in pressure application to biology, medicine, food technology and industry in the near future.     

Teil II: Ergebnisse bei der Bestrahlung einzelner Nahrungsmittelgruppen (Zusammenfassender Bericht)

Nachdem im ersten Teil dieser Arbeit [170] einige Grundprobleme der Nahrungsmittelbestrahlung behandelt wurden, sollen nun die bei der Bestrahlung wichtiger Nahrungsmittelgruppen erzielten Ergebnisse dargelet und eine Einschätzung der Entwicklungstendenzen versucht werden.     

Theoretical analysis of the radiation effect on the transient behavior of optoelectronic integrated devices

Theoretical analysis of the radiation effect on transient behavior of an optoelectronic integrated device composed of a heterojunction phototransistor and a light emitting diode is studied theoretically. First, the transient behavior and the rise time of this device before radiation are investigated based on the frequency response of the constituent devices and the optical feedback inside the device. Second, the effect of neutron irradiation flux on the transient behavior of this device is theoretically studied. The results show that, by increasing the optical feedback inside the device, the rise time in the amplification mode is increased along with an increasing output, while that in the switching mode can be reduced effectively, and the neutron irradiation reduces the transient response and the rise time in both the amplification and switching modes. This type of model can be exploited as optical amplifier, optical switching device, and other applications.     

Ab initio calculation of phonons in bulk HfC and the HfC(001)(1 × 1) surface

Structural, elastic and dynamical properties of the rock-salt HfC have been studied by employing an ab initio pseudopotential method and a linear response scheme, within the generalised gradient approximation. In addition to achieving good agreement with experimental measurements of the phonon dispersion results along the symmetry direction Γ-X, we have presented accurate dispersion results along several other directions in the Brillouin zone. Sharp features in the phonon density of states are ascertained and their origin discussed. This is followed by investigations of the structural, electronic and phonon properties of the HfC(001) surface. The agreement between our surface phonon spectrum and experimental measurements is very good. By analysing the atomic displacement patterns of the zone-centre and zone-edge phonon modes we have determined the energy locations and polarisation characteristics of Fuchs–Kliewer, Wallis, Lucas and Rayleigh modes.     

Calculation on the CO2 influences on the structure,stability of (MgO)m (m = 1–6) clusters

ABSTRACT

The concentration of carbon dioxide (CO₂) has a significant influence on the morphology of thermal decomposition products of magnesite. So, structures, stabilities and adsorption mechanisms of (MgO)_m (m?=?1–6) clusters by one or two CO₂ molecules were calculated by the GGA-PW91 method. The results show that the stability of the considered clusters is (MgO)_m(CO₂)₂ clusters > (MgO)_m(CO₂) clusters > (MgO)_m clusters by the average binding energy. Certain low-lying isomers of (MgO)_m(CO₂) and (MgO)_m(CO₂)₂ clusters which have an isolated O atom are deviating from the cluster center which possess higher kinetic activity. (MgO)_m clusters prefer to adsorb a CO₂ molecule, while (MgO)₃(CO₂) clusters prefer to adsorb a CO₂ molecule rather than the neighbors. Magnesite is difficult to transit to (MgCO₃)₂ clusters at room temperature. However, magnesite will spontaneously transit to (MgO)₂ clusters and further transit to MgO crystal which need to adsorb more energy at 700?K.     

Studies upon Qualification of Meat from Animals Irradiated and Contaminated with Radiocaesium

Abstract

The problem concerning qualification of food originated from animals irradiated and contaminated with ¹³⁷caesium appeared especially after the Chernobyl accident. So, it was a reason to undertake respective studies on 108 rabbits divided into three groups: group I – non-irradiated rabbits, group II – irradiated with a dose of 103 mCkg^?1 (400 R), group III – irradiated with a dose of 206 mCkg^?1 (800 R). All animals were contaminated intragastrically with an aqueous solution of ¹³⁷CsCl. After slaughter samples of the muscles were cured in 1, 3, 5, 10, and 15% brine or were cooked for 2 hrs. In the case of curing the radioactivities of meat and brine, and the concentrations of salt in cured meat were estimated after 7, 14, and 21 days. The radioactivities of cooked meat, broth, and condensed water vapour were estimated after 1 and 2 hrs. Taking into account the decrease of the radioactivities, duration of curing, and concentrations of salt in cured meat the optimum results were achieved when the meat from non-irradiated rabbits was cured for 7 days in 3% brine, and that of irradiated rabbits in 5% brine with regard to a lower stability of this meat. The decontamination effectiveness of cooking was similar in all examined rabbits. Radiocaesium penetrates into the brine or broth and escapes with water vapour thereafter.     

The critical behavior of Kac-type models for semi-infinite systems

The critical behavior of the layer magnetizations and local susceptibilities of theD-vector lattice models with Kac-type ferromagnetic interactions for a semi-infinite system is studied. These local quantities behave less singularly than the bulk ones, showing that this is not peculiar to the two-dimensional Ising model. Moreover, the limiting form (at the critical point) of the magnetization profile can be obtained, which, when properly scaled, satisfies the minimum condition in the Landau theory for a semi-infinite continuous system. Landau-type critical behavior is thus recovered.     

一类泛函微分方程周期解的存在性与应用

本文给出了一类滞后型泛函微分方程有一个周期解的四个充分性定理，其结果明显地优于著名的Ｙｏｓｈｉｚａｗａ周期解定理，最后给出了应用实例。     

并苯纳米环[6]CA及其衍生物的电子结构和光物理性质的密度泛函理论研究

采用密度泛函理论PBE0方法在6-31G(d, p) 基组水平上对比研究并六苯纳米环[6]CA及BN取代纳米环[6]CA-BN的几何结构及电子性质. 同时探讨锂离子掺杂对不同体系的芳香性、前线分子轨道、电子吸收光谱及传输性质的影响. 通过电离势、亲合势及重组能的计算, 预测纳米环体系得失电子的能力及传输性能. 结果表明:[6]CA的能隙很小, BN取代后, 能隙明显增大; 锂离子掺杂到两种纳米环中, 在不明显改变前线分子轨道分布的前提下, 几乎同步降低了最高占据轨道、 最低未占据轨道能级, 锂离子掺杂使载流子传输性能得到很大改善; 电子吸收光谱拟合发现, BN取代使吸收光谱很大程度蓝移, 吸收强度明显减小; 而锂离子掺杂对光谱的强度及吸收范围没有明显影响. 关键词： 碳纳米环 硼氮纳米环 锂离子掺杂 密度泛函理论