On the connection between the principal chiral model and the multiflavour chiral Gross-Neveu model

The infinite flavour limit of the multiflavour chiral Gross-Neveu (MCGN) partition function is shown to be equal to the principal chiral σ-model (PCM) partition function where in addition one integrates over twisted boundary conditions. This last interpretation restricts the space of states to the left (or right) singlet sector. In the course of this derivation, a rigorous paramagnetic inequality for the Dirac determinant is proved. The critical (conformal invariant) points of the MCGN are investigated in connection with critical WZW σ-models.     

Accretion model for a hot source formation in 72MeV proton induced 3He and 4He emission

Energy spectra and angular distributions of the (p, ^3,4He) reaction on ⁵⁸Ni, ⁹⁰Zr, ²⁰⁹Bi and ²³²Th are analyzed in the framework of an extended, moving-hot-source model. The mass-temperature relation of the hot source is described as the result of an accretion process. The cooling curve and the total emission cross sections are calculated and presented as a function of the emission time.     

Sensitivity of continuous review stochastic (s,S) inventory systems to ordering delays

This paper examines continuous review stochastic (s, S) inventory systems with ordering delays. That is, systems where the difference between the time the order should be placed and the time the order is actually placed is non-trivial. The traditional inventory ordering, holding and penalty costs are included and the average cost for an (s, S) policy is developed and examined. Computational results are presented for two cases. In the first case, the manager is aware of the delay and uses the policy that minimizes all costs. We present the increase in cost due to having a delay. In the second case the manager is unaware of the delay and uses the (integer) square root formula. We present the increase in cost due to using the square root formula when it is inappropriate and in fact our computational results indicate that there may very well be a large increase in cost due to being unaware of the ordering delay.     

Monopoles connected by strings and the monopole problem

To clarify the status of proposed causality arguments limiting the annihilation rate of monopoles, we present a three-dimensional model for the formation of monopoles connected by strings. The length distribution of the strings has been found using a Monte carlo simulation of the phase transition. The result is that long strings connecting monopoles are exponentially suppressed in agreement with the theoretical predictions of Mitchell and Turok [1]. The implications of our results for the monopole problem are discussed.     

新型4,4-二甲基异噁唑-3-酮衍生物的合成及生物活性研究

以Baylis-Hillman加成物为起始原料,设计并合成了5个结构新颖的4,4-二甲基异唑-3-酮衍生物。所合成的化合物经IR、1HNMR和元素分析确证。生物活性测试结果表明,所合成的目标产物在2000gai/ha的剂量下均具有较好的除草活性。中间体1-(2,4-二氯苯基)-2-溴甲基丙烯酸乙酯具有杀虫活性,在600gai/ha的剂量下对朱砂叶螨防效为100%。     

Application of radiation chemistry for conservation of archaeological waterlogged wood and osteological objects

The application of radiation chemistry to the conservation of archaeological objects is described. Methyl methacrylate is introduced into the voids of the objects to be conserved either by an exchange process or—if allowed by the mechanical strength of the object—by vacuum impregnation. It is neither necessary nor desirable to fill the object completely with the monomer that is subsequently polymerized with ⁶⁰Co γ-rays.     

螺栓松动边界下纤维增强复合薄板的振动测试方法

提出了基于预埋压力传感器的量化测试方法,研究了螺栓松动边界对纤维增强复合薄板振动特性的影响。首先,自主设计并开发了带有预埋压力传感器的螺栓松动边界下复合薄板的振动测试系统,并详细介绍了系统各个部件的组成和功能;然后,归纳出一套合理、规范的松动边界下复合薄板的振动测试流程,并对HF10碳纤维/树脂复合薄板进行了实际测试。结果表明:随着螺栓松动程度的不断增加,复合薄板的固有频率逐渐降低,模态振型的节线位置也发生了不同程度的变化,但其阻尼结果呈现先增大后减小的趋势;而共振和非共振响应呈现先减小后增大的趋势。     

Modified Gerchberg–Saxton (G-S) Algorithm and Its Application

The Gerchberg–Saxton (G-S) algorithm is a phase retrieval algorithm that is widely used in beam shaping and optical information processing. However, the G-S algorithm has difficulty obtaining the exact solution after iterating, and an approximate solution is often obtained. In this paper, we propose a series of modified G-S algorithms based on the Fresnel transform domain, including the single-phase retrieval (SPR) algorithm, the double-phase retrieval (DPR) algorithm, and the multiple-phase retrieval (MPR) algorithm. The analysis results show that the convergence of the SPR algorithm is better than that of the G-S algorithm, but the exact solution is not obtained. The DPR and MPR algorithms have good convergence and can obtain exact solutions; that is, the information is recovered losslessly. We discuss the security advantages and verification reliability of the proposed algorithms in image encryption. A multiple-image encryption scheme is proposed, in which n plaintexts can be recovered from n ciphertexts, which greatly improves the efficiency of the system. Finally, the proposed algorithms are compared with the current phase retrieval algorithms, and future applications are discussed. We hope that our research can provide new ideas for the application of the G-S algorithm.     

Some physical properties of the TiO2 semiconductor electrode

Some physical properties of n-TiO₂ single crystals have been studied by electrochemical and photoelectrochemical techniques. X-ray diffractometry confirmed the TiO₂ basic rutile type structure. For the TiO₂/0.5 N NaOH system in the dark a Tafel slope of 0.11 V/decade was observed between 0.50 and 0.61 V versus SCE, suggesting a one-electron process. The potential, at which the gaseous oxygen evolution was confirmed, was well over 2.0 V versus SCE. On the other hand the potential for oxygen evolution was markedly decreased to −0.75 V versus SCE, when the TiO₂ was illuminated. From these facts and the observation of passivation, transpassivation and current saturation an oxygen-pumping mechanism is proposed for the polarization behaviour of the TiO₂ electrode in the dark. The spectral responses of photocurrent generated from TiO₂ at 0.0 V bias versus SCE showed that the peak illumination current at 360 nm is larger than the dark current by three orders of magnitude. The band gap of TiO₂ was determined as 3.1 eV by assuming that the photoelectrolysis of water involves an indirect energy transition. An anomalous photoresponse was observed at 1.8 eV, which is due to the presence of surface states at the TiO₂/electrolyte interface.