密封容器中钚材料同位素丰度和年龄的测量

根据相对效率法的原理，利用PC/FRAM分析软件，开展了用高分辨γ谱仪测量密封容器中钚材料的同位素丰度和年龄的实验研究.研究结果表明，同位素丰度和年龄的分析精度随能谱测量精度的提高而提高，如果能谱的测量精度不够，通过PC/FRAM分析得出的钚材料的同位素丰度和年龄有偏低的可能.因此，在能谱测量过程中，建议通过监测某个特征峰的峰面积计数来判定239Pu丰度和年龄的测量精度是否已满足测量要求.Based on the concept of relative detection efficiency, some experiments have been conducted to measure the isotopic abundance and the age of the plutonium material in a sealed container by a high-resolution γ-ray spectrometer. The PC/FRAM software analyzes the spectra. The study shows that the analysis precision of the isotopic abundance and the age will rise as the spectral measurement precision increases, and that If the spectral measurement precision is not enough, the analyzed results by the PC/FRAM software might be lower. Hence, the study suggests that a spectral peak is monitored to show lights on the spectral measurement precision during the process of spectrum acquirement.     

建筑节能镀膜玻璃热传递系数的研究

建筑节能镀膜玻璃的热传递系数ｋ是反映节能薄膜性能的重要指标，本文提出其热传递系数的计算和测量方法，并介绍部分测量结果，研究结果表明节能薄膜确能较大地降建筑物的能耗。     

The Possibility of the Use of Coprecipitation with Lanthanum Fluoride for Preparation of Samples for Alpha-Spectrometric Determination of Plutonium

At present time the content of ²³⁹Pu, ²³⁸Pu especially in biological and environmental samples and nuclear fuels is frequently determinated. After radiochemical separation is plutonium usually electrodeposited on a metallic disk [1, 2]. Alpha-activity is then detected by silicon surface barrier detector.

The method of electrodeposition shows several disadvantages. The solution to be electrolyzed must have a definite composition, certain elements, e.g. iron, must not be present. The method is rather time-consuming and requires special equipment. Several other methods for preparation of samples using coprecipitations [3] or inorganic ionexchangers [4] have been studied. In this work was investigated the possibility of the use of coprecipitation of Pu³⁺ with LaF₃ for preparation of samples for alpha-speetroinetric determination of plutonium.     

Age of Information of Parallel Server Systems with Energy Harvesting

Motivated by current communication networks in which users can choose different transmission channels to operate and also by the recent growth of renewable energy sources, we study the average Age of Information of a status update system that is formed by two parallel homogeneous servers and such that there is an energy source that feeds the system following a random process. An update, after getting service, is delivered to the monitor if there is energy in a battery. However, if the battery is empty, the status update is lost. We allow preemption of updates in service and we assume Poisson generation times of status updates and exponential service times. We show that the average Age of Information can be characterized by solving a system with eight linear equations. Then, we show that, when the arrival rate to both servers is large, the average Age of Information is one divided by the sum of the service rates of the servers. We also perform a numerical analysis to compare the performance of our model with that of a single server with energy harvesting and to study in detail the aforementioned convergence result.     

Analytical Method for Energy Spectra and Eigenstates in the Process of k-Photon Down-Conversion with Quantized Pump

In this paper, using the arguments of Wu et al. [Phys. Rev. Lett. 86 (2001) 2200] we analytically discussthe energy spectra and corresponding eigenstates for the process of k-photon down-conversion with quantized pump ina high-Q cavity by the aid of the computer programme. Remarkably, it is also shown that such a method can be usedfor solving numerically the equations in a much simpler manner than the previous ones.     

Analytical Method for Energy Spectra and Eigenstates in the Process of κ-Photon Down-Conversion with Quantized Pump

In this paper, using the arguments of Wu et al. [Phys. Rev. Left. 86 (2001) 2200] we analytically discuss the energy spectra and corresponding eigenstates for the process of κ-photon down-conversion with quantized pump in a high-Q cavity by the aid of the computer programme. Remarkably, it is also shown that such a method can be used for solving numerically the equations in a much simpler manner than the previous ones.     

自动巡航的混合交通系统的能耗

基于自动巡航控制的元胞自动机交通流模型,研究了单车道上不同类型车辆的最大速度、混合比例、速度期望因子以及质量对混合交通系统的能耗影响.通过计算机数值模拟,得到了混合交通系统在不同参数下的能耗,同时借助于平均场理论对其进行解析.理论解析与数值模拟结果相一致. 关键词： 元胞自动机 自动巡航控制 混合交通 能耗     

Synthesis of superheavy nuclei in the reactions of 244Pu and 248Cm with 48Ca

This paper presents results of the experiments aimed at producing long-lived superheavy elements located near the spherical-shell closures with Z ⩾ 114 and N ⩾ 172 in the ²⁴⁴Pu + ⁴⁸Ca and ²⁴⁸Cm + ⁴⁸Ca reactions. The large measured α-particle energies of the newly observed nuclei, together with the long decay times and spontaneous fission terminating the chains, offer evidence of the decay of nuclei with high atomic numbers. The decay properties of the synthesized nuclei are consistent with the consecutive α-decays originating from the parent nuclides ^{288, 289}114 and ²⁹²116, produced in the 3n and 4n evaporation channels with cross-sections of about a picobarn. The present observations can be considered as experimental evidence of the existence of the “island of stability” of superheavy elements. Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002 RID="a" ID="a"e-mail: utyonkov@sungns.jinr.ru     

Energy conditions of the f(T,B) gravity dark energy model with the validity of thermodynamics

In this article, the analysis of Tsallis holographic dark energy(which turns into holographic dark energy for a particular choice of positive non-additivity parameter δ) in modified f(T, B) gravity with the validity of thermodynamics and energy conditions for a homogeneous and isotropic FLRW Universe has been studied. The enlightenment of the field equation towards f(T,B)=αT~m+βB~n, made possible by the fact that the model is purely accelerating,corresponds to q=-0.54(Mamon and Das 2017 Eur. Phys.J.C 77 49). The generalized second law of thermodynamics is valid not only for the same temperature inside the horizon, but also for the apparent horizon for a change in temperature. The essential inspiration driving this article is to exhibit the applicability that the holographic dark energy achieved from standard Tsallis holographic dark energy and the components acquired from f(T, B) gravity are identical for the specific bounty of constants. The analysis of energy conditions confirms that the weak energy condition and the null energy condition are fulfilled throughout the expansion, while violation of the strong energy condition validates the accelerated expansion of the Universe.With the expansion, the model becomes a quintessence dominated model. The dominant energy condition is not observed initially when the model is filled with genuine baryonic matter,whereas it appears when the model is in the quintessence dominated era.     

Mechanism for the Correlated Swinging of Photoluminescence Intensity and Peak Energy Shift with Sizes of Nanoscale Si Particles

Based on the quantum confinement-luminescence center model, we focus on the relationship between the photoluminescence (PL) spectra and sizes of nanoscale silicon particles.We find that when there are two kinds of luminescence centers (LC) in the oxide layer surrounding the silicon particles, both the integrated PL intensity and the spectral peak position swing with reducing the sizes of silicon particles, which is different from the monotonous blueshift of peak position predicted by quantum confinement model. By changing the concentrations of LC we find the correlation between the spectral peak position and the integrated PL intensity when the size of silicon particles is reduced. The effects of other parameters such as the half width of size distribution and the position of photon emission levels of LC are also found to be important.