高温二氧化碳气体红外辐射实验研究

主要介绍了依托高频等离子体风洞建立的高温气体辐射测量平台,并在此平台上开展了高温二氧化碳气体红外辐射实验测量。介绍了高频等离子体风洞的运行原理、流场特性及工作介质;介绍了实验测量的条件、装置、标定、数据处理方法和结果分析;通过自建的高温气体发射光谱测量平台实验测量了二氧化碳气体在1 500～3 000 K范围内4个温度点的红外发射光谱;介绍了Abel变换在测量二氧化碳气体红外辐射空间分布中的应用,通过Abel变换获得了高温下二氧化碳气体红外辐射的空间分布结果; 分析了高温二氧化碳气体在4.3 μm附近的红外辐射的强度及其中心波长随温度变化的分布,得到了发射峰中心波长随温度的升高向长波方向展开的结果,并与文献结果进行了对比分析。     

核科学百年讲座第五讲辐射化学与辐射加工

介绍辐射化学和辐射加工的发展与应用，以及基本原理，侧重介绍辐射加工在高分子辐射交联改性、食品的辐照处理和医疗用品消毒等方面的应用．     

光谱法测量煤粉火焰温度和黑度的研究

利用由ＣＣＤ线阵组成的微型光纤光谱仪研制了现场火焰光谱测量装置。通过测量３５０ＭＷ电站锅炉的煤粉火焰从 ５３３ｎｍ至１０５０ｎｍ波段的辐射光谱,发现煤粉火焰的辐射非常接近灰体辐射。根据这一特点,从维恩公式出发,利用最优化方法处理测得的火焰辐射光谱信号,得到了火焰的温度和黑度。     

Frequency plasma opening switches and their application in the technology of high-power accelerators

The main results reported here were obtained in a cycle of studies on plasma opening switches (POSs) and their application in frequency-pulse accelerators; those studies were carried out at the Russian Research Center, Kurchatov Institute from 1986 to 1997. That research was the basis for the development of frequency-pulse generators based on POS technology for quasi-constant generation of an electron beam and bremsstrahlung radiation. Several generators have been built for use in commercial radiation processing technologies. We give the parameters and basic circuit designs and discuss the prospects for further development of generators using POSs. The competitiveness in comparison with existing accelerating systems is examined. Thermonuclear Institute, Russian Research Center, Kurchatov Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 47–55, December, 1997.     

Development of ultra-short pulse VUV laser system for nanoscale processing

We have developed intense vacuum ultraviolet (VUV) radiation sources for advanced material processing, such as photochemical surface reactions and precise processing on a nanometer scale. We have constructed a new VUV laser system to generate sub-picosecond pulses at the wavelength of 126 nm. A seed VUV pulse was generated in Xe as the 7th harmonic of a 882-nm Ti:sapphire laser. The optimum conversion was achieved at the pressure of 1.2 Torr. The seed pulse will be amplified by the Ar₂^*\mathrm{Ar}_{2}^{*} media generated by an optical-field-induced ionization Ar plasma produced by the Ti:sapphire laser. We have obtained a gain coefficient of g=0.16 cm⁻¹. Our developing system will provide VUV ultra-short pulses with sub-μJ energy at a repetition rate of 1 kHz.     

Femtosecond pulse processing

We discuss Fourier methods for shaping and processing femtosecond optical signals. Examples of applications in optical communications and in generation of terahertz radiation are presented.     

Structure of a laser field of various polarizations in the focal region of an ideal focusing lens. Calculation by methods of scalar diffraction theory

Within the framework of the scalar diffraction theory, we elaborate the method of calculating the electromagnetic-field structure in the ideal-lens focal plane. Using the method of quaternions for describing the rotation in three-dimensional space and diffraction integrals, we derive analytic formulas for the intensity distribution in the fields in the vicinity of the lens focal plane. We generalize the Debye method for an arbitrary polarization of the incident laser beam, in particular, for the linear, radial, and azimuthal polarizations. Such an approach, in view of the analytic formulas obtained, allows us to decrease the processing speed by an order. We show that the algorithm elaborated allows us to calculate the field amplitude?Cphase structure in the case of multimode laser radiation with a random phase.     

真空条件下低温红外辐射测量技术研究

针对红外载荷在轨服役期间低温目标的红外辐射探测需求,提出一种真空条件下的低温红外辐射测量方案,并研制了测量装置。测量装置主要由低温红外光学系统、低温机械结构、低温红外探测系统及微弱信号处理系统构成。低温红外辐射经过光学系统会聚到探测器像面,锁相放大器利用相干检测技术将目标信号提取,完成低温红外辐射的测量。测量装置研制完成后,在真空仓内使用标准黑体辐射源,在198 K～423 K温度范围内进行了低温红外辐射定标试验,取得了有效的试验数据,测量不确定度在5%以内。该文提出的真空条件下低温红外辐射测量技术可为在轨空间红外载荷低温红外目标探测设计提供重要数据支撑。     

Enhancement of efficiency of storage and processing of food raw materials using radiation technologies

The work is dedicated to improvement of efficiency of storage and processing of food raw materials using radiation technologies. International practice of radiation processing of food raw materials is presented and an increase in the consumption of irradiated food products is shown. The prospects of using radiation technologies for the processing of food products in Russia are discussed. The results of studies of radiation effects on various food products and packaging film by γ radiation and accelerated electrons are presented.     

Investigations of the barbell ultrasonic transducer operated in the full-wave vibrational mode

In this paper, the resonance frequency equation and expression of displacement amplitude magnifications of a full-wave barber ultrasonic horn are obtained. By discussing the relationships between the displacement amplitude magnifications and the geometrical dimensions, the optimized design of the horn for the largest magnification is proposed, which is helpful to improve the radiation power and the transfer efficiency of the acoustic energy of the ultrasonic oscillatory system. Based on the optimized design of the horn, we introduced a barbell ultrasonic transducer operated in the longitudinal full-wave vibrational model and obtained the resonance frequency equations. For comparison, the resonance frequencies of the full-wave barbell horn and the full-wave barbell transducer are also analyzed by finite element method (FEM). It is shown that the values obtained by theoretical analysis and FEM are in good agreement with experimental observations. We hope that the research of this paper is helpful for the use of the barbell horn and transducer in the applications such as ultrasonic liquid processing.     

电子束辐射加工研究进展

综述了北京师范大学低能核物理所的ＢＦ－５电子直线加速器在辐射加工中的研究应用情况，着重介绍了在电子辐照硅功率器件，高分子聚合物的辐射改性以及辐射加工剂量学等方面的研究和开发进展． The main recent progress on radiation processing by electron beam electron irradiation modification on silicon power devices, radiation crosslinking of wires and cables by electron beam and dosimetry for radiation processing are described.     

The exoelectronic emission of germanium and silicon

The experimental results of a study of the exoemission of germanium and silicon following irradiation and mechanical processing are given. An analysis of the data obtained shows the correlation between the exoelectronic emission and the defects in the surface layers of the semiconductor. The relationships obtained are useful for understanding the mechanism of exoemission, as well as for the application of the exoemission method for estimating the physical condition of surface layers which are damaged as a result of mechanical action or radiation.     

Visualization of high radiation field by radiophotoluminescence photography

We have proposed a simple technique for the visualization of high radiation fields by radiophotoluminescence (RPL) photography. Pulverized RPL glass particles were encapsulated into hundreds of polystyrene balls of accumulation-type RPL detectors. The RPL detectors were placed near an intense gamma-ray source. After irradiation, the RPL detectors were uniformly brightened with a UV illuminator. Orange RPL could be observed by the naked eye at doses above 5 Gy. For a dose above 0.5 Gy, a clear RPL photograph was taken with a digital camera. The spatial dose distribution was obtained through digital image processing of the RPL photograph. Therefore, this simple RPL photographing technique using RPL detectors is useful for detecting high levels of radioactivity.     

Spatial frequency analysis of fluorescent nuclear track detectors irradiated in mixed neutron–photon fields

A new image processing method for the dosimetry of mixed neutron–photon fields using fluorescent nuclear track detectors (FNTDs) is investigated. Images obtained from FNTDs were processed using spatial frequency analysis to determine doses for both low and high LET radiations. Spatial frequency analysis extended the dynamic range of detectible neutron doses from 4 orders of magnitude for track counting only to at least 6 orders of magnitude by combining track counting with the new image processing method. Two different converters of indirectly ionizing radiation to secondary charged particles were used in conjunction with image processing to separate signals induced by neutron and gamma fields.     

Cherenkov radiation of a spinning particle

We consider the Cherenkov radiation of a neutral particle with magnetic moment, and the spin-dependent contribution to the Cherenkov radiation of a charged spinning particle. The corresponding radiation intensity is obtained for an arbitrary value of spin and for an arbitrary spin orientation with respect to velocity. The article is published in the original.     

Investigation of the possibility of γ-background discrimination in a neutron spectrometer with a proportional counter of recoil protons

The possibility of expanding the range of neutron spectrum measurements to lower energies in fields of mixed n-γ radiation via separation of pulses from recoil protons and γ-induced electrons, using the proportional counter developed for neutron spectrometry at the All-Russia Research Institute of Experimental Physics, has been investigated. With the use of a digital oscilloscope, a data set on the shape of counter pulses under irradiation in a field of mixed n-γ radiation (²⁵²Cf) and in a field of γ rays (SOSGI-M set) has been obtained. Mathematical processing of the obtained data set showed a possibility of distinguishing pulses from recoil protons and electrons; hence, for the ²⁵²Cf source, the lower boundary of the neutron spectrometer operating range can be reduced to ≈80 keV.     

Radiation and five-dimensional cosmology

We investigate the cosmological character of five-dimensional (Kaluza-Klein type) solutions of the Einstein equations. We show that the vacuum solutions of these equations give rise to an effective radiation density connected with the existence of the extra dimension. We examine the connection between this case and the solutions obtained by assuming a five-dimensional radiation source.     

同步辐射讲座 第二讲 同步辐射X射线荧光及其在植物微量元素分析中的应用

比较了同步辐射（SR）X射线荧光（XRF），电子和质子激发的X射线谱，介绍了XRF谱的采集方法及数据处理方法（主要是能谱方法），智能方法的无标样（基本参数法）定量分析原理，以及近期在植物微量元素分析中得到的结果。     

A review of time-domain impedance modelling and applications

Time-domain impedance boundary conditions are reviewed and similarities between the models are shown. The extended Helmholtz resonator model is used with a time-domain impedance boundary condition for impedance eduction and simulation of the noise radiation from a lined aeroengine nozzle. Model parameters obtained by impedance eduction from flow duct measurements and then used to predict the noise radiation for realistic aeroengine nozzle flow and geometry. The prediction of sound radiation from a coaxial jet nozzle at approach conditions with the educed model parameters is performed in 2D and 3D. Various features of the numerical method that enable it to be used for realistic applications are presented. This includes the suppression of flow instabilities in the linear inviscid solution and analysis of the solution to prove the global conservation of acoustic energy in each individual result. It is found that the current approach is too time consuming for optimisation, even for a 2D simulation using parallel processing. Thus, finally the potential of porting a CAA method to the graphics processing unit (GPU) is shown in one example. The GPU based computation is about 100 times faster. The results are encouraging, even though the GPU variant needs further validation.