某矿山核子计源的放射防护检测与评价

为了解某矿山核子计源的放射防护情况,检测了使用核子计源的工作场所,并对结果进行辐射防护评价。结果显示,核子计源的辐射剂量水平符合国家放射防护标准要求,在正常运行工况下,核子计源不会对周围环境及工作人员产生不良的辐射影响。

核子计中的自然对数快速算法

基于麦克劳林级数公式计算自然对数,构造计算式向1逼近,从而加快级数的收敛速度。该算法应用于核子计的数据处理,其计算速度和精度达到了设计要求。

基于TMS320LF24系列DSP的核子计联合功能教学仪的设计

提出了针对实验室核子计(包括料位计、密度计、厚度计)实验的核子计联合功能教学仪设计方案,阐述分为硬件设计和软件设计两部分。硬件设计方案包括系统硬件组成以及基于TMS320LF24系列DSP的信号处理单元的电路原理设计,它涉及电源转换、时钟和复位、液晶显示模块和PC串行接口模块,信号处理单元采用DSP芯片,提高了数据采集处理速度;软件设计方案采用模块化的设计思想,给出了主程序的流程图及数据处理的相关说明。

核子计周围辐射水平的评价

使用FD-3013型数字γ辐射仪，对丹东地区l998～2003年间生产的核子秤和料位计的放射源（模拟工作状态下）进行空气比释动能率的测试。依据国家标准GB18871-2002、GBZ125-2002对核子计周围的辐射水平进行评价。结果表明，在核子计周围及源室表面进行安装、检修和标定等工作的放射工作人员，若把腹部剂量率作为全身均匀照射考虑，其腹部剂量率平均值和最高值低于国家标准中所规定的放射工作人员连续5a平均年剂量限值10μGy／h（按每周工作40h导出）。说明放射工作人员在常规下操作该地区生产的核子秤和料位计是比较安全的，但在实际工作中应注意对密封源的保管，防止丢失。

核子计周围辐射水平的评价

使用FD-3013型数字γ辐射仪，对丹东地区2003年以来五年间生产的核子秤和料位计的放射源（模拟工作状态下）进行空气比释动率的测试。依据国家标准GB18871—2002、2002对核子计周围的辐射水平进行评价。结果表明，在核子计周围及源室表面进行安装、检修和标定等工作的放射工作人员，若把腹部剂量率作为全身均匀照射，其腹部剂量率平均值和最高值在国家标准中所规定的放射工作人员连续5a平均年剂量限值10μGy／h以下（按每周工作40h导出）。说明放射工作人员在常规下操作我市生产的核子秤和料位计是比较安全的，但在实际工作中应注意对密封源的保管，防止丢失。

核测用电缆的屏蔽

阐述了超高屏蔽核测用电缆的结构及性能要求,着重介绍了超高屏蔽电缆所使用屏蔽材料的性能,尤其是其高屏蔽特性。对超高屏蔽核测用电缆屏蔽设计中的几个重要问题进行了分析。

Empirical Bayes Absolute Error Loss Estimation for Parameter of One-Side Truncation Distribution Families

In this paper we propose an absolute error loss EB estimator for parameter of one-side truncation distribution families. Under some conditions we have proved that the convergence rates of its Bayes risk is o, where 0<λ,r≤1,Mn≤lnln n (for large n),Mn→∞ as n→∞.

Groundwater Waves in a Coastal Fractured Aquifer of the Third Phase Qinshan Nuclear Power Engineering Field

Tidal fluctuations of Hangzhou Bay produce progressive pressure waves in adjacent field fractured aquifers, as the pressure waves propagate, groundwater levels and hydraulic gradients continuously fluctuate. The effect of tidal fluctuations on groundwater flow can be determined using the mean hydraulic gradient that can be calculated by comparing mean ground and surface water elevations.Tidal fluctuation is shown to affect the piezometer readings taken in a nearshore fractured aquifer around the nuclear power engineering field. Continuous monitoring of a network of seven piezometers provided relations between the tidal cycle and the piezometer readings. The relations can be expressed in times of a time and amplitude scaling factor. The time lag and the tidal efficiency factor and wavelength are calculated using these parameters. It provides significant scientific basis to prevent tide and groundwater for the nuclear power engineering construction and safety run of nuclear power station in the future.

Nuclear Level Density with Non-zero Angular Momentum

The statistical properties of interacting fermions have been studied for various angular momentum with the inclusion of pairing interaction. The dependence of the critical temperature on angular momentum for several nuclei, have been studied. The yrast energy as a function of angular momentum for 28Si and 24 Mg nuclei have been calculated up to 60.0 MeV of excitation energy. The computed limiting angular momenta are compared with the experimental results for ^26Al produced by ^12C＋ 14N reaction. The relevant nuclear level densities for non-zero angular momentum have been computed for ^44Ti and ^136 Ba nuclei. The results are compared with their corresponding values obtained from the approximate formulas.

Pade Expansion and Nucleon-Nucleon Scattering in Coupled Channels

We extend our Pade-aided analysis of the nonperturbative renormalization of nucleon-nucleon scatteringto the case of coupled channels.

Total Routhian Surface Calculations on Hf Isotopes

The two-dimensional total routhian surface calculations have been carried out to stud）, the triaxial superdeformed structure of a neutron-rich nucleus ^173 Hf firstly. In particular the effects of the rotational frequency ω and pairing-energy gap parameter A are discussed in detail in the course of shaping its triaxial superdeformation; additionally the neutron-shell correction energy is analyzed with emphasis in the confirmed triaxial superdeformed nucleus ^173Hf. Finally, more systematical results have been investigated for some confirmed superdeformed nuclei experimentally and a few predicted triaxial superdeformed nuclei theoretically with quadropole deformation ε2 ≈0.4 and triaxial deformation γ≈20° or 30° in the Z = 72 region.

Boundeness of a Class of Maximal Operators on H^p Spaces on Compact Lie Groups

In this paper we discuss the weak type(IP,I)boundedness of a class of maximal operators T and themaximal strong,mean boundedness of a family of the operators {T on the atomic IP spaces on compaet Lie groups.Also,we obtain the correspoding convergent rosults.

RADIONUCLIDES IN RICE IN HONG KONG

Radionuclide contents in imported rice are determined using the EG&G ORTEC photon spectrometer system. Most of the natural radionuclides are found to have specific activities below the detectable limit. 40K has values ranging from 0.104to 32.97 Bq/kg; 137Cs from 0.009 to 0.52 Bq/kg; and 95Zr less than 0.077 Bq/kg. The annual effective dose for a male and a female adult is 18μSv and 12.7μSv, respectively. Both are less than the value recommended by the International Commission of Radiological Protection.

Study of Nucleon Unpolarized Structure Functions

Nucleon unpolarized structure functions in the ep elastic scattering are discussed. A new unpolarized structure function F^-3 due to the two-photon-exchange is given. Numerical results of the new structure function in the limit of x →1 are displayed.

Influence of Quantal and Statistical Fluctuations on Phase Transitions in Finite Nuclei

Investigations on thermal evolution of pairing-phase transition and shape-phase transition in light nuclei are made as a function of pair gap, deformation, temperature and angular momentum using a finite temperature statistical approach with main emphasis to fluctuations. The occurrence of a peak structure in the specific heat predicted as signals of the pairing-phase and shape-phase transitions are reviewed and it is found that they are not actually true phase transitions and it is only an artifact of the mean field models. Since quantal number and spin fluctuations and statistical fluctuations in pair gap, deformation degrees of freedom and energy when incorporated, it wash out the pairing-phase transition and smooth out the shape-phase transition. Phase transitions due to collapse of pair gap and deformation is discussed and a clear picture of pairing-phase transition in light nuclei is presented in which pairing transition is reconciled.

Effect of Woods-Saxon Potential on the ^16O＋^20Ne Reaction Cross Section

The excitation function and angular distributions for the ^16O+^20Ne system have been explained using the distorted wave Born approximation (DWBA) calculations. The real and imaginary Woods Saxon optical potentials are assumed to be energy-dependent. The gross resonant structures observed in the ^20Ne(^16O,^16O)^20 Ne excitation function are well described by the present DWBA calculations. Although the elastic and elastic-transfer analyses introduce a qualitative description of the experimental data, the coherent sum of the two reaction processes exhibit a much better result for both forward and large-angle data.

Shell Model Description of Neutron-Deficient Sn Isotopes

The shell model calculations in the sdgh major shell for the neutron-deficient ^106,107,108,109Sn isotopes have been carried out by using CD-Bonn and Nijmegenl two-body effective nucleon-nucleon interactions. The singleshell states and the corresponding matrix elements needed for describing Sn isotopes are reconstructed to calculate the coefficient of fractional parantage by reducing the calculation requirements. This reconstruction allows us to do the shell model calculations of the neutron deficient Sn isotopes in very reasonable time. The results are compared to the recent high-resolution experimental data and found to be in good agreement with experiments.

Non-perturbative QCD Effect on K-Factor of Drell-Yan Process

By using a non-perturbative quark propagator with the lowest-dimensional condensate contributions from the QCD vacuum, the non-perturbative egect to K-factor of the Drell-Yan process is numerically investigated for 6^12C- 6^12C collision at the center-of-mass energy √s- 200 GeV, 630 GeV respectively. Calculated results show that the non-perturbative QCD effect has just a weak influence on K-factor in the two cases.

Decoding the Information of Life

We link nuclear force with gravity. We use statistical entropy to link fine-structure constant （ct） and cosmological constant, showing mystical number 137 （as reciprocal of increasing entropy of the universe） as negative entropy needed for life to exist. If our computational route applies to the physical universe, it should apply to life. Molecular biology is searching for the fundamental source of information that would link to the information in DNA.

Statistical Behaviors of Quantum Spectra in Superheavy Nuclei

From the point of view of the interplay between order and chaos, the most regular single-particle motion of neutrons has been found in the superheavy system with and based on the Skyrme–Hartree–Fock model and in the system with and based on the relativistic mean-field model. It has been shown that the statistical analysis of spectra can give valuable information about the stability of suprheavy systems. In addition it may yield deep insight into the single-particle motion in the mean field formed by the superheavy system.