In the metrology of radon, an environmental lung carcinogen, the integrated measurements necessary for epidemiological studies are made very often using the tracks detector LR 115 type 2. For dosimetric analysis, the ...In the metrology of radon, an environmental lung carcinogen, the integrated measurements necessary for epidemiological studies are made very often using the tracks detector LR 115 type 2. For dosimetric analysis, the etched tracks from radon alpha particles on this detector are usually counted by means of an optical microscope or a spark counter. An optimal reading of the track densities which must be converted into radon concentrations, can’t be done without a good mastery of the mode of operation and use of these devices. Furthermore, investigations to know as to whether or not each of those can be used to determine radon concentration are necessary. These are the objectives of the present work in which LR 115 samples exposed to radon for at least 3 months, were chemically developed under standard conditions and read. The track densities obtained with the microscope are very much higher than those of the counter for each sample. These results are consistent with those published by other authors. However, each of these devices can be used interchangeably for alpha tracks counting, as both provide radon concentrations with a very good linear correlation coefficient of 0.95 taking into account their respective calibration factors for the reading of this detector. In addition, the saturation phenomenon for the spark counter reading of LR 115 detector occurs beyond 11,000 tr/cm<sup>2</sup>, a density never reached during our environmental radon measurements.展开更多
火力分配作为集群目标来袭防御任务规划的关键环节,对提高防御效果具有重要意义。针对高炮反无人机的火力分配问题,将高炮性能指标约束和转火时间约束转化为可拦截因子,提出一种基于可拦截因子的高炮反无人机火力分配模型,减小非线性约...火力分配作为集群目标来袭防御任务规划的关键环节,对提高防御效果具有重要意义。针对高炮反无人机的火力分配问题,将高炮性能指标约束和转火时间约束转化为可拦截因子,提出一种基于可拦截因子的高炮反无人机火力分配模型,减小非线性约束转化为惩罚函数带来的计算量及误差,进而提升整体效能。基于此模型,针对来袭目标与火力节点之间的火力优化匹配问题,采用改进混合遗传粒子群算法(Hybrid GA and PSO,HGAPSO)优化算法对模型进行最优值求解。仿真试验结果表明该模型合理有效,HGAPSO算法有较高的收敛精度和较快的收敛速率。展开更多
A spherical tissue equivalent proportional counter(TEPC) for neutron monitoring has been developed. It was properly designed to produce a uniform electric field intensity around the anode wire. An internal ^(241)Am al...A spherical tissue equivalent proportional counter(TEPC) for neutron monitoring has been developed. It was properly designed to produce a uniform electric field intensity around the anode wire. An internal ^(241)Am alpha source was adopted for lineal energy calibration. The TEPC was characterized in terms of dose equivalent response in a standard ^(252)Cf neutron field, and was tested with 2.45 MeV neutrons. Microdosimetric spectra, frequency mean lineal energy and dose-average mean lineal energy of 2.45 MeV neutrons were obtained and compared with FLUKA Monte Carlo simulation results. The measurement and simulation results agreed well. The mean quality factor and dose equivalent values evaluated from the 2.45 MeV neutron measurement were in good agreement with the recommended effective quality factor and ambient dose equivalent H*(10),respectively. Preliminary results have proved the availability of the developed TEPC for neutron monitoring.展开更多
The electronic structure of protein chains L and M in photosynthetic reaction center (PRC) of Rhodobacter sphaeroides (Van Niel) Imhoff, Truper et Pfennig) was studied by using the Overlapping Dimer Approximation meth...The electronic structure of protein chains L and M in photosynthetic reaction center (PRC) of Rhodobacter sphaeroides (Van Niel) Imhoff, Truper et Pfennig) was studied by using the Overlapping Dimer Approximation method and the Extended Negative Factor Counter method at ab initio level. The result indicated that: (1) Amino acid residues, the molecular orbitals of which composed the main components of frontier orbitals of protein chain L (M), are located at the random coil areas of chain L (alpha helix areas of chain M). Since the random coil is flexible and more easy to change its conformation in the electron transfer process and to reduce the energy of the system, and the structure of the alpha helix is reletively stable, this difference might be one of the causes for the electron transfer in photosynthetic reaction center (PRC) only takes place along the L branch. (2) The His residues which axially coordinated to the 'special pair' P and accessory chlorophyll molecules (ABChls) are essentially important for the E-LUMO levels of P and ABChl. But, the corresponding molecular orbitals of these His residues do not appear in the composition of frontier orbitals of protein chains. It means that the interaction between pigment molecules and protein chains do not influence the contribution to the frontier orbitals of protein chains explicitly, but influences the corresponding E-LUMO levels significantly.展开更多
文摘In the metrology of radon, an environmental lung carcinogen, the integrated measurements necessary for epidemiological studies are made very often using the tracks detector LR 115 type 2. For dosimetric analysis, the etched tracks from radon alpha particles on this detector are usually counted by means of an optical microscope or a spark counter. An optimal reading of the track densities which must be converted into radon concentrations, can’t be done without a good mastery of the mode of operation and use of these devices. Furthermore, investigations to know as to whether or not each of those can be used to determine radon concentration are necessary. These are the objectives of the present work in which LR 115 samples exposed to radon for at least 3 months, were chemically developed under standard conditions and read. The track densities obtained with the microscope are very much higher than those of the counter for each sample. These results are consistent with those published by other authors. However, each of these devices can be used interchangeably for alpha tracks counting, as both provide radon concentrations with a very good linear correlation coefficient of 0.95 taking into account their respective calibration factors for the reading of this detector. In addition, the saturation phenomenon for the spark counter reading of LR 115 detector occurs beyond 11,000 tr/cm<sup>2</sup>, a density never reached during our environmental radon measurements.
文摘火力分配作为集群目标来袭防御任务规划的关键环节,对提高防御效果具有重要意义。针对高炮反无人机的火力分配问题,将高炮性能指标约束和转火时间约束转化为可拦截因子,提出一种基于可拦截因子的高炮反无人机火力分配模型,减小非线性约束转化为惩罚函数带来的计算量及误差,进而提升整体效能。基于此模型,针对来袭目标与火力节点之间的火力优化匹配问题,采用改进混合遗传粒子群算法(Hybrid GA and PSO,HGAPSO)优化算法对模型进行最优值求解。仿真试验结果表明该模型合理有效,HGAPSO算法有较高的收敛精度和较快的收敛速率。
基金Supported by the Key Technology of Fusion Reactor Radiation Protection Foundation(No.2014GB112005)
文摘A spherical tissue equivalent proportional counter(TEPC) for neutron monitoring has been developed. It was properly designed to produce a uniform electric field intensity around the anode wire. An internal ^(241)Am alpha source was adopted for lineal energy calibration. The TEPC was characterized in terms of dose equivalent response in a standard ^(252)Cf neutron field, and was tested with 2.45 MeV neutrons. Microdosimetric spectra, frequency mean lineal energy and dose-average mean lineal energy of 2.45 MeV neutrons were obtained and compared with FLUKA Monte Carlo simulation results. The measurement and simulation results agreed well. The mean quality factor and dose equivalent values evaluated from the 2.45 MeV neutron measurement were in good agreement with the recommended effective quality factor and ambient dose equivalent H*(10),respectively. Preliminary results have proved the availability of the developed TEPC for neutron monitoring.
文摘The electronic structure of protein chains L and M in photosynthetic reaction center (PRC) of Rhodobacter sphaeroides (Van Niel) Imhoff, Truper et Pfennig) was studied by using the Overlapping Dimer Approximation method and the Extended Negative Factor Counter method at ab initio level. The result indicated that: (1) Amino acid residues, the molecular orbitals of which composed the main components of frontier orbitals of protein chain L (M), are located at the random coil areas of chain L (alpha helix areas of chain M). Since the random coil is flexible and more easy to change its conformation in the electron transfer process and to reduce the energy of the system, and the structure of the alpha helix is reletively stable, this difference might be one of the causes for the electron transfer in photosynthetic reaction center (PRC) only takes place along the L branch. (2) The His residues which axially coordinated to the 'special pair' P and accessory chlorophyll molecules (ABChls) are essentially important for the E-LUMO levels of P and ABChl. But, the corresponding molecular orbitals of these His residues do not appear in the composition of frontier orbitals of protein chains. It means that the interaction between pigment molecules and protein chains do not influence the contribution to the frontier orbitals of protein chains explicitly, but influences the corresponding E-LUMO levels significantly.
