Numerical simulation of high-energy neutron radiation effect of scintillation fiber

Due to their low cost,flexibility,and convenience for long distance data transfer,plastic scintillation fibers (PSF) have been increasingly used in building detectors or sensors for detecting various radiations and imaging. In this paper,GEANT4 Monte Carlo simulation tool was used to obtain some radiation effects of PSF under high-energy neutron irradiation. BCF-20,a plastic fiber material,produced by Saint-Gobain,was used in the simulation. The fiber consists of a core scintillating material of polystyrene and an acrylic outer cladding. Incident neutrons produce energy deposition in fiber through neutron induced recoil proton events. The relationships between energy deposition efficiency and fiber length,fiber radius and incident neutron energy are presented. The variation with those parameters and parameter selection are also analyzed.

Study of “Radiation Effects of Nuclear High Energy Particles” on Electronic Circuits and Methods to Reduce Its Destructive Effects

This research concerns on (TID), (DD) and (SEE) effects also high energy particles’ effects on electronic properties of silicon. It investigates the silicon electronic properties exposed to these particles using a laboratory neutron radiation sources. Some Pieces of a silicon wafer were under neutron radiation at different times and the electrical properties of each one was illustrated by plate resistance measurement and also the strength of the current voltage was simulated by Fluka and MCNP software. Based on these results, authorized limit of silicon tolerance was obtained against high energy neutrons radiation. We put them in the electric furnace under thermal recovery to overcome the unusual behavior of irradiated samples.

Optimization of hole-boring radiation pressure acceleration of ion beams for fusion ignition

In contrast to ion beams produced by conventional accelerators,ion beams accelerated by ultrashort intense laser pulses have advantages of ultrashort bunch duration and ultrahigh density,which are achieved in compact size.However,it is still challenging to simultaneously enhance their quality and yield for practical applications such as fast ion ignition of inertial confinement fusion.Compared with other mechanisms of laser-driven ion acceleration,the hole-boring radiation pressure acceleration has a special advantage in generating high-fluence ion beams suitable for the creation of high energy density state of matters.In this paper,we present a review on some theoretical and numerical studies of the hole-boring radiation pressure acceleration.First we discuss the typical field structure associated with this mechanism,its intrinsic feature of oscillations,and the underling physics.Then we will review some recently proposed schemes to enhance the beam quality and the efficiency in the hole-boring radiation pressure acceleration,such as matching laser intensity profile with target density profile,and using two-ion-species targets.Based on this,we propose an integrated scheme for efficient high-quality hole-boring radiation pressure acceleration,in which the longitudinal density profile of a composite target as well as the laser transverse intensity profile are tailored according to the matching condition.

Theoretical study on the carbon nanotube used as hard X-radiation source

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Glacier mass balance in High Mountain Asia inferred from a GRACE release-6 gravity solution for the period 2002–2016

We provide estimates of glacier mass changes in the High Mountain Asia (HMA) area from April2002 to August 2016 by employing a new version of gravity solutions of the Gravity Recovery and ClimateExperiment (GRACE) twin-satellite mission. We find a total mass loss trend of the HMA glaciers at a rateof –22.17 (±1.96) Gt/a. The largest mass loss rates of –7.02 (±0.94) and –6.73 (±0.78) Gt/a are found forthe glaciers in Nyainqentanglha Mountains and Eastern Himalayas, respectively. Although most glaciers inthe HMA area show a mass loss, we find a small glacier mass gain of 1.19 (±0.55) and 0.77 (±0.37) Gt/a inKarakoram Mountains and Western Kunlun Mountains, respectively. There is also a nearly zero massbalance in Pamirs. Our estimates of glacier mass change trends confirm previous results from the analysisof altimetry data of the ICESat (ICE, Cloud and Land Elevation Satellite) and ASTER (AdvancedSpaceborne Thermal Emission and Reflection Radiometer) DEM (Digital Elevation Model) satellites inmost of the selected glacier areas. However, they largely differ to previous GRACE-based studies which weattribute to our different post-processing techniques of the newer GRACE data. In addition, we explicitlyshow regional mass change features for both the interannual glacier mass changes and the 14-a averagedseasonal glacier mass changes. These changes can be explained in parts by total net precipitation (netsnowfall and net rainfall) and net snowfall, but mostly by total net radiation energy when compared to datafrom the ERA5-Land meteorological reanalysis. Moreover, nearly all the non-trend interannual masschanges and most seasonal mass changes can be explained by the total net radiation energy data. The massloss trends could be partly related to a heat effect due to increased net rainfall in Tianshan Mountains, QilianMountains, Nyainqentanglha Mountains and Eastern Himalayas. Our new results for the glacier mass changein this study could help improve the understanding of glacier variation in the HMA area and contribute tothe study of global change. They could also serve the utilization of water resources there and in neighboringareas.

Induction of adaptive response in utero by ionizing radiation:A radiation quality dependent phenomenon

Investigation on possible induction of adaptive response(AR)by high-liner energy transfer(LET)particle radiation for protection against low-LET photon radiation-induced detrimental effects has not yet been performed in utero.This study verified if an AR could be induced by high-LET particle radiation from accelerated heavy ions against low-LET X-ray radiation-induced detrimental effects on fetal mice.Total body irradiation of pregnant C57BL/6J mice were performed by delivering a priming dose ranging from 10 mGy to 320 mGy of particle radiation on gestation day 11 followed one day later by a challenge dose at 3500 mGy from X-ray radiation.The monoenergetic beams of carbon,silicon and iron with the LET values of about 15,55,and 200 KeV/μm,respectively,were examined.Significant suppression by the priming radiation of the detrimental effects(fetal death,malformation,or low body weight)was used as the endpoints for judgment of a successful AR induction on gestation day 18.Existence of AR was not observed.On the other hand,the priming dose of high-LET particle radiation,in some cases,even increased the detrimental effects induced by the challenge dose from low-LET X-ray radiation.Although existence of AR induced by high-LET radiation in cultured mammalian cells in vitro and in certain tissues of laboratory mice in vivo was demonstrated,the present study did not suggest that low dose of high-LET particle radiation could induce an AR in fetal mice in utero under the setup of our experimental system.

Ultrahard X-ray multifunctional application beamline at the SSRF

The ultrahard X-ray multifunctional application beamline(BL12SW)is a phase-II beamline project at the Shanghai Syn-chrotron Radiation Facility.The primary X-ray techniques used at the beamline are high-energy X-ray diffraction and imaging using white and monochromatic light.The main scientific objectives of ultrahard X-ray beamlines are focused on two research areas.One is the study of the structural properties of Earth’s interior and new materials under extreme high-temperature and high-pressure conditions,and the other is the characterization of materials and processes in near-real service environments.The beamline utilizes a superconducting wiggler as the light source,with two diamond windows and SiC discs to filter out low-energy light(primarily below 30 keV)and a Cu filter assembly to control the thermal load entering the subsequent optical components.The beamline is equipped with dual monochromators.The first was a meridional bending Laue monochromator cooled by liquid nitrogen,achieving a full-energy coverage of 30-162 keV.The second was a sagittal bending Laue monochromator installed in an external building,providing a focused beam in the horizontal direction with an energy range of 60-120 keV.There were four experimental hutches:two large-volume press experimental hutches(LVP1 and LVP2)and two engineering material experimental hutches(ENG1 and ENG2).Each hutch was equipped with various near-real service conditions to satisfy different requirements.For example,LVP1 and LVP2 were equipped with a 200-ton DDIA press and a 2000-ton dual-mode(DDIA and Kawai)press,respectively.ENG1 and ENG2 provide in situ tensile,creep,and fatigue tests as well as high-temperature conditions.Since June 2023,the BL12SW has been in trial operation.It is expected to officially open to users by early 2024.

Establishment of Energy Dispersive X-ray Diffraction Experimental System With Synchrotron Radiation Under High Pressure

Because the interactions between molecules and atoms in mediums can be dramatically changed by compression, high pressure studies on materials can provide much information on fundamental properties including phase transition and

Effects of high-energy-pulse-electron beam radiation on biomacromolecules

To study the molecular mechanism of high mutation frequency induced by high-energy-pulse-electron (HEPE) beam radiation, the effects of HEPE radiation on yeast cells, plasma membrane, plasmid DNA, and protein activity were investigated by means of cell counting, gel electrophoresis, AO/EB double fluorescent staining, etc. The results showed that the viability of yeast cells declined statistically with increase of absorbed doses. The half lethal dose (LD50) was 134 Gy. HEPE beam radiation had little influence on the function of plasma membrane and protein, while it could induce much DNA damage of single strand breaks (SSB) and double strand breaks (DSB) that were required for gene mutation. The G-value for DSB formation of HEPE beam radiation in aqueous solution was 5.7 times higher than that caused by 60Co gamma rays. HEPE can be a new effective method for induced mutation breeding and deserves further research in the future.

高功率离子束模拟材料的X射线热-力学效应研究

主要介绍了利用高功率离子束模拟1keV黑体辐射X射线对材料的热-力学效应(thermal-mechanicaleffects)的初步研究结果。计算了“闪光二号”加速器产生的高功率离子束(质子束)和1keV黑体辐射X射线在材料中的能量沉积剖面,计算结果表明二者的能量沉积范围和剖面变化趋势基本一致。给出了利用“闪光二号”加速器高功率离子束辐照不同材料样品的初步实验结果。所辐照的样品表面镀层被剥离掉,Cu和Al样品表面有明显的熔融痕迹,样品的质量损失约几十毫克,3mm厚的石墨样品碎裂成数块,1mm厚的Al靶形变达到6mm。实测的5mm厚硬Al靶背面应力波峰值约35MPa。因而可以利用“闪光二号”加速器产生的高功率离子束模拟1keV黑体辐射X射线的热-力学效应。

HL-1装置中的相对论性非热辐射

在垂直于大半径方向用两个固定频率((?)0和(?)5GHz)的毫米波段外差接收机研究了在HL-1装置中等离子体的非热辐射。根据这些辐射与等离子体密度的关系,HL-1装置的放电可分为4种类型,并得到两个临界密度。这些辐射特性被认为是与逃逸放电性质和逃逸动力学不稳定现象有关。在实验中还观察到了与这种不稳定性有关的一系列等离子体宏观现象以及由此引起的逃逸损失。

Molecular Mechanism of High Energy Proton Radiation——Raman Spectroscopic Character of Microcosmic Damage in the Space Structure of DNA

High energy proton is an important type of the space radiation. The paper investigates the radiatione ffect of high energy proton (27.9 MeV) on DNA aqueous solution in the field of the molecular mechanism. The following information about the microcosmic damage to the space structure of DNA was obtained: (ⅰ) breakage of a part of interbase hydrogen bonds which maintained double helical structure of DNA; (ⅱ) damage on four bases, in which the damage on adenine ring was the most serious; (ⅲ) obvious change of deoxyribose; (ⅳ) serious damage on backbone phosphate ion (PO_2^-) and phosphate diester (PO_2) and the occurrence of scissions of double-stranded and single-stranded DNAs; (ⅴ) obvious decrease in the amount of B-form conformation.

New Activated Carbon with High Thermal Conductivity and Its Microwave Regeneration Performance

Using a walnut shellas a carbon source and ZnCl_2 as an activating agent,we resolved the temperature gradient problems of activated carbon in the microwave desorption process.An appropriate amount of silicon carbide was added to prepare the composite activated carbon with high thermalconductivity while developing VOC adsorption-microwave regeneration technology.The experimentalresults show that the coefficient of thermalconductivity of SiC-AC is three times as much as those of AC and SY-6.When microwave power was 480 W in its microwave desorption,the temperature of the bed thermaldesorption was 10 ℃ to 30 ℃ below that of normalactivated carbon prepared in our laboratory.The toluene desorption activation energy was 16.05 k J·mol^（-1）,which was 15% less than the desorption activation energy of commercialactivated carbon.This study testified that the process could maintain its high adsorption and regeneration desorption performances.

DFT Study on Two C_4N_(12)O_4 Isomers with Pagodane- and Isopagodane-like Structures

Geometries, energies, and vibrational frequencies for two C4N12O4 isomers with pagodane- and isopagodane-like structures have been calculated at the B3LYP/6-31G＊ level.Isomers 1 and 2 are of D2h and D2d symmetry, respectively. Heats of formation for the two C4N12O4 isomers have been estimated in this paper, indicating they would be reasonable candidates for high energy density materials.

Influence of Microstructures on Thermal Shock and Sintering Behavior of YSZ-based Thermal Barrier Coatings

In this study, two thermal barrier coatings based on YSZ were produced by using a commercially available agglomerated and sintered powder and a special spray powder prepared by high energy ball milling. Both thermal barrier coatings exhibited similar overall porosities, but significantly different microstructures. Application of the special spray powder prepared by high energy ball milling led to a microstructure with numerous inclusions of semi-molten agglomerates, which introduced a plethora of clusters of fine pores into the coating and several more microstructural defects. This microstructure resulted in a significantly better thermal shock behavior compared to the conventional thermal barrier coating. The heat treatment of both thermal barrier coatings atθ=1150℃for t=100 h led to a sintering of both coatings. The results were reduced overall porosity and significantly increased fracture toughness. A correlation between the fracture toughness of both coatings after the heat treatment and the thermal shock life time could not be identified.

The Dosimetric Effects of Different Beam Energy on Physical Dose Distributions in IMRT Based on Analysis of Physical Indices

This work aimed at evaluating the effect of 6- and 10-MV photon energies on intensity-modulated radiation therapy (IMRT) treatment plan outcome in different selected diagnostic cases. For such purpose, 19 patients, with different types of non CNS solid tumers, were selected. Clinical step-and-shoot IMRT treatment plans were designed for delivery on a Siemens Oncor accelerator with 82 leafs;multi-leaf collimators (MLCs). To ensure that the similarity or difference among the plans is due to energy alone, the same optimization constraints were applied for both energy plans. All the parameters like beam angles, number of beams, were kept constant to achieve the same clinical objectives. The Comparative evaluation was based on dose-volumetric analysis of both energy IMRT plans. Both qualitative and quantitative methods were used. Several physical indices for Planning Target Volume (PTV), the relevant Organs at Risk (OARs) as mean dose (Dmean), maximum dose (Dmax), 95% dose (D95), integral dose, total number of segments, and the number of MU were applied. Homogeneity index and conformation number were two other evaluation parameters that were considered in this study. Collectively, the use of 6 MV photons was dosimetrically comparable with 10 MV photons in terms of target coverage, homogeneity, conformity, and OAR savings. While 10-MV plans showed a significant reduction in the number of MUs that varied between 4.2% and 16.6% (P-value = 0.0001) for the different cases compared to 6-MV. The percentage volumes of each patient receiving 2 Gy and 5 Gy were compared for the two energies. The general trend was that 6-MV plans had the highest percentage volume, (P-value = 0.0001, P-value = 0.006) respectively. 10-MV beams actually decreased the integral dose (from average 183.27 ± 152.38 Gy-Kg to 178.08 ± 147.71 Gy-Kg, P-value = 0.004) compared with 6-MV. In general, comparison of the above parameters showed statistically significant differences between 6-MV and 10-MV groups. Based on the present results, the 10-MV is the optimal energy for IMRT, regardless of the concerns about a potential risk of radiation-induced malignancies. It is recommended that the choice to treat at 10 MV be taken as a risk vs. benefit as the clinical significance remains to be determined on case by case basis.

GJT-高温辐射陶瓷涂料在电站锅炉上的应用

哈尔滨炼油厂在自备电站 3 # 锅炉水冷壁管外表面及炉墙上喷涂黑龙江省石油化学研究院研制的GJT -高温辐射陶瓷涂料 ,经测试 ,效果良好 ,使锅炉排烟温度降低 ,锅炉热效率得到提高。

地震和爆炸的P波层析成像——第二部分:由时频地震图得到的2004年苏门答腊-安达曼地震的断层破裂特征(英文)

本文分析了2004年12月26日苏门答腊-安达曼地震的宽频带地震图。目的是通过不同频率成分的子事件的发生时间了解断层的破裂过程。具体分析的是由相应宽频带地震记录得到的P波的时频地震图。分析结果说明,在S波到达前的时窗内发生了最大辐射强度的相应频率低于1 Hz的15次较大子事件,但在同样的时窗内,还发生了最大辐射强度的频率更高的数百次小事件,形成了准连续的次声频率的蜂鸣声,在远至8 000 km的距离上都还能观测到。由于高频波在射线传播路径上存在较强的吸收,因而可以断定,地震期间有一大部分的地震能量是以蜂鸣声的形式被释放了。

Effect of Depth-Dependent Nociceptor Density on the Heat-Induced Withdrawal Reflex

Previously we introduced a concise dose-response model for the heat-induced withdrawal reflex caused by millimeter wave radiation. The model predicts the occurrence of withdrawal reflex from the given spatial temperature profile. It was formulated on the assumption that the density of nociceptors in skin is uniform, independent of the depth. The model has only two parameters: the activation temperature of heat-sensitive nociceptors and the critical threshold on the activated volume for triggering withdrawal reflex. In this study, we consider the case of depth-dependent nociceptor density in skin. We use a general parametric form with a scaling parameter in the depth direction to represent the nociceptor density. We analyze system behaviors for four density types of this form. Based on the theoretical results, we develop a methodology for 1) identifying from test data the density form of nociceptors distribution, 2) finding from test data the scaling parameter in the density form, and 3) determining from test data the activation temperature of nociceptors.

形状记忆聚合物及其复合材料空间辐照环境效应研究进展

形状记忆聚合物及其复合材料具有密度低、可回复变形大、刺激方式可控、成本低等优点,可应用于空间可展开结构,但空间辐照环境对其在轨安全带来了严重的威胁。首先介绍了形状记忆聚合物及其复合材料的分类,接着总结了基于形状记忆聚合物的空间可展开结构应用现状,然后分析了高能电磁辐射、高能粒子辐射和原子氧等空间环境对形状记忆聚合物及其复合材料性能的影响,最后对形状记忆材料空间辐照环境效应的研究成果进行了总结并对未来发展方向进行了展望。