Radioisotope production using lasers:From basic science to applications

The discovery of chirped pulse amplification has led to great improvements in laser technology,enabling energetic laser beams to be compressed to pulse durations of tens of femtoseconds and focused to a few micrometers.Protons with energies of tens of MeV can be accelerated using,for instance,target normal sheath acceleration and focused on secondary targets.Under such conditions,nuclear reactions can occur,with the production of radioisotopes suitable for medical application.The use of high-repetition lasers to produce such isotopes is competitive with conventional methods mostly based on accelerators.In this paper,we study the production of^(67)Cu,^(63)Zn,^(18)F,and^(11)C,which are currently used in positron emission tomography and other applications.At the same time,we study the reactions^(10)B(p,α)^(7)Be and^(70)Zn(p,4n)^(67)Ga to put further constraints on the proton distributions at different angles,as well as the reaction^(11)B(p,α)^(8)Be relevant for energy production.The experiment was performed at the 1 PW laser facility at VegaⅢin Salamanca,Spain.Angular distributions of radioisotopes in the forward(with respect to the laser direction)and backward directions were measured using a high purity germanium detector.Our results are in reasonable agreement with numerical estimates obtained following the approach of Kimura and Bonasera[Nucl.Instrum.Methods Phys.Res.,Sect.A 637,164–170(2011)].

P3: An installation for high-energy density plasma physics and ultra-high intensity laserematter interaction at ELI-Beamlines

ELI-Beamlines(ELI-BL),one of the three pillars of the Extreme Light Infrastructure endeavour,will be in a unique position to perform research in high-energy-density-physics(HEDP),plasma physics and ultra-high intensity(UHI)ð>10^(22) W=cm^(2)) lasereplasma interaction.Recently the need for HED laboratory physics was identified and the P3(plasma physics platform)installation under construction in ELI-BL will be an answer.The ELI-BL 10 PW laser makes possible fundamental research topics from high-field physics to new extreme states of matter such as radiation-dominated ones,high-pressure quantum ones,warm dense matter(WDM)and ultra-relativistic plasmas.HEDP is of fundamental importance for research in the field of laboratory astrophysics and inertial confinement fusion(ICF).Reaching such extreme states of matter now and in the future will depend on the use of plasma optics for amplifying and focusing laser pulses.This article will present the relevant technological infrastructure being built in ELI-BL for HEDP and UHI,and gives a brief overview of some research under way in the field of UHI,laboratory astrophysics,ICF,WDM,and plasma optics.

适应患儿大小、临床指征和既往检查次数的小儿CT扫描参数降低剂量及其依从性的研究

目的根据病人体质量、临床指征、既往检查次数和自动曝光控制建立小儿胸部和腹部新的CT扫描参数，评价其依从性和放射剂量减低的结果。材料与方法本研究经学术委员会批准并符合健康医疗保险要求，免除知情同意书。根据临床指征和患儿既往CT检查的次数．新的小儿CT扫描参数编制为6个彩色区。对新的CT方法进行回顾性评价。扫描参数根据病人体质量进行调节。

腹部CT:迭代统计重建法与滤波反投影重建技术的比较

目的比较在不同X线管电流时间(50～200mAs)条件下通过迭代重建法(ASIR)与滤波反投影重建技术(FBP)获得腹部CT影像质量及病变显示能力。

Finite deformation analysis of crack tip fields in plastically compressible hardening–softening–hardening solids

Crack tip fields are calculated under plane strain small scale yielding conditions. The material is characterized by a finite strain elastic-viscoplastic constitutive relation with various hardening-softening-hardening hardness functions. Both plastically compressible and plastically incompressible solids are considered. Displacements corresponding to the isotropic linear elastic mode I crack field are prescribed on a remote boundary. The initial crack is taken to be a semi-circular notch and symmetry about the crack plane is imposed. Plastic compressibility is found to give an increased crack opening displacement for a given value of the applied loading. The plastic zone size and shape are found to depend on the plastic compressibility, but not much on whether material softening occurs near the crack tip. On the other hand, the near crack tip stress and deformation fields depend sensitively on whether or not material softening occurs. The combination of plastic compressibility and softening (or softening-hardening) has a particularly strong effect on the near crack tip stress and deformation fields.

发展中国家筛查结核病接触者合适吗?1996-1998年尼泊尔东部地区的经验

背景:此项结核病研究是由一家非政府组织在尼泊尔东部8个丘陵及山区地区实施的。目的:评价筛查接触者对病例发现的作用。设计:对1996—1998年诊断并登记的"首登病例"(index cases),即涂片阳性、涂片阴性和肺外结核病例的接触者进行回顾性队列研究。首登病例的家庭成员为接触者,接触者经疫检筛查,2份痰涂片阳性者确定为涂阳肺结核病例。结果:大约从50%(668)的登记病人中确定接触者;在确定的接触者中75%(2298)送检1个或以上的痰标本。从接触者中共筛查出14例(0.61%)涂阳肺结核病例,除1例外,13例涂阳肺结核病人都是从涂阳肺结核首登病例的接触者中检出的。从涂阳菌量≥2+的首登病例接触者中检出的涂阳肺结核病人是涂阳菌量1+者的7.2倍(P=0.04)。讨论:在这样的背景下,从涂阴肺结核或肺外结核病人的家庭接触者中用痰检筛查是不合适的。为了评价筛查没有症状的涂阳肺结核病例接触者的实用性以及通过筛查痰菌量大(>24)病例的接触者是否可以改善费用效益,有必要进一步的评估。

Higher-order approximate solutions of fractional stochastic point kinetics equations in nuclear reactor dynamics

Stochastic point kinetics equations(SPKEs) are a system of Ito? stochastic differential equations whose solution has been obtained by higher-order approximation.In this study, a fractional model of SPKEs has been analyzed. The efficiency of the proposed higher-order approximation scheme has been discussed in the results section. The solutions of SPKEs in the presence of Newtonian temperature feedback have also been provided to further discuss the physical behavior of the fractional model.

Ultraviolet ZnO Photodetectors with High Gain

Fabrication and characterization of metal-semiconductor-metal ultraviolet （MSM UV） photodetector based on ZnO ultra thin （nano scale） films with Pd Schottky contact are reported. The ZnO thin film was grown on glass substrate by thermal oxidation of preeposited zinc films using vacuum deposition technique. With applied voltage in the range from -3V to 3V, the contrast ratio, responsivity, and detectivity for an incident radiation of 0.1 mW at 365 nm wavelength were estimated. The proposed device exhibited a high gain which was attributed to the hole trapping at semiconductor-metal interface. I-V characteristics were studied and the parameters, such as ideality factor, leakage current, resistance-areaproduct, and barrier height, were extracted from the measured data.

带交-直装置的自励异步发电机稳态分析

一、前言本文论述自励异步发电机(SEIG)的稳态分析。对一台作为独立电源的SEIG的运行,电机的端电压及频率取决负载及原动机的转速。可采用交-直-交变换方案控制SEIG的电压及频率。这种交-直-交线路使用一只固定电容器及可变换向电容器。固定电容器与电机永久联接,以维持额定转速、空载时电机的端电压;可变电容器则是当负载在一定范围内波动时,不断切换。

Influence of Vitamin E on Preventive or Therapeutic Effect of MFA and DTPA in Cadmium Toxicity

The influence of vitamin E supplementation on the ability of α-mercapto-β(2-furyl)acrylic acid (MFA) or calcium trisodium dicthylenetriamine pentaacetate (DTPA) to reduce body burden of cadmium and reverse Cd-induced biochemical alterations was investigated in Cd-exposed rats. The treatment with MFA-vitamin E or CaNa3 DTPAvitandn E was more effective than either vitamin E or chelating agent alone, in depleting blood and tissue Cd. However, the combined treatment showed only limited advantage over the individuals in restoring Cd-induced biochemical changes. Further, the treatment with chelator-vitamin E concomitantly with the exposure to Cd was more effective than post-Cd exposure treatment.

Copper-Induced Changes in the Urea Uptake and Urease Activity in the Cyanobacteria Anabaena doliolum and Anacystis nidulans:Interaction With Sulphur Containing Amino Acids

Copper-induced changes in the urea uptake and urease activity have been investigated in the cyanobacteria Anabaena doliolum and Anacystis nidulans. Copper, at and above 5 μmol/L concentration, inhibited urea uptake and urease activity systems in both the cyanobacteria in a concentration dependent manner. However, the urea uptake and urease activity systems in A. nidulans appeared slightly more tolerant to copper than that of A.doliolum. The inhibitory effect of copper on urea uptake and urease activity was mitigated by sulphur containing amino acids (cystine and cysteine), however, methionine could not do so, indicating the involvement of sulfhydryl (-SH) groups in the assimilation of urea in cyanobacteria

Renal Toxicity of Nickel,Sodium Lauryl Sulphate and Their Combination after Dermal Application in Guinea Pigs

The guinea pigs were dermally exposed to nickel (Ni), sodium lauryl sulphate (SLS) and in their combination for 7 and 14 days. The exposure to Ni and SLS produced changes in enzymes and lipid peroxidation in kidney. The exposure to Ni or SLS depicted slight changes while combined exposure to Ni plus SLS exhibited more degenerative changes in kidney. The result of the study suggests that industrial workers and/or populations exposed simultaneously to Ni and SLS produces more damage to kidney.

Dermal Toxicity of Paraphenylenediamine

The guinea pigs were dermally exposed to paraphenylenediamine (PPD) and in presence of an oxidising agent hydrogen peroxide for 15 and 30 d to assess their effects on some enzymes, lipid peroxidation and histamine contents in the skin. The activities of acid and alkaline phosphatases, β-glucuronidase, gamma glutamyl transpeptidase, histidase and tyrosinase were enhanced after application of either PPD or PPD plus hydrogen peroxide. The lipid peroxidation and histamine contents also showed marked elevation following exposure to the chemicals.

黑麦性状在小麦遗传背景下的表达

利用一个可自交的、纯合矮秆黑麦品种与小麦杂交,研究了17个黑麦性状在24个普通小麦×黑麦和8个硬粒小麦×黑麦杂交种中的表达情况。在所有的杂交种中,黑麦花梗上的茸毛性状表现都很明显。在硬粒小麦×黑麦的杂交种中,叶片呈深绿色的性状与黑麦相似,而这一性状在普通小麦×黑麦的杂种中只是部分地表达。黑麦的叶耳不具茸毛,在多数硬粒小麦×黑麦的杂交中也没有;但是,在普通小麦×黑麦的杂种中则不然。由此表明,这些性状的有无常常受小麦D染色体组的控制,而不是由A或B染色体组控制。多数蛋白质含量较低的杂种,其叶鞘上具有很厚的粉霜,基部没有未发育小穗,这些特征与黑麦相似。同样,绝大多数双单倍体的子叶鞘、茎和茎节的花色素也与黑麦的相似。小麦中,存在着由A或B染色体组控制的一些限制因子,表明有些小麦基因型表达了黑麦性状,例如很厚的蜡被、茎节上的花色素以及基部没有未发育小穗。杂种颖片中脉上的刚毛密度和长度提高,可能是因为小麦与黑麦相互作用的结果。如同黑麦一样,小花和小穗数减少,说明在不同的小麦遗传背景下其特性表达程度不同。部分黑麦基因的表达可能还受着黑麦基因与小麦细胞质互作或与环境互作的影响。

催化气候条件下抗结核药物固定剂量复合剂的物理与化学稳定性

目的:检测印度市场销售的抗结核药物固定剂量复合剂(FDC)中的利福平、异烟肼、吡嗪酰胺及乙胺丁醇的物理及化学稳定性。方法:包装或散装药品储存于有光照或避光的ICH/WHO催化条件下(40℃/75%相对湿度)3个月。结果:RMP、INH、PZA的初始含量界于标注剂量的90-110%之间。然而,药品的某些化学特性甚至在观察刚开始时就不稳定。有一种片剂还存在物理性质的不稳定。在催化条件下,散装产品性状改变严重,包装制剂也有物理及化学性状的变化,光照条件下物理改变更为明显。PZA或许还有EMB可促进INH与RMP间的相互作用,这是一项有意义的发现。结论:本研究提示非坚固包装的抗结核药物FDC性状不稳定,应对抗结核药物FDC的药剂发展、包装以及稳定性检测试验予以关注。

发展中国家筛查结核病接触者合适吗?1996-1998年尼泊尔东部地区的经验

背景:此项结核病研究是由一家非政府组织在尼泊尔东部8个丘陵及山区地区实施的。 目的:评价筛查接触者对病例发现的作用。 设计:对1996-1998年诊断并登记的“首登病例”(index cases),即涂片阳性、涂片阴性和肺外结核病例的接触者进行回顾性队列研究。首登病例的家庭成员为接触者,接触者经痰检筛查,2份痰涂片阳性者确定为涂阳肺结核病例。 结果:大约从50％(668)的登记病人中确定接触者;在确定的接触者中75％(2298)送检1个或以上的痰标本。从接触者中共筛查出14例(0.61％)涂阳肺结核病例,除1例外,13例涂阳肺结核病人都是从涂阳肺结核首登病例的接触者中检出的。从涂阳菌量≥2+的首登病例接触者中检出的涂阳肺结核病人是涂阳菌量1+者的7.2倍(P=0.04)。 讨论:在这样的背景下,从涂阴肺结核或肺外结核病人的家庭接触者中用痰检筛查是不合适的。为了评价筛查没有症状的涂阳肺结核病例接触者的实用性以及通过筛查痰菌量大(≥2+)病例的接触者是否可以改善费用效益,有必要进一步的评估。

Metrology for sub-Rayleigh-length target positioning in~10^(22)W/cm^(2)laser-plasma experiments

Tight focusing with very small f-numbers is necessary to achieve the highest at-focus irradiances.However,tight focusing imposes strong demands on precise target positioning in-focus to achieve the highest on-target irradiance We describe several near-infrared,visible,ultraviolet and soft and hard X-ray diagnostics employed in a~10^(22)W/cm^(2)laser±plasma experiment.We used nearly 10 J total energy femtosecond laser pulses focused into an approximately1.3-μm focal spot on 5±20μm thick stainless-steel targets.We discuss the applicability of these diagnostics to determine the best in-focus target position with approximately 5μm accuracy(i.e.,around half of the short Rayleigh length)and show that several diagnostics(in particular,3ωreflection and on-axis hard X-rays)can ensure this accuracy.We demonstrated target positioning within several micrometers from the focus,ensuring over 80%of the ideal peak laser intensity on-target.Our approach is relatively fast(it requires 10±20 laser shots)and does not rely on the coincidence of low-power and high-power focal planes.

Computational simulations of near-continuum gas flow using Navier-Stokes-Fourier equations with slip and jump conditions based on the modal discontinuous Galerkin method

Blunt-body configurations are the most common geometries adopted for non-lifting re-entry vehicles.Hypersonic re-entry vehicles experience different flow regimes during flight due to drastic changes in atmospheric density.The conventional Navier-Stokes-Fourier equations with no-slip and no-jump boundary conditions may not provide accurate information regarding the aerothermodynamic properties of blunt-bodies in flow regimes away from the continuum.In addition,direct simulation Monte Carlo method requires significant computational resources to analyze the near-continuum flow regime.To overcome these shortcomings,the Navier-Stokes-Fourier equations with slip and jump conditions were numerically solved.A mixed-type modal discontinuous Galerkin method was employed to achieve the appropriate numerical accuracy.The computational simulations were conducted for different blunt-body configurations with varying freestream Mach and Knudsen numbers.The results show that the drag coefficient decreases with an increased Mach number,while the heat flux coefficient increases.On the other hand,both the drag and heat flux coefficients increase with a larger Knudsen number.Moreover,for an Apollo-like blunt-body configuration,as the flow enters into non-continuum regimes,there are considerable losses in the lift-to-drag ratio and stability.

New Exact Solutions for the Wick-Type Stochastic Kudryashov–Sinelshchikov Equation

In this article, exact solutions of Wick-type stochastic Kudryashov–Sinelshchikov equation have been obtained by using improved Sub-equation method. We have used Hermite transform for transforming the Wick-type stochastic Kudryashov–Sinelshchikov equation to deterministic partial differential equation. Also we have applied inverse Hermite transform for obtaining a set of stochastic solutions in the white noise space.