分类： 化学 >> 核化学 提交时间： 2024-07-22
摘要： 在核燃料循环后段中，锝对高放废液的玻璃固化以及高放废物的地质处置有较大的影响，因此有必要在乏燃料后处理过程中将锝提取出来，以消除其不利影响。本工作提出了以NTAamide(C8)作为萃取剂从后处理硝酸介质中提取锝的优化工艺流程。基于NTAamide(C8)萃取锝、碳酸铵反萃锝以及草酸洗涤杂质离子的原理，设计了从后处理尾液中提取、纯化锝的工艺流程，通过串级萃取工艺实验进行了初步验证。结果表明，锝的回收率为99.9%，锝中除锶、铯、锆、钌的净化系数分别达到6.9×103、7.9×104、4.3×102、45。
分类： 化学 >> 核化学 提交时间： 2024-07-11
摘要： 医用放射性核素99mTc广泛应用于SPECT显像，其主要来源于母核99Mo衰变。占全球99Mo供应量90%的五座反应堆将陆续停堆，99Mo面临不能稳定供应的情况，使用质子加速器照射100Mo靶生产99Mo和99mTc成为重要的补充手段。一些科研人员使用蒙特卡罗软件FLUKA模拟计算放射性核素的产额并发现计算结果与实验测量结果存在差异。为检验FLUKA能否正确模拟质子照射100Mo靶生成99Mo和99mTc，本文计算了FLUKA所使用的激活函数并与多个数据库及核反应程序TALYS计算结果相比较，提出了一种结合FLUKA和其它数据库激活函数计算产额的方法，使用不同的激活函数计算了质子照射100Mo靶并冷却一段时间后99Mo和99mTc的产额。结果表明FLUKA计算99Mo产额偏小，约为使用TENDL2023激活函数计算结果的59%-67%；99mTc产额偏大，约为使用TENDL2023激活函数计算结果的245%-260%。差异来源于FLUKA的质子-核反应截面与其它数据库存在较大区别且FLUKA无法正确处理不同激发态核素的产生。
分类： 化学 >> 核化学 提交时间： 2024-07-08
摘要： 塑料闪烁微球（PSm）是一种新型闪烁材料，在放射性核素测量领域显示出良好的应用前景。本研究利用Hidex 300SL液闪计数器，研究了不同测量条件对PSm的本底计数率和计数效率的影响及其规律。结果表明，PSm与水混合后产生弱化学发光和光致发光干扰信号，可通过避光措施消除。随着PSm用量的增加，背景计数率呈正相关增加；随着PSm高度的增加，计数效率呈正相关提高。此外，液闪瓶材质对PSm测量的影响较小，其中使用20 mL的塑料液闪瓶的最小检测活度（MDA）最低。对比活度为574.5~3825.6 Bq·L-1的14C溶液进行测量，测量值与期望值一致性良好。研究结果表明，尽管PSm的本底计数率和计数效率受到多种因素影响，但在固定测量条件下，PSm测量具有良好的准确性。
分类： 化学 >> 核化学 提交时间： 2024-06-18
摘要： 质子治疗作为一种先进的放射治疗技术，因其精准的剂量分布和对周围正常组织的最小化损伤而受到重视。然而，质子束的精确剂量测量是确保治疗效果和安全性的关键。光纤剂量计因其独特的优势，如高空间分辨率、实时监测能力、水等效性和抗电磁干扰能力，成为质子治疗剂量学研究的热点。基于此，本文综述了光纤剂量计在质子治疗剂量测定中的技术原理、应用现状、发展挑战和未来趋势，首先，本文概述了光纤剂量计的发光机制，并对它们的工作原理进行了介绍。接着，本文讨论了基于不同发光机制的光纤剂量计在临床质子治疗中的实用性，对高剂量率适应性和准确性。同时，论文也指出了当前光纤剂量计技术面临的挑战及解决方案，如应用闪烁淬灭矫正、提高时间响应性、优化数据采集系统和增强对干扰因素的校正能力。最后，本文展望了光纤剂量计技术的发展前景，特别是在超高剂量率治疗如Flash治疗中的应用潜力，以及如何通过材料科学和光电技术的创新来克服现有限制。通过本综述，旨在为研究人员和临床医生提供一个全面的视角，以提高质子治疗的精确性和治疗效果。
分类： 化学 >> 核化学 提交时间： 2024-06-12
摘要： 背景 Ir-192近距治疗源是一种高剂量率γ射线放射源，其具有中心剂量率高且边缘剂量迅速下降的特性。在临床治疗过程中，这种剂量分布特性使得Ir-192放射源能够有效地保护肿瘤周围的正常组织和器官。目的 参考美国医学物理师协会（AAPM）在TG43-U1中推荐的Ir-192源的剂量学参数，基于蒙特卡罗模拟软件，建立国产高剂量率近距离治疗Ir-192放射源的精细结构模型，进行模拟计算。方法 使用蒙特卡罗软件建立国产高剂量率近距离治疗Ir-192放射源的精细结构模型，模拟计算剂量学参数，其中包括：剂量率常数Λ、单位活度空气比释动能强度、径向剂量函数以及各向异性函数。结果 模拟计算得到的剂量率常数为1.105 cGy·h-1·U-1，与文献报告的差异在1.2%以内；单位活度空气比释动能率为9.788×10-8 UBq-1，与文献报道结果的差异为0.23%。在放射源中垂线0.5至20厘米范围内得到了径向剂量函数，并拟合得到经验公式。结论 基于蒙特卡罗软件建立的国产Ir-192放射源模型，在剂量学参数上与文献报告的数据具有较好一致性，表明该模型可以用于国产Ir-192源的临床实践应用，具有一定的指导意义。
分类： 化学 >> 核化学 提交时间： 2024-06-07
摘要： 背景 Ir-192近距治疗源是一种高剂量率γ射线放射源，其具有中心剂量率高且边缘剂量迅速下降的特性。在临床治疗过程中，这种剂量分布特性使得Ir-192放射源能够有效地保护肿瘤周围的正常组织和器官。目的 参考美国医学物理师协会（AAPM）在TG43-U1中推荐的Ir-192源的剂量学参数，基于蒙特卡罗模拟软件，建立国产高剂量率近距离治疗Ir-192放射源的精细结构模型，进行模拟计算。方法 使用蒙特卡罗软件建立国产高剂量率近距离治疗Ir-192放射源的精细结构模型，模拟计算剂量学参数，其中包括：剂量率常数Λ、单位活度空气比释动能强度、径向剂量函数以及各向异性函数。结果 模拟计算得到的剂量率常数为1.105 cGy·h-1·U-1，与文献报告的差异在1.2%以内；单位活度空气比释动能率为9.788×10-8 UBq-1，与文献报道结果的差异为0.23%。在放射源中垂线0.5至20厘米范围内得到了径向剂量函数，并拟合得到经验公式。结论 基于蒙特卡罗软件建立的国产Ir-192放射源模型，在剂量学参数上与文献报告的数据具有较好一致性，表明该模型可以用于国产Ir-192源的临床实践应用，具有一定的指导意义。
分类： 化学 >> 核化学 提交时间： 2024-05-02
摘要： 背景：人表皮生长因子受体2(HER2)广泛存在于多种恶性肿瘤，且与预后不良有关。尤其在乳腺癌中，但HER2表达存在异质性，目前常用免疫组织化学和荧光原位杂交在评估HER2状态存在明显局限性。HER2受体显像有明显优势。放射性标记的模拟肽是检测HER2阳性病变的潜在选择。目的：制备一种18F标记的人表皮生长因子受体２（HER2）模拟肽显像剂18F-NFP-B2-S22-AFA（以下简称为18F-NFP-TP1296），探讨其microPET显像及生物分布。方法 采用一步法标记18F-NFP-TP1296被应用于HER2乳腺癌异种移植小鼠的PET-CT成像。在SKBR-3乳腺癌模型中进行了体外研究和MicroPET成像。结果18F-NFP-TP1296制备过程大约30分钟内完成，总标记率为1.5%，放化纯＞95%。MicroPET成像显示，SKBR-3异种肿瘤清晰可见，注射30、60和120min后，SKBR-3移植瘤摄取值分别为5.63±0.14%ID/g、6.26±0.27%ID/g和5.83±0.44%ID/g。30、60和120min肿瘤与血液和肿瘤与肌肉的比率分别为3.21±0.32、4.08±0.73和1.69±0.18；1.55±0.11、1.84±0.12和3.10±0.30。另外肺转移瘤注射后30、60和120min肿瘤的摄取值2.2%ID/g、2.5%ID/g及2.1%ID/g。结论：18F-NFP-B2-S22-AFA具有合成简便、药代动力学良好等优点，有望成为体内检测HER2状态的示踪剂，对肿瘤的鉴别诊断、分子靶向治疗及预后判断有一定的参考价值。
分类： 生物学 >> 生物物理学 分类： 化学 >> 物理化学 分类： 生物学 >> 生物物理学 提交时间： 2024-04-16
摘要： Transcription factor (TF) are proteins that regulates the transcription of genetic information from DNA to messenger RNA by binding to a specific DNA sequence.Nucleic acid-protein interactions are crucial in regulating transcription in biological systems. This work presents a quick and convenient method for constructing tight-binding models and offers physical insights into the electronic structure properties of transcription factor complexes and DNA motifs. The tight binding Hamiltonian parameters are generated using the random forest regression algorithm, which reproduces the given ab-initiolevel calculations with reasonable accuracy. We present a library of residue-level parameters derived from extensive electronic structure calculations over various possible combinations of nucleobases and amino acid side chains from high-quality DNA-protein complex structures. As an example, our approach can reasonably generate the subtle electronic structure details for the orthologous transcription factors human AP-1 and Epstein-Barr virus Zta within a few seconds on a laptop. This method potentially enhances our understanding of the electronic structure variationsof gene-protein interaction complexes, even those involving dozens of proteins and genes. We hope this study offers a powerful tool for analyzing transcription regulation mechanisms at an electronic structural level.
分类： 化学 >> 核化学 提交时间： 2024-04-09
摘要： 近年来，在核医学科建设加速发展过程中，含碘-131放射性废水暂存时间、衰变池建设等成为医院、环评机构、生态环境监管部门等十分关心的问题。《电离辐射防护与辐射源安全基本标准》（GB 18871）、《核医学辐射防护与安全要求》（HJ 1188）、《关于核医学标准相关条款咨询问题的回函》规定了衰变池中放射性废水（主要核素为碘-131）的合规排放方式。本文通过理论推导，给出了在满负荷情况下、衰变池存满时碘-131活度的理论计算公式；证明了含碘-131放射性废水三种合规的排放方式中，按GB 18871规定的排放方式排放对医院核医学科运营最为有利；提出了RJ方程组，解决了含碘-131放射性废水最小暂存时间和衰变池容量应如何确定的问题。4家医院的实际监测数据结果表明，含碘-131放射性废水暂存时间达到RJ方程组计算出的最小暂存时间后，总的碘-131排放量符合国家生态环境标准要求。以上可对医院核医学科衰变池建设、废水排放管理以及监管部门的监督检查提供明确、具体的指导。
分类： 化学 >> 应用化学 提交时间： 2024-01-23
摘要： 针对传统的配方设计方法繁琐费时、物料损耗多、优化效果差的缺陷，将拉丁超立方设计（LHD）算法与多层感知器（MLP）神经网络相结合，形成铝合金清洗剂配方优化的新方法。利用LHD算法全面探索参数空间和 MLP 神经网络的高效建模能力，成功优化了铝合金清洗剂配方。经过优化的配方，净洗力从 87.9 %，提升到 98.24 %，腐蚀量从 4.2 mg，下降到0.3 mg。对模型预测数据与实验数据进行回归直线拟合后，大于 0.98，证明预测与实验数据保持一致性。
分类： 化学 >> 化学物理学 提交时间： 2023-12-09
摘要： Based on the energy conversion of the dynamic electric effect from the solid/liquid contact double electric layer is the dynamic electromotive potential, this paper studies the static appearance and the release of the electric field energy of the solid/liquid contact double electric layer, so a special capacitor (P/L/N capacitor) of solid conductor P / polar liquid L / solid conductor N is constructed. The observations based on experiments are as follows: (i) the contact double electric layer derived from the internal potential difference polarization of the solid conductor / polar liquid is equivalent to the external electric field polarization of the ordinary capacitor. The formation process of the contact double electric layer is the spontaneous charging process of the P/L/N capacitor, and the P/L/N capacitor still shows the electric field energy of the contact double electric layer. (ii) Because the polarized external potential difference of the solid conductor / polar liquid contacting the double electric layer is always less than the internal potential difference, the short-circuit P/L/N capacitor also has a continuous electromotive force after the discharge, statically releasing the electric field energy contacting the double electric layer. (iii) The contact double electric layer of solid conductor / polar liquid is produced spontaneously caused by mutual contact, and it is also a self-organizing process of absorbing the environmental heat energy into the electric field energy of the contact double electric layer. P/L/N capacitors realize thermoelectric conversion by releasing the electric field energy of the contact double electric layer. The above-mentioned phenomenon provides the possibility for the development of self-generated capacitors and self-supplied power supply.
分类： 化学 >> 核化学 提交时间： 2023-06-13
摘要： Objective: We herein fabricated a branched structure containing AO groups on polypropylene/polyethylene spun-laced nonwoven (PP/PE SNW) fibers using grafting polymerization induced by radiation (RIGP) to improve AO utilization. Methods: The chemical structures, thermal properties, and surface morphologies of the raw and treated PP/PE SNW fibers were studied. The adsorption properties were investigated using batch adsorption experiments in simulated seawater with an initial uranium concentration of 500 gL-1 (pH 4, 25℃). Results: The maximum adsorption capacity of the adsorbent material was 137.3 mgg-1 within 24 h; moreover, the uranyl removal reached 96% within 240 min. Limitations: Only simulated seawater adsorption experiments have been conducted, and real seawater adsorption experiments are yet to be conducted. Conclusions: The adsorbent had an AO utilization rate of 1/3.5 and was stable over a pH range of 410, with good selectivity and reusability, demonstrating its potential for seawater uranium extraction.
分类： 化学 >> 核化学 提交时间： 2023-06-06
Zhang, Hang
Ao, Yin-Yong
Wang, Yue
Zhao, Shang-Jie
Sun, Jia-Yang
Zhai, Mao-Lin
Li, Jiu-Qiang
Peng, Jing
Li, Hui-Bo
摘要： N,N,N,N-Tetraoctyl diglycolamide (TODGA) is one of the most promising extractants tailored for high-level liquid radioactive waste treatment during nuclear fuel reprocessing. The -radiolysis of TODGA (0.2 mol/L) in n-dodecane (nDD) solution with and without pre-equilibrated 3.0 mol/L HNO3 was investigated using HPLC and UPLC-QTOF-MS and compared with the -radiolysis of neat TODGA in this study. With increased absorbed doses, the concentration of TODGA decreased exponentially for the studied systems. Moreover, pre-equilibration with HNO3 (3.0 mol/L) slightly influenced the -radiolysis of TODGA in nDD. Seven radiolytic products generated from the rupture of the C C, C O, and C N bonds in TODGA were identified in the studied extraction system. The influence of -radiation on TODGA/nDD for the extraction of Eu(III) was evaluated using the first combination of extraction experiments and density functional theory (DFT) calculations, in which the complexations of Eu(III) with TODGA and its radiolytic products were systematically compared. Based on the radiolysis kinetic model of TODGA, the slope curve of the distribution ratio of Eu(III) (DEu ) and the absorbed dose, and fluorescence titration analysis, the empirical equation of the absorbed dose and DEu was obtained successfully. Below 300 kGy, the experimental DEu agreed well with the obtained empirical equation for TODGA/nDD. Conversely, at a high absorbed dose, the experimental DEu was higher than the theoretical DEu based on the empirical equation because the radiolytic products of TODGA with similar coordination structures still possessed partial complexation toward Eu(III), which was confirmed by DFT calculations. This work provides a method to predict the extraction distribution ratio of an irradiated extractant system and to understand the complex extraction process.
分类： 化学 >> 核化学 提交时间： 2023-05-31
摘要： The rapid development of advanced techniques for selective and efficient U(VI) extraction from aqueous solutions is essential for addressing U(VI) environmental pollution and energy issues. Here, we share recent progress in U(VI) extraction from aqueous solutions, especially the most frequently applied techniques such as adsorption, catalysis (photocatalysis, piezocatalysis, and electrocatalysis), chemical deposition, and reduction by zero-valent metal particles. We attempt toelucidate the strategies and various mechanisms that contribute to the enhancement of selective U(VI) extraction. At the end of our review, we highlight the outlook, challenges, and prospects for the development of this field.
分类： 生物学 >> 生物物理学 分类： 材料科学 >> 生物材料 分类： 化学 >> 化学生物学 分类： 医学、药学 >> 基础医学 提交时间： 2023-02-09
摘要： Nanotechnology has provided considerable promise for the biological and medical fields, especially in the subjects of biological and medical imaging for the last two decades. Here, we outline different nanoparticles to contribute to biological and medical imaging disciplines. These concerned nanoparticles are soft nanoparticles, which are based on biomacromolecule/polymer or organic molecule components, hard nanoparticles that are derived from various inorganic components and hard-soft nanoparticles that are based on both inorganic components and biomacromolecule/polymer or organic molecule ones. We also discuss the imaging modalities in biology and medicine that various nanoparticles became involved in are: (1) optical imaging (OI), (2) computed tomography (CT), (3) magnetic resonance imaging (MRI), (4) ultrasonography (USG), (5) positron emission tomography (PET). We will also describe various nanoparticles to serve for one/some of those five modalities in biology and medicine imaging in this review paper.
分类： 化学 >> 应用化学 提交时间： 2020-03-05
摘要： [目的] 微波辅助合成具有潜在神经保护作用的梓醇全丙酰化产物（CP-6）。 [方法] 以梓醇、丙酰酐为原料，吡啶为溶剂和缚酸剂，微波辅助合成梓醇全丙酰化衍生物。CP-6经FT-IR、HRMS、NMR表征，采用MTT法筛查其神经保护活性。 [结果] 当丙酸酐与梓醇摩尔比为18，微波反应器反应温度 80 ℃，反应时间6 h, 梓醇在吡啶中浓度 25 g/L时梓醇全丙酰化产物产率可达98.51%。CP-6具有潜在的神经保护活性。 [结论] CP-6可经微波合成制得，其具有神经保护作用，是一种潜在的神经保护作用药物。
分类： 化学 >> 化学物理学 提交时间： 2018-11-28
Taixiang Liu
Ke Yang
Zhuo Zhang
Lianghong Yan
Beicong Huang
Heyang Li
Chuanchao Zhang
Xiaodong Jiang
Hongwei Yan
摘要： Large-scale, high-power laser facility is currently a basis for the research of inertial confinement fusion (ICF). In the laser facility, fused silica optics plays irreplaceable role to conduct extremely high-intensity ultraviolet laser to fusion target. However, the surface fractures, such as surface pit, crack, scratch, and laser damage site, of the optics will lower the beam quality of transmitted laser, weaken the laser damage-resistance, shorten the lifetime of the optics, and thus limit the output performance of the laser facility. In this work, to mitigate the surface fractures, hydrofluoric acid-based (HF-based) etching effect on the surface fractures is experimentally and theoretically studied. From the experimental study, with the result of three-dimensional (3D) morphological evolution of surface fractures, it is shown that the surface fractures will be passivated and their profiles will get smoothed after etching, indicating HF-based etching is a promising way to improve the local surface quality of the fractures. Especially, it is found HF-based etching can greatly suppress the laser damage growth of laser damage site by mitigating its surface and subsurface fractures, and thus is a promising wet chemical method for repairing laser-induced damage optics. In the theoretical study, an explicit local-curvature dependent etching model is proposed. Based on this model, the result from finite difference time domain (FDTD) simulation agrees very well with that of experiment, which can reveal the detailed physical process of HF-based etching. It is demonstrated that the FDTD simulation can be a reliable and efficient way to predict the morphological evolution of the surface fractures during etching.
分类： 化学 >> 无机化学 提交时间： 2018-10-04
Chao, Zhao
Can, Xiong
Man, Qiao
Tongwei, Yuan
Jing, Wang
Yunteng, Qu
XiaoQian, Wang
Fangyao, Zhou
Zhijun, Li
Qian, Xu
Shiqi, Wang
Min, Chen
Wenyu, Wang
Yafei, Li
Yuen, Wu
Yadong, Li
摘要： 在这里，我们报告了一种高温气体迁移策略来制备多相的单原子铁催化剂，并展示其优良的类天然酶的活性（定义为单原子酶，SAE）。 结果表明，Fe SAE的局部定义明确的FeN4位点与含血红素的天然酶的活性金属中心高度相似。 Fe SAE表现出超级高的类过氧化物酶，氧化酶和过氧化氢酶的活性，超过了Fe3O4纳米酶40倍。更重要的是，Fe SAE可以有效活化过氧化氢（H2O2）产生羟基自由基（•OH）。 这使得其可以作为一种多相化的类Fenton系统，可以应对不断增加的环境污染。 我们的研究结果开辟了一个新的人造材料家族-模仿天然
分类： 物理学 >> 原子与分子物理学 分类： 化学 >> 化学物理学 提交时间： 2018-05-19
摘要： 见英文摘要
分类： 化学 >> 物理化学 提交时间： 2017-11-05 合作期刊: 《结构化学》
摘要： In order to enhance water-solubility and biological utilization rate of tectochrysin, sodium 5-hydroxyl-7-methoxyflavone-6-sulfonate (1) was synthesized and its structure was identified on the basis of 1H NMR, FT-IR and elemental analysis. 5-Hydroxyl-7-methoxyflavone-6-sulfonate was assembled with Ni(II) or Mn(II), hexaquanickel(II) bis(5-hydroxyl-7-methoxyflavone-6-sulfonate) tetrahydrate (2) and hexaquamanganese(II) bis(5-hydroxyl-7-methoxyflavone-6-sulfonate) tetrahydrate (3) were obtained and characterized by IR spectroscopy. The crystal structures of 2 and 3 were determined by X-ray single-crystal diffraction analysis. The results showed that 2 and 3 are isomorphous crystals and crystallize in monoclinic crystal system, space group C2/c. In 2 and 3, the supramolecular structures are organized into hydrophilic and hydrophobic regions. Hydrophilic regions are generated by O–H×××O hydrogen bonds among sulfonate groups, latticed water molecules and coordinated water molecules. The π-π stacking interactions assemble the flavone skeletons into columns and these columns form hydrophobic regions. The sulfonate groups play an important role as a bridge of the hydrophilic and hydrophobic regions as well as the inorganic and organic components. Three-dimensional networks of 2 and 3 are furnished by extensive array of hydrogen bonds, π-π stacking interactions and electrostatic interactions. The anti-proliferative activities of 1～3 in vitro against human leukemia cells K562 and human lung cancer cells A549 were evaluated by the standard MTT assay. The pharmacological activity results showed that the introduction of sulfonic acid groups enhanced the antitumor activity of tectochrysin.
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