基于热工水力分析确定LOCA破口尺寸及CDF定量化

论文以30万千瓦压水堆核电机组为对象,基于热工水力分析确定了大、中、小LOCA的破口尺寸范围,并根据尺寸范围确定LOCA始发频率。与概率安全评价(PSA)常用的NUREG/CR-6928通用数据相比较,小LOCA破口尺寸范围更宽因而始发频率更高,中LOCA的下限尺寸更大故始发频率更低,大LOCA则与通用数据接近。通过事件树对堆芯损伤频率(CDF)进行定量化分析。结果表明,与直接采用通用数据的始发频率相比较,LOCA的CDF降低明显。基于热工水力分析确定LOCA破口尺寸及CDF定量化可更现实的评估LOCA风险。     

水介质O形圈密封阻力研究

为了研究水介质O形圈的密封阻力特性，通过ANSYS软件建立O形圈二维轴对称有限元模型，分析不同预压缩率和流体压力对O形圈密封性能的影响，通过2种滑动摩擦力理论算法，计算出不同流体压力下O形圈的摩擦力，与实验测量的摩擦力进行对比分析，探究流体压力和往复速度对摩擦力与摩擦因数的影响。结果表明：随着预压缩率增大，O形圈von Mises应力和接触长度增大；随着流体压力的增大，O形圈von Mises应力增大，接触压力和接触长度随之增大，流体压力超过30 MPa,接触长度减小；微元法和实验得到的摩擦力较为接近，可用于O形圈摩擦力预估；相同往复速度下，随着流体压力增大，O形圈摩擦力增大；相同流体压力下，随着往复速度增大，摩擦力也增大。     

Stepwise Crystallization of Millimeter Scale Thorium Cluster Single Crystals as a Bifunctional Platform for X-ray Detection and Shielding

Monitoring and shielding of X-ray radiation are of paramount importance across diverse fields. However, they are frequently realized in separate protocols and a single material integrating both functions remained elusive. Herein, a hexanuclear cluster [Th₆(µ₃-OH)₄(µ₃-O)₄(H₂O)₆](pba)₆(HCOO)₆ ( Th-pba-0D ) incorporating high-Z thorium cations and 3-(pyridin-4-yl)benzoate ligands that can function as a brand-new dual-module platform for visible detection and efficient shielding of ionizing radiation is demonstrated. Th-pba-0D exhibits rather unique reversible radiochromism upon alternating X-ray and UV irradiation. Moreover, the millimeter scale crystal size of Th-pba-0D renders the penetration depth of X-ray visible to naked eye and leads to the unearthing of its high X-ray attenuation efficiency. Indeed, the shielding efficacy of Th-pba-0D is comparable to that of lead glass containing 40% PbO, and a Th-pba-0D pellet with a thickness of merely 1.2 mm can shield 99.73% X-ray (16 keV). These studies portend the possible utilization of thorium-bearing materials as a bifunctional platform for radiation detection and shielding.     

Zebrafish as model organisms for toxicological evaluations in the field of food science

Food safety has long been an area of concern. The selection of stable and efficient model organisms is particularly important for food toxicology studies. Zebrafish (Danio rerio) are small model vertebrates, and 70% of human genes have at least one zebrafish ortholog. Zebrafish have advantages as model organisms due to their short life cycle, strong reproductive ability, easy rearing, and low cost. Zebrafish embryos have the advantage of being sensitive to the breeding environment and thus have been used as biosensors. Zebrafish and their embryos have been widely used for food toxicology assessments. This review provides a systematic and comprehensive summary of food toxicology studies using zebrafish as model organisms. First, we briefly introduce the multidimensional mechanisms and structure–activity relationship studies of food toxicological assessment. Second, we categorize these studies according to eight types of hazards in foods, including mycotoxins, pesticides, antibiotics, heavy metals, endocrine disruptors, food additives, nanoparticles, and other food-related ingredients. Finally, we list the applications of zebrafish in food toxicology studies in line with future research prospects, aiming to provide a valuable reference for researchers in the field of food science.     

Achieving Stable Lithium Metal Anode at 50 mA cm−2 Current Density by LiCl Enriched SEI

Lithium metal batteries are intensively studied due to the potential to bring up breakthroughs in high energy density devices. However, the inevitable growth of dendrites will cause the rapid failure of battery especially under high current density. Herein, the utilization of tetrachloroethylene (C₂Cl₄) is reported as the electrolyte additive to induce the formation of the LiCl-rich solid electrolyte interphase (SEI). Because of the lower Li ion diffusion barrier of LiCl, such SEI layer can supply sufficient pathway for rapid Li ion transport, alleviate the concentration polarization at the interface and inhibit the growth of Li dendrites. Meanwhile, the C₂Cl₄ can be continuously replenished during the cycle to ensure the stability of the SEI layer. With the aid of C₂Cl₄-based electrolyte, the Li metal electrodes can maintain stable for >300 h under high current density of 50 mA cm⁻² with areal capacity of 5 mAh cm⁻², broadening the compatibility of lithium metal anode toward practical application scenarios.     

三芯随动式水基比例阀位置跟随特性

高压大流量水基比例方向阀是煤矿液压支架实现智能化的核心控制元件，关系到整个工作面的精准控制效果和支护安全性。提出一种新型三芯随动式水基比例阀，解决现有水基比例阀难以满足液压支架高压大流量工况及难控制的问题。通过理论分析、AMESim建模仿真及试验对比的综合分析方法，验证三芯随动原理的可行性，探索该阀的位置跟随特性。结果表明：新型水基比例阀具备快速响应能力，额定工作条件下的全行程阶跃响应开启时间为84 ms，关闭时间约为35 ms；斜坡连续控制时，摩擦效应导致三芯随动机构位置跟随效果不佳，小阶跃步进控制能较好克服摩擦效应，使比例阀展示良好的位置跟随特性。研究成果为液压支架高压大流量水基比例阀设计提供参考，同时丰富了水基比例阀类型。     

不同加热条件对ω-3鸡蛋中脂肪酸含量的影响

ω-3脂肪酸因其含有较多的不饱和双键而表现出不稳定性,在储存和加工过程中易被氧化.ω-3鸡蛋是一种新型的营养强化食物,以鸡蛋为载体,将ω-3脂肪酸进行营养强化,研究旨在探究ω-3鸡蛋中脂肪酸在加热条件下的变化情况,为ω-3鸡蛋的烹饪加工和食用提供参考.分别以ω-3鸡蛋的带壳鸡蛋和全蛋液为实验对象,将鸡蛋加工成为温泉蛋、...     

浙江温黄平原典型河流水质改善方案研究

选取台州市东官河作为浙江温黄平原典型河流的代表,构建MIKE11河网水环境数学模型,基于水量、水质同步实测数据对模型进行率定验证。为保证东官河控制断面水质达标,综合考虑水文条件、污染物削减和引水3个方面因素,提出了9套研究区域模型计算方案。结果表明,近期区域内污染物削减60%,控制长潭水库调水量为2 000万m3时,东官河水质可达Ⅳ类;远期区域内污染物削减90%时,东官河水质基本可达Ⅲ类即功能区水质目标。本研究旨在为东官河水环境综合整治提供技术支撑。