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Numerical analysis of the activity of irradiated alloy-N in an FHR

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Nuclear Science and Techniques 2016年第2期27卷 149-154页

作者： Chao Peng Xing-Wang Zhu Guo-Qing Zhang zhao-zhong he Kun Chen Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China University of Chinese Academy of Sciences Beijing 100049China

The fluoride salt-cooled high-temperature reactor(FHR) uses molten FLi Be salt as the coolant, which introduces a corrosive effect on the alloy-N structure material. Fission neutrons activate the corroded alloy-N,along with alloy-N structures inside the reactor vessel. The activation products of the alloy-N have a big impact on radiation protection during operation, maintenance, and decommissioning of the reactor. We have constructed a SCALE 6.1 model for the core of a typical 10 MW th FHR and analyzed the activity of each constituent of the irradiated alloy-N. The results show that the activity is predominantly due to short-lived^(28) Al,^(60m) Co,^(56) Mn,^(51)Ti, and ^(52) V, as well as long-lived ^(60) Co,^(51)Cr,^(55)Fe,^(59)Fe, and ^(54) ***, because of their relatively long half-life and high-energy c-rays emissions,^(60) Co and ^(54)Mn are the major contributors to the radiation source terms introduced by alloy-N activation. The yield of ^(60)Co and ^(54)Mn per unit mass of alloy-N under the current core design is 5.58*10~5 and 1.55 * 10~3 Bq MWd^(-1)g^(-1), *** results of this paper, combined with future corrosion studies, may provide a basis for evaluating long-term radiation source terms of the primary loop salt and components.

关键词：数值分析反应堆容器辐照腐蚀作用辐射防护辐射源项反应堆退役结构材料

Nuclear apoptosis induced by isolated mitochondria

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Cell Research 2000年第3期10卷 221-232页

作者： JIANG ZheNG FAN, YUN zhao, XIA HONG, zhong he ZHAI (College of Life Sciences, Peking University, Beijing, 100871 China) College of Life Sciences Peking University Beijing China

We isolated and purified mitochondria from mouse livers and spinach leaves. When added into egg extracts of Xenopus laevis, they caused nuclei of mouse liver to undergo apoptotic changes. Chromatin condensation, margination and DNA ladder were observed. After incubating isolated mitochondria in some hypotonic solutions, and centrifuging these mixtures at high speed, we got mitochondrial supernatants. It was found that in the absence of cytosolic factor, the supernatant alone was able to induce apoptotic changes in nuclei. The effective components were partly of protein. DNA fragmentation was partly inhibited by caspase inhibitors AC-DEVD-CHO and AC- YVADCHO. Meanwhile, caspase inhibitors fully blocked chromatin condensation. Primary characterization of the nuclear endonuclease(s) induced by mitochondrial supernatants was also conducted. It was found that this endonuclease is different from endonuclease G, cytochrome c-induced nuclease, or Ca2+-activated endonuclease.

关键词： Mitochondria supernatant apoptosis egg ex- tract nuclei DNA cleavage.

Radionuclides in primary coolant of a fluoride salt-cooled hightemperature reactor during normal operation

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Nuclear Science and Techniques 2017年第3期28卷 109-114页

作者： Guo-Qing Zhang Shuai Wang Hai-Qing Zhang Xing-Wang Zhu Chao Peng Jun Cai zhao-zhong he Kun Chen Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China University of Chinese Academy of Sciences Beijing 100049China

The release of fission products from coated particle fuel to primary coolant, as well as the activation of coolant and impurities, were analysed for a fluoride saltcooled high-temperature reactor(FHR) system, and the activity of radionuclides accumulated in the coolant during normal operation was calculated. The release rate(release fraction per unit time) of fission products was calculated with STACY code, which is modelled mainly based on the Fick's law, while the activation of coolant and impurities was calculated with SCALE code. The accumulation of radionuclides in the coolant has been calculated with a simplified model, which is generally a time integration considering the generation and decay of radionuclides. The results show that activation products are the dominant gamma source in the primary coolant system during normal operation of the FHR while fission products become the dominant source after shutdown. In operation condition,health-impacts related nuclides such as ~3H, and ^(14)C originate from the activation of lithium and coolant impurities including carbon, nitrogen, and oxygen. According to the calculated effective cross sections of neutron activation,~6Li and ^(14)N are the dominant ~3H production source and ^(14)C production source, respectively. Considering the high production rate,~3H and ^(14)C should be treated before being released to the environment.

关键词： Source term FHR Primary coolant Fick’s law Diffusion

Data-driven Wasserstein distributionally robust chance-constrained optimization for crude oil scheduling under uncertainty

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Chinese Journal of Chemical Engineering 2024年第5期69卷 152-166页

作者： Xin Dai Liang zhao Renchu he Wenli Du Weimin zhong Zhi Li Feng Qian Key Laboratory of Smart Manufacturing in Energy Chemical Process Ministry of EducationEast China University of Science and TechnologyShanghai 200237China Engineering Research Center of Process System Engineering Ministry of EducationEast China University of Science and TechnologyShanghai 200237China

Crude oil scheduling optimization is an effective method to enhance the economic benefits of oil *** uncertainties,including uncertain demands of crude distillation units(CDUs),might make the production plans made by the traditional deterministic optimization models infeasible.A data-driven Wasserstein distributionally robust chance-constrained(WDRCC)optimization approach is proposed in this paper to deal with demand uncertainty in crude oil ***,a new deterministic crude oil scheduling optimization model is developed as the basis of this *** Wasserstein distance is then used to build ambiguity sets from historical data to describe the possible realizations of probability distributions of uncertain demands.A cross-validation method is advanced to choose suitable radii for these ambiguity *** deterministic model is reformulated as a WDRCC optimization model for crude oil scheduling to guarantee the demand constraints hold with a desired high probability even in the worst situation in ambiguity *** proposed WDRCC model is transferred into an equivalent conditional value-at-risk representation and further derived as a mixed-integer nonlinear programming *** case studies from a real-world refinery are conducted to show the effectiveness of the proposed ***-of-sample tests demonstrate that the solution of the WDRCC model is more robust than those of the deterministic model and the chance-constrained model.

关键词： Distributions Model Optimization Crude oil scheduling Wasserstein distance Distributionally robust chance constraints

Switchable shape memory polymer bio-inspired adhesive and its application for unmanned aerial vehicle landing

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Chinese Journal of Aeronautics 2024年第3期37卷 380-390页

作者： Qingsong he Zefang zhao Qiyun zhong Siyuan LIU Kai DENG Yongqi LIU Ning ZHANG Zijie zhao Fengjiang ZHAN Jianfeng zhao Jiangsu Provincial Key Laboratory of Bionic Functional Materials College of Mechanical and Electrical EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Advanced Technology for Small and Medium-Sized UAV Ministry of Industry and Information TechnologyUnmanned Aerial Vehicles Research InstituteNanjing University of Aeronautics and AstronauticsNanjing 210016China State Key Laboratory of Mechanics and Control of Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China Functional Morphology and Biomechanics Institute of ZoologyKiel UniversityKiel 24098Germany

Controlled and switchable adhesion is commonly observed in biological *** recent years,many scholars have focused on making switchable bio-inspired ***,making a bio-inspired adhesive with high adhesion performance and excellent dynamic switching properties is still a challenge.A Shape Memory Polymer Bio-inspired Adhesive(SMPBA)was successfully developed,well realizing high adhesion(about 337 kPa),relatively low preload(about90 kPa),high adhesion-to-preload ratio(about 3.74),high switching ratio(about 6.74),and easy detachment,which are attributed to the controlled modulus and contact area by regulating temperature and the Shape Memory Effect(SME).Furthermore,SMPBA exhibits adhesion strength of80–337 kPa on various surfaces(silicon,iron,and aluminum)with different roughness(Ra=0.021–10.280)because of the conformal contact,reflecting outstanding surface *** finite element analysis verifies the bending ability under different temperatures,while the adhesion model analyzes the influence of preload on contact area and ***,an Unmanned Aerial Vehicle(UAV)landing device with SMPBA was designed and manufactured to achieve UAV landing on and detaching from various *** study provides a novel switchable bio-inspired adhesive and UAV landing method.

关键词： Bio-inspired adhesive Shape memory polymers Switchable adhesive Unmanned aerial vehicle Landing

Mechanism of high-energy pulsed current-assisted rolling of 08AL carbon steel ultra-thin strip

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Journal of Iron and Steel Research International 2024年第2期31卷 416-427页

作者： zhong-kai Ren Ya-nan Xu Jia-zhao Chen he Li Rui-lin Yuan Zhen-hua Wang Tao Wang Xiao Liu College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan030024ShanxiChina Engineering Research Center of Advanced Metal Composites Forming Technology and Equipment(Ministry of Education) Taiyuan University of TechnologyTaiyuan030024ShanxiChina National Key Laboratory of Metal Forming Technology and heavy Equipment China National Heavy Machinery Research Institute Co.Ltd.Xi’an710016ShaanxiChina

To improve the plastic deformation performance of a 08AL carbon steel ultra-thin strip,a pulsed electric field was integrated into the plastic processing of the ultra-thin strip,and the effects of high-energy current on its deformation ability were ***-assisted tensile tests were employed,and the results clarified that the pulsed current could reduce the activation energy of faults and promoted dislocation slip within grains and at grain boundaries,leading to a decrease in the deformation resistance of the metal and an increase in its plastic *** the current density of 2.0 A/mm2,the yield strength,tensile strength,and elongation of the rolled sample reached 425 MPa,467 MPa,and 12.5%,*** the rolling process,it was found that the pulsed current promoted the dynamic recrystallization of the ultra-thin strip,reduced its dislocation density and deformation resistance,and promoted the coordinated deformation of the metal.

关键词： 08AL ultra-thin strip High-energy pulsed current Mechanical property Dislocation density Dynamic recrystallization

Embedded high-quality ternary GaAs_(1−x)Sb_(x) quantum dots in GaAs nanowires by molecular-beam epitaxy

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Journal of Semiconductors 2024年第8期45卷 18-24页

作者： Xiyu Hou Lianjun Wen Fengyue he Ran Zhuo Lei Liu Hailong Wang Qing zhong Dong Pan Jianhua zhao State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of SciencesBeijing 100049China

Semiconductor quantum dots are promising candidates for preparing high-performance single photon sources.A basic requirement for this application is realizing the controlled growth of high-quality semiconductor quantum ***,we report the growth of embedded GaAs_(1−x)Sb_(x) quantum dots in GaAs nanowires by molecular-beam *** is found that the size of the GaAs_(1−x)Sb_(x) quantum dot can be well-defined by the GaAs *** dispersive spectroscopy analyses show that the antimony content x can be up to 0.36 by tuning the growth *** GaAs_(1−x)Sb_(x) quantum dots exhibit a pure zinc-blende *** addition,we have developed a new technology to grow GaAs passivation layers on the sidewalls of the GaAs_(1−x)Sb_(x) quantum *** from the traditional growth process of the passivation layer,GaAs passivation layers can be grown simultaneously with the growth of the embedded GaAs_(1−x)Sb_(x) quantum *** spontaneous GaAs passivation layer shows a pure zinc-blende phase due to the strict epitaxial relationship between the quantum dot and the passivation *** successful fabrication of embedded high-quality GaAs_(1−x)Sb_(x) quantum dots lays the foundation for the realization of GaAs_(1−x)Sb_(x)-based single photon sources.

关键词： semiconductor quantum dot nanowire GaAs_(1−x)Sb_(x) molecular-beam epitaxy

Electrochemical oxidation of perfluoroalkyl and polyfluoroalkyl substances: Mechanisms, implications, and challenges

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Science China Technological Sciences 2024年第10期67卷 2972-2990页

作者： ZHOU XuDong zhong YaShi TIAN XiaoChun zhao Feng CAS Key Laboratory of Urban Pollutant Conversion Institute of Urban EnvironmentChinese Academy of Sciences University of Chinese Academy of Sciences College of Environment & Safety Engineering Fuzhou University

Perfluoroalkyl and polyfluoroalkyl substances(PFASs) have recently gained considerable attention due to their potential risks to human health and ecosystems. The response to these concerns has led to regulations and bans on legacy PFASs, such as perfluorooctanoic acid and perfluorooctane sulfonic acid. Thus, fluoride production has shifted toward short-chain PFASs and emerging fluorinated alternatives. Several technologies are available for PFAS degradation, among which electrochemical oxidation(EO) is a promising method to mineralize legacy PFASs and other emerging fluorinated alternatives in water *** review provides an overview of the recent advancements in EO, comprehensively elucidating PFAS degradation mechanisms at the anode and exploring key factors that influence PFAS removal efficiency, such as anode materials as well as reactor designs and configurations. Moreover, the review elucidates the impact of operating conditions and parameters, including current density, electrolytes, pH, initial PFAS concentrations, and other coexisting pollutants, on the EO process. Finally, the constraints in the EO process are discussed when considering practical implementations, including undesired by-product generation, incomplete mineralization resulting in the accumulation of short-chain PFASs, and low PFAS concentrations in the natural environment leading to mass transfer limitations and low defluorination efficiency. Consequently, this review provides a perspective on potential solutions integrating the pre-concentration steps and EO process for effective PFAS remediation.

关键词： electrochemical oxidation legacy PFASs fluorinated alternatives degradation mechanisms influencing factors

An efficient strategy enabling solution processable thermally activated delayed fluorescence emitter with high horizontal dipole orientation

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Chinese Journal of Structural Chemistry 2024年第6期43卷 4-5页

作者： Zheng zhao Ben zhong Tang School of Science and Engineering Shenzhen Institute of Aggregate Science and TechnologyThe Chinese University of Hong KongShenzhen(CUHK-Shenzhen)Guangdong518172China

Organic light-emitting diodes(OLEDs)based on highly efficient aggregate emitters present a significant breakthrough in realizing low-cost displays and solid-state lighting,thus drawing considerable research interest i... 详细信息

关键词： emitter breakthrough dipole