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Preparation of SiC coated graphite composite powders by nitriding combustion synthesis

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Journal of Advanced Ceramics 2023年第10期12卷 1930-1945页

作者： Biao Zhang Wenqi Xie Huaizhi Lin Zhilei Wei Zhichao xiao kai He Zhongqi Shi State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China China Nuclear Power Engineering Co. Ltd.Beijing 100840China

Ceramic-coated graphite powders are considered as effective raw materials to fabricate three-dimensional continuous ceramic skeleton-reinforced graphite matrix composites which can overcome their inherent poor densification and improve their mechanical and antioxidation properties.However,the morphology and thickness regulation of ceramic coatings on graphite particles are still a great challenge.Herein,SiC-coated graphite(graphite@SiC)powders were prepared by nitriding combustion synthesis using Si and graphited mesocarbon microbead(MCMB)as raw powders with polytetrafluoroethylene(PTFE)as a promoter.The effects of the PTFE content and the Si/MCMB molar ratio on the phase composition and coating morphology were investigated.The phase transition and microstructure evolution of a combustion synthesis(CS)process were revealed by a gas-released quenching experiment.When the Si/MCMB molar ratio was 1:3 and the PTFE content was 10 wt%,the thickness of the SiC coating synthesized under 2 MPa N_(2)reached 1.14μm.The corresponding sintered graphite@SiC composite had relative density of 99.2%and flexural strength of 231 MPa,accompanied by a significant improvement in high-temperature antioxidation properties.The as-synthesized graphite@SiC powders with good sinterability and antioxidation properties show great promise for applications in the nuclear industry and other extreme fields.

关键词： SiC-coated graphite powders nitriding combustion synthesis(CS) antioxidation properties

Construction of a full-thickness human corneal substitute from anterior acellular porcine corneal matrix and human corneal cells

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International Journal of Ophthalmology(English edition) 2019年第3期12卷 351-362页

作者： kai Zhang xiao-xiao Ren Ping Li Kun-Peng Pang Hong Wang Department of Ophthalmology Shandong Provincial Western Hospital Shandong Institute of Otolaryngology Department of Ophthalmology Qilu Hospital Shandong University Department of Ophthalmology Shandong Provincial Hospital Affiliated to Shandong University

AIM: To construct functional human full-thickness corneal replacements.METHODS: Acellular porcine corneal matrix(APCM) was developed from porcine cornea by decellulariztion. The biomechanical properties of anterior-APCM(AAPCM) and posterior-APCM(PAPCM) were checked using uniaxial tensile testing. Human corneal cells were obtained by cell culture. Suspending ring was designed by deformation of an acupuncture needle. MTT cytotoxicity assay was used to check the cytotoxicity of suspending ring soaking solutions. A new three-dimensional organ culture system was established by combination of suspending ring, 48-well plate and medium together. A human full-thickness corneal substitute was constructed from human corneal cells with AAPCM in an organ coculture system. Biochemical marker expression of the construct was measured by immunofluorescent staining and morphological structures were observed using scanning electron microscopy. Pump function and biophysical properties were examined by penetrating keratoplasty and follow-up clinical observations.RESULTS: There were no cells in the AAPCM or PAPCM, whereas collagen fibers, Bowman's membrane, and Descemet's membrane were retained. The biomechanical property of AAPCM was better than PAPCM. Human corneal cells grew better on the AAPCM than on the PAPCM.There was no cytotoxicity for the suspending ring soaking solutions. For the constructed full-depth human corneal replacements keratocytes scattered uniformly throughout the AAPCM and expressed vimentin. The epithelial layer was located on the surface of Bowman's membrane and composed of three or four layers of epithelial cells expressing cytokeratin 3. One layer of endothelial cells covered the stromal surface of AAPCM, expressed Na+/K+ATPase and formed the endothelial layer. The construct was similar to normal human corneas, with many microvilli on the epithelial cell surface, stromal cells with a long shuttle shape, and zonula occludens on the interface of endothelial cells. The construct withstood surgical procedures du

关键词： full-thickness human corneal substitute anterior-acellular porcine corneal matrix posterior-acellular porcine corneal matrix human corneal cells

Responses of photosynthetic characteristics and enzyme activity of nitrogen metabolism to low nitrogen in maize with different nitrogen tolerance

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International Journal of Agricultural and Biological Engineering 2020年第6期13卷 133-143页

作者： Pengtao Ji Yongwei Cui Xiangling Li Kai Xiao Peijun Tao Yuechen Zhang College of Agronomy Hebei Agricultural University/State Key Laboratory of North China Crop Improvement and RegulationBaoding 071001HebeiChina Academy of Agricultural Planning and Engineering Ministry of Agriculture and Rural AffairsBeijing 100125China College of Agronomy and Biotechnology Hebei Normal University of Science&TechnologyQinhuangdao 066004HebeiChina

Understanding the physiological processes associated with leaf photosynthetic characteristics and nitrogen(N)assimilation during grain-filling stage are helpful for enhancing nitrogen utilization efficiency(NUtE)of maize.In this study,the leaf photosynthetic and N assimilation parameters in maize,including Zhengdan 958(ZD958),a low-N tolerance cultivar and Huanong 138(HN138),a low-N sensitive cultivar under different N rates were examined.Results showed that ZD958 displayed significant increases on grain yield and NUtE than that in HN138.Analyses on the leaf photosynthetic and N assimilation-associated processes indicated that ZD958 had higher leaf N remobilization(Rem N),net photosynthetic rate(Pn)and photosynthetic N use efficiency(PNUE)with respect to those of HN138 during grain-filling stage.In addition,ZD958 was also shown to be higher activities of leaf nitrate reductase(NR),glutamine synthetase(GS),nitrate reductase(GDH)and glutamine synthetase(GAGOT)than those of HN138.The leaf PNUE was significantly positively correlated with NR,GS,GDH,GOGAT suggesting that leaf PNUE and NR,GS,GDH,GOGAT jointly determined the N remobilization efficiency and the leaf N remobilization during post-silking.These results suggested that ZD958 possessed improved PNUE,NR and GS activities in leaves during grain-filling stage that contributes improve grain weights and yield formation capacities upon under low-N conditions.

关键词： low-N photosynthesis nitrogen assimilation nitrogen utilization efficiency maize

Light-driven directional ion transport for enhanced osmotic energy harvesting

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National Science Review 2021年第8期8卷 178-185页

作者： Kai Xiao Paolo Giusto Fengxiang Chen Ruotian Chen Tobias Heil Shaowen Cao Lu Chen Fengtao Fan Lei Jiang Max Planck Institute of Colloids and Interfaces Department of Colloid Chemistry Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education School of ChemistryBeihang University State Key Laboratory of New Textile Materials and Advanced Processing Technologies Wuhan Textile University State Key Laboratory of Catalysis 2011-iChEMDalian National Laboratory for Clean Energy (DNL)Dalian Institute of Chemical Physics(DICP)Chinese Academy of Sciences State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology

Light-driven ion(proton) transport is a crucial process both for photosynthesis of green plants and solar energy harvesting of some archaea. Here, we describe use of a TiO2/C3N4semiconductor heterojunction nanotube membrane to realize similar light-driven directional ion transport performance to that of biological systems. This heterojunction system can be fabricated by two simple deposition steps. Under unilateral illumination, the TiO2/C3N4heterojunction nanotube membrane can generate a photocurrent of about 9 μA/cm~2, corresponding to a pumping stream of ～5500 ions per second per nanotube. By changing the position of TiO2and C3N4, a reverse equivalent ionic current can also be realized. Directional transport of photogenerated electrons and holes results in a transmembrane potential, which is the basis of the light-driven ion transport phenomenon. As a proof of concept, we also show that this system can be used for enhanced osmotic energy generation. The artificial light-driven ion transport system proposed here offers a further step forward on the roadmap for development of ionic photoelectric conversion and integration into other applications, for example water desalination.

关键词： ion pump ion transport nanofluidic porous membrane carbon nitride

Hybrid transcytosis nanopomegranates for sensitizing breast cancer radiotherapy in deep tumor tissue

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Nano Research 2023年第5期16卷 7260-7268页

作者： Li Wang Liang xiao Zhengyang Zhao kai Zhong Weiliang Zhu Hao Liu xiaoqiu Li Department of Oncology Zhujiang HospitalSouthern Medical UniversityGuangzhou 510282China Guangdong Provincial Key Laboratory of Tumor Interventional Diagnosis and Treatment Zhuhai People's Hospital(Zhuhai Hospital Affiliated with Jinan University)Zhuhai 519000China Department of Radiation Oncology Affiliated Cancer Hospital&Institute of Guangzhou Medical UniversityGuangzhou 510095China Department of Radiation Oncology The First Affiliated Hospital of Anhui Medical UniversityHefei 230022China

As a standard cancer treatment method,radiotherapy(RT)has cured or alleviated over half cancer bearing patients worldwide more than 100 years.However,the therapeutic outcome is seriously hindered by the resistant tumor microenvironment(TME).Hypoxia is a critical factor of vicious TME that causes radiation resistance owing to the insufficiency of oxygen for DNA damage maintenance.Moreover,severe vascular dysfunction and pyknomorphic extracellular matrix(ECM)in deep tumor tissues substantially limit radiosensitizer penetration and oxygen diffusion from vessels into tightly packed tumor core.In this study,we develop a hybrid transcytosis nanopomegranate(HTP)with high transcytosis potential in response to TME condition.HTP is architected by self-assembly of small CuS and Au nanoparticles(NPs)at normal physiological condition.HTP can rapidly collapse to transcytosis NPs(CuS and Au NPs)in TME with cationized surface,which enables excellent transcytosis potential and effectively elevates the penetration of CuS and Au into deep tumor tissues.Following the second near-infrared(NIR(II))biowindow laser irradiation,CuS heats the tumor and enhances blood perfusion,eliciting tumor hypoxia alleviation and DNA damage aggravation.Moreover,Au NPs enriched in deep tumor tissues effectively sensitize radio-therapeutic response.Our study provides a new and potential nano-platform to ameliorate tumor hypoxia and sensitize deep tumor tissue radiotherapy.

关键词： breast cancer transcytosis hybrid nanopomegranate hypoxia alleviation radiosensitization

基于非易失存储器的版本化进程细粒度容错（英文）

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Frontiers of Information Technology & Electronic Engineering 2018年第2期19卷 192-205页

作者： Wen-zhe ZHANG kai LU xiao-ping WANG Science and Technology on Parallel and Distributed Processing Laboratory College of ComputerNational University of Defense Technology

新型非易失存储器(NVRAM)提供的字节粒度持久且非易失新特性,将有力支持新型容错技术的设计。提出一个基于NVRAM的新型容错进程模型——版本化进程(versionized process,VerP)。该进程模型通过在传统软硬件之间引入一个软件中间层,将软... 详细信息

新型非易失存储器(NVRAM)提供的字节粒度持久且非易失新特性,将有力支持新型容错技术的设计。提出一个基于NVRAM的新型容错进程模型——版本化进程(versionized process,VerP)。该进程模型通过在传统软硬件之间引入一个软件中间层,将软硬件解耦合,在NVRAM上重新组织进程所有数据,从而支持进程在NVRAM的天然容错。进一步,赋予进程中每个数据一个版本号,通过更新版本号实现进程非易失数据的一致性更新。与传统检查点机制相比,VerP可高效支持细粒度容错。

关键词：容错机制随机存取不稳定纹理存储器 NVRAM 进程状态过程数据

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Finite barrier bound state

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Light(Science & Applications) 2024年第4期13卷 664-671页

作者： Tao Liu kai Bai Yicheng Zhang Duanduan Wan Yun Lai C.T.Chan Meng xiao Key Laboratory of Artificial Micro-and Nano-structures of Ministry of Education and School of Physics and Technology Wuhan University430072 WuhanChina. National Laboratory of Solid State Microstructures School of Physicsand Collaborative Innovation Center of Advanced MicrostructuresNanjing University210093 NanjingChina. Department of Physics The Hong Kong University of Science and TechnologyClear Water BayKowloon999077Hong KongChina. Wuhan Institute of Quantum Technology 430206 WuhanChina

A boundary mode localized on one side of a finite-size lattice can tunnel to the opposite side which results in unwanted couplings.Conventional wisdom tells that the tunneling probability decays exponentially with the size of the system which thus requires many lattice sites before eventually becoming negligibly small.Here we show that the tunneling probability for some boundary modes can apparently vanish at specific wavevectors.Thus,similar to bound states in the continuum,a boundary mode can be completely trapped within very few lattice sites where the bulk bandgap is not even well-defined.More intriguingly,the number of trapped states equals the number of lattice sites along the normal direction of the boundary.We provide two configurations and validate the existence of this peculiar finite barrier-bound state experimentally in a dielectric photonic crystal at microwave frequencies.Our work offers extreme flexibility in tuning the coupling between localized states and channels as well as a new mechanism that facilitates unprecedented manipulation of light.

关键词： boundary state eventually

Heterogeneities at multiple length scales in 2D layered materials:From localized defects and dopants to mesoscopic heterostructures

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Nano Research 2021年第6期14卷 1625-1649页

作者： Hui Cai Yiling Yu Yu-Chuan Lin Alexander A.Puretzky David B.Geohegan Kai Xiao Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTN37831USA

Two-dimensional(2D)materials hold great promise for applications in optoelectronics,quantum information science,and energy conversion due to their remarkable properties imbued by their physical characteristics.Although heterogeneities in their intrinsic structure are the major challenges limiting their synthesis and predictable properties,they also provide a pathway to controllably tune the properties and broaden the potential of 2D materials.Heterogeneities that can be tailored,including defects,dopants,strain,edges,and layer stackings offer transformative opportunities in heterogeneous 2D materials through the introduction of novel properties for technological applications.This article provides a review of recent progress in studying heterogeneities in 2D materials.The review uses examples from our work to develop a strategy to understand the heterogeneities across multiple length scales to link the effect of heterogeneity at the nanoscale with the macroscale properties of 2D materials.We describe specific types of heterogeneities and explore novel synthesis and processing methods for their controlled production with example of the potential impact and applications enabled by their intriguing properties.Finally,we provide a perspective on how to extend the range of tunable properties through further engineering the heterogeneities in 2D materials.

关键词： wo-dimensional(2D)materials heterogeneity defect strain grain boundary heterostructures phase

Comparison of Aspirin and Naoxintong Capsule(脑心通胶囊)with Adjusted-Dose Warfarin in Elderly Patients with High-Risk of Non-Valvular Atrial Fibrillation and Genetic Variants of Vitamin K Epoxide Reductase

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Chinese Journal of Integrative Medicine 2018年第4期24卷 247-253页

作者： WANG Huan ZHOU xiao-kai ZHENG Li-fan WU xiao-ying CHEN Hui Department of Internal Medicine Fujian Provincial Cardiovascular Disease InstituteProvincial Clinical College of Fujian Medical University Cardiovascular Internal Medicine Quzhou People's Hospital of Zhejiang Province Cardiovascular Internal Medicine the Affiliated Hospital in Putian College of Fujian Province

Objective： To compared the therapeutic effect of a Chinese patent medicine Naoxintong Capsule（脑心通胶囊, NXT） and aspirin with adjusted-dose warfarin in Chinese elderly patients（over 65 years） with nonvalvular atrial fibrillation（NVAF） and genetic variants of vitamin K epoxide reductase（VKORC1）, who are at high-risk of thromboembolism. Methods： A total of 151 patients, with NVAF and AA genotype of VKORC1-1639（a sensitive genotype to warfarin） and a CHA2 DS2-VASc clinical risk score of 2 or above, were chosen for this study. Patients were randomized into two groups and orally treated with a combination of aspirin（100 mg/day） and NXT（1.6 g thrice a day） or adjusted-dose warfarin [international normalized ratio 2.0–3.0）. The primary end points including ischemic stroke and death as well as the secondary end points including hemorrhage events were followed up for at least 1 year. Results： Baseline clinical data and the rates of primary end points were similar between groups. However, the rate of serious bleeding（secondary event） in the combination therapy group was lower than that in the adjusted-dose warfarin group（0% vs. 7.9%, odds ratio： 0.921, 95% confidence interval： 0.862–0.984, P=0.028）. Conclusions： Aspirin combined with NXT and warfarin displayed comparable rates of primary end point including ischemic stroke and all-cause death during the 1-year follow-up. However, as compared with warfarin, the combination therapy reduced the rate of serious bleeding. Therefore, aspirin combined with NXT might provide an alternative pharmacotherapy in preventing ischemic stroke for elderly patients with NAVF who cannot tolerate warfarin.（No. ChiC TR-TRC-13003596）

关键词： atrial fibrillation antithrombotic therapy genetic variants warfarin aspirin combined with Naoxintong Chinese medicine alternative medicine

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