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Understanding the Thermal Impeda.ce of Silicone Rubber/Hexagonal Boron Nitride Composites as Thermal Interface Materials

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Chinese Journal of Polymer Science 2024年第3期42卷 352-363,I0008页

作者： Yuan Ji Shi-da.Han Hong Wu Shao-Yun Guo feng-Shun Zhang Jian-Hui Qiu The State Key Laboratory of Polymer Materials Engineering Sichuan Provincial Engineering Laboratory of Plastic/Rubber Complex Processing TechnologyPolymer Research InstituteSichuan UniversityChengdu 610065China Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900China Department of Mechanical Engineering Faculty of Systems Science and TechnologyAkita Prefectural UniversityAkita 015-0055Japan

Silicone rubber(SR) composites are most widely used as thermal interface materials(TIMs) for electronics heat dissipation. Thermal impeda.ce as the main bottleneck limiting the performance of TIMs is usually neglected. Herein, the thermal impeda.ce of SR composites loaded with different levels of hexagonal boron nitride(h-BN) as TIMs was elaborated for the first time by the ASTM D 5470 standa.d test and finite element analysis. It was found that elastic modulus and surface roughness of SR composites increased with the increase of h-BN content, indicating that the conformity was reduced. When the assembly pressure was 0.69 MPa, there existed an optimal h-BN content at which the contact resistance was minimum(0.39 K·cm^(2)·W^(-1)). Although the decreased bond line thickness(BLT) by increasing the assembly pressure was beneficial to reduce the thermal impeda.ce, the proper assembly pressure should be selected to prevent the warpage of the contact surfaces and the increase in contact resistance, according to the compression properties of the SR composites. This study provides valuable insights into fabrication of high-performance TIMs for modern electronic device applications.

关键词： Thermal interface materials Hexagonal boron nitride Thermal impeda.ce Surfaces

Geochemical Anomalies Identified by Multifractal Modeling: Implications for Mineral Exploration in the Ziyoutun Cu-Au District, Jilin Province, China

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Acta Geologica Sinica(English Edition) 2024年第4期98卷 1111-1124页

作者： MA Huchao WANG da.BAI feng LIU Meng GONG Anzhou HU Haiyan State Key Laboratory of Geological Processes and Mineral Resources School of Earth Sciences and ResourcesChina University of GeosciencesBeijing 100083China School of Gemmology China University of GeosciencesBeijing 100083China Guizhou Nengda.Electric Power Design Co. Ltd.Guiyang 550002China Chongqing Chuandongnan Survey&Design Institute Co. Ltd.Chongqing 400038China

The Ziyoutun Cu-Au district is located in the Jizhong–Yanbian Metallogenic Belt and possesses excellent prospects. However, the thick regolith and complex tectonic settings present challenges in terms of detecting and decomposition of weak geochemical anomalies. To address this challenge, we initially conducted a comprehensive analysis of 1:10,000-scale soil geochemical da.a. This analysis included multivariate statistical techniques, such as correlation analysis, R-mode cluster analysis, Q–Q plots and factor analysis. Subsequently, we decomposed the geochemical anomalies, identifying weak anomalies using spectrum-area modeling and local singularity analysis. The results indicate that the assemblage of Au-Cu-Bi-As-Sb represents the mineralization at Ziyoutun. In comparison to conventional methods, spectrumarea modeling and local singularity analysis outperform in terms of identification of anomalies. Ultimately, we considered four specific target areas(AP01, AP02, AP03 and AP04) for future exploration, based on geochemical anomalies and favorable geological factors. Within AP01 and AP02, the geochemical anomalies suggest potential mineralization at depth, whereas in AP03 and AP04 the surface anomalies require additional geological investigation. Consequently, we recommend conducting drilling, following more extensive surface fieldwork, at the first two targets and verifying surface anomalies in the last two targets. We anticipate these findings will significantly enhance future exploration in Ziyoutun.

关键词： geochemical anomalies multivariate statistical analysis spectrum-area model local singularity analysis mineral prospecting Jilin Province

Therapeutic utility of human umbilical cord-derived mesenchymal stem cells-based approaches in pulmonary diseases:Recent advancements and prospects

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World Journal of Stem Cells 2024年第2期16卷 70-88页

作者： Min Meng Wei-Wei Zhang Shuang-feng Chen da.Rui Wang Chang-Hui Zhou Department of Central Laboratory Liaocheng People’s HospitalLiaocheng 252000Shandong ProvinceChina Department of Clinical Laboratory Liaocheng People’s HospitalLiaocheng 252000Shandong ProvinceChina

Pulmonary diseases across all ages threaten millions of people and have emerged as one of the major public health issues *** diverse disease con-ditions,the currently available approaches are focused on alleviating clinical symptoms and delaying disease progression but have not shown significant therapeutic effects in patients with lung *** umbilical cord-derived mesenchymal stem cells(UC-MSCs)isolated from the human UC have the capacity for self-renewal and multilineage ***,in recent years,these cells have been demonstrated to have unique advantages in the treatment of lung *** searched the Public Clinical Trial da.abase and found 55 clinical trials involving UC-MSC therapy for pulmonary diseases,including coronavirus disease 2019,acute respiratory distress syndrome,bron-chopulmonary dysplasia,chronic obstructive pulmonary disease,and pulmonary *** this review,we summarize the characteristics of these registered clinical trials and relevant published results and explore in depth the challenges and opportunitiesfaced in clinical ***,the underlying mole-cular mechanisms involved in UC-MSC-based therapy for pulmonary diseases are also analyzed in *** brief,this comprehensive review and detailed analysis of these clinical trials can be expected to provide a scientific reference for future large-scale clinical application.

关键词： Pulmonary diseases Mesenchymal stem cells Human umbilical cord Cell therapy Clinical trials

Application of ^(18)F-fluorodeoxyglucose positron emission tomography/computed tomography imaging in recurrent anastomotic tumors after surgery in digestive tract tumors

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World Journal of Gastrointestinal Surgery 2024年第8期16卷 2474-2483页

作者： Deng-feng Ge Hao Ren Zi-Chen Yang Shou-Xiang Zhao Zhen-Ting Cheng da.da.Wu Bin Zhang Department of Cardiothoracic Surgery Nanjing University of Chinese MedicineNanjing 210023Jiangsu ProvinceChina Department of Gastrointestinal Surgery Shanghai Sixth People’s HospitalShanghai 250063China

BACKGROUND This study was to investigate the application value of whole-body dynamic ^(18)F-fluorodeoxyglucose(FDG)positron emission tomography/computed tomogra-phy(PET/CT)imaging in recurrent anastomotic tumors of digestive tract after gastric and esophageal cancer *** patients with gastric and esophageal cancer have a high risk of tumor recurrence,and traditional imaging methods have certain limitations in early detection of recurrent ***-body dynamic ^(18)F-FDG PET/CT imaging,due to its high sensitivity and specifi-city,can provide comprehensive information on tumor metabolic activity,which is expected to improve the early diagnosis rate of postoperative recurrent tumors,and provide an important reference for clinical treatment *** A retrospective analysis was performed on 53 patients with upper digestive tract tumors after operation and systemic dynamic ^(18)F-FDG PET/CT imaging indi-cating abnormal FDG uptake by anastomosis,including 29 cases of gastric cancer and 24 cases of esophageal *** to the follow-up results of gas-troscopy and other imaging examinations before and after PET/CT examination,the patients were divided into an anastomotic recurrence group and anastomotic inflammation *** multi-parameter analysis software was used to obtain the metabolic rate(MRFDG),volume of distribution maximum(DVmax)of anastomotic lesions,and MRmean and DVmean of normal liver *** lesion/background ratio(LBR)was calculated by dividing the MRFDG and DVmax of the anastomotic lesion by the MRmean and DVmean of the normal liver tissue,respectively,to obtain LBR-MRFDG and *** independent sample t test was used for statistical analysis,and a receiver operating characteristic curve was used to analyze the differential diagnostic efficacy of each parameter for anastomotic recurrence and *** The dynamic ^(18)F-FDG PET/CT imaging parameters MRFDG,DVmax,LBR-MRFDG,and LBR-DVmax of post

关键词： Gastric cancer Esophageal cancer Anastomosis Dynamic positron emission tomography Differential diagnosis Metabolic rate

Single-crystalline hole-transporting layers for efficient and stable organic light-emitting devices

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Light(Science & Applications) 2024年第7期13卷 1341-1353页

作者： Gao-da.Ye Ran Ding Su-Heng Li Lei Ni Shu-Ting da. Nian-Ke Chen Yue-feng Liu Runda.Guo Lei Wang Xian-Bin Li Bin Xu Jing feng State Key Laboratory of Integrated Optoelectronics College of Electronic Science and EngineeringJilin University2699 Qianjin Street130012 ChangchunChina. State Key Laboratory of Supermolecular Structures and Materials The Institute of Theoretical ChemistryJilin University2699 Qianjin Street130012 ChangchunChina. Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology430074 WuhanChina

Efficient charge-carrier injection and transport in organic light-emitting devices(OLEDs)are essential to simultaneously achieving their high efficiency and long-term ***,the charge-transporting layers(CTLs)deposited by various vapor or solution processes are usually in amorphous forms,and their low charge-carrier mobilities,defectinduced high trap densities and inhomogeneous thickness with rough surface morphologies have been obstacles towards high-performance ***,organic single-crystalline(SC)films were employed as the hole-transporting layers(HTLs)instead of the conventional amorphous films to fabricate highly efficient and stable *** highmobility and ultrasmooth morphology of the SC-HTLs facilitate superior interfacial characteristics of both HTL/electrode and HTL/emissive layer interfaces,resulting in a high Haacke’s figure of merit(FoM)of the ultrathin top electrode and low series-resistance joule-heat loss ratio of the ***,the thick and compact SC-HTL can function as a barrier layer against moisture and oxygen *** a result,the SC-OLEDs show much improved efficiency and stability compared to the OLEDs based on amorphous or polycrystalline HTLs,suggesting a new strategy to developing advanced OLEDs with high efficiency and high stability.

关键词： crystalline amorphous charge

Enhancing nitrogen removal in constructed wetlands: The role of influent substrate concentrations in integrated vertical-flow systems

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Environmental Science and Ecotechnology 2024年第5期21卷 103-112页

作者： Tongtong Liu da.Li Yan Tian Jiajie Zhou Ye Qiu Dongyi Li Guohong Liu Yujie feng State Key Laboratory of Urban Water Resource and Environment School of EnvironmentHarbin Institute of TechnologyNo.73 Huanghe RoadNangang DistrictHarbin 150090China Institute of Chemical Engineering in Heilongjiang Province 3#Nanhu loadHigh Tech R&D Zone of Harbin CityHarbin 150028China

Recent advancements in constructed wetlands(CWs)have highlighted the imperative of enhancing nitrogen(N)removal ***,the variability in influent substrate concentrations presents a challenge in optimizing N removal strategies due to its impact on removal efficiency and *** we show the interplay between influent substrate concentration and N removal processes within integrated vertical-flow constructed wetlands(IVFCWs),using wastewaters enriched with NO_(3)^(-)-N and NH4þ-N at varying carbon to nitrogen(C/N)ratios(1,3,and 6).In the NO_(3)^(-)-N enriched systems,a positive correlation was observed between the C/N ratio and total nitrogen(TN)removal efficiency,which markedly increased from 13.46±2.23%to 87.00±2.37%as the C/N ratio escalated from 1 to ***,in NH4þ-N enriched systems,TN removal efficiencies in the A-6 setup(33.69±4.83%)were marginally 1.25 to 1.29 times higher than those in A-3 and A-1 systems,attributed to constraints in dissolved oxygen(DO)levels and *** community analysis and metabolic pathway assessment revealed that anaerobic denitrification,microbial N assimilation,and dissimilatory nitrate reduction to ammonium(DNRA)predominated in NO_(3)^(-)-N systems with higher C/N ratios(C/N 3).In contrast,aerobic denitrification and microbial N assimilation were the primary pathways in NH4þ-N systems and low C/N NO_(3)^(-)-N systems.A mass balance approach indicated denitrification and microbial N assimilation contributed 4.12-47.12%and 8.51e38.96%in NO_(3)^(-)-N systems,respectively,and 0.55e17.35%and 7.83e33.55%in NH4þ-N systems to TN *** enhance N removal,strategies for NO_(3)-N dominated systems should address carbon source limitations and electron competition between denitrification and DNRA processes,while NH4þ-N dominated systems require optimization of carbon utilization pathways,and ensuring adequate DO and alkalinity supply.

关键词： Constructed wetland Nitrogen removal pathway Denitrification Microbial nitrogen assimilation Enhanced strategy

Mineralogical properties and co-sintering characteristics of fluxed iron ore with magnetite concentrates

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Journal of Iron and Steel Research International 2024年第2期31卷 318-328页

作者： Le-le Niu Zheng-jian Liu Jian-liang Zhang Yao-zu Wang Zhen-xing Yang Si-da.Li Chang-dong Shan Ben feng School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China Institute of Artificial Intelligence University of Science and Technology BeijingBeijing100083China Xinxing Casting Pipe Xinjiang Co. Bayingol841300XinjiangChina

To investigate the feasibility of co-sintering of fluxed iron ore with magnetite concentrates, the mineralogical properties of a novel fluxed iron ore were studied using particle size analysis, microscopic morphology characterization, and X-ray diffraction Rietveld analysis. Following that, the experiments for granulation performance and basic sintering characteristics were designed under seven different fluxed iron ore ratios, and the integrated ranking of different fluxed iron ore ratios was determined using gray relation analysis. Finally, the results of the industrial trails were combined with the feasibility analysis. Test and experimental results show that the fraction of the fluxed iron ore particles larger than 0.5 mm can account for more than 48%, and the particles have two morphologies: spherical-rough and flaky-smooth. Ca elements are found in the form of calcite (CaCO3) and dolomite (CaMg(CO3)2). The average particle size of granules and powder removal rate can be improved from 2.50 to 3.16 mm and 39.60% to 24.20%, respectively, with the increase in the fluxed iron ore ratio. Furthermore, the fluxed iron ore can improve assimilability and liquid fluidity of magnetite concentrates. In terms of overall granulation performance and sintering characteristics, the fluxed iron ore ratios are graded from best to worst as follows: 12%, 15%, 9%, 18%, 21%, 6% and 3%. The industrial trails show that when the fluxed iron ore ratio is increased, the beneficial effect of the superior sintering characteristics of the fluxed iron ore itself is ideally balanced with the negative effect of the lower amount of additional CaO at 12% ratio, and thus, it is feasible to bring the fluxed iron ore into production at a level of roughly 12%.

关键词： Fluxed iron ore Magnetite concentrate Granulation performance Sintering characteristics Gray relation analysis

A novel method for AFRPs burrs removal:Principle of mechanochemo-induced fiber fracture

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Chinese Journal of Aeronautics 2024年第7期37卷 522-538页

作者： Jie XU Bo LI Pingfa feng Qiang WANG feng feng Division of Advanced Manufacturing Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Changhe Aircraft Industry(Group)Co.Ltd Jingdezhen 333000China

Burrs generated during the machining of Aramid-Fiber-Reinforced Composites(AFRPs)pose a challenge for the production efficiency of aircraft and helicopter housing *** studies have generally attempted to suppress burrs by referring to delamination suppression *** contrast to stratification,burrs are remediable machining *** such,a mechanochemical method with burrs trimming technological strategy are implemented to effectively combat ***,we clarify the mechanism by which aramid fibers cannot be cut off using analytical and numerical *** addition,the mechanism of fiber fracture with Modified Polyurethane Reactive Polymer(M-PUR),and development of anti-burr devices(thermostatic adhesive sealed generator)are ***,the experimental results show that the reduction rate in burr length is 87%-91%through the mechanochemical *** method not only opens a new avenue to solve the burr problem of aramid fibers but also builds an interdisciplinary bridge between polymer science and composite machining.

关键词： Mechanochemical method Burrs Orthogonal cutting Aramid fiber-reinforced composites Milling

Molecular Ferroelastic Induced by Mono-/Double-Protonation Strategy

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Chinese Journal of Chemistry 2024年第15期42卷 1706-1712页

作者： Jia-Qi Luo Meng-Meng Lun Qiang-Qiang Jia Zhi-Jie Wang Hai-feng Lu Yi Zhang da.Wei Fu Institute for Science and Applications of Molecular Ferroelectrics Key Laboratory of the Ministry of Education for Advanced Catalysis MaterialsZhejiang Normal UniversityJinhuaZhejiang 321004China Ordered Matter Science Research Center Jiangsu Key Laboratory for Science and Applications of Molecular FerroelectricsSoutheast UniversityNanjingJiangsu 211189China

Molecular ferroelastics with the natural features of mechanical flexibility and switchable spontaneous strain have attracted widespread attention in the scientific community due to their potential applications in tunable gratings,flexible memorizers,strain sensors,and intelligent ***,most designs of molecular ferroelastics remain in the stage of blind exploration,posing a challenge to achieve a functional ferroelastic more ***,we have successfully obtained a molecular ferroelastic,[Me_(2)NH(CH_(2))_(2)NH_(3)](ReO_(4))_(2)(Me_(2)NH(CH_(2))_(2)NH_(3)=N,N-dimethylethylenediammonium),under the guida.ce of the mono-/double-protonation ***_double-protonated[Me_(2)NH(CH_(2))_(2)NH_(3)](ReO_(4))_(2) undergoes a paraelastic-ferroelastic phase transition with the Aizu notation of 2/mFi at 322 ***,the theoretical calculation and experimental measurement simultaneously show that[Me_(2)NH(CH_(2))_(2)NH_(3)](ReO_(4))_(2) possesses good mechanical flexibility,because its elastic modulus(E)of 8.26 GPa and hardness(H)of 0.45 GPa are smaller than the average values of organic crystals(E of 12.05 GPa and H of 0.5 GPa),which makes it promising to apply in wearable pressure sensors,implantable medical sensors,high-precision tuners,*** work further enriches the molecular ferroelastic family and demonstrates that mono-/double-protonation is one of the effective molecular modification strategies for designing ferroelastics.

关键词： Molecular crystal Ferroelastic Mono-/double-protonation Mechanical flexibility Phase transition Crystal engineering Computational chemistry Molecular dynamics