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A study of self-diffusion coefficient and prediction model of nano-confined supercritical water

PHYSICS OF FLUIdS 2025年第4期37卷

作者： Zhang, Bowei Zhang, Jie Li, Xiaoyu Wu, Hongtu Zhang, Tongjia Wang, Junying Jin, Hui Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn SKLMF 28 Xianning West Rd Xian 710049 Shaanxi Peoples R China

The diffusion of nano-confined fluids plays a crucial role in nano-energy research. We developed three molecular models to calculate the diffusion behavior of both supercritical water (SCW) at 673-1173 K, 250 atm, and room water (300 K, 1 atm), confined in carbon nanotubes (CNTs) ranging from 9.49 to 50.17 & Aring;. We analyzed the diffusion mechanism of water confined in various CNTs using the time coefficient. We calculated the self-diffusion coefficient of water in Fickian-like diffusion mode and examined the factors influencing it. The results indicate that in small-diameter CNT (7,7), SCW primarily follows a Fickian-like diffusion mode, while room temperature (300 K, 1 atm) water exhibits a superdiffusion mode. For CNT diameters larger than 20 & Aring;, both room temperature water and SCW predominantly exhibit Fickian-like diffusion. Additionally, the self-diffusion coefficient of SCW increases linearly with temperature, displaying clear Arrhenius behavior. The self-diffusion activation energy of SCW in different types of CNTs shows a strong correlation with the hydrogen bond structure. Finally, we combined the saturated relationship between CNT diameter and self-diffusion coefficient to propose a predictive model for the self-diffusion coefficient of confined SCW. The model is simple, requiring only three parameters, with a mean absolute relative error of less than 6.5%.

关键词： Hydrogen bonds

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Insights Into the digestibility, Properties, and Structure of Highland Barley Starch Using dry Heat Treatment, Heat Moisture Treatment, and Annealing Treatment

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STArCH-STArKE 2025年

作者： Gu, Xinzhe Wang, Zhengwu Shanghai Jiao Tong Univ Sch Agr & Biol Dept Food Sci & Technol Shanghai Peoples R China

The changes of digestibility, several processing properties, and structure of highland barley starch induced by dry heat treatment (dHT), heat moisture treatment (HMT), and annealing treatment (AT) were investigated. And the interrelationship between modification conditions, structure, and functional properties was also investigated. For dHT, the starch was treated at 110 degrees C for 4 , 8, and 12 h, respectively. For HMT, the starch was adjusted to moisture contents of 20%, 25%, and 30%, and then heated at 110 degrees C for 4 h. For AT, the starch was treated at 50 degrees C for 12 and 24 h, respectively. The results indicated that dHT, HMT and AT all positively impacted the total content of slowly digestible starch (SdS) and resistant starch (rS) in the starch samples, and HMT was the best method in leading to the conversion of a portion of rapidly digestible starch (rdS) into SdS and rS. Among them, HMT-20% resulted in a decrease in the rdS content from 91.19% to 81.50%, while simultaneously causing an increase in the SdS and rS content from 5.54% and 3.27% to 8.73% and 9.77%. Moreover, HMT significantly affected the thermal properties, rheological properties, crystallinity, molecular structure, and particle morphology of starch. Therefore, our research suggested that utilizing hydrothermal treatment or heat treatment could be a potential approach for controlling the digestibility of starch products according to desired specifications. This experiment innovatively focused on highland barley starch, a less-researched material. Using dHT, HMT, and AT, it measured different digestible starch contents and explored the links between treatment conditions, rS contents, structure, and function, providing new ideas for its application in functional foods.

关键词： annealing treatment dry heat treatment heat moisture treatment highland barley starch in vitro digestibility

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Experimental study on macro spray, combustion and emission characteristics of biodiesel and diethyl carbonate blends

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INTErnational JOUrNAL OF ENVIrONMENTAL SCIENCE ANd TECHNOLOGY 2025年第7期22卷 5455-5470页

作者： Zhao, L. Zhu, X. Zhao, r. Tian, J. Qian, d. Lin, Q. Univ Sci & Technol China Dept Thermal Sci & Energy Engn 96 Jinzhai Rd Hefei 230026 Anhui Peoples R China Anhui Jianghuai Automobile Grp Co Ltd 99 Ziyun Rd Hefei 230601 Anhui Peoples R China Hefei Technol Coll Dazhong Rd Hefei 230012 Anhui Peoples R China

Biodiesel has a higher viscosity and poorer atomization effect compared to traditional diesel fuel, resulting in lower combustion efficiency. This study investigated the effects of exhaust gas recirculation and a diethyl carbonate additive on the combustion and emission of biodiesel blends. Biodiesel was blended with dEC (90% volume biodiesel + 10% volume dEC: B90dEC10). Experiments were conducted at various brake mean effective pressures (BMEP: 0.2, 0.6, 1.0, 1.6, and 2.0 MPa) and EGr rates (0, 5, and 15%) on a direct injection and high pressure common rail diesel engine that met Euro VI emission standards. The results revealed that the viscosity and atomization effects of B90dEC10 were improved, and the premixed combustion period was longer and the heat release rate (Hrr) was higher compared to traditional diesel. The maximum Hrr of B90dEC10 was 20% higher than that of diesel at 0.6 MPa. Compared to diesel, the particulate matter emissions of B90dEC10 were reduced by 92%, and total hydrocarbons and carbon monoxide emissions were significantly reduced. However, there was an increase of 8-20% in nitrogen oxide emissions. At an EGr rate of 15%, the NOx emissions of B90dEC10 were reduced by 45%, while having minimal impact on PM emissions and brake thermal efficiency. Therefore, it was concluded that B90dEC10 is a potential alternative to diesel, and the combustion performance and emissions control were optimized when using a higher EGr rate (15%).

关键词： Biodiesel diethyl carbonate Spray Combustion Emission

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diagnosis and treatment recommendations for glucose transporter 1 defciency syndrome

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World Journal of Pediatrics 2025年第2期21卷 149-158页

作者： Mei-Jiao Zhang de Wu Li-Fei Yu Hua Li dan Sun Jian-Min Liang Xiao-Peng Lu rong Luo Qing-Hui Guo rui-Feng Jin Hong-Wei Zhang Ge-Fei Lei ruo-Peng Sun Man Wang You-Feng Zhou Ying-Yan Wang Ji-Hong Tang Ying Hua Xu-Lai Shi Xiao-Ming Liu Xiu-Yu Shi Guang Yang Hua Wang Feng Gao Tian-Ming Jia Ji-Wen Wang Jian-Xiang Liao Xin-Hua Bao The First Hospital of Peking University BeijingChina The First Afliated Hospital of Anhui Medical University AnhuiChina Children’s Hospital of Fudan University ShanghaiChina Guangdong Sanjiu Brain Hospital GuangdongChina Huazhong University of Science and Technology TongjiMedical College Afliated Wuhan Children’s Hospital WuhanChina Department of Pediatric Neurology Children’sMedical CenterThe First Hospital of Jilin UniversityChangchun 130021JilinChina Children’s Hospital of Nanjing Medical University NanjingChina Second Hospital of West China of Sichuan University SichuanChina The Second Hospital Cheeloo College of MedicineShandong UniversityShandongChina Children’s Hospital Afliated to Shandong University ShandongChina Qilu Hospital of Shandong University ShandongChina Shanghai Deji Hospital ShanghaiChina Fujian Children’s Hospital(Fujian Branch of ShanghaiChildren’s Medical Center) College of Clinical Medicinefor Obstetrics&Gynecology and PediatricsFujian MedicalUniversityFujianChina Shanghai Children’s Medical Center Shanghai Jiao TongUniversity School of MedicineShanghaiChina Children’s Hospital of Soochow University JiangsuChina Wuxi Children’s Hospital JiangsuChina The Second Afliated Hospital and Yuying Children’sHospital of Wenzhou Medical University ZhejiangChina Xuzhou Children’s Hospital JiangsuChina General Hospital of the Chinese People’s Liberation Army BeijingChina Shengjing Hospital of China Medical University LiaoningChina Children’s Hospital afliated to Zhejiang University Schoolof Medicine HangzhouChina The Third Afliated Hospital of Zhengzhou University HenanChina Shenzhen Children’s Hospital ShenzhenChina

Background Glucose transporter 1 defciency syndrome(Glut1dS)was initially reported by de Vivo and colleagues in *** disease arises from mutations in the SLC2A1 and presents with a broad clinical *** is a treatable neurometabolic condition,where prompt diagnosis and initiation of ketogenic dietary therapy can markedly enhance the ***,due to its rarity,Glut1dS is susceptible to misdiagnosis or missed diagnosis,which can lead to delayed treatment and irreversible dysfunction of the central nervous *** promote diagnostic awareness and efective treatments,the recommendations for diagnosis and treatment have been *** The panel on Glut1dS included 28 participants from the members of the Ketogenic diet Professional Committee of the Chinese Epilepsy Association and Chinese experts with extensive experience in managing *** authors extensively reviewed the literature,and the survey results were discussed in detail over several online *** multiple deliberative sessions,all participants approved the fnal manuscript for *** Early diagnosis and timely treatment of Glut1dS are crucial for improving *** should be alert to suspiction of this disease if the following clinical manifestations appear:seizures,episodic or persistent movement disorders(often triggered by fasting,fatigue,or exercise),delayed motor and cognitive *** clinical presentations may include seizures combined with movement disorders,episodic eye-head movements,and paroxysmal exerciseinduced dyskinesia(PEd).In these cases,genetic testing should be promptly completed,and a lumbar puncture should be performed if *** ketogenic diet is internationally recognized as the frst-line treatment;the earlier it is started,the better the *** can efectively control seizures and improve motor *** drug treatment is generally inefective or provides limited symptom imp

关键词： Consensus diagnosis GlutldS Treatment

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The Favorable Effects of Incorporating Bulky rigid Moieties Into Polymethylsilane (PMS) on the Melt-Spinnability of Its derived Preceramic Polymer

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JOUrNAL OF POLYMEr SCIENCE 2025年第2期63卷 522-531页

作者： Shen, Guobo Liao, Mingdong Xu, Ping Hu, Xiebo Zeng, Chen Zhang, Ze Zhong, Chenghao Zhang, Mingyu Su, Zhean Huang, Qizhong Cent South Univ Natl Key Lab Sci & Technol High Strength Struct Ma Changsha Peoples R China

The wide applications of continuous silicon carbide fiber (SiCf) are constrained by the high cost of its common raw material, polycarbosilane (PCS). Polymethylsilane(PMS) exhibits higher reactivity and a lower production cost than PCS. Nevertheless, the disadvantages of pyrophoric nature and thermoset properties in raw PMS necessitate improvements for practical applications. Herein, benzoxazine resin (VBr) with vinyl functional groups is utilized to modify PMS via hydrosilylation. After modification, a stable preceramic polymer with excellent processability is obtained. The ordered and symmetrical molecular architecture of the initial PMS is changed. This results in an increase of the molecular rigidity, which in turn constrains the alteration of molecular conformation and diminishes the tendency toward crystallization. The modified PMS exhibits a shear-thinning behavior and thermoplastic properties upon heating, making it suitable for melt-spinning. The molecular orientation of the newly formed network structure in the modified PMS is aligned with the shear force during melt-spinning, facilitating the extrusion of green fibers and thereby imparting superior spinnability to the modified PMS. By optimizing the temperature of melt-spinning to 210 degrees C, we produce continuous SiC green fibers with lengths exceeding 10 km. This work presents a promising candidate for the economic preparation of SiC fiber.

关键词： modification polymethylsilane preceramic polymers rheological behaviors silicon carbide fibers

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Modeling and data Analysis of Bistatic Bottom reverberation from a Towed Horizontal Array

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rEMOTE SENSING 2025年第2期17卷 192-192页

作者： Su, Zhaohua Zhuo, Jie Sun, Chao Northwestern Polytech Univ Sch Marine Sci & Technol Xian 710072 Peoples R China Shaanxi Key Lab Underwater Informat Technol Xian 710072 Peoples R China

The spatial-temporal structures of bottom reverberation are associated with seafloor features. In a bistatic bottom reverberation experiment involving a vertical transmitting array and a towed horizontal receiving array, stable stripe structures were observed within the beam-time domain. In this study, a bistatic reverberation model based on ray theory is presented to interpret the experimental phenomena. The conventional empirical scattering function is primarily applicable to small grazing angles. Moreover, the regional segmentation method simulates reverberations across various receiving beams, ignoring scatterers in other areas. To address these issues, we substitute the empirical scattering function with a small-slope approximation (SSA) that is appropriate for full grazing angles. Furthermore, we utilize the beam pattern of arrays to incorporate the effects of each scatterer, and derive the expression for bottom reverberation intensity in both the array and beam domains. The established model demonstrates its applicability in simulating and interpreting the stripe structures of bottom reverberation, and the comparison shows that the model outputs are in agreement with the experimental results. The analysis indicates that the vertical stripes within the structures originate from eigenrays in the mirror reflection direction. Furthermore, the convex stripes are predominantly affected by the direct ray and the surface reflection ray among the scattered eigenrays, whereas the concave and elliptical stripes are primarily affected by the bottom-surface reflection ray and the surface-bottom-surface reflection ray within the scattered eigenrays.

关键词： bottom reverberation spatial-temporal structures bistatic sonar model establishment

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Bibliometric analysis and systematic review on the electrokinetic remediation of contaminated soil and sediment

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ENVIrONMENTAL GEOCHEMISTrY ANd HEALTH 2025年第1期47卷 1-23页

作者： Li, Zhonghong Li, Xiaoguang Beijing Univ Civil Engn & Architecture Sch Environm & Energy Engn Beijing 100044 Peoples R China Chinese Res Inst Environm Sci Basin Res Ctr Water Pollut Control Beijing 100012 Peoples R China

Electrokinetic remediation (EKr) is a proficient, environmentally friendly separation technology for in-situ removal of contaminants in soil/sediment, distinguished for its ease of implementation and minimal prerequisites compared to other remediation technologies. To comprehensively understand the research focus and progress related to EKr of contaminated soil/sediment, a bibliometric analysis was conducted on 1593 publications retrieved from the Web of Science Core Collection (WOSCC) database. This analysis utilized data mining and knowledge discovery techniques through Bibliometrix, VOSviewer, and CiteSpace software. The results revealed a rising trend in annual publication numbers, with china leading in the number of publications. The primary journals in this field included the Journal of Hazardous Materials, Chemosphere, and Separation and Purification Technology. The primary disciplines contributed to this field included "Environmental Sciences", "Engineering, Environmental", "Engineering, Chemical", and "Electrochemistry". keyword co-occurrence and burst analysis indicated that current EKr-related research mainly focuses on the remediation of soil/sediments contaminated by heavy metals (HMs) and organic pollutants (OPs). Furthermore, the EKr remediation improvement method emerged as the prevailing and future research hotspots and development directions. Future research could integrate numerical simulations and various methodologies to predict and assess the migration of pollutants and the efficiency of remediation efforts. Additionally, these studies could explore the effects of EKr on the physicochemical properties and microbial diversity of soil/sediment to provide a theoretical foundation for applying EKr in soil/sediment remediation.

关键词： Electrokinetic remediation Bibliometric analysis research hotspot Heavy metals Organic pollutant

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Synthesis of UiO-66-NH2(Ti/Zr) and its Catalytic Conversion of Cellulose to 5-HMF

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CATALYSIS LETTErS 2025年第2期155卷 1-18页

作者： Xu, Lingling Pan, Xiaomei Gao, Lijing Wei, ruiping Li, Jihang Wen, Xiu Li, Yuanzhuang Xiao, Guomin Southeast Univ Sch Chem & Chem Engn Nanjing 211189 Peoples R China

UiO-66-NH2(Ti/Zr) modified by Ti metal oxide (TiO2) was used to catalyze the hydrolysis of cellulose to prepare 5-HMF. Under the optimal reaction conditions of H2O(NaCl)/THF(1/4 mL), 190 degrees C, 2 h and 50 mg UNT-3(Ti/Zr) (TiO2 and UiO-66-NH2 with mass of 1.5 and 0.1 g, respectively), the yield of 5-hydroxymethylfurfural reached 59.88%. UiO-66-NH2(Ti/Zr) nanocomposites with different mass ratios were successfully prepared by simple solvent evaporation method. SEM and TEM have shown that the modified UiO-66-NH2(Ti/Zr) are wrapped into sphere by TiO2 densely attached to the surface of UiO-66-NH2, which provides favorable conditions for the uniform dispersion of TiO2 and coordination of the Lewis acidic site of UiO-66-NH2. NH3-TPd results confirmed the existence of super-strong, strong, middle and weak acid sites in UiO-66-NH2(Ti/Zr), and Py-FTIr confirmed the existence of Bronsted and Lewis acids. After four cycles, the yield of 5-HMF and FUr decreased slightly from 59.88 to 51.89% and 9.11 to 7.66%, respectively, and the yield of 5-HMF could still remain above 50%. The results showed that the modified composite treatment of TiO2 with rich Lewis acid/base and UiO-66-NH2 could provide a certain idea for the extensive application of biomass research in the future.

关键词： Cellulose Biomass 5-hydroxymethylfurfural TiO2 UiO-66-NH2

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A novel micro-flow control valve with zonal design based on Knudsen number

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JOUrNAL OF THE BrAZILIAN SOCIETY OF MECHANICAL SCIENCES ANd ENGINEErING 2025年第5期47卷 1-13页

作者： Liu, Yaping du, Hui Wang, Bincheng Li, Jingmin Dalian Univ Technol Sch Mech Engn Dalian 116024 Peoples R China Dalian Univ Technol Liaoning Key Lab Micro Nano Technol & Syst Dalian 116024 Liaoning Peoples R China

Micro-flow control valves are critical for precise propellant regulation in aerospace propulsion systems, yet existing designs face challenges in flow stability and accuracy under small openings where rarefied gas effects dominate. This study presents a novel zonal design micro-flow control valve optimized via Knudsen number (Kn)-based flow regime partitioning. A gas flow model was established to correlate valve openings (10-50 mu m) with flow characteristics, enabling derivation of a polynomial-fitted spool profile that aligns with dynamic flow area requirements. Comparative simulations revealed that the polynomial-section spool significantly enhances flow field stability at a 50 mu m opening, reducing maximum throttle velocity by 35.5% and suppressing turbulent vortices compared to conventional trapezoidal designs. Numerical analysis demonstrated progressive flow stabilization as the opening increased: maximum throttle velocity rose from 7.99 to 52.46 m/s, while vortex count decreased from four to one. A prototype was fabricated and tested, achieving a maximum flow deviation of < 0.5% under varying voltages (15-55V dC), validating precision control. By integrating Knudsen number-driven zonal modeling, polynomial spool optimization, and experimental verification, this work advances the design of micro-flow valves for high-accuracy aerospace applications, particularly in slip and transition flow regimes.

关键词： Micro-flow control valve Knudsen number Polynomial spool profile Flow field stability rarefied gas dynamics

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Effect of powder particle size on the microscopic morphology and mechanical properties of 316 L stainless steel hollow spheres

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GrANULAr MATTEr 2025年第1期27卷 1-14页

作者： Li, Jianliang Cui, Xu Sun, Qianfei Guo, Chunhuan Jiang, Fengchun Zhang, Hexin Harbin Engn Univ Coll Mat Sci & Chem Engn Minist Educ Key Lab Superlight Mat & Surface Technol Harbin 150001 Peoples R China Yantai Res Inst Yantai 26401 Peoples R China Harbin Engn Univ Grad Sch Yantai 26401 Peoples R China

316 L stainless steel powder with varying particle sizes was chosen as the raw material for the fabrication of metal hollow spheres using powder metallurgy techniques. The powder's particle size, composition, and micro-morphology were examined, followed by porosity and capillary force calculations, compressive testing, and fracture analysis. The findings reveal significant disparities in the micro-morphology and mechanical properties among the metal powders with different particle sizes. Smaller particle sizes result in denser bonding of the hollow spheres, leading to higher compressive yield strength. Conversely, larger powder particle sizes substantially increase the porosity of the hollow sphere wall, resulting in a sharp decline in mechanical properties and a transition from ductile fracture to brittle fracture in its failure mode. This study's innovation lies in its meticulous examination of the relationship between particle size distribution and the resulting microstructural and mechanical properties of 316 L stainless steel hollow spheres, providing valuable data that enhances the understanding of powder metallurgy processes and drives the development of advanced materials for aerospace applications.

关键词： Particle size Metal hollow spheres Powder metallurgy Compressive property

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