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Numerical study on ignition start-up process of an underwater solid rocket motor across a wide depth range

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Chinese Journal of Aeronautics 2024年第10期37卷 136-157页

作者： Deyou WANG Shipeng LI Ge JIN Ruyao WANG Dian guan Ningfei WANG School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Beijing System Design Institute of Electro-mechanic Engineering Beijing 100854China

Solid rocket motors have important applications in the propulsion of trans-media vehicles and underwater launched *** this paper,the ignition start-up process of an underwater solid rocket motor across a wide depth range has been numerically studied.A novel multi-domain integrated model has been developed by combining the solid propellant ignition and combustion model with the volume of fluid multiphase *** integrated model enables the coupled simulation of the propellant combustion and gas flow inside the motor,along with the gas jet evolution in the external water *** detailed flow field developments in the combustion chamber,nozzle,and wake field are carefully *** variation rules of the internal ballistics and thrust performance are also *** effects of environmental medium and operating depth on the ignition start-up process are systematically *** results show that the influence of the operating environment on the internal ballistic characteristics is primarily reflected in the initial period after the nozzle closure *** development of the gas jet in water lags significantly compared with that in *** the water depth increases,the ignition delay time of the motor is shortened,and the morphology evolution of the gas jet is significantly compressed and ***,the necking and bulging of the jet boundary near the nozzle outlet and the consequent shock oscillations are intensified,resulting in stronger fluctuations in the wake pressure field and motor thrust.

关键词： Underwater propulsion Solid rocket motor Ignition start-up process Underwater gas jet Thrust oscillation

Analysis of conductance and interfacial polarisation behaviours of silicone rubber based on frequency domain spectroscopy

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High Voltage 2024年第1期9卷 56-65页

作者： Hao Hu Zhidong Jia Xilin Wang Ruiyang guan Weinan Fan Simin Luo Tsinghua Shenzhen International Graduate School Tsinghua UniversityShenzhenChina guangzhou Power Supply China Southern Power Grid Company Ltd.GuangzhouChina

Silicone rubber(SR)is widely used for cable insulation and operates in multi-stress coupling *** dielectric properties and ageing performance are the essential factors affecting cable *** this study,the frequency domain spectroscopy of unaged SR and SR aged under various conditions is *** dielectric responses before and after ageing are analysed in depth by the conjoint analysis via multiple complex planes(permittivity,conductivity,and modulus).Typical conductivity and interfacial polarisation properties,as well as property changes resulting from thermal and tensile ageing,are *** results show that tensile ageing promotes conductance and interfacial polarisation,while thermal ageing shows the opposite *** on the multi-core model and charge carrier hopping transport model,thermal and tensile ageing mechanisms on the conductance and interfacial polarisation behaviours of SR are *** behaviours exhibit positively correlated changing characteristics,suggesting that the two behaviours may originate from a common *** carrier transport process,promoted by the tensile effect and slightly suppressed by the thermal effect,is the primary factor and considered an important indicator to evaluate the dielectric properties of SR insulation.

关键词： interfacial rubber insulation

Degradation of iopamidol in the permanganate/sulfite process:Evolution of iodine species and effect on the subsequent formation of disinfection by-products

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Journal of Environmental Sciences 2024年第1期135卷 345-352页

作者： Yimin Lin Hongyu Dong Yating Zhu Gongming Zhou Junlian Qiao Xiaohong guan State Key Laboratory of Pollution Control and Resources Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China Department of Environmental Science School of Ecological and Environmental SciencesEast China Normal UniversityShanghai 200241China

Permanganate/sulfite(Mn(VII)/S(IV))process is a promising pre-oxidation technology for sequestering the emerging organic contaminants in drinking water treatment ***(IPM),a representative of iodinated X-ray contrast media,has been widely detected in water sources and has the risk of forming iodinated disinfection byproducts(I-DBPs)in water treatment *** this study,we investigated the evolution of iodine species during the IPM degradation by the Mn(VII)/S(IV)process and its effect on the subsequent formation of I-DBPs during chlorination at pH 7.0 and *** could be effectively degraded in the Mn(VII)/S(IV)process at environmentally relevant pH(pH 7.0 and 8.0).The results of quenching and competitive oxidation kinetic experiments revealed that SO^(·-)_(4)was the major reactive oxidizing species contributing to the degradation of IPM whereas the contributions of HO·and reactive manganese species were negligible in the Mn(VII)/S(IV)process.I–and IO–3were generated while no HOI was detected during the degradation of IPM in the Mn(VII)/S(IV)*** effects of IPM oxidation by Mn(VII)/S(IV)on the subsequent formation of chlorinated disinfection by-products(Cl-DBPs)during chlorination were related to the category of *** pre-oxidation of IPM by Mn(VII)/S(IV)resulted in the generation of I-DBPs during the disinfection process although no I-DBPs were detected if no pre-oxidation was *** finding of this study suggested that attention should be paid to the toxicity of DBPs when water containing iodinated organic contaminants is treated by Mn(VII)/S(IV)process or other pre-oxidation technologies.

关键词： Permanganate/sulfite Iopamidol Sulfate radical Iodinated disinfection byproducts Pre-oxidation

Bacteria colonization and gene expression related to immune function in colon mucosa is associated with growth in neonatal calves regardless of live yeast supplementation

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Journal of Animal Science and Biotechnology 2024年第5期15卷 1980-1995页

作者： Koki Nishihara Clothilde Villot Lautaro Cangiano Le Luo guan Michael Steele Department of Animal Biosciences Animal Science and NutritionUniversity of GuelphGuelphON N1G 1Y2Canada Department of Agricultural Food and Nutritional ScienceUniversity of AlbertaEdmonton T6G 2P5Canada Lallemand SAS Blagnac F‑31702France Department of Animal and Dairy Sciences University of Wisconsin-MadisonMadisonWIUSA Faculty of Land and Food Systems The University of British ColumbiaVancouverBC V6T 1Z4Canada Present Address:Department of Animal Biosciences University of GuelphGuelphON N1G 2W1Canada

Background As Holstein calves are susceptible to gastrointestinal disorders during the first week of life,understanding how intestinal immune function develops in neonatal calves is important to promote better intestinal *** probiotics in early life may contribute to host intestinal health by facilitating beneficial bacteria colonization and developing intestinal immune *** objective of this study was to characterize the impact of early life yeast supplementation and growth on colon mucosa-attached bacteria and host immune *** Twenty Holstein bull calves received no supplementation(CON)or Saccharomyces cerevisiae boulardii(SCB)from birth to 5 d of *** tissue biopsies were taken within 2 h of life(D0)before the first colostrum feeding and 3 h after the morning feeding at d 5 of age(D5)to analyze mucosa-attached bacteria and colon *** sequencing showed that there was no difference inαandβdiversity of mucosa-attached bacteria between day and treatment,but bacteria related to diarrhea were more abundant in the colon mucosa on D0 compared to *** addition,q PCR indicated that the absolute abundance of Escherichia coli(***)decreased in the colon mucosa on D5 compared to D0;however,that of Bifidobacterium,Lactobacillus,and Faecalibacterium prausnitzii,which could competitively exclude ***,increased in the colon mucosa on D5 compared to ***-sequencing showed that there were no differentially expressed genes between CON and SCB,but suggested that pathways related to viral infection such as“Interferon Signaling”were activated in the colon mucosa of D5 compared to *** Growth affected mucosa-attached bacteria and host immune function in the colon mucosa during the first 5 d of life in dairy calves independently of SCB *** early life,opportunistic pathogens may decrease due to intestinal environmental changes by beneficial bacteria and/or host immune *** activation

关键词： Colon biopsy Dairy calves RNA-sequencing Saccharomyces cerevisiae boulardii 16S rRNA amplicon-sequencing

Lactate metabolism in neurodegenerative diseases

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Neural Regeneration Research 2024年第1期19卷 69-74页

作者： Chaoguang Yang Rui-Yuan Pan Fangxia guan Zengqiang Yuan The Brain Science Center Beijing Institute of Basic Medical SciencesBeijingChina School of Life Sciences Zhengzhou UniversityZhengzhouHenan ProvinceChina

Lactate,a byproduct of glycolysis,was thought to be a metabolic waste until the discovery of the Warburg *** not only functions as a metabolic substrate to provide energy but can also function as a signaling molecule to modulate cellular functions under pathophysiological *** Astrocyte-Neuron Lactate Shuttle has cla rified that lactate plays a pivotal role in the central nervous ***,protein lactylation highlights the novel role of lactate in regulating transcription,cellular functions,and disease *** review summarizes the recent advances in lactate metabolism and its role in neurodegenerative diseases,thus providing optimal pers pectives for future research.

关键词： Alzheimer's disease Astrocyte-Neuron Lactate Shuttle brain central nervous system glucose metabolism glycolysis neuroinflammation Parkinson's disease protein lactylation signaling molecule

Factors hindering the degradation of pharmaceuticals from human urine in an iron-activated persulfate system

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Journal of Environmental Sciences 2024年第1期135卷 130-148页

作者： Yiruiwen Xie Dao guan Yangfan Deng Yugo Sato Yu Luo guanghao Chen Department of Civil and Environmental Engineering Water Technology LabHong Kong Branch of Chinese National Engineering Research Center for Control&Treatment of Heavy Metal PollutionThe Hong Kong University of Science&TechnologyHong Kong 999077China

This study investigated the degradation of clofibric acid(CFA),bezafibrate(BZF),and sulfamethoxazole(SMX)in synthetic human urine using a novel mesoporous iron powderactivated persulfate system(mFe-PS system),and identified the factors limiting their degradation in synthetic human urine.A kinetic model was established to expose the radical production in various reaction conditions,and experiments were conducted to verify the modeling *** the phosphate-containing mFe-PS system,the 120 min removal efficiency of CFA decreased from 95.1%to 76.6%as the phosphate concentration increased from 0.32 to 6.45 mmol/L,but recovered to 90.5%when phosphate concentration increased to 16.10 mmol/***,the increased concentration of phosphate from 0.32 to 16.10mmol/L reduced the BZF degradation efficacy from 91.5%to 79.0%,whereas SMX removal improved from 37.3%to 62.9%.The m Fe-PS system containing(bi)carbonate,from 4.20 to166.70 mmol/L,reduced CFA and BZF removal efficiencies from 100%to 76.8%and 80.4%,respectively,and SMX from 83.5%to 56.7%within a 120-min reaction *** addition,alkaline conditions(pH≥8.0)inhibited CFA and BZF degradations,while nonacidic pH(pH≥7.0)remarkably inhibited SMX *** of the kinetic model indicated the formation of phosphate(H_(2)PO_(4)^(·)/HPO_(4)^(·-))and/or carbonate radicals(CO_(3)^(·-))could limit pharmaceutical *** transformation products(TPs)of the pharmaceuticals revealed more incompletely oxidized TPs occurred in the phosphate-and(bi)carbonate-containing m Fe-PS systems,and indicated that H_(2)PO_(4)^(·)/HPO_(4)^(·-)mainly degraded pharmaceuticals via a benzene ring-opening reaction while CO_(3)^(·-)preferentially oxidized pharmaceuticals via a hydroxylation reaction.

关键词： Pharmaceutical degradation Human urine Iron-activated persulfate system Phosphate radicals Carbonate radicals Transformation products

A novel structure of ultra-high-loading small moleculesencapsulated ZIF-8 colloid particles

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Nano Research 2024年第4期17卷 2929-2940页

作者： Pengfei Duan Yunhe An Xiaoxiao Wei Yanjie Tian Di guan Xiangwen Liu Lanqun Mao Institute of Analysis and Testing Beijing Academy of Science and Technology(Beijing Center for Physical and Chemical Analysis)Beijing 100089China College of Chemistry Beijing Normal UniversityBeijing 100875China

The safety of nanoparticle-based drug delivery systems(DDSs)for cancer treatment is still a challenge,restricted by the intrinsic cytotoxicity of drug carriers and leakage of loaded ***,we propose a novel nanocarrier’s cytotoxicity avoidance strategy by synthesizing an encapsulation core–shell structure of zeolitic imidazolate framework-8(ZIF-8)-based colloid particles(CPs)with an amorphous ZIF-8 *** encapsulation structure achieves an ultra-high loading rate(LR)of 90%(i.e.,9 mg doxorubicin(DOX)per 1 mg ZIF-8)for DOX and the protection of DOX from ***,to deliver unit-dose drug,this ultra-high LR of 90%significantly reduces the usage of ZIF-8 to 1.2%(2 orders of magnitude)compared to that of DOX@ZIF-8 with a 10%LR,in which cytotoxicity of ZIF-8 could well below the safety limit and then be relatively ***,drug delivery efficacy,scale-up ability,and universality of this encapsulation structure have been further *** findings suggest the great potential of this ZIF-8-based encapsulation core–shell structure in the field of drug delivery.

关键词： metal-organic frameworks zeolitic imidazolate framework-8(ZIF-8) drug delivery nanoparticles nanostructures

Communication-Aware Mobile Relaying via an AUV for Minimal Wait Time:A Broad Learning-Based Solution

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 797-799页

作者： Wenqiang Cao Jing Yan Xian Yang Cailian Chen Xinping guan the Institute of Electrical Engineering Yanshan UniversityQinhuangdao 066004China IEEE the Institute of Information Science and Engineering Yanshan UniversityQinhuangdao 066004China the Department of Automation Shanghai Jiao Tong UniversityShanghai 200240China

Dear Editor,This letter studies the communication-aware mobile relaying via an autonomous underwater vehicle(AUV)for minimal wait *** with the analysis-based channel prediction solution,the proposed discrete Kirchhoff... 详细信息

关键词： underwater autonomous estimation

Thermal stability of permafrost under U-shaped crushed rock embankment of the Qinghai-Tibet Railway

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Advances in Climate Change Research 2024年第1期15卷 158-169页

作者： Kun-Ming XU guan-Li JIANG Ji CHEN Qing-Bai WU State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China Beiluhe Observation Station of Frozen Soil Environment and Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou730000China

The U-shaped crushed rock embankment(UCRE),of which widely utilized in the permafrost regions along the Qinghai-Tibet Railway,has the capability to rapidly reduce the ground temperature of the underlying ***,there remains uncertainty regarding the adaptation of UCRE to climate change and its long-term cooling *** study focuses on nine UCRE monitoring sites along the Qinghai-Tibet Railway to analyze the dynamic variations of the ground temperature underlying permafrost from 2006 to *** efficiency of UCRE in stabilizing permafrost temperature in different permafrost zones is evaluated by considering the permafrost table,ground temperature,and MAGT,as well as the temperature difference between the top and bottom of the crushed rock layer and the ground temperature variation index(GTVI).The results show that UCRE is suitable for application in extremely unstable warm permafrost regions where the MAGT is higher than-0.5℃.Moreover,UCRE effectively diminishes the disparity in permafrost thermal stability between the sunny and shaded shoulders of the *** short-term and long-term effect of cooling permafrost is experiencing a change related with permafrost ***,in stable cold permafrost regions with MAGT lower than-1.5℃,the long-term cooling effect of UCRE on permafrost seems to gradually di-minishes,but UCRE continues to fulfill the role of stabilizing the underlying permafrost thermal state over the *** results show that UCRE can quickly restore and stabilize the thermal state of permafrost in the early stages of construction,and adapt to the influence of future climate *** findings provide important guidance for understanding the variations of permafrost thermal stability beneath the embankment in permafrost regions,as well as for improving the embankment stability and operational safety of the Qinghai-Tibet Railway.

关键词： Qinghai-Tibet Railway U-shaped crushed rock embankment Climate change Permafrost zone Ground temperature variation index Long-term coolingrole