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determination of the critical rainfall of runoff-initiated debris flows by the perspective of physical mechanics and Shields stress

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Journal of Mountain science 2024年第4期21卷 1160-1173页

作者： ma Chao zhu Yongtai LU Lu DU Cui LYU Liqun DONG Jie School of Soil and Water Conservation Beijing Forestry UniversityBeijing 100083China Beijing Institute of Geological Hazard Prevention Beijing 100120China School of Software engineering Chengdu University of Information TechnologyChengdu610225China Civil and Environmental engineering department Clarkson UniversityNY 13699USA

The critical rainfall of runoff-initiated debris flows is utmost importance for local early hazard *** paper presents research on the critical rainfall of runoff-initiated debris flows through comparisons between slope gradients and three key factors,including topographic contributing area,dimensionless discharge,and Shields *** rainfall amount was estimated by utilizing in-situ rainfall records and a slope-dependent Shields stress model was *** created model can predict critical Shields stress more accurately than the other two ***,a new dimensionless discharge equation was proposed based on the corresponding discharge-gradient *** new equation,along with factors such as contributing area above bed failure sites,channel width,and mean diameter of debris flow deposits,predicts a smaller rainfall amount than the in-situ measured *** the slope-dependent Shields stress model performs well and the estimated rainfall amount is lower than the in-situ records,the sediment initiation in the experiments falls within sheet flow regime due to a large Shields ***,further sediment initiation experiments at a steeper slope range are expected in the future to ensure that the sediment transport belongs to mass failure regime characterized by a low level of Shields ***,a more accurate hazard forecast on the runoff-initiated debris flow holds promise when the corresponding critical slope-dependent dimensionless discharge of no motion,fluvial sediment transport,mass flow regime,and sheet flow regime are considered.

关键词： Infinite slope stability Shields stress Contributing area-slope gradient Rainfall back estimation

In^(3+)-doped Sr_(2)Fe_(1.5)Mo_(0.5)O_(6−δ)cathode with improved performance for an intermediate-temperature solid oxide fuel cell

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Nano Research 2024年第1期17卷 407-415页

作者： Yumei ma Lijie Zhang Kang zhu Binze Zhang Ranran Peng Changrong Xia Ling Huang State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources College of ChemistryXinjiang UniversityUrumqi 830046China department of materials science and engineering University of Science and Technology of ChinaHefei 230026China

Promoting the oxygen reduction reaction(ORR)is critical for commercialization of intermediate-temperature solid oxide fuel cells(IT-SOFCs),where Sr_(2)Fe_(1.5)Mo_(0.5)O_(6)−δ(SFM)is a promising cathode by working as a mixed ionic and electronic *** this work,doping of In^(3+)greatly increases the oxygen vacancy concentration and the content of adsorbed oxygen species in Sr_(2)Fe_(1.5)Mo_(0.5−x)InxO_(6−δ)(SFMInx),and thus effectively promotes the ORR *** a typical example,SFMIn_(0.1)reduces the polarization resistance(R_(p))from 0.089 to 0.046Ω∙cm^(2)at 800°C,which is superior to those doped with other metal *** addition,SFMIn0.1 increases the peak power density from 0.92 to 1.47 W∙cm^(−2)at 800°C with humidified H_(2)as the fuel,indicating that In3+doping at the Mo site can effectively improve the performance of SOFC cathode material.

关键词： solid oxide fuel cell cathode In3+doping oxygen reduction reaction(ORR) Sr_(2)Fe_(1.5)Mo_(0.5)O_(6-δ)

Effect of dynamic loading orientation on fracture properties of surrounding rocks in twin tunnels

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Journal of Rock Mechanics and Geotechnical engineering 2024年第2期16卷 393-409页

作者： Ze deng Zheming zhu Lei Zhou Leijun ma Jianwei Huang Yao Zhang Key Laboratory of deep Earth and engineering(Ministry of Education) College of Architecture and EnvironmentSichuan UniversityChengdu610065China Failure Mechanics and engineering Disaster Prevention Key Laboratory of Sichuan Province College of Architecture and EnvironmentSichuan UniversityChengdu610065China Institute for Disaster management and Reconstruction Sichuan UniversityChengdu610065China

For expedited transportation,vehicular tunnels are often designed as two adjacent tunnels,which frequently experience dynamic stress waves from various orientations during blasting *** analyze the impact of dynamic loading orientation on the stability of the twin-tunnel,a split Hopkinson pressure bar(SHPB)apparatus was used to conduct a dynamic test on the twin-tunnel *** two tunnels were rotated around the specimen’s center to consider the effect of dynamic loading ***-DYNA software was used for numerical simulation to reveal the failure properties and stress wave propagation law of the twin-tunnel *** findings indicate that,for a twin-tunnel exposed to a dynamic load from different orientations,the crack initiation position appears most often at the tunnel corner,tunnel spandrel,and tunnel *** the impact direction is created by a certain angle(30°,45°,60°,120°,135°,and 150°),the fractures are produced in the middle of the line between the left tunnel corner and the right tunnel *** the impact loading angle(a)is 90°,the tunnel sustains minimal damage,and only tensile fractures form in the surrounding *** orientation of the impact load could change the stress distribution in the twin-tunnel,and major fractures are more likely to form in areas where the tensile stress is concentrated.

关键词： Twin-tunnel Dynamic load Split Hopkinson pressure bar(SHPB) Fracture mode Stress distribution Displacement field distribution

Laser ablation mechanism and performance of glass fiber-reinforced phenolic composites:An experimental study and dual-scale modelling

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Chinese Journal of Aeronautics 2024年第8期37卷 470-485页

作者： Ran BI Pengfei SHEN Longyu zhu Zhengzheng ma Chuyang LUO Yongfeng LI Lijian PAN Shanghai Key Laboratory of Lightweight Composite Donghua UniversityShanghai 201620China Shanghai High Performance Fibers and Composites Center(Province-Ministry Joint) Center for Civil Aviation CompositesDonghua UniversityShanghai 201620China AVIC Composite Corporation Ltd Beijing 101300China

Both experimental and simulation approaches were employed to investigate the laser ablation mechanism and performances of Glass Fiber Reinforced Phenolic Composites(GFRP).During the ablation process,the difference in thermal conductivities of the glass fibers and the resin matrix as well as their discrepant physical and chemical reactions form a conical ablation *** formation of a residual carbon layer effectively mitigates the ablation rate in the thickness direction.A higher power density results in a faster ablation rate,while a longer irradiation time leads to a larger ablation pit *** account for the variation in thermal conductivity between the fiber and resin,a macro-mesoscale model was developed to differentiate the matrix from the fiber *** element analysis revealed that laser irradiation leads to phenolic decomposition,glass fiber melting vaporization,and residual carbon skeleton *** dual-scale model exhibits precise prediction capabilities concerning the laser ablation process of GFRP,and its accuracy is confirmed through the comparison of simulation and experimental results for the GFRP laser ablation *** model provides a feasible method for performance evaluation and lifetime prediction of GFRP subjected to continuous wave laser irradiation.

关键词： polymer-matrix composites Continuous-wave laser Microstructural analysis Ablation mechanism Finite element method

Microbial flocculant and its application in environmental protection

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Journal of Environmental sciences 1999年第1期11卷 5-16页

作者： Zhang Tong, Lin Zhe department of Environmental engineering, East china university of science and technology, Shanghai 200237, china zhu Huai lan department of Environmental science, East china Normal university, Shanghai 200062, china

The microbial flocculant is a kind of natural bio polymer and has promising future to be used in the fermentation industry and wastewater treatment. It has been studied in details in many countries, such as U.S.A, Japan. This paper reviewed the development on microbial flocculant basic studies and applications, including flocculant production microorganisms, chemical and components of microbial flocculants, flocculation mechanism of microbial flocculants, capability of microbial flocculants and influence factors, and culture conditions for flocculant production. The application cases of microbial flocculants were also discussed.

关键词： microorganism flocculant flocculation.

Acupotomy alleviates knee osteoarthritis in rabbit by regulating chondrocyte mitophagy via Pink1-Parkin pathway

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Journal of Traditional Chinese Medicine 2024年第3期44卷 468-477页

作者： zhu Wenting GUO Changqing DU Mei ma Yunxuan CUI Yongqi CHEN Xilin GUO Changqing the Third Affiliated Hospital of Beijing university of Chinese Medicine Beijing 100029China School of Acupuncture-Moxibustion and Tuina Beijing University of Chinese MedicineBeijing 100029China department of Medical technology Shijiazhuang Medical CollegeHebei 050599China

OBJECTIVE:To investigate the effect of acupotomy,on mitophagy and the Pink1-Parkin pathway in chondrocytes from rabbits with knee osteoarthritis(KOA).METHODS:A KOA model was established via the modified Videman *** were randomly divided into a control group(CON),KOA group and KOA+acupotomy group(Acu).Rabbits in the acupotomy group were subjected to acupotomy for 4 weeks after model *** behavior of the rabbits before and after intervention was *** degeneration was evaluated by optical microscopy and fluorescence *** level of mitophagy was evaluated by transmission electron microscopy,immunofluorescence and enzyme-linked immunosorbent assay(ELISA).The expression of phosphatase and tensin homolog(PTEN)-induced kinase 1(Pink1)-Parkin mitophagy pathway components was evaluated by immunofluorescence,Western blotting and real-time polymerase chain ***:In rabbits with KOA,joint pain,mobility disorders and cartilage degeneration were observed,the mankin score was increased,collagen typeⅡ(Col-Ⅱ)expression was significantly decreased,mitophagy was inhibited,mitochondrial function was impaired,and factors associated with the Pink1-Parkin pathway were *** regulated the expression of Pink1-Parkin pathway-related proteins,the mitophagy-related protein microtubule-associated protein-1 light chain-3,the translocase of the outer membrane,and the inner mitochondrial membrane 23;increased the colocalization of mitochondria and autophagosomes;promoted the removal of damaged mitochondria;restored mitochondrial adenosine-triphosphate(ATP)production;and alleviated cartilage degeneration in rabbits with ***:Acupotomy played a role in alleviating KOA in rabbits by activating mitophagy in chondrocytes via the regulation of proteins that are related to the Pink1-Parkin pathway.

关键词： acupuncture therapy osteoarthritis knee mitophagy PTEN phosphohydrolase cartilage

The Preparation of Unsymmetrical Diaminodimethylsilanes and the Cleavage of Silicon-Nitrogen Bonds by Acid Chloride

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Chinese Chemical Letters 1997年第11期8卷 945-946页

作者： Guo Bin RONG Ru Jian ma Chong Ying ZHOU zhu Liang JIN Wan Nian WU Qing WANG (department of Chemistry, East china university of science and technology, Shanghai, 200237) E china Univ Sci & Technol Dept Chem Shanghai 200237 Peoples R China

Seven unsymmetrical diaminodimethylsilanes were prepared. The reactions of these silylamine with benzoyl chloride indicated that in comparison with electronic, the steric effect played more important role on the reactivity of Si-N bond. As a new method, unsymmetrical diamide can produced by the reaction of the title compounds with diacid chloride.

关键词： Si The Preparation of Unsymmetrical Diaminodimethylsilanes and the Cleavage of Silicon-Nitrogen Bonds by Acid Chloride

A multiple flame-retardant,early fire-warning,and highly sensitive thread-shaped all-fabric-based piezoresistive sensor

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science china(Technological sciences) 2024年第4期67卷 1151-1159页

作者： LI WeiBiao ZHANG Shuai ma ShuQi WANG JiaCheng WANG Huan YANG QiRong SONG YongTao zhu Jie North china Institute of Aerospace engineering Langfang 065000China Langfang Fire and Rescue Division of Hebei Province Langfang 065000China School of Information science and engineering Xinjiang College of Science and TechnologyKorla 841000China

In the artificial intelligence age,multifunctional and intelligent fireproof fabric-based electronics are urgently ***,a novel thread-shaped all-fabric-based piezoresistive sensor(denoted as TAFPS)with properties such as flame retardancy,firewarning,and piezoresistivity is proposed,which is composed of an inner nickel-plated fabric electrode,a multifunctional double helix fabric,and an external flame-retardant encapsulation *** to the multiple flame-retardant properties of glass fiber tubular fabric,aminated carbon nanotubes(ACNTs),and ammonium polyphosphate,the char residue of the TAFPS reaches40.3 wt%at 800℃.In addition,the heat-sensitive effect of ACNTs during combustion causes a rapid decrease in the TAFPS resistance,triggering the fire alarm system within 2 ***,benefiting from the force-sensitive behavior of the double helix layer and tightly wrapped pattern of the external heat-shrinkable tubular fabric,TAFPS demonstrated a high sensitivity of4.40 kPa^(-1)(0–5.81 k Pa)and good stability for 10000 *** its excellent flame resistance,high sensitivity,and agreeable stability,the developed TAFPS can be integrated into fire suits to monitor the exercise training process and the external fire *** work offers a novel approach for fabricating all-fabric-based piezoresistive sensors in the future for fire prevention and fire alarms,with promising applications in fire protection,the Internet of Things,and smart apparel.

关键词： all-fabric piezoresistive sensor multiple flame retardancy agile fire-warning high sensitivity

Multifunctional dual-anion compensation of amphoteric glycine hydrochloride enabled highly stable perovskite solar cells with prolonged carrier lifetime

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Nano Research 2024年第6期17卷 5131-5137页

作者： Lina Qin Mengfei zhu Yuren Xia Xingkai ma Daocheng Hong Yuxi Tian Zuoxiu Tie Zhong Jin State Key Laboratory of Coordination Chemistry MOE Key Laboratory of Mesoscopic ChemistryMOE Key Laboratory of High Performance Polymer Materials and TechnologyJiangsu Key Laboratory of Advanced Organic MaterialsSchool of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China Nanjing Tieming Energy technology Co.Ltd. Nanjing 210093China Suzhou Tierui New Energy technology Co.Ltd. Suzhou 215228China

Throughout years,the two-step spin-coating process is the most common method to prepare organic lead halide perovskite ***,the short reaction time of dropping the solution at the second step means that PbI2 cannot be completely transformed into perovskite *** solve this problem,we report the introduction of glycine hydrochloride(GlyHCl)into the second step of the two-step spin-coating process to prepare a FA_(0.9)ma_(0.1)PbI_(3-x)%-GlyHCl perovskite material(namely FAma-x%-GlyHCl,where FA=formamidinium,ma=methylammonium,and x%stands for the molar ratio of GlyHCl added in FA iodide/ma iodide(FAI/maI)precursor solution).The Cl−ion in GlyHCl assists the formation ofα-phase perovskite,and the-COO−group coordinates with Pb2+cation in a bridging way,making up for the anion vacancy in perovskite lattice and resulting in high absorption *** perovskite solar cells(PSCs)based on FAma-9%-GlyHCl achieve a long carrier lifetime(527.0 ns),a photoelectric conversion efficiency(PCE)of 19.40%and good thermal stability,maintaining 85.8%of the initial PCE after being continuously heated at 60℃for 500 *** study helps to solve the problem of incomplete reaction in the two-step spin-coating process and puts forward a new solution for preparing high coverage perovskite films with large grain size.

关键词： dual-anion compensation glycine hydrochloride perovskite solar cells carrier lifetime thermal and moisture stability