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Design and experimental research of a sub-Newton N_(2)O monopropellant thruster with inner-heater

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Chinese Journal of Aeronautics 2022年第5期35卷 309-318页

作者： Kaiyang LI Jie FANG wei sun bing sun Guobiao CAI School of Astronautics Beihang UniversityBeijing 100083China Key Laboratory of Spacecraft Design Optimization and Dynamic Simulation Technologies of Ministry of Education Beihang UniversityBeijing 100083China China Academy of Space Technology Beijing 100094China

Nitrous oxide(N_(2)O)is a green propellant with excellent application prospects.A subNewton N_(2)O monopropellant thruster with inner-heater and a N_(2)O self-pressurization stable supply system with regenerative heat compensation are designed in this paper.The experimental research of the thruster is described,including measurements of preheating power,activation temperature,vacuum thrust,specific impulse,life-span and pulsed operation performance.By inserting the heater into the catalyst-bed,preheating efficiency of the heater is significantly improved compared to the thruster with outer-heater.Thus,the preheating power demand of the thruster is successfully reduced to around 10 W.The mean vacuum thrust of 322 mN is attained and the corresponding specific impulse reaches 162s at the mass flow rate of 0.2 g/s.Successful activation temperature of 523 K is achieved,and the activation performance of the thruster is affected by the loading factor.A long term hot-firing test longer than 12000 s is attained.The pulsed operation performance of the inner-preheating thruster is also studied by measuring chamber pressure.Impulses with different magnitudes are produced by adjusting the opening duration of the control valve.A minimum impulse of 81 mN·s is attained.Finally,the performance of the thruster is evaluated by comparison with other thrusters of the same type.The results indicate that the proposed thruster with inner-heater is superior in terms of preheating power,activation temperature and specific impulse performance.

关键词： Green propellant Monopropellant thruster Nitrous oxide Regenerative heat compensation Self-pressurization

Heterologous production of bioactive xenoacremone analogs in Aspergillus nidulans

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Chinese Journal of Natural Medicines 2023年第6期21卷 436-442页

作者： LIU Zhiguo LI wei ZHANG Peng sun Yi YIN Wen-bing State Key Laboratory of Mycology Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China Institute of Chinese Materia Medica China Academy of Chinese Medical SciencesBeijing 100700China Savaid Medical School University of Chinese Academy of SciencesBeijing 100049China

Tyrosine-decahydrofluorene derivatives are a class of hybrid compounds that integrate the properties of polyketides and nonribosomal peptides.These compounds feature a[6.5.6]tricarbocyclic core and a para-cyclophane ether moiety in their structures and exhibit anti-tumor and anti-microbial activities.In this study,we constructed the biosynthetic pathway of xenoacremones from Xenoacremonium sinensis ML-31 in the Aspergillus nidulans host,resulting in the identification of four novel tyrosine-decahydrofluorene analogs,xenoacremones I–L(1-4),along with two known analogs,xenoacremones A and B.Remarkably,compounds 3 and 4 contained a 12-membered para-cyclophane ring system,which is unprecedented among tyrosine-decahydrofluorene analogs in X.sinensis.The successful reconstruction of the biosynthetic pathway and the discovery of novel analogs demonstrate the utility of heterologous expression strategy for the generation of structurally diverse natural products with potential biological activities.

关键词： Heterologous expression Xenoacremones Tyrosine-decahydrofluorene PKS-NRPS Natural products

Prediction of blast furnace gas generation based on data quality improvement strategy

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Journal of Iron and Steel Research(International) 2023年第5期30卷 864-874页

作者： Shu-han Liu Wen-qiang sun wei-dong Li bing-zhen Jin Department of Energy Engineering School of MetallurgyNortheastern UniversityShenyang 110819LiaoningChina State Environmental Protection Key Laboratory of Eco-Industry(Northeastern University) Ministry of Ecology and EnvironmentShenyang 110819LiaoningChina State Key Laboratory of Metal Material for Marine Equipment and Application Anshan 114009LiaoningChina Ansteel Iron and Steel Research Institute Ansteel Group Corporation LimitedAnshan 114009LiaoningChina General Heavy Section Mill Angang Steel Company LimitedAnshan 114021LiaoningChina

The real-time energy flow data obtained in industrial production processes are usually of low quality.It is difficult to accurately predict the short-term energy flow profile by using these field data,which diminishes the effect of industrial big data and artificial intelligence in industrial energy system.The real-time data of blast furnace gas(BFG)generation collected in iron and steel sites are also of low quality.In order to tackle this problem,a three-stage data quality improvement strategy was proposed to predict the BFG generation.In the first stage,correlation principle was used to test the sample set.In the second stage,the original sample set was rectified and updated.In the third stage,Kalman filter was employed to eliminate the noise of the updated sample set.The method was verified by autoregressive integrated moving average model,back propagation neural network model and long short-term memory model.The results show that the prediction model based on the proposed three-stage data quality improvement method performs well.Long short-term memory model has the best prediction performance,with a mean absolute error of 17.85 m3/min,a mean absolute percentage error of 0.21%,and an R squared of 95.17%.

关键词： Blast furnace gas Iron and steel industry Data quality improvement Artificial intelligence Gas generation prediction

Numerical investigation of transcritical liquid film cooling in a methane/oxygen rocket engine

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航空动力学报 2011年第4期26卷 903-916页

作者： YANG wei sun bing School of Astronautics Beijing University of Aeronautics and Astronautic Beijing 100191 China

Transcritical film cooling was investigated by numerical study in a methane cooled methane/oxygen rocket engine.The respective time-averaged Navier-Stokes equations have been solved for the compressible steady three-dimensional(3-D) flow.The flow field computations were performed using the semi-implicit method for pressure linked equation(SIMPLE) algorithm on several blocks of nonuniform collocated grid.The calculation was conducted over a pressure range of 202 650.0 Pa to 1.2×107 Pa and a temperature range of 120.0 K to 3 568.0 K.Twenty-nine different cases were simulated to calculate the impact of different factors.The results show that mass flow rate,length,diameter,number and diffused or convergence of film jet channel,injection angle and jet array arrangements have great impact on transcritical film cooling effectiveness.Furthermore,shape of the jet holes and jet and crossflow turbulence also affect the wall temperature distribution.Two rows of film arranged in different axial angles and staggered arrangement were proposed as new liquid film arrangement.Different radial angles have impact on the film cooling effectiveness in two row-jets cooled cases.The case of in-line and staggered arrangement are almost the same in the region before the second row of jets,but a staggered arrangement has a higher film cooling effectiveness from the second row of jets.

关键词： liquid film cooling numerical study rocket transcritical semi-implicit method for pressure linked equation(SIMPLE) film cooling effectiveness

Study on fluid-structure interaction in liquid oxygen feeding pipe systems using finite volume method

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Acta Mechanica Sinica 2011年第5期27卷 706-712页

作者： Xin wei bing sun Institute of Telecommunication Satellite China Academy of Space Technology100194 Beijing China School of Astronautics Beihang University 100191 Beijing China

The fluid-structure interaction may occur in space launch vehicles,which would lead to bad performance of vehicles,damage equipments on vehicles,or even affect astronauts＇ health.In this paper,analysis on dynamic behavior of liquid oxygen （LOX） feeding pipe system in a large scale launch vehicle is performed,with the effect of fluid-structure interaction （FSI） taken into consideration.The pipe system is simplified as a planar FSI model with Poisson coupling and junction coupling.Numerical tests on pipes between the tank and the pump are solved by the finite volume method.Results show that restrictions weaken the interaction between axial and lateral vibrations.The reasonable results regarding frequencies and modes indicate that the FSI affects substantially the dynamic analysis,and thus highlight the usefulness of the proposed model.This study would provide a reference to the pipe test,as well as facilitate further studies on oscillation suppression.

关键词： Fluid-structure interaction · Liquid oxygen · Finite volume method

Insight into the dynamic adsorption behavior of graphene oxide multichannel architecture toward contaminants

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Chinese Journal of Chemical Engineering 2023年第1期53卷 124-132页

作者： Jian Tian Gen Li Wang He Kok bing Tan Daohua sun Junfu wei Qingbiao Li Department of Chemical and Biochemical Engineering College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China College of Chemistry and Chemical Engineering Tiangong UniversityTianjin 300387China College of Food and Biological Engineering Jimei UniversityXiamen 361021China

Graphene oxide(GO) channels exhibit unique mass transport behaviors due to their flexibility, controllable thinness and extraordinary physicochemical properties, enabling them to be widely used for adsorption and membrane separation. Nevertheless, the adsorption behavior of nanosized contaminants within the channels of GO membrane has not been fully discussed. In this study, we fabricated a GO membrane(PGn, where n represents the deposition cycles of GO) with multi channels via the crosslinking of GO and multibranched poly(ethyleneimine)(PEI). Phenol was used as molecular probe to determine the correlations between dynamic adsorption behavior and structural parameters of the multilevel GO/PEI membrane. PG8 shows higher adsorption capacities and affinity, which is predominantly attributed to the multichannel structure providing a large specific surface for phenol adsorption, enhancing the accessibility of active sites for phenol molecules and the transport of phenol. Density functional theory calculations demonstrate that the adsorption mechanism of phenol within GO channel is energetically oriented by hydrogen bonds, which is dominated by oxygen-containing groups compared to amino groups. Particularly, the interfaces which facilitate strong π-π interaction and hydrogen bonds maybe the most active regions. Moreover, the as-prepared PG8 membrane showed outstanding performance for other contaminants such as methyl orange and Cr(VI). It is anticipated that this study will have implications for design of GO-related environmental materials with enhanced efficiency.

关键词： Graphene oxide Multichannel Adsorptive behavior Phenol DFT calculations

Application of ultrasonic vibration to shape-casting based on resonance vibration analysis

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China Foundry 2023年第4期20卷 339-346页

作者： Zong-hang Han Zhi-ming Wang Zhi-ping sun bing-rong Zhang wei-feng Rao School of Mechanical Engineering Qilu University of Technology(Shandong Academy of Sciences)Jinan 250353China Jinan Shengquan Group Jinan 250204China

The application of ultrasonic vibration during the casting process has been proven to refine the microstructure and enhance the properties of the casting.By using the direct inserting method,wherein the ultrasonic horn is inserted directly into the melt,ultrasonic treatment can be utilized in the semi-continuous casting process to produce aluminum ingots with simple shapes.However,due to the attenuation of ultrasound,it is challenging to apply the direct inserting method in the die casting process to produce complex castings.Thus,in this study,the impact of ultrasonic vibration on the microstructure of a gravity die-cast AlSi9Cu3end cap was investigated by applying ultrasonic vibration on the core(indirect method).It is found that the effect of ultrasonic vibration relies greatly on the resonance mode of the core.Selection of ultrasonic vibration schemes mainly depends on the core structure,and only a strong vibration can significantly refine the microstructure of the casting.For castings with complex structures,an elaborated ultrasonic vibration design is necessary to refine the microstructure of the specified casting.In addition,strong vibration applied on the feeding channel can promote the feeding ability of casting by breaking the dendrites during solidification,and consequently reduce the shrinkage porosity.

关键词： resonance mode ultrasonic vibration feeding channel aluminum alloy casting

PLEK2 promotes cancer stemness and tumorigenesis of head and neck squamous cell carcinoma via the c-Myc-mediated positive feedback loop

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Cancer Communications 2022年第10期42卷 987-1007页

作者： Xinyuan Zhao Dalong Shu Wenjuan sun Shanshan Si wei Ran bing Guo Li Cui Department of Endodontics Stomatological HospitalSouthern Medical UniversityGuangzhouGuangdong 510280P.R.China Department of Oral and Maxillofacial Surgery The First Affiliated HospitalSun Yat-sen UniversityGuangzhouGuangdong 510080P.R.China Department of Stomatology The Third Affiliated HospitalSun Yat-sen UniversityGuangzhouGuangdong 510630P.R.China Department of Oral Emergency Stomatological HospitalSouthern Medical UniversityGuangzhouGuangdong 510280P.R.China Department of Dentistry The First Affiliated HospitalSun Yat-sen UniversityGuangzhouGuangdong 510080P.R.China Department of Oral and Maxillofacial Surgery Stomatological HospitalSouthern Medical UniversityGuangzhouGuangdong 510280P.R.China Division of Oral Biology and Medicine School of DentistryUniversity of CaliforniaLos AngelesLos AngelesCalifornia 90095United States

Background:Head and neck squamous cell carcinoma(HNSCC)is one of the most frequent malignancies worldwide and is characterized by unfavorable prognosis,high lymph node metastasis and early recurrence.However,the molecular events regulating HNSCC tumorigenesis remain poorly understood.Therefore,uncovering the underlying mechanisms is urgently needed to identify novel and promising therapeutic targets for HNSCC.In this study,we aimed to explore the role of pleckstrin-2(PLEK2)in regulating HNSCC tumorigenesis.Methods:The expression pattern of PLEK2 and its clinical significance in HNSCC were determined by analyzing publicly assessable datasets and our own independent HNSCC cohort.In vitro and in vivo experiments,including cell proliferation,colony formation,Matrigel invasion,tumor sphere formation,ALDEFLUOR,Western blotting assays and xenograft mouse models,were used to investigate the role of PLEK2 in regulating the malignant behaviors of HNSCC cells.The underlying molecular mechanisms for the tumor-promoting role of PLEK2 were elucidated using co-immunoprecipitation,cycloheximide chase analysis,ubiquitination assays,chromatin immunoprecipitation-quantitative polymerase chain reaction,luciferase reporter assays and rescue experiments.Results:The expression levels of PLEK2 mRNA and protein were significantly increased in HNSCC tissues,and PLEK2 overexpression was strongly associated with poor overall survival and therapeutic resistance.Additionally,PLEK2 was important for maintaining the proliferation,invasion,epithelial-mesenchymal transition,cancer stemness and tumorigenesis of HNSCC cells and could alter the cellular metabolism of the cancer cells.Mechanistically,PLEK2 interacted with c-Myc and reduced the association of F-box and WD repeat domain containing 7(FBXW7)with c-Myc,thereby avoiding ubiquitination and subsequent proteasome-mediated degradation of c-Myc.Moreover,the c-Myc signaling activated by PLEK2 was important for sustaining the aggressive malignant phenotypes and tumorigenesis of HNSCC cells.c-M

关键词： c-Myc cancer stemness FBXW7 HNSCC PLEK2 positive feedback loop tumorigenesis ubiquitination-mediated degradation

Differences in distributions, assembly mechanisms, and putative interactions of AOB and NOB at a large spatial scale

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Frontiers of Environmental Science & Engineering 2023年第10期17卷 55-64页

作者： bing Zhang Chenxiang sun Huimin Lin wei Liu Wentao Qin Tan Chen Ting Yang Xianghua Wen College of Life and Environmental Sciences Minzu University of ChinaBeijing 100081China Environmental Simulation and Pollution Control State Key Joint Laboratory School of EnvironmentTsinghua UniversityBeijing 100084China Institute of Plant Protection Beijing Academy of Agriculture and Forestry SciencesBeijing 100097China

Ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) play crucial roles in removing nitrogen from sewage in wastewater treatment plants (WWTPs) to protect water resources. However, the differences in ecological properties and putative interactions of AOB and NOB in WWTPs at a large spatial scale remain unclear. Hence, 132 activated sludge (AS) samples collected from 11 cities across China were studied by utilizing 16S rRNA gene sequencing technology. Results indicated that Nitrosomonas and Nitrosospira accounted for similar ratios of the AOB community and might play nearly equal roles in ammonia oxidation in AS. However, Nitrospira greatly outnumbered other NOB genera, with proportions varying from 94.7% to 99.9% of the NOB community in all WWTPs. Similar compositions and, hence, a low distance–decay turnover rate of NOB (0.035) across China were observed. This scenario might have partly resulted from the high proportions of homogenizing dispersal (~13%). Additionally, drift presented dominant roles in AOB and NOB assembling mechanisms (85.2% and 81.6% for AOB and NOB, respectively). The partial Mantel test illustrated that sludge retention time and temperature were the primary environmental factors affecting AOB and NOB communities. Network results showed that NOB played a leading role in maintaining module structures and node connections in AS. Moreover, most links between NOB and other microorganisms were positive, indicating that NOB were involved in complex symbioses with bacteria in AS.

关键词： Activated sludge Spatial distributions Microbial assembly Co-occurrence patterns Nitrifying bacteria