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Mechanical properties of rock materials with related to mineralogical characteristics and grain size through experimental investigation： a comprehensive review

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Frontiers of Structural and Civil Engineering 2017年第3期11卷 322-328页

作者： Wenjuan Sun Linbing WANG Yaqiong WANG USTB-Virginia Tech Joint Lab on Multifunctional Materials National Center for Materials Service Safety University of Science and Technology Beijing Beijing China Virginia Tech Blacksburg VA 24061 United States Shaanxi Provincial Key Laboratory for Highway Bridge & Tunnel Chang'an University Xi'an 710064 China

Mechanical properties of rock materials are related to textural characteristics. The relationships between mechanical properties and textural characteristics have been extensively investigated for differently types of rocks through experimental tests. Based on the experimental test data, single- and multiple- variant regression analyses are conducted among mechanical properties and textural characteristics. Textural characteristics of rock materials are influenced by the following factors： mineral composition, size, shape, and spatial distribution of mineral grains, porosity, and inherent microcracks. This study focuses on the first two： mineral composition and grain size. This study comprehensively summarizes the regression equations between mechanical properties and mineral content and the regression equations between mechanical properties and grain size. Further research directions are suggested at the end of this study.

关键词： Mechanical properties rock material texture mineral characteristics

Insights into the cross-amyloid aggregation of Aβ_(40) and its N-terminal truncated peptide Aβ_(11-40) affected by epigallocatechin gallate

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Chinese Journal of Chemical Engineering 2022年第5期35卷 284-293页

作者： Yue Liang wenjuan Wang Yan sun Xiaoyan Dong Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering(Ministry of Education) School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300354China

Inhibition of protein misfolding and aggregation is a great challenge in the field of biochemical and biopharmaceutical engineering.Alzheimer’s disease(AD)is a protein-misfolding disease,and the interactions between 40-amino-acid-residueβ-amyloid peptide(Aβ_(40)) and its N-terminal truncated peptide Aβ_(11-40) demonstrate that Aβ_(11-40) may play an important role in the pathological process of AD.However,the effect of inhibitors on Aβ_(11-40) aggregation and on the cross-amyloid aggregation(coassembly)between Aβ_(40) and Aβ_(11-40) has never been studied.Herein,coaggregation and seeding interactions between Aβ_(40) and Aβ_(11-40) as well as the effect of epigallocatechin gallate(EGCG),a small molecule inhibitor,on the cross-amyloid aggregation have been investigated by extensive analyses.It is found that Aβ_(11-40) participates in the aggregation of Aβ_(40) and leads to the formation of coaggregates that contain lessβ-sheet structures than pure Aβ_(40) aggregates.The aggregation kinetics along with morphologies and secondary structures of the coaggregates are also significantly affected by the Aβ_(40)/Aβ_(11-40) ratio.EGCG accelerates the nucleation of Aβ_(40) but retards that of Aβ_(11-40) by affecting their elongation and secondary nucleation processes in solution and on solid surfaces.Meanwhile,EGCG makes the conformations of the seeding-induced Aβaggregates more compact,especially for the homologous seedings.Isothermal titration calorimetry measurement indicates that hydrophobic interactions mainly contribute to the inhibition of the two Aβisoforms by EGCG.The findings of this research have provided new insights into Aβaggregation and the effect of an important inhibitor and the results would benefit in the development of potent inhibitors against co-assembly of different amyloid proteins.

关键词： Protein Aggregation Kinetics Nucleation Elongation Molecular interactions

Preparation of high-purity fluorite and nanoscale calcium carbonate from low-grade fluorite

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1198-1207页

作者： Qianqian Lu Haisheng Han Wenjuan Sun Xingfei Zhang Weiwei Wang Bilan Zhang Wensheng Chen Qin Zou School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083China Hunan Nonferrous Chenzhou Fluoride Chemical Co. Ltd.Chenzhou 423000China State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization Baotou Research Institute of Rare EarthsBaotou 014030China Hunan Shizhuyuan Nonferrous Metal Co. Ltd.Chenzhou 423000China

Flotation separation of calcite from fluorite is a challenge on low-grade fluorite flotation that limits the recovery and purity of fluorite concentrate.A new acid leaching–flotation process for fluorite is proposed in this work.This innovative process raised the fluor-ite’s grade to 97.26wt%while producing nanoscale calcium carbonate from its leachate,which contained plenty of calcium ions.On the production of nanoscale calcium carbonate,the impacts of concentration,temperature,and titration rate were examined.By modifying the process conditions and utilizing crystal conditioning agents,calcite-type and amorphous calcium carbonates with corresponding particle sizes of 1.823 and 1.511μm were produced.The influence of the impurity ions Mn^(2+),Mg^(2+),and Fe^(3+)was demonstrated to reduce the particle size of nanoscale calcium carbonate and make crystal shape easier to manage in the fluorite leach solution system compared with the calcium chloride solution.The combination of the acid leaching–flotation process and the nanoscale calcium carbonate preparation method improved the grade of fluorite while recovering calcite resources,thus presenting a novel idea for the effective and clean usage of low-quality fluorite resources with embedded microfine particles.

关键词： fluorite calcite nanoscale calcium carbonate waste recovery

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

Mapping the vertical distribution of maize roots in China in relation to climate and soil texture

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Journal of Plant Ecology 2018年第6期11卷 899-908页

作者： Sheng Wang Yao Huang Wenjuan Sun Lingfei Yu State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of Sciences20 NanxincunXiangshanBeijing 100093China University of Chinese Academy of Sciences No.19 Yuquan RoadShijingshan DistrictBeijing 100049China

Aims Optimizing water and fertilizer management for crops requires an understanding of root distribution.Maize(Zea mays L.)is currently the most widely planted cereal crop in China,yet the vertical dis-tribution of maize roots across different regions remains unknown.The aims of this work were(i)to quantify the effects of climate and soil texture on the vertical distribution of maize roots,and(ii)to show the depth distribution of root biomass in China.Methods We used data of maize root biomass from 11 Chinese ecological stations with discontinuous observations from 2004 to 2014 to fit the regression coefficientβfor an asymptotic equation Y=1-βd,where d is the soil depth and Y is the proportion of root biomass from the surface to depth d.A statistical model was then developed to quantify the effects of climate and soil texture on the fittedβval-ues.Using the statistical model,we map the depth distribution of maize root biomass in China.Important Findings Maize root biomass in the 0-100 cm soil depth varied by an order of magnitude at different stations,from 64 to 268 g m−2.Maize planted in sandy soils and/or maize with high accumu-lated temperature for development had higher root biomass and deeper rooting systems.The fittedβvalues ranged from 0.785 to 0.977,which can be modeled by an integration of the accu-mulated temperature during the maize growing period and the soil clay and sand fractions(R2=0.66,n=50,P<0.001).Up to 82%of maize planting regions in China showed shallower rooting systems where more than 90%and 95%of the root bio-mass occurred in the top 20 and 30 cm soil layers,respectively.Deeper rooting systems occurred in some temperate arid and temperate semi-arid regions,with less than 80%of the root bio-mass in the top 20 cm soil.Our findings highlighted the vertical distribution of maize roots,and underlined the spatial variability in the vertical distribution of roots across China’s planting areas of maize.

关键词： accumulated temperature maize root soil texture statistical model vertical distribution

Design and validation of a variable camber wing structure

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Chinese Journal of Aeronautics 2024年第2期37卷 1-11页

作者： Xiasheng sun Jingfeng XUE Jin ZHOU Zhigang WANG wenjuan WANG Mengjie ZHANG Chinese Aeronautical Establishment Beijing 100012China School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China Aircraft Strength Research Institute of China Xi’an 710065China Graduate School of Chinese Aeronautical Establishment Yangzhou 225002China

Variable camber wing technology is one of the important development trends of green aviation at present.Through smooth,seamless,continuous and adaptive change of wing camber,the aerodynamic performance is improved in achieving increase in lift and reduction in resistance and noise.Based on the aerodynamic validation model CAE-AVM,Chinese Aeronautical Establishment(CAE)has carried out the design and validation of a variable camber wing,proposed an aerodynamic deformation matrix for the leading and trailing edges of aircraft wings in takeoff,landing and cruise conditions.Various structures and driving schemes are compared,and several key technology problems of leading and trailing edge deformation are solved.A full-size leading edge wind tunnel test piece with a span of 2.7 m and a trailing edge ground function test piece are developed.The deformation and shape maintenance capabilities of the leading edge is verified under real wind load conditions,and the load bearing and deformation capabilities of the trailing edge is verified under simulated follow-on load.The results indicate that the leading and trailing edges of the variable camber wing can achieve the required deformation angle and have a certain load-bearing capacity.Our study can provide some insights into the application of variable camber wing technology for civil aircraft.

关键词： Variable camber wing Leading edge Trailing edge Structure Measurement and control Test

PtCo-based nanocatalyst for oxygen reduction reaction:Recent highlights on synthesis strategy and catalytic mechanism

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Chinese Journal of Chemical Engineering 2023年第1期53卷 101-123页

作者： wenjuan Yan Puhua sun Chen Luo Xingfan Xia Zhifei Liu Yuming Zhao Shuxia Zhang Liang sun Feng Du State Key Laboratory of Heavy Oil Processing Center for Chemical Engineering Experimental TeachingOil Industry Training CenterChina University of PetroleumQingdao 266580China Petrochemical Research Institute PetroChinaBeijing 102200China

Oxygen reduction reaction over Pt-based catalyst is one of the most significant cathode reactions in fuel cells.However,low reserves and high price of Pt have motivated researchers worldwide seeking enhanced utilization efficiency and durability by doping non-noble metals to form Pt-based alloy catalysts.Alloying Pt with Co has been recognized as one of the most effective approaches to achieve this goal.PtCo bimetal combination is one of the most promising candidates to synthesize highly efficient catalysts for oxygen reduction reaction(ORR)applications,owing to its relatively more suitable oxygen binding energy for four-electron transfer reactions.Recently,impressive strategies have been developed to fabricate more active and stable PtCo-based multimetallic alloys with tailorable size and morphology.This paper aims to summarize the most recent highlights on the study of the relationship between preparation strategies,morphologies,electroactivities of the PtCo-based catalyst at atomic level and further the relevant reaction mechanism.The challenges and opportunities on the further development of electrocatalysts for fuel cells are included to provide reference for the practical application.

关键词： Electrochemistry Catalysis Oxygen reduction reaction Fuel cells PtCo nanoalloy Multimetallic

Using Organic Matter and pH to Estimate the Bulk Density of Afforested/Reforested Soils in Northwest and Northeast China

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Pedosphere 2017年第5期27卷 890-900页

作者： CHEN Yue HUANG Yao sun wenjuan State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences

Regression models for predicting soil bulk density(BD) have usually been related to organic matter content, but it remains unknown whether soil acidity modifies this relationship, particularly for afforested/reforested soils. We measured soil BD along with organic matter content and pH in an afforested/reforested area in Northwest and Northeast China. Using these measurements, we parameterized and validated three BD models: the Adams equation, and exponential and radical models. Model validation showed that the Adams equation failed to predict the BD of the afforested/reforested soils, producing a large overestimation. Incorporation of soil pH into the Adams equation significantly improved its performance. The exponential and radical models parameterized by the measured data simulated soil BD quite well, particularly when soil pH was incorporated. However, incorporation of soil texture variables into these models did not improve model performance compared with the pH-modified models. This led to the conclusion that the Adams equation, exponential, and radical models with pH modification are applicable to afforested/reforested soils with various acidities.

关键词：土壤pH值有机质含量土壤容重造林绿化中国西北体积密度东北模型预测

改造与新生——20世纪五六十年代“海派”艺术家与新国画

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美术 2022年第10期 144-146页

作者：孙文娟上海美术学院

中华人民共和国成立后,上海城市性质及艺术家生存空间发生巨大改变。在新文艺政策的号召下,上海艺术家们积极深入生活,创作了一批反映劳动主题的工业题材海派新国画,并从传统绘画格局加“工业符号”和现实主义题材“微弱的现代主义回声... 详细信息

中华人民共和国成立后,上海城市性质及艺术家生存空间发生巨大改变。在新文艺政策的号召下,上海艺术家们积极深入生活,创作了一批反映劳动主题的工业题材海派新国画,并从传统绘画格局加“工业符号”和现实主义题材“微弱的现代主义回声”中,开拓了海派新国画的地域特色,形成了海派新国画在20世纪五六十年代改造中独有的审美价值与艺术特征。

关键词：海派艺术家新国画工业题材