期刊文献+
共找到109篇文章
< 1 2 6 >
每页显示 20 50 100
Invariant and energy analysis of an axially retracting beam 被引量:4
1
作者 Yang Xiaodong Liu Ming +1 位作者 Zhang Wei Roderick V.N.Melnik 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2016年第4期952-961,共10页
The mechanism of a retracting cantilevered beam has been investigated by the invariant and energy-based analysis. The time-varying parameter partial differential equation governing the transverse vibrations of a beam ... The mechanism of a retracting cantilevered beam has been investigated by the invariant and energy-based analysis. The time-varying parameter partial differential equation governing the transverse vibrations of a beam with retracting motion is derived based on the momentum theorem. The assumed-mode method is used to truncate the governing partial differential equation into a set of ordinary differential equations (ODEs) with time-dependent coefficients. It is found that if the order of truncation is not less than the order of the initial conditions, the assumed-mode method can yield accurate results. The energy transfers among assumed modes are discussed during retraction. The total energy varying with time has been investigated by numerical and analytical methods, and the results have good agreement with each other. For the transverse vibrations of the axially retracting beam, the adiabatic invariant is derived by both the averaging method and the Bessel function method. (C) 2016 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license. 展开更多
关键词 Adiabatic invariants Asymptotic analysis retracting beam Time-varying systems Transient dynamics
原文传递
Reliability Analysis of Retracting Actuator with Multi-State Based on Goal Oriented Methodology 被引量:3
2
作者 周琳玕 董海平 +2 位作者 伊枭剑 李媛媛 赖岳华 《Journal of Shanghai Jiaotong university(Science)》 EI 2015年第3期307-311,共5页
In order to conduct effective reliability analysis of retracting actuator with multi-state(success state,safety failure state and action failure state), we redefine type-3 operator in goal oriented(GO) method to descr... In order to conduct effective reliability analysis of retracting actuator with multi-state(success state,safety failure state and action failure state), we redefine type-3 operator in goal oriented(GO) method to describe three states of main charge of retracting actuator and improve type-15 operator in GO method to describe the logic relations of multi-state output. The quantitative and qualitative reliability analyses of retracting actuator are made based on GO method in this paper. The system state probability of retracting actuator is obtained through quantitative analysis, and its weakness is found through qualitative analysis. The analysis results show that GO method is effective to improve the reliability of retracting actuator, and this method is also feasible for reliability analysis of other complicated initiating explosive systems. 展开更多
关键词 retracting actuator goal oriented(GO) methodology OPERATOR MULTI-STATE reliability analysis
原文传递
A comparative study on characteristics of retracted publications across different open access levels
3
作者 Er-Te Zheng Hui-Zhen Fu 《Journal of Data and Information Science》 CSCD 2024年第2期22-40,共19页
Purpose:Recently,global science has shown an increasing open trend,however,the characteristics of research integrity of open access(OA)publications have rarely been studied.The aim of this study is to compare the char... Purpose:Recently,global science has shown an increasing open trend,however,the characteristics of research integrity of open access(OA)publications have rarely been studied.The aim of this study is to compare the characteristics of retracted articles across different OA levels and discover whether OA level influences the characteristics of retracted articles.Design/methodology/approach:The research conducted an analysis of 6,005 retracted publications between 2001 and 2020 from the Web of Science and Retraction Watch databases.These publications were categorized based on their OA levels,including Gold OA,Green OA,and non-OA.The study explored retraction rates,time lags and reasons within these categories.Findings:The findings of this research revealed distinct patterns in retraction rates among different OA levels.Publications with Gold OA demonstrated the highest retraction rate,followed by Green OA and non-OA.A comparison of retraction reasons between Gold OA and non-OA categories indicated similar proportions,while Green OA exhibited a higher proportion due to falsification and manipulation issues,along with a lower occurrence of plagiarism and authorship issues.The retraction time lag was shortest for Gold OA,followed by non-OA,and longest for Green OA.The prolonged retraction time for Green OA could be attributed to an atypical distribution of retraction reasons.A comparative study on characteristics of retracted publications across different open access levels Research limitations:There is no exploration of a wider range of OA levels,such as Hybrid OA and Bronze OA.Practical implications:The outcomes of this study suggest the need for increased attention to research integrity within the OA publications.The occurrences offalsification,manipulation,and ethical concerns within Green OA publications warrant attention from the scientific community.Originality/value:This study contributes to the understanding of research integrity in the realm of OA publications,shedding light on retraction patterns and reasons across different OA levels. 展开更多
关键词 Open access Retracted publications Reasons for retraction Retraction time lag BIBLIOMETRICS
下载PDF
Amend:An integrated platform of retracted papers and concerned papers
4
作者 Menghui Li Fuyou Chen +2 位作者 Sichao Tong Liying Yang Zhesi Shen 《Journal of Data and Information Science》 CSCD 2024年第2期41-55,共15页
Purpose:The notable increase in retraction papers has attracted considerable attention from diverse stakeholders.Various sources are now offering information related to research integrity,including concerns voiced on ... Purpose:The notable increase in retraction papers has attracted considerable attention from diverse stakeholders.Various sources are now offering information related to research integrity,including concerns voiced on social media,disclosed lists of paper mills,and retraction notices accessible through journal websites.However,despite the availability of such resources,there remains a lack of a unified platform to consolidate this information,thereby hindering efficient searching and cross-referencing.Thus,it is imperative to develop a comprehensive platform for retracted papers and related concerns.This article aims to introduce“Amend,”a platform designed to integrate information on research integrity from diverse sources.Design/methodology/approach:The Amend platform consolidates concerns and lists of problematic articles sourced from social media platforms(e.g.,PubPeer,For Better Science),retraction notices from journal websites,and citation databases(e.g.,Web of Science,CrossRef).Moreover,Amend includes investigation and punishment announcements released by administrative agencies(e.g.,NSFC,MOE,MOST,CAS).Each related paper is marked and can be traced back to its information source via a provided link.Furthermore,the Amend database incorporates various attributes of retracted articles,including citation topics,funding details,open access status,and more.The reasons for retraction are identified and classified as either academic misconduct or honest errors,with detailed subcategories provided for further clarity.Findings:Within the Amend platform,a total of 32,515 retracted papers indexed in SCI,SSCI,and ESCI between 1980 and 2023 were identified.Of these,26,620(81.87%)were associated with academic misconduct.The retraction rate stands at 6.64 per 10,000 articles.Notably,the retraction rate for non-gold open access articles significantly differs from that for gold open access articles,with this disparity progressively widening over the years.Furthermore,the reasons for retractions have shifted from traditional individual behaviors like falsification,fabrication,plagiarism,and duplication to more organized large-scale fraudulent practices,including Paper Mills,Fake Peer-review,and Artificial Intelligence Generated Content(AIGC).Research limitations:The Amend platform may not fully capture all retracted and concerning papers,thereby impacting its comprehensiveness.Additionally,inaccuracies in retraction notices may lead to errors in tagged reasons.Practical implications:Amend provides an integrated platform for stakeholders to enhance monitoring,analysis,and research on academic misconduct issues.Ultimately,the Amend database can contribute to upholding scientific integrity.Originality/value:This study introduces a globally integrated platform for retracted and concerning papers,along with a preliminary analysis of the evolutionary trends in retracted papers. 展开更多
关键词 Research Integrity Retraction Rate Academic Misconduct Reasons for Retraction Temporal Trends
下载PDF
A new technique for correction of iatrogenic upper eyelid retraction by using a composite flap of the orbicularis muscle and fascia on the anterior surface of the tarsal plate
5
作者 Kaichong Nie Lidan Chen +4 位作者 Xinzhu Qi Shiruo Zhang Xuanyu Yin Miaomiao Zhao Yuanyuan Du 《Chinese Journal of Plastic and Reconstructive Surgery》 2024年第3期116-123,共8页
Background:Upper eyelid retraction is a challenging complication of cosmetic upper eyelid blepharoplasty.To avoid extra trauma,we developed a new technique for correcting iatrogenic upper eyelid retraction by postmigr... Background:Upper eyelid retraction is a challenging complication of cosmetic upper eyelid blepharoplasty.To avoid extra trauma,we developed a new technique for correcting iatrogenic upper eyelid retraction by postmigrating a compound flap of the orbicularis muscle and fascia(OFC)on the anterior surface of the tarsal plate.This method extends the aponeurosis of the levator palpebrae superioris muscle(LPS),which can achieve a good correction for post-blepharoplasty retraction.Methods:We collected data from 15 patients with mild to moderate iatrogenic upper eyelid retraction who were treated at our hospital between February 2017 and December 2019.The OFC was used to replace the missing part of the LPS,and post-migration of the LPS and fixation of the OFC to the tarsal margin were conducted.Postoperative outcome measurements included postoperative binocular symmetry,double eyelid smoothness,eyelid fullness,margin reflex distance(MRD1),degree of eyelid closure,and exposure keratitis.The patients were followed-up at seven days,one month,and six months postoperatively.Results:One patient with moderate eyelid retraction showed undercorrection 6 months postoperatively,with the upper eyelid margin located at the upper edge of the pupil.The remaining patients had the upper eyelid margin stabilized at 1.0–2.0 mm below the upper corneal margin.Other observational indicators were satisfactory,including binocular symmetry,double eyelid fluency,and eyelid fullness.During the follow-up,no exposure keratitis was identified.The MRD1 indexes after the operation were significantly different(P<0.001)from those before the procedure.Conclusions:Extension and post-migration of the LPS using the orbicularis muscle and OFC structure can effectively correct mild iatrogenic eyelid retraction after ptosis with less damage and good postoperative eyelid morphology and closure function. 展开更多
关键词 Upper eyelid retraction Levator palpebrae superioris Orbicularis muscle and fascia MIGRATION
下载PDF
Retraction note:Clinical analysis of colistin sulfate in the treatment of pneumonia caused by carbapenem-resistant Gram-negative bacteria
6
作者 Jia-Ping Yan Jin-Lei Wang 《World Journal of Clinical Cases》 SCIE 2024年第19期4029-4030,共2页
In this retraction note,we describe the World Journal of Clinical Cases(WJCC)Editorial Office’s decision and reason for retracting an article published in WJCC,volume 12,issue 13.
关键词 World Journal of Clinical Cases Retraction note
下载PDF
Retraction note to:RNA-binding protein CPSF6 regulates IBSP to affect pyroptosis in gastric cancer
7
作者 Xue-Jun Wang Yong Liu +2 位作者 Bin Ke Li Zhang Han Liang 《World Journal of Gastrointestinal Oncology》 SCIE 2024年第6期2865-2866,共2页
The authors have decided to retract the article published on World J Gastrointest Oncol(2023)for further consideration due to data errors and some misunderstandings in communication.
关键词 Retraction note
下载PDF
Retraction note to:Association between triglyceride-glucose index and colorectal polyps:A retrospective cross-sectional study
8
作者 Ya-Jie Teng Ying-Xue Yang +5 位作者 Jing-Jing Yang Qiu-Yan Lu Jia-Yi Shi Jian-Hao Xu Jie Bao Qing-Hua Wang 《World Journal of Gastrointestinal Endoscopy》 2024年第8期500-501,共2页
We have decided to retract the above article because we have concluded that the limitations in our data sample may potentially lead to misinterpretation of the findings.
关键词 World Journal of Gastrointestinal Endoscopy Retraction note
下载PDF
Using Flowable Composite as Gingival Retraction Cord in Prosthodontics Dentistry: Two Case Reports: A Dental Technique
9
作者 Fahad Hussain Alqahtani 《Open Journal of Stomatology》 2024年第2期118-131,共14页
One of the most challenging factors affecting impression quality and good marginal fit is the gingival retraction method, which aims to separate the gingiva from the tooth to expose the finishing line of the prepared ... One of the most challenging factors affecting impression quality and good marginal fit is the gingival retraction method, which aims to separate the gingiva from the tooth to expose the finishing line of the prepared tooth. Bleeding and contamination from the crevicular fluid may compete for space with the impression material within the sulcus, leading to indistinct preparations and a lack of detail at the margin. In addition, such procedures might damage the PDL and cause permanent recession. Flowable composite cable, as opposed to traditional retraction cords, offers the proper marginal seal and visibility during the impression record because of its lower viscosity, improved adaptability, and elastic properties. The aim of this report is to present a brand-new, innovative method for controlling gingival hemorrhage in addition to the gingival retraction in restorative and prosthodontic treatment by utilizing a flowable composite during the final impression record procedure. In these case reports, the flowable composite cord technique is used instead of traditional gingival cords to modify and refine the gingival tissue before taking the traditional final impression or digital scan. Two cases were done for patients undergoing fixed prosthodontics and veneer treatment within a 2-year follow-up period. In addition, the flowable composite cord was used as temporary restoration before the final prosthetic cementation or under the provisional crowns. As a result, clean and healthy gingival tissues render cementation of the final prosthesis quicker and easier to perform. The patients in both cases claimed that their prosthodontic treatments, which involved the application of a flowable composite cord to temporarily retraction the gingiva, had produced good outcomes at the yearlong follow-up. In conclusion, the flowable composite cord technique is found to be a useful tool to improve the quality of impressions in fixed prosthodontics by providing excellent access for impression material to record fine details of the finish line of the prepared tooth structure, and to alter the inflamed tissue into a healthy tissue. 展开更多
关键词 Flowable Composite Gingival Retraction Methods Impression Material Marginal Integrity Final Cementation
下载PDF
Research misconduct in hospitals is spreading:A bibliometric analysis of retracted papers from Chinese university-affiliated hospitals 被引量:2
10
作者 Zi-han Yuan Yi Liu 《Journal of Data and Information Science》 CSCD 2023年第4期84-101,共18页
Purpose: The number of retracted papers from Chinese university-affiliated hospitals is increasing, which has raised much concern. The aim of this study is to analyze the retracted papers from university-affiliated ho... Purpose: The number of retracted papers from Chinese university-affiliated hospitals is increasing, which has raised much concern. The aim of this study is to analyze the retracted papers from university-affiliated hospitals in China’s mainland from 2000 to 2021. Design/methodology/approach: Data for 1,031 retracted papers were identified from the Web of Science Core collection database. The information of the hospitals involved was obtained from their official websites. We analyzed the chronological changes, journal distribution, discipline distribution and retraction reasons for the retracted papers. The grade and geographic locations of the hospitals involved were explored as well.Findings: We found a rapid increase in the number of retracted papers, while the retraction time interval is decreasing. The main reasons for retraction are plagiarism/self-plagiarism(n=255), invalid data/images/conclusions(n=212), fake peer review(n=175) and honesty error(n=163). The disciplines are mainly distributed in oncology(n=320), pharmacology & pharmacy(n=198) and research & experimental medicine(n=166). About 43.8% of the retracted papers were from hospitals affiliated with prestigious universities. Research limitations: This study fails to differentiate between retractions due to honest error and retractions due to research misconduct. We believe that there is a fundamental difference between honest error retractions and misconduct retractions. Another limitation is that authors of the retracted papers have not been analyzed in this study.Practical implications: This study provides a reference for addressing research misconduct in Chinese university-affiliated hospitals. It is our recommendation that universities and hospitals should educate all their staff about the basic norms of research integrity, punish authors of scientific misconduct retracted papers, and reform the unreasonable evaluation system.Originality/value: Based on the analysis of retracted papers, this study further analyzes the characteristics of institutions of retracted papers, which may deepen the research on retracted papers and provide a new perspective to understand the retraction phenomenon. 展开更多
关键词 Retracted papers RETRACTION Research integrity Research misconduct Chinese university-affiliated hospitals
下载PDF
Retraction note to:Beneficial effect of probiotics supplements in reflux esophagitis treated with esomeprazole:A randomized controlled trial 被引量:4
11
作者 Qing-Hua Sun Hong-Yan Wang +2 位作者 Shi-Dong Sun Xin Zhang Han Zhang 《World Journal of Gastroenterology》 SCIE CAS 2023年第1期221-222,共2页
We have decided to retract the above article for further consideration due to a data labelling error.
关键词 Retraction note
下载PDF
Assessment of retracted papers,and their retraction notices,from a cancer journal associated with“paper mills” 被引量:1
12
作者 Jaime A.Teixeira da Silva Serhii Nazarovets 《Journal of Data and Information Science》 CSCD 2023年第2期118-125,共8页
Cancer research is occasionally described as being in a reproducibility crisis.The cancer literature has ample papers retracted due to misconduct,including the use of paper mills,invalid authorship,or fake data.The ob... Cancer research is occasionally described as being in a reproducibility crisis.The cancer literature has ample papers retracted due to misconduct,including the use of paper mills,invalid authorship,or fake data.The objective of this paper was to gain an appreciation of the balance of retractions and associated retraction notices of 23 retracted Cancer Biotherapy and Radiopharmaceuticals papers associated with paper mills.By 23 March 2023,these retracted papers had already accumulated 287 citations according to Web of Science Core Collection,253 according to Scopus,and 365 according to Google Scholar,i.e.,metrically speaking,they were highly rewarded.All authors had an affiliation(71%being a hospital)in China.Most(12/21;57%)of corresponding authors had emails with a@163.com suffix.Four of the retraction notices(i.e.,17%)explicitly indicated paper mills as a reason for retraction although,in general,the retraction notices lacked details and background that could assist readers’understanding of the retractions. 展开更多
关键词 INDEXING ONCOLOGY Publishing history PUBMED Retraction Notices TRANSPARENCY
下载PDF
Cyclophilin D-induced mitochondrial impairment confers axonal injury after intracerebral hemorrhage in mice 被引量:1
13
作者 Yang Yang Kai-Yuan Zhang +10 位作者 Xue-Zhu Chen Chuan-Yan Yang Ju Wang Xue-Jiao Lei Yu-Lian Quan Wei-Xiang Chen Heng-Li Zhao Li-Kun Yang Yu-Hai Wang Yu-Jie Chen Hua Feng 《Neural Regeneration Research》 SCIE CAS CSCD 2023年第4期849-855,共7页
The mitochondrial permeability transition pore is a nonspecific transmembrane channel.Inhibition of mitochondrial permeability transition pore opening has been shown to alleviate mitochondrial swelling,calcium overloa... The mitochondrial permeability transition pore is a nonspecific transmembrane channel.Inhibition of mitochondrial permeability transition pore opening has been shown to alleviate mitochondrial swelling,calcium overload,and axonal degeneration.Cyclophilin D is an important component of the mitochondrial permeability transition pore.Whether cyclophilin D participates in mitochondrial impairment and axonal injury after intracerebral hemorrhage is not clear.In this study,we established mouse models of intracerebral hemorrhage in vivo by injection of autologous blood and oxyhemoglobin into the striatum in Thy1-YFP mice,in which pyramidal neurons and axons express yellow fluorescent protein.We also simulated intracerebral hemorrhage in vitro in PC12 cells using oxyhemoglobin.We found that axonal degeneration in the early stage of intracerebral hemorrhage depended on mitochondrial swelling induced by cyclophilin D activation and mitochondrial permeability transition pore opening.We further investigated the mechanism underlying the role of cyclophilin D in mouse models and PC12 cell models of intracerebral hemorrhage.We found that both cyclosporin A inhibition and short hairpin RNA interference of cyclophilin D reduced mitochondrial permeability transition pore opening and mitochondrial injury.In addition,inhibition of cyclophilin D and mitochondrial permeability transition pore opening protected corticospinal tract integrity and alleviated motor dysfunction caused by intracerebral hemorrhage.Our findings suggest that cyclophilin D is used as a key mediator of axonal degeneration after intracerebral hemorrhage;inhibition of cyclophilin D expression can protect mitochondrial structure and function and further alleviate corticospinal tract injury and motor dysfunction after intracerebral hemorrhage.Our findings provide a therapeutic target for preventing axonal degeneration of white matter injury and subsequent functional impairment in central nervous diseases. 展开更多
关键词 axonal injury corticospinal tract cyclophilin D cyclosporin A intracerebral hemorrhage mitochondrial impairment mitochondrial permeability transition pore motor dysfunction retraction bulb white matter
下载PDF
Efficacy of invisible advancement correction for mandibular retraction in adolescents based on Pancherz analysis 被引量:1
14
作者 Lei Kong Xin-Qiang Liu 《World Journal of Clinical Cases》 SCIE 2023年第6期1299-1309,共11页
BACKGROUND Mandibular retraction is the main etiological mechanism of class II malocclusion in China and the subsequent distal molar relationship can cause functional discomfort in mastication,breathing and the tempor... BACKGROUND Mandibular retraction is the main etiological mechanism of class II malocclusion in China and the subsequent distal molar relationship can cause functional discomfort in mastication,breathing and the temporomandibular joint.The use of mandibular advancement(MA)devices has recently emerged as an adolescent mandibular retraction treatment;however,current studies regarding the effect thereof are relatively few,and there is lack of sufficient clinical support.AIM To investigate the clinical effect of invisalign MA on the treatment of mandibular retraction in adolescents.METHODS This study included 30 adolescent patients who underwent treatment with the MA appliances from December 2017 to June 2021.The lateral cephalometric data before and after treatment were collected and imported into Dolphin Imaging software.The changes were measured by linear measurement superimposed with lateral cephalometric trajectory based on the Pancherz technology.RESULTS There was no significant difference in the length and position of maxilla before and after the treatment.The position of the mandible moved 3.13 mm,the length increased 4.14 mm,the mandibular ramus length increased 4.09 mm,the body length increased 4.25 mm,and the position of the condyle moved 1.03 mm forward after treatment.Additionally,changes in the incisor sagittal position and labial inclination were observed.The position of the upper incisor point moved back 1.33 mm,without statistical difference,the inclination and tooth angle decreased by 3.44°and 4.06°,respectively;the position of the lower incisor point was moved 2.98 mm,and the inclination and tooth angle increased by 2.62°and 1.23°,respectively.Furthermore,changes in the incisor overjet and molar relationship were seen.Overjet decreased by 4.31 mm,of which 1.78 mm was due to dental factors,accounting for 41.3%of the effect as opposed to 58.7%due to skeletal factors.Molar relationship improved 3.87 mm,with 1.34 mm due to dental factors,and dental and skeletal factors were accounted for 34.6%and 65.4%of the effect,respectively.CONCLUSION For adolescent patients with mandible retraction,invisalign MA can effectively promote the mandible growth,and it was proven to be mainly due to skeletal effects. 展开更多
关键词 Mandibular retraction ADOLESCENT Pancherz technology Functional correction Invisible appliance Mandibular advancement
下载PDF
Reliability analysis of retractable drill bit with air reverse circulation used for drilling while casing
15
作者 WANG Minqi YIN Qilei +3 位作者 CHEN Baoyi QI Bo BO Kun CAO Pinlu 《Global Geology》 2023年第1期47-56,共10页
Casing-while-drilling(CWD)with down the hole(DTH)hammer drilling technology has been widely used in unconsolidated formations,due to its advantages in protecting the borehole wall,excellent rock cuttings capacity,and ... Casing-while-drilling(CWD)with down the hole(DTH)hammer drilling technology has been widely used in unconsolidated formations,due to its advantages in protecting the borehole wall,excellent rock cuttings capacity,and fast penetration rate in hard rock.As an important component of the CWD system,the structure of the retractable drill bit needs not only to ensure to form stronger reverse circulation,but also to be expandable or retractable as needed,otherwise the drill bit cannot be lift and put down smoothly in the casing,and may lead to drilling accidents.This paper developed a new type of reverse circulation DTH hammer drill bit used for CWD drilling technology.The retractable performance of this type of drill bit is studied using ADAMS software.The results show that it is smoothly expandable and retractable as designed under the conditions of the weight of the bit(WOB)of 0.5–2.0 t and the rotation speed of 30–60 r/min.To investigate the reverse circulation effect of the drill bit,Fluent software was used to simulate the flow characteristic inside it.The simulation results indicated that it can form strong reverse circulation,and the entrainment ratio h can reach 9.5%. 展开更多
关键词 DTH hammer drilling air reverse circulation casing-while-drilling retractable drill bit
下载PDF
2018-2022年我国材料科学领域论文撤稿情况分析与思考
16
作者 姜春明 《出版与印刷》 2023年第6期73-79,共7页
研究我国材料科学领域论文撤稿情况,为防范学术不端行为提供参考。基于Retraction Watch数据库,文章统计分析了2018-2022年我国材料科学领域论文的撤稿情况,包括撤稿论文的作者、撤稿论文所属期刊以及合作出版商、撤稿论文被引频次、撤... 研究我国材料科学领域论文撤稿情况,为防范学术不端行为提供参考。基于Retraction Watch数据库,文章统计分析了2018-2022年我国材料科学领域论文的撤稿情况,包括撤稿论文的作者、撤稿论文所属期刊以及合作出版商、撤稿论文被引频次、撤稿周期以及撤稿原因等。从科研工作者、学术期刊以及科研管理部门(科研所属机构)等三方面提出思考与建议,包括:加强对科研工作者的科研诚信教育,树立科研工作者是科研诚信第一责任人的观念;学术期刊在出版工作中优化论文审查,严格把控同行评议质量,并加强与出版商的沟通与交流;相关部门完善科研诚信监管体系等。 展开更多
关键词 材料科学 撤稿 学术诚信 Retraction Watch数据库
下载PDF
Existence of solutions for fourth-order boundary value problem with parameter 被引量:2
17
作者 杨阳 张吉慧 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2010年第3期377-384,共8页
This paper is a sequel to a previous paper (Yang, Y. and Zhang, J. H. Existence of solutions for some fourth-order boundary value problems with parameters. Nonlinear Anal. 69(2), 1364-1375 (2008)) in which the n... This paper is a sequel to a previous paper (Yang, Y. and Zhang, J. H. Existence of solutions for some fourth-order boundary value problems with parameters. Nonlinear Anal. 69(2), 1364-1375 (2008)) in which the nontrivial solutions to the fourthorder boundary value problems were studied. In the current work with the same conditions near infinity but different near zero, the positive, negative, and sign-changing solutions are obtained by the critical point theory, retracting property, and invariant sets. 展开更多
关键词 boundary value problem critical point invariant sets retracting property
下载PDF
GEOMETRIC DESIGN OF DEPLOYABLE/RETRACTABLE MAST 被引量:1
18
作者 杨玉龙 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2006年第4期250-256,共7页
To simplify the complicated design process of deployable/retractable structures, a new design process is developed. The process is divided into three phases: the concept design phase, the model phase and the optimiza... To simplify the complicated design process of deployable/retractable structures, a new design process is developed. The process is divided into three phases: the concept design phase, the model phase and the optimization phase. In each phase, different parameter targets have to be fulfilled. According to three phases, a deployable/retractable mast composed of four right triangle prism modules in the longitudinal direction is designed. It can be deployed and folded simultaneously by the linear movements of sleeve-joints. The deployable and retractable movement of the mast is analyzed and key joint forms are designed. Then bar diameters and joint forms are modified based on mast structural mechanics characteristics in the optimization phase. Finally a 1:1 scaled model mast is built to verify the design and the optimization. Analytical results show that the model mast has the advantages of simple locking mechanism, fewer types of joints and bars, so it can be easily manufactured. 展开更多
关键词 deployable/retractable mast geometric design design process OPTIMIZATION
下载PDF
Analysis and Design Innovation on Underground Gasifier for Medium-Deep Coal Seam 被引量:1
19
作者 Kong Lingfeng Zhan Enqiang Zhao Chenhui 《China Oil & Gas》 CAS 2019年第4期32-37,共6页
Over the past 80 years,dozens of underground coal gasification(UCG)mine field tests have been carried out around the world.However,in the early days,only a small number of shallow UCG projects in the former Soviet Uni... Over the past 80 years,dozens of underground coal gasification(UCG)mine field tests have been carried out around the world.However,in the early days,only a small number of shallow UCG projects in the former Soviet Union achieved commercialised production.In this century,a few pilot projects in Australia also achieved short-term small-scale commercialised production using modern UCG technology.However,the commercialisation of UCG,especially medium-deep UCG projects with good development prospects but difficult underground engineering conditions,has not progressed smoothly around the world.Considering investment economy,a single gasifier must realise a high daily output and accumulated output,as well as hold a long gasification tunnel to control a large number of coal resources.However,a long gasification tunnel can easily be affected by blockages and failure,for which the remedial solutions are difficult and expensive,which greatly restricts the investment economy.The design of the underground gasifier determines the success or failure of UCG projects,and it also requires the related petroleum engineering technology.Combining the advantages of the linear horizontal well(L-CRIP)and parallel horizontal well(P-CRIP),this paper proposes a new design scheme for an“inclined ladder”underground gasifier.That is to say,the combination of the main shaft of paired P-CRIP and multiple branch horizontal well gasification tunnels is adopted to realise the control of a large number of coal resources in a single gasifier.The completion of the main shaft by well cementation is beneficial for maintaining the integrity of the main shaft and the stability of the main structure.The branch horizontal well is used as the gasification tunnel,but the length and number of retracting injection points are limited,effectively reducing the probability of blockage or failure.The branch horizontal well spacing can be adjusted flexibly to avoid minor faults and large cracks,which is conducive to increasing the resource utilisation rate.In addition,for multi-layer thin coal seams or ultra-thick coal seams,a multi-layer gasifier sharing vertical well sections can be deployed,thereby saving investment on the vertical well sections.Through preliminary analysis,this gasifier design scheme can be realised in engineering,making it suitable for largescale deployment where it can increase the resource utilisation rate and ensure stable and controllable operations.The new gasifier has outstanding advantages in investment economy,and good prospects for application in the commercial UCG projects of medium-deep coal seams. 展开更多
关键词 UNDERGROUND COAL Gasification(UCG) Medium-deep COAL Seam Controlled retracting Injection Point(CRIP) Parallel HORIZONTAL WELL Pair Branch HORIZONTAL WELL “Inclined Ladder”Underground GASIFIER Cluster Coiled Tubing Flexible and Combustible Tubing GASIFICATION Tunnel GASIFICATION Chamber Coal-based Syngas
下载PDF
Duane综合征合并内耳道畸形1例
20
作者 侯静 龚树生 张罗 《中国耳鼻咽喉头颈外科》 CSCD 2014年第2期107-108,共2页
Duane综合征(Duane’s retraction syndrome,DRS)为常染色体显性遗传疾病,症状多表现在眼科,即眼球外展受限和眼球内陷。部分患者可伴有耳部发育不良,听力下降或其他系统的发育畸形。因该疾病临床少见,耳鼻咽喉科对其了解较少,现报道1例... Duane综合征(Duane’s retraction syndrome,DRS)为常染色体显性遗传疾病,症状多表现在眼科,即眼球外展受限和眼球内陷。部分患者可伴有耳部发育不良,听力下降或其他系统的发育畸形。因该疾病临床少见,耳鼻咽喉科对其了解较少,现报道1例。1临床资料患儿,男,4岁,主诉反复头疼,高热,呕吐3年。患儿3年前无明显诱因出现头疼,高热,呕吐,在当地医院诊断为'化脓性脑膜炎',抗感染治疗可好转。但此后每间隔20 d到半年时间症状反复,共发作脑膜炎6次。 展开更多
关键词 Duane眼球后退综合征(Duane RETRACTION Syndrome) 耳道(Ear Canal) 畸形(Abnormalities)
下载PDF
上一页 1 2 6 下一页 到第
使用帮助 返回顶部