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A comparative study on characteristics of retracted publications across different open access levels
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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
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Amend:An integrated platform of retracted papers and concerned papers
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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
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Using Flowable Composite as Gingival Retraction Cord in Prosthodontics Dentistry: Two Case Reports: A Dental Technique
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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
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Retraction note:Clinical analysis of colistin sulfate in the treatment of pneumonia caused by carbapenem-resistant Gram-negative bacteria
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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
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Retraction note to:RNA-binding protein CPSF6 regulates IBSP to affect pyroptosis in gastric cancer
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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
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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
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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
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Retraction note to:Association between triglyceride-glucose index and colorectal polyps:A retrospective cross-sectional study
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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
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Research misconduct in hospitals is spreading:A bibliometric analysis of retracted papers from Chinese university-affiliated hospitals 被引量:2
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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
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Retraction note to:Beneficial effect of probiotics supplements in reflux esophagitis treated with esomeprazole:A randomized controlled trial 被引量:4
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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
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Assessment of retracted papers,and their retraction notices,from a cancer journal associated with“paper mills” 被引量:1
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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
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Efficacy of invisible advancement correction for mandibular retraction in adolescents based on Pancherz analysis 被引量:1
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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
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Reliability analysis of retractable drill bit with air reverse circulation used for drilling while casing
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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
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液压挖掘机斗杆内收流量分配节能设计
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作者 高韶坤 艾建军 《液压与气动》 北大核心 2024年第4期142-150,共9页
为解决小型挖掘机挖掘工况(正负载)下斗杆内收速度慢、系统压力高、存在溢流损失等问题,提出一种斗杆内收节能系统,挖掘工况下,使斗杆内收通过节能阀回油,即斗杆内收流量不再生时增大回油面积。给出了该节能系统工作原理和仿真参数,基于... 为解决小型挖掘机挖掘工况(正负载)下斗杆内收速度慢、系统压力高、存在溢流损失等问题,提出一种斗杆内收节能系统,挖掘工况下,使斗杆内收通过节能阀回油,即斗杆内收流量不再生时增大回油面积。给出了该节能系统工作原理和仿真参数,基于AMESim搭建了斗杆内收节能系统仿真模型,对比仿真了有无节能阀系统的斗杆内收速度、压力、流量等动态特性,分析了节能阀直径对斗杆内收动态特性的影响效果,进行了系统实际应用可行性分析,挖掘机整机测试有效验证了仿真结论。结果表明:引入节能阀,斗杆内收速度增加18%,斗杆油缸进油压力降低65%;节能阀直径对斗杆内收系统输出流量、回油总流量、系统压力影响不大;通过挖掘机整机测得斗杆内收速度提高19%。 展开更多
关键词 液压挖掘机 斗杆内收 流量分配 节能阀
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收放伞绳对十字型伞静态气动特性影响的数值模拟研究
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作者 胡俊 于菲 于勇 《北京理工大学学报》 EI CAS CSCD 北大核心 2024年第1期10-17,共8页
为研究十字型降落伞作为主动控制装置时,其可控性与气动特性的规律,建立了不同伞绳收缩比δ为0、10.0%、12.5%、15.0%、20.0%、25.0%时十字型伞无限质量充气的有限元模型,基于任意拉格朗日-欧拉方法进行数值模拟,分析了十字型降落伞收... 为研究十字型降落伞作为主动控制装置时,其可控性与气动特性的规律,建立了不同伞绳收缩比δ为0、10.0%、12.5%、15.0%、20.0%、25.0%时十字型伞无限质量充气的有限元模型,基于任意拉格朗日-欧拉方法进行数值模拟,分析了十字型降落伞收缩伞绳,引起伞面几何构型不对称对气动特性的影响.结果表明:不同攻角为0°、5°、10°时,十字型降落伞的平均阻力系数随伞绳收缩比δ的增大而减小;十字型伞的瞬时升力峰值随着伞绳收缩比δ的增加而增大,方向始终由伞绳收缩一侧指向另一侧,具有较强的时变特性. 展开更多
关键词 十字型降落伞 伞绳收缩 气动特性 数值模拟 任意拉格朗日欧拉方法
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Twin-block在骨性Ⅱ类错[牙合]下颌后缩患儿中的应用
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作者 陈菁菁 王密 +2 位作者 刘芳 乔柱 赵虎 《中国美容医学》 CAS 2024年第9期53-57,共5页
目的:探讨Twin-block在骨性Ⅱ类错[牙合]下颌后缩患儿中的应用效果。方法:选取2019年1月-2021年1月笔者医院接收的84例骨性Ⅱ类错[牙合]下颌后缩患儿设置为研究对象,按随机抽签法分为对照组、研究组,各42例,对照组采用直丝弓矫治器,研... 目的:探讨Twin-block在骨性Ⅱ类错[牙合]下颌后缩患儿中的应用效果。方法:选取2019年1月-2021年1月笔者医院接收的84例骨性Ⅱ类错[牙合]下颌后缩患儿设置为研究对象,按随机抽签法分为对照组、研究组,各42例,对照组采用直丝弓矫治器,研究组采用Twin-block矫治器。比较两组治疗前后咀嚼功能、牙齿咬合力、下颌骨变化、软组织面型变化、上气道矢状径,并统计家属治疗满意度。结果:治疗后,研究组咀嚼功能、牙齿咬合力、下颌骨变化指标、软组织面型变化指标均优于对照组(P<0.05);治疗后,研究组上气道矢状径高于对照组(P<0.05);研究组家属治疗满意度(95.24%)明显高于对照组(73.81%)(P<0.05)。结论:Twin-block应用于骨性Ⅱ类错[牙合]下颌后缩患儿治疗中,能改善咀嚼功能,增强牙齿咬合力,促进下颌骨生长,提高面型美观度,扩大上气道矢状径,利于改善呼吸功能,获得家属对治疗效果的高度评价。 展开更多
关键词 TWIN-BLOCK 直丝弓矫治器 骨性Ⅱ类错[牙合] 下颌后缩 软组织面型变化 上气道矢状径
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撤销论文的科研合作规模与模式差异对比分析
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作者 程鑫 王珂 张丽华 《科技管理研究》 CSSCI 2024年第16期232-242,共11页
在积极推动科研诚信建设的背景下,分析撤销论文的科研合作特征是建立良性的合作模式及科研秩序的重要视角。以撤稿观察数据库(RWD)收录的社会科学、人文艺术、应用科学和自然科学四大领域共5884篇撤销论文为研究对象,分析不同领域撤销... 在积极推动科研诚信建设的背景下,分析撤销论文的科研合作特征是建立良性的合作模式及科研秩序的重要视角。以撤稿观察数据库(RWD)收录的社会科学、人文艺术、应用科学和自然科学四大领域共5884篇撤销论文为研究对象,分析不同领域撤销论文的合作规模、合作模式差异,研究撤销论文中科研合作存在的主要问题。研究发现:撤销论文中合作规模出现频次最高的为3~5人,其中国际合作年均占比为20%左右;多数国家合作论文的国际合作比例与其论文撤销率呈负相关关系,其中跨国合作形式为南北合作的论文数量最多。由此说明合作模式、合作规模与论文撤销现象之间有显著关联性,说明在科研合作框架下,更广泛的合作交流、构建相互监督机制对于有效降低科研不当行为的发生率具有积极作用。 展开更多
关键词 科研合作 科研诚信 撤销率 合作规模 合作模式
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书法擒纵论
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作者 潘池勇 《赤峰学院学报(哲学社会科学版)》 2024年第8期60-63,共4页
擒纵是总结吸收前人用笔经验的基础上所提出的技法。擒是内擫笔法,表现为蓄势紧束与劲健。纵是外拓笔法,表现为郁勃奔放与开阔。用擒纵能高效地控制笔锋,写出的线条节奏变化丰富,点画生动美妙,书风通灵超脱,从而遏制因平拖直过单一运笔... 擒纵是总结吸收前人用笔经验的基础上所提出的技法。擒是内擫笔法,表现为蓄势紧束与劲健。纵是外拓笔法,表现为郁勃奔放与开阔。用擒纵能高效地控制笔锋,写出的线条节奏变化丰富,点画生动美妙,书风通灵超脱,从而遏制因平拖直过单一运笔所形成的点画僵滞、书风呆板的缺点。擒纵是对书家用笔技巧难度和高度的协调统一。知擒纵才可以明晰收放之度,字法才开张奇险,章法字字侵让连贯不断,表现书写主体雄肆的气势与激昂的情志。擒纵也代表着破法、变法与创新,是书写主体创造力的张扬。 展开更多
关键词 擒纵 气势 笔法 字法 收放
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基于可伸缩型注意力机制的神经网络地震数据去噪方法
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作者 张敏 许一卓 易继东 《物探与化探》 CAS 2024年第4期1065-1075,共11页
地震资料中的随机噪声会影响地震数据的质量,从而影响后续处理与解释的准确性。传统去噪方法受先验条件的约束,效率低下,神经网络具有强大的特征提取能力,能够弥补这些缺点。然而,由于传统神经网络卷积核的局限性,可能会导致全局信息丢... 地震资料中的随机噪声会影响地震数据的质量,从而影响后续处理与解释的准确性。传统去噪方法受先验条件的约束,效率低下,神经网络具有强大的特征提取能力,能够弥补这些缺点。然而,由于传统神经网络卷积核的局限性,可能会导致全局信息丢失。为了克服这个缺点,本文在卷积神经网络(CNN)的基础上,添加了可伸缩型注意力机制。该机制在网络中同时呈现密集和稀疏两种类型的自注意力模块,这两种注意力模块交替使用可以显著增强神经网络的表现能力,扩大接受场。通过卷积层和注意力模块提取地震数据浅层特征和深层特征,结合CNN的局部建模能力和Transformer的全局建模能力,有利于提升网络的全局交互作用,增强其去除噪声和处理细节的能力。最后,合成和实际地震数据实验结果均表明,该方法相较于Unet和DnCNN,具有更好的噪声压制与保留地震数据有效信息的能力,可以大幅提高信噪比,为地震数据的处理和解释提供帮助。 展开更多
关键词 随机噪声 卷积神经网络 可伸缩型注意力机制 TRANSFORMER
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关于魔力弹簧的收缩时间和上端运动问题
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作者 于凤军 张希威 +2 位作者 汤振杰 鞠林 田俊龙 《大学物理》 2024年第5期13-18,共6页
针对有关魔力弹簧研究中的几个问题进行探讨和澄清.建立了预收缩力弹簧的模型,推出其形变规律.根据质心运动定理,导出这种弹簧自由下落时,收缩到原长所用的时间、其上端的运动方程和速度公式.研究表明,对于通常演示所用的魔力弹簧,在自... 针对有关魔力弹簧研究中的几个问题进行探讨和澄清.建立了预收缩力弹簧的模型,推出其形变规律.根据质心运动定理,导出这种弹簧自由下落时,收缩到原长所用的时间、其上端的运动方程和速度公式.研究表明,对于通常演示所用的魔力弹簧,在自由下落时的收缩阶段,其上端不是作匀速直线运动. 展开更多
关键词 魔力弹簧 预收缩力弹簧 收缩时间 质心运动定理
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脉冲气体保护焊引弧和收弧控制技术研究
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作者 苏立虎 《上海电气技术》 2024年第2期40-43,共4页
熔化极脉冲气体保护焊引弧焊接时出现断弧、顶丝、上燃等不良现象,焊接结束进入收弧阶段存在焊丝回烧形成的熔球大小不一致等问题,对此,研究了脉冲气体保护焊引弧和收弧控制技术。引弧阶段采用送丝控制与焊接电源输出能量相匹配的控制方... 熔化极脉冲气体保护焊引弧焊接时出现断弧、顶丝、上燃等不良现象,焊接结束进入收弧阶段存在焊丝回烧形成的熔球大小不一致等问题,对此,研究了脉冲气体保护焊引弧和收弧控制技术。引弧阶段采用送丝控制与焊接电源输出能量相匹配的控制方法,使引弧顺畅,可重复性高。收弧时除送丝速度与电流、电压等参数匹配外,还需要对输出脉冲数量进行调整,使焊接结束后焊丝熔球大小一致。所研究的引弧和收弧控制技术经实际焊接验证效果良好,在焊接碳钢、不锈钢、铝等材料时也可使用,具有通用性。 展开更多
关键词 焊接 引弧 收弧 控制 研究
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