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Exploring Nominalization in English Abstracts of Applied Linguistics Research Articles:A Comparative Study Between Chinese and International Journals
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作者 Gong Yingrui Zhao Yibu 《Contemporary Social Sciences》 2024年第4期122-142,共21页
Researchers around the world strive to communicate new knowledge,primarily via publication,with the abstract being crucial in conveying core insights.Previous research has generally analyzed the discourse features of ... Researchers around the world strive to communicate new knowledge,primarily via publication,with the abstract being crucial in conveying core insights.Previous research has generally analyzed the discourse features of abstracts from a macro perspective and often employed either outdated texts,such as those over a decade old,or papers written by authors with lower English academic writing proficiency as research material.In this study,we analyzed forty abstracts from leading journals in applied linguistics,evenly split between Chinese and international journals.It revealed that the use of nominalization in abstracts by Chinese and international scholars showed similarities due to the universal academic requirement for conciseness.However,due to cultural and educational differences,each group differed in their respective language choices and nominalization usage.By analyzing the application of nominalization in different cultural contexts,the results of our study offered practical suggestions for crafting abstracts that effectively convey information,thereby,contributing to the broader academic community. 展开更多
关键词 NOMINALIZATION abstractS comparative study applied linguistics
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C1C2 Wiring and Posttraumatic Atlantoaxial Dislocation: An Effective and Cheap Surgical Procedure in a Developing Country
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作者 Ibrahim Dao Massimiliano Visocchi +11 位作者 Salah Sow John Jabang Ousmane Ouattara Astride Somda Abdoulaye Sanou Elie Dibloni Nassoum Arsène Tossou Narcisse Ouedraogo Frédéric Bako Massadiami Soulama Malick Diallo Patrick Wendpouiré Hamed Dakouré 《Surgical Science》 2024年第5期357-370,共14页
Objectives: Atlantoaxial dislocation remains a rare and serious condition with a high preoperative and postoperative morbidity and mortality. Its successful surgical management is still challenging and gratifying for ... Objectives: Atlantoaxial dislocation remains a rare and serious condition with a high preoperative and postoperative morbidity and mortality. Its successful surgical management is still challenging and gratifying for neurosurgeons. Several technics have been described such as wiring, trans articular screwing, C1C2 screwing with plate and screw introduced by Goel et al., and modified by insertion of polyaxially screw and rod many years later by Harms. Unavailability and expensiveness of upper cervical spine instrumentation device led us to C1C2 Wiring resulting in a good outcome. Finally, a quadriplegic patient with a more comfortable financial condition had ordered devices from abroad and benefit for Goel and Harms screwing technique and improved dramatically from ASIA A to ASIA E. Material and methods: This is a retrospective study of patients managed in our department by a same neurosurgeon from January 2019 to April 2024. Results: We defined 6 men and 1 woman with an average age of 33 years. Unrestrained driver in a rollover motor vehicle accident was most common. Only one patient was neurologically intact on admission. Neurovegetative disorders were noticed in one patient. Dislocation was associated to a fracture of the dens in two patients. Three patients have been successfully operated with remarkable outcome, mostly from ASIA A to E. Conclusion: C1C2 dislocation is a serious condition and C1C2 Wiring represents an effective and cheaper technic. Therefore, this technic should deserve consideration above all in low incomes countries when screwing devices are not available. Seatbelt should be demanded for motor vehicle drivers and passengers. 展开更多
关键词 Superior Cervical Spine DISLOCATION Fracture wiring Screwing Neurovegetative Disorders
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Embodied Meaning in Comprehending Abstract Chinese Counterfactuals
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作者 Xueyan LI Yahui ZHAO +1 位作者 Huili WANG Xue ZHANG 《Chinese Journal of Applied Linguistics》 2024年第3期414-432,524,共20页
Embodied cognition theories propose that language comprehension triggers a sensorimotor system in the brain.However,most previous research has paid much attention to concrete and factual sentences,and little emphasis ... Embodied cognition theories propose that language comprehension triggers a sensorimotor system in the brain.However,most previous research has paid much attention to concrete and factual sentences,and little emphasis has been put on the research of abstract and counterfactual sentences.The primary challenges for embodied theories lie in elucidating the meanings of abstract and counterfactual sentences.The most prevalent explanation is that abstract and counterfactual sentences are grounded in the activation of a sensorimotor system,in exactly the same way as concrete and factual ones.The present research employed a dual-task experimental paradigm to investigate whether the embodied meaning is activated in comprehending action-related abstract Chinese counterfactual sentences through the presence or absence of action-sentence compatibility effect(ACE).Participants were instructed to read and listen to the action-related abstract Chinese factual or counterfactual sentences describing an abstract transfer word towards or away from them,and then move their fingers towards or away from them to press the buttons in the same direction as the motion cue of the transfer verb.The action-sentence compatibility effect was observed in both abstract factual and counterfactual sentences,in line with the embodied cognition theories,which indicated that the embodied meanings were activated in both action-related abstract factuals and counterfactuals. 展开更多
关键词 action-sentence compatibility effect EMBODIMENT abstract COUNTERFACTUALS language comprehension
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A Comparative Analysis of Syntactic Complexity in Applied Linguistics Abstracts Written by Chinese Novice Writers and Native English Advanced Writers
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作者 Mingming Zhao Tianshuang Ge 《Open Journal of Applied Sciences》 2024年第1期1-26,共26页
The rhetorical structure of abstracts has been a widely discussed topic, as it can greatly enhance the abstract writing skills of second-language writers. This study aims to provide guidance on the syntactic features ... The rhetorical structure of abstracts has been a widely discussed topic, as it can greatly enhance the abstract writing skills of second-language writers. This study aims to provide guidance on the syntactic features that L2 learners can employ, as well as suggest which features they should focus on in English academic writing. To achieve this, all samples were analyzed for rhetorical moves using Hyland’s five-rhetorical move model. Additionally, all sentences were evaluated for syntactic complexity, considering measures such as global, clausal and phrasal complexity. The findings reveal that expert writers exhibit a more balanced use of syntactic complexity across moves, effectively fulfilling the rhetorical objectives of abstracts. On the other hand, MA students tend to rely excessively on embedded structures and dependent clauses in an attempt to increase complexity. The implications of these findings for academic writing research, pedagogy, and assessment are thoroughly discussed. 展开更多
关键词 Syntactic Complexity Rhetorical Functions Research Article abstract L2 Academic Writing
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Weakly Supervised Abstractive Summarization with Enhancing Factual Consistency for Chinese Complaint Reports
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作者 Ren Tao Chen Shuang 《Computers, Materials & Continua》 SCIE EI 2023年第6期6201-6217,共17页
A large variety of complaint reports reflect subjective information expressed by citizens.A key challenge of text summarization for complaint reports is to ensure the factual consistency of generated summary.Therefore... A large variety of complaint reports reflect subjective information expressed by citizens.A key challenge of text summarization for complaint reports is to ensure the factual consistency of generated summary.Therefore,in this paper,a simple and weakly supervised framework considering factual consistency is proposed to generate a summary of city-based complaint reports without pre-labeled sentences/words.Furthermore,it considers the importance of entity in complaint reports to ensure factual consistency of summary.Experimental results on the customer review datasets(Yelp and Amazon)and complaint report dataset(complaint reports of Shenyang in China)show that the proposed framework outperforms state-of-the-art approaches in ROUGE scores and human evaluation.It unveils the effectiveness of our approach to helping in dealing with complaint reports. 展开更多
关键词 Automatic summarization abstractive summarization weakly supervised training entity recognition
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Novel multi‐domain attention for abstractive summarisation
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作者 Chunxia Qu Ling Lu +2 位作者 Aijuan Wang Wu Yang Yinong Chen 《CAAI Transactions on Intelligence Technology》 SCIE EI 2023年第3期796-806,共11页
The existing abstractive text summarisation models only consider the word sequence correlations between the source document and the reference summary,and the summary generated by models lacks the cover of the subject ... The existing abstractive text summarisation models only consider the word sequence correlations between the source document and the reference summary,and the summary generated by models lacks the cover of the subject of source document due to models'small perspective.In order to make up these disadvantages,a multi‐domain attention pointer(MDA‐Pointer)abstractive summarisation model is proposed in this work.First,the model uses bidirectional long short‐term memory to encode,respectively,the word and sentence sequence of source document for obtaining the semantic representations at word and sentence level.Furthermore,the multi‐domain attention mechanism between the semantic representations and the summary word is established,and the proposed model can generate summary words under the proposed attention mechanism based on the words and sen-tences.Then,the words are extracted from the vocabulary or the original word sequences through the pointer network to form the summary,and the coverage mechanism is introduced,respectively,into word and sentence level to reduce the redundancy of sum-mary content.Finally,experiment validation is conducted on CNN/Daily Mail dataset.ROUGE evaluation indexes of the model without and with the coverage mechanism are improved respectively,and the results verify the validation of model proposed by this paper. 展开更多
关键词 abstractive summarisation attention mechanism Bi‐LSTM coverage mechanism pointer network
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Abstraction and Representation:Form and Meaning in the Philosophy of Images
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作者 YUAN Zhen-wei 《Journal of Literature and Art Studies》 2023年第9期716-720,共5页
This article examines the complex interplay between abstraction and representation in the ontology of images.Images inhabit an in-between space as tangible artifacts that also convey intangible ideas and meanings.The ... This article examines the complex interplay between abstraction and representation in the ontology of images.Images inhabit an in-between space as tangible artifacts that also convey intangible ideas and meanings.The analysis synthesizes perspectives from across the history of philosophy to elucidate how images bridge abstraction and representation through their form and function.It engages with ongoing epistemological and aesthetic debates concerning the dual nature of images.Plato’s theory of ideal forms is outlined as an early attempt to define abstraction.Modern semiotic theories are discussed for their insights into how images create meaning through codes and signs.Phenomenology offers an alternative approach by prioritizing the sensorial,affective impact of images.Poststructuralism problematizes representation in the context of mechanical reproduction and simulacra.While diverse,these philosophical frameworks all grapple with the issues images pose between abstract essence and concrete appearance,conceptual ideas and sensory manifestations.The article reveals the richness of images as liminal constructs that collapse dualisms in their creative interfacing of material forms and immaterial meanings.It concludes that this ontological ambiguity empowers images as mediators between imagination and perception,subjectivity and reality. 展开更多
关键词 abstractION IMAGES SEMIOTICS DUALISM PLATO
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A Method of Integrating Length Constraints into Encoder-Decoder Transformer for Abstractive Text Summarization
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作者 Ngoc-Khuong Nguyen Dac-Nhuong Le +1 位作者 Viet-Ha Nguyen Anh-Cuong Le 《Intelligent Automation & Soft Computing》 2023年第10期1-18,共18页
Text summarization aims to generate a concise version of the original text.The longer the summary text is,themore detailed it will be fromthe original text,and this depends on the intended use.Therefore,the problem of... Text summarization aims to generate a concise version of the original text.The longer the summary text is,themore detailed it will be fromthe original text,and this depends on the intended use.Therefore,the problem of generating summary texts with desired lengths is a vital task to put the research into practice.To solve this problem,in this paper,we propose a new method to integrate the desired length of the summarized text into the encoder-decoder model for the abstractive text summarization problem.This length parameter is integrated into the encoding phase at each self-attention step and the decoding process by preserving the remaining length for calculating headattention in the generation process and using it as length embeddings added to theword embeddings.We conducted experiments for the proposed model on the two data sets,Cable News Network(CNN)Daily and NEWSROOM,with different desired output lengths.The obtained results show the proposed model’s effectiveness compared with related studies. 展开更多
关键词 Length controllable abstractive text summarization length embedding
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Analysis of Common Mistakes in English Abstract Writing of Scientific and Technological Papers:A Case Study of Automotive Practical Technology
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作者 Wenjuan Huang Yuansheng Zhou 《Journal of Contemporary Educational Research》 2023年第10期52-58,共7页
Abstract is the epitome of the core idea of a journal paper.Excellent English abstract plays an important role in ensuring the quality of the paper and promoting its academic value in international exchanges.However,t... Abstract is the epitome of the core idea of a journal paper.Excellent English abstract plays an important role in ensuring the quality of the paper and promoting its academic value in international exchanges.However,there are still many problems in the English abstracts of many papers published in academic journals.This paper analyzes and summarizes the grammatical errors of articles,singular and plural nouns,predicate verbs,conjunctions,Chinglish from other English abstracts of some papers in a vehicle engineering academic journal retrieved from CNCN.cn,and then corrects them.It is expected to provide some guidance for editors,academic workers,and engineering students in writing papers. 展开更多
关键词 Scientific and technological papers English abstract GRAMMAR
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我国电线电缆产品的质量监管模式研究 被引量:1
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作者 贾贺峰 朱翔华 谢波 《中国标准化》 2024年第1期178-181,188,共5页
本文阐述了电线电缆产品和行业的基本情况,分析了我国电线电缆的质量监管方式、监督抽查和风险监测情况,研究了我国电线电缆行业监管中存在的主要问题及原因,并提出了相应的解决措施。
关键词 电线电缆 质量 监管
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《资本论》的时间辩证法:资本逻辑的时间叙事及其解放 被引量:1
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作者 白刚 王世强 《中南大学学报(社会科学版)》 北大核心 2024年第4期14-24,共11页
《资本论》的时间概念与资本批判紧密相连。马克思在该书中分析指出,时间在资本的作用下呈现出具体和抽象的二重性质。具体时间与个体的社会劳动结合在一起,抽象时间则表现为价值的独立运动。资本周转与时间转化交织浸润,资本逻辑的建... 《资本论》的时间概念与资本批判紧密相连。马克思在该书中分析指出,时间在资本的作用下呈现出具体和抽象的二重性质。具体时间与个体的社会劳动结合在一起,抽象时间则表现为价值的独立运动。资本周转与时间转化交织浸润,资本逻辑的建构体现为从具体转化为抽象的时间规范。作为一种将时间抽象化的强制力量,资本将个体的生命时间统摄于它的结构之内,这导致劳动者无可规避地处于被奴役和支配的异化状态。除了建构时间的抽象统治结构,资本主义还造就了一种瓦解资本逻辑的历史动力——从抽象还原到具体的自由时间。资本增殖的空间来源于劳动者被压缩的可支配的自由时间,只有对资本的批判“代表一个阶级”,劳动者才能真正推翻时间的抽象统治。要完全超越资本,必须要在整个社会范围内解放自由时间。只有在社会主义社会中,时间才能从异化劳动的空间转化为自由发展的空间。马克思在《资本论》中的上述分析,不仅解开了“资本之谜”,也解开了“时间之谜”和“自由之谜”,在揭示资本逻辑限度的同时,为当代社会主义世界中人的自由解放指明了方向。 展开更多
关键词 《资本论》 资本逻辑 具体时间 抽象时间 自由时间
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竞技运动专家的认知优势及其形成机制——基于自动性特点和抽象化表征 被引量:1
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作者 褚昕宇 王泽军 《心理科学进展》 CSCD 北大核心 2024年第4期689-699,共11页
目前对于竞技运动专家如何从长期训练中获得和迁移、提炼和更新专业知识与技能的机制尚未有清晰的阐释。基于专家-新手范式的研究表明,从表征学习的角度看竞技运动专家的认知优势主要体现在注意优势和记忆优势两方面,而竞技运动专家知... 目前对于竞技运动专家如何从长期训练中获得和迁移、提炼和更新专业知识与技能的机制尚未有清晰的阐释。基于专家-新手范式的研究表明,从表征学习的角度看竞技运动专家的认知优势主要体现在注意优势和记忆优势两方面,而竞技运动专家知识与技能的自动性特点和抽象化表征是其认知优势效应形成的两个关键原因。从生成模型的角度探讨竞技运动专家知识系统的抽象化表征机制,为能更好地理解竞技运动专家的认知优势效应,助其突破认知局限性提供了新的理论依据。 展开更多
关键词 运动专家知识系统 表征学习 自动性 抽象化 生成模型
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数学教学视域下理解与应用皮亚杰建构主义理论
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作者 张涛 代钦 李春兰 《数学教育学报》 北大核心 2024年第3期96-102,共7页
建构主义是皮亚杰发生认识论的核心,同时也是现代建构主义教学的主要理论基础,对建构主义教学思想的发展和国际教育改革均产生了重要影响.其理论从心理学的角度阐述了有变化的“重复”能够促进认知的发展,能够有效地促进学生的数学学习... 建构主义是皮亚杰发生认识论的核心,同时也是现代建构主义教学的主要理论基础,对建构主义教学思想的发展和国际教育改革均产生了重要影响.其理论从心理学的角度阐述了有变化的“重复”能够促进认知的发展,能够有效地促进学生的数学学习.在阐述平衡机制、反省抽象等相关内容的基础上,研究得出反省抽象范畴之间的关系框架图、在数学教学中的应用路径,以及皮亚杰建构主义理论对当下数学教学的启示:数学教学应关注过程教育、数学教学过程中应把经验抽象与反省抽象有机结合、数学抽象思维教学应遵循思维发展的阶段性、数学教学应重视学生批判性思维能力的培养. 展开更多
关键词 皮亚杰 建构主义 发生认识论 反省抽象 数学教学
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关节腔内移植物长度测量在前交叉韧带全内重建的应用研究 被引量:1
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作者 龚时国 谢荣辉 +1 位作者 汪建样 刘牧子 《中国骨伤》 CAS CSCD 2024年第7期655-663,共9页
目的:探讨关节镜下测量关节腔内移植物长度在前交叉韧带(anterior cruciate ligament,ACL)全内重建应用的临床疗效。方法:回顾性分析2020年1月至2022年1月收治的ACL损伤患者60例的资料,其中男37例,女23例,年龄22~44岁。按照手术方式的不... 目的:探讨关节镜下测量关节腔内移植物长度在前交叉韧带(anterior cruciate ligament,ACL)全内重建应用的临床疗效。方法:回顾性分析2020年1月至2022年1月收治的ACL损伤患者60例的资料,其中男37例,女23例,年龄22~44岁。按照手术方式的不同,分为传统手术组(常规组)和拉线测量组(测量组),每组各30例。常规组男20例,女10例,年龄(30.00±3.95)岁;身体质量指数(body mass index,BMI)为(22.58±1.41)kg·m^(-2);左侧9例,右侧21例;受伤至手术时间(3.00±1.35)d。测量组男17例,女13例,年龄(32.00±4.29)岁;BMI为(23.29±1.39)kg·m^(-2);左侧12例,右侧18例;受伤至手术时间(3.00±1.27)d。记录患者术前及术后6、12个月的临床资料。从术后视觉模拟评分法(visual analogue scale,VAS)、膝关节损伤与骨关节炎评分(knee injury and osteoarthritis outcome score,KOOS)、Lysholm评分、国际膝关节文献委员会(International Knee Documentation Committee,IKDC)膝关节评估表、膝关节稳定性(Lachman试验、前抽屉试验和轴移试验)、术后不同阶段CT测量骨隧道直径增宽程度和MRI评分系统等方面比较两种方法的临床疗效。结果:术后6个月两组VAS比较差异无统计学意义(P>0.05),术后12个月测量组VAS(2.23±1.01)分,低于常规组(3.30±1.02)分(P<0.001)。术后12个月,两组KOOS评分除症状评分差异无统计学意义(P=0.221),其余各项评分差异均有统计学意义(P<0.05)。术后6个月,测量组Lysholm总分和IKDC总分均高于常规组(P<0.05)。术后12个月,测量组Lachman试验、前抽屉试验和轴移试验和常规组比较,差异均无统计学意义(P>0.05);但是,整体膝关节不稳定性分析,测量组膝关节稳定性优于对照组(P=0.038)。术后2 d及术后6、12个月两组患者影像学评估结果显示,测量组股骨和胫骨的肌腱隧道直径增宽程度均较常规组术后减少(P<0.05);MRI评分测量组患者均高于常规组(P<0.05)。结论:关节镜下测量关节腔内移植物长度在全内技术ACL重建,肌腱利用率高,稳定性好,1年内膝关节功能恢复满意,疗效肯定。 展开更多
关键词 关节镜 前交叉韧带重建 拉线法 关节内移植物长度
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经皮克氏针横行固定与微型钢板置入治疗第五掌骨干骨折的比较 被引量:1
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作者 张政 张岱捷 李朋 《中国组织工程研究》 CAS 北大核心 2024年第30期4842-4847,共6页
背景:第五掌骨干骨折在临床上常见,手术治疗多采用切开复位钢板固定,但术后大多数患者要求取出内固定物,需二次住院治疗。经皮克氏针横行固定具有创伤小、切口小、不需再次住院手术取出等优点,但对第五掌骨干骨折的应用效果不明确。目的... 背景:第五掌骨干骨折在临床上常见,手术治疗多采用切开复位钢板固定,但术后大多数患者要求取出内固定物,需二次住院治疗。经皮克氏针横行固定具有创伤小、切口小、不需再次住院手术取出等优点,但对第五掌骨干骨折的应用效果不明确。目的:对比分析经皮克氏针横行固定与微型钢板置入治疗第五掌骨干骨折的临床疗效。方法:回顾性分析滨州医学院附属医院在2018年5月至2020年5月收治的第五掌骨干骨折并行手术治疗患者60例,根据治疗方式分为2组,钢板组30例采用切开复位微型钢板内固定置入治疗,克氏针组30例采用闭合复位经皮克氏针横行固定(其中5例小切口切开辅助)治疗。比较两组患者的住院时间、手术时间、切口愈合等级、手术切口长度、术中出血量、术中透视次数及术后并发症的发生情况,记录两组患者骨折愈合时间、握力、第五掌指关节活动度等,采用中华医学会手外科学会手指关节总活动度法评估患者的手指功能。结果与结论:①两组患者均获得随访,随访时间13-18个月;两组患者住院时间、手术时间、切口愈合等级相比差异无显著性意义(P>0.05);②克氏针组术中出血量、手术切口长度均小于钢板组(P<0.05),钢板组术中透视次数少于克氏针组(P<0.05),两组骨折愈合时间比较差异无显著性意义(P>0.05);③末次随访时,依据手指关节总活动度法评估疗效,克氏针组优良率为87%,钢板组优良率为90%,两组比较差异无显著性意义;两组末次随访的第五掌指关节活动度、握力比较差异无显著性意义(P>0.05);④克氏针组术后有1例发生钉道感染,周围略有红肿,给予碘伏加强换药后感染得到控制;1例出现针尾刺激皮肤症状,拔除克氏针后症状消失;钢板组有12例因个人原因于术后12个月以后住院行钢板取出术,克氏针组全都在门诊取出;钢板组出现3例第五掌骨远端背侧及小指指背侧皮肤感觉麻木,术后口服甲钴胺,症状逐渐消失;两组均未出现骨不愈合及内固定取出再骨折等情况;⑤结果表明,这两种术式治疗第五掌骨干骨折均获得良好疗效,手指功能恢复佳,但经皮克氏针横行固定具有创伤小、切口小、费用低、内固定取出方便等优点。 展开更多
关键词 微型钢板 克氏针 横行固定 第五掌骨干骨折 掌骨骨折 内固定
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带线锚钉+空心钉内固定治疗髌骨骨折的疗效 被引量:1
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作者 王强 吕欣 +1 位作者 李兴业 刘晋元 《临床骨科杂志》 2024年第2期257-260,共4页
目的探讨带线锚钉+空心钉内固定治疗髌骨骨折的疗效。方法将60例髌骨骨折患者按照内固定方式不同分为观察组(采用带线锚钉+空心钉内固定治疗,30例)和对照组(采用克氏针张力带+钢丝捆扎内固定治疗,30例)。记录两组手术时间、骨折愈合情... 目的探讨带线锚钉+空心钉内固定治疗髌骨骨折的疗效。方法将60例髌骨骨折患者按照内固定方式不同分为观察组(采用带线锚钉+空心钉内固定治疗,30例)和对照组(采用克氏针张力带+钢丝捆扎内固定治疗,30例)。记录两组手术时间、骨折愈合情况、术后并发症发生率。采用Lysholm评分评价膝关节功能。结果患者均获得随访,观察组随访时间12~36(17.47±6.17)个月,对照组随访时间12~30(17.70±4.06)个月。手术时间观察组短于对照组(P<0.01)。两组骨痂形成时间2~3个月,骨折愈合时间4~6个月。术后并发症发生率观察组低于对照组(P<0.05)。末次随访时Lysholm评分评价的膝关节功能优良率两组比较差异无统计学意义(P>0.05)。结论带线锚钉+空心钉内固定治疗髌骨骨折能有效缩短手术时间、降低手术难度、减少术后并发症的发生,而且内固定稳定、牢靠,患者术后膝关节功能恢复良好。 展开更多
关键词 髌骨骨折 带线锚钉 空心钉 克氏针张力带 膝关节功能
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基于断裂力学的腐蚀钢丝疲劳S-N曲线研究 被引量:1
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作者 叶华文 叶杨帆 +2 位作者 邓雪峰 杨军川 徐勋 《铁道科学与工程学报》 EI CAS CSCD 北大核心 2024年第5期1990-2000,共11页
高强冷拔钢丝因其优异的力学性能被广泛应用于缆索承重结构,服役过程中钢丝腐蚀与断裂威胁着结构安全。钢丝腐蚀后表面的蚀坑因应力集中效应易产生疲劳裂纹,因此腐蚀钢丝剩余疲劳寿命主要取决于裂纹的扩展阶段,且裂纹扩展受到腐蚀程度(... 高强冷拔钢丝因其优异的力学性能被广泛应用于缆索承重结构,服役过程中钢丝腐蚀与断裂威胁着结构安全。钢丝腐蚀后表面的蚀坑因应力集中效应易产生疲劳裂纹,因此腐蚀钢丝剩余疲劳寿命主要取决于裂纹的扩展阶段,且裂纹扩展受到腐蚀程度(初始损伤)的显著影响。精确表征腐蚀程度并准确评估服役期钢丝腐蚀后的剩余寿命,仍是亟待解决的维修难题。首先采用蚀坑最大深度表征钢丝腐蚀程度,以应力强度因子幅作为裂纹扩展驱动力指标,基于断裂力学的Paris公式建立受拉钢丝裂纹扩展理论模型,进而推导腐蚀钢丝的疲劳S-N曲线。大量既有的腐蚀钢丝疲劳试验结果与理论预测值的比较验证了所提理论模型及疲劳S-N曲线的合理性和有效性。含多个蚀坑的钢丝裂纹扩展有限元模拟表明,等效单裂纹适用于多腐蚀坑钢丝疲劳寿命的简化分析。参数分析表明,蚀坑深度和腐蚀环境是腐蚀钢丝疲劳强度的关键影响因素,而应力比和疲劳加载频率影响较小,所提出的S-N曲线在钢丝常规服役条件下适用于评估其剩余寿命,可得到合理的预测结果。基于断裂力学所提的理论方法和疲劳S-N曲线可为腐蚀钢丝的疲劳强度和寿命评估提供参考。 展开更多
关键词 冷拔钢丝 腐蚀 剩余寿命 S-N曲线 蚀坑深度
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PCCP断丝破坏规律Ⅱ:数值模拟研究
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作者 窦铁生 董晓农 +3 位作者 牛文龙 李炎隆 宁靖华 黎康平 《水利学报》 EI CSCD 北大核心 2024年第1期48-59,70,共13页
目前预应力钢筒混凝土管(Prestressed Concrete Cylinder Pipe,PCCP)断丝的数值模拟要么整圈删除断丝,要么将断丝的预应力损失范围假设为固定值,无法依据砂浆损伤程度来判断断丝预应力损失范围是否扩展。本文通过抽象分析砂浆、预应力... 目前预应力钢筒混凝土管(Prestressed Concrete Cylinder Pipe,PCCP)断丝的数值模拟要么整圈删除断丝,要么将断丝的预应力损失范围假设为固定值,无法依据砂浆损伤程度来判断断丝预应力损失范围是否扩展。本文通过抽象分析砂浆、预应力钢丝和管芯混凝土之间的两两相互作用机制,引入弹簧单元、内聚力模型和塑性损伤模型,提出了管芯混凝土预压应力施加、任意位置钢丝割断和断丝预应力损失范围扩展的全过程模拟方法,明确了调控断丝预应力损失范围的初始大小、扩展时机和扩展幅度的关键参数。基于原型试验建立了恒定内压下集中和离散断丝的数值模型,从内压加载到断丝破坏的全过程角度验证了新模拟方法的合理性,揭示了管芯的预应力损失和破坏规律,使实际工程中各种三维断点分布的模拟成为可能,可为更精准地预测和评估断丝PCCP结构性能提供新手段。 展开更多
关键词 PCCP 集中断丝 离散断丝 数值模拟方法 预应力损失 破坏
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基于等效复数磁导率的利兹线绕组损耗计算模型 被引量:1
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作者 赵志刚 王丽美 +2 位作者 陈天缘 赵安琪 卢子奇 《电工技术学报》 EI CSCD 北大核心 2024年第4期947-955,共9页
绕组损耗是高频变压器总体损耗的重要组成部分,是影响磁性元件体积、效率和温升的关键性参数。由于利兹线的高频损耗小而广泛应用于高频变压器绕组,但其复杂的三维扭转结构导致准确、快速地计算绕组损耗十分困难。解析方法需要进行简化... 绕组损耗是高频变压器总体损耗的重要组成部分,是影响磁性元件体积、效率和温升的关键性参数。由于利兹线的高频损耗小而广泛应用于高频变压器绕组,但其复杂的三维扭转结构导致准确、快速地计算绕组损耗十分困难。解析方法需要进行简化和近似处理,难以准确地表征绕组的高频涡流特性,有限元数值方法需要对每匝绕组精细化建模,导致计算资源耗费严重。采用具有等效复值材料特性的区域替代绕组区域的均匀化技术,能够实现二维磁场对涡流效应的表征,降低了精细化建模的计算成本。但等效区域的材料特性需要利用数值方法获得,增加了计算的复杂性。因此该文通过分析利兹线损耗机理,考虑利兹线截面形状对等效区域材料特性的影响,实现了圆形利兹线绕组等效复数磁导率的明确解析描述。建立了圆形利兹线绕组损耗计算模型,验证了等效复数磁导率计算邻近效应的准确性,实现了较宽频率范围内绕组损耗的准确预测。 展开更多
关键词 利兹线 绕组损耗 等效复数磁导率 趋肤效应 邻近效应
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潜水系统非稳定流抽水试验智能优化配线
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作者 何立新 李翔 +1 位作者 张峥 张勇 《水电能源科学》 北大核心 2024年第3期33-37,共5页
精确求解水文地质参数是地下水数值模拟、地下水资源评价与开发的前提。为此,基于抽水试验降深—时间数据,采用随机权重粒子群优化(RandWPSO)算法对考虑给水滞后的博尔顿模型智能优化配线,实现潜水完整井非稳定流水文地质参数反演。结... 精确求解水文地质参数是地下水数值模拟、地下水资源评价与开发的前提。为此,基于抽水试验降深—时间数据,采用随机权重粒子群优化(RandWPSO)算法对考虑给水滞后的博尔顿模型智能优化配线,实现潜水完整井非稳定流水文地质参数反演。结果表明,RandWPSO算法选择的曲线拟合参数精度r/D值为0.1753,较人工选择的0.2精确度更高。该方法显著提高了反演参数精度,可为曲线族标准曲线拟合方法在实际工作中难以应用的问题提供借鉴。 展开更多
关键词 水文地质参数 RandWPSO算法 潜水含水层 优化配线
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