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Empowering Rice Farmers in Nueva Ecija, Philippines: A Strategic Approach to Boosting Income through Special Purpose Rice Production
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作者 Armando C. Lagasca Eugenia G. Baltazar +3 位作者 Johnah Jefferson S. Mercado Randy L. Kwan Erwin M. Valiente Jerski Jarzen C. Duria 《Open Journal of Ecology》 2024年第3期199-214,共16页
Low income is the main problem of millions of farmers who are cultivating 4.81 million hectares in the Philippines. This problem is attributed to challenges specifically low yield, low quality of produce, and signific... Low income is the main problem of millions of farmers who are cultivating 4.81 million hectares in the Philippines. This problem is attributed to challenges specifically low yield, low quality of produce, and significant post-harvest losses, particularly in a resource-scarce setting. This study aimed to help increase the farmers’ income in selected towns of Nueva Ecija through the promotion and use of special purpose rice production technology. Twenty (20) farmer-cooperators in three towns of Nueva Ecija were selected to demonstrate the production technology covering a total area of 4.75 hectares during the dry season, and 3.3 hectares during the wet season, both in 2023. Extension modalities such as training, techno-demo establishment, information material and technical assistance provision, and market linkage were undertaken to enhance their knowledge, attitude, and skills on special rice production and enterprise. The study utilized the descriptive quantitative method wherein the data were gathered through surveys, specifically personal interviews. Results showed that 70% of the farmer-cooperators were male and 60% were living below the poverty threshold. The farmers were 53 years old on average and engaged in farming as their primary source of income. The average yield of special purpose rice particularly the CLS-2 variety was higher (6.46 MT/ha and 6.22 MT/ha during dry and wet seasons, respectively) than that of inbred or non-special rice. The income per hectare from special purpose rice production per hectare was Php 75,420.00, which is higher than that of regular rice at Php 29,389.00, giving a higher benefit of Php 46,031.00. The technology adopters and area planted increased (from 6 to 9 and from 1.4 hectares to 2.75 hectares, respectively) in Licab, Nueva Ecija. The opposite was true in Sto. Domingo and Guimba, Nueva Ecija where farmers were discouraged by the marketing issues that arose. 展开更多
关键词 Special purpose Rice Technology Promotion Extension Modality
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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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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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Discussion on the Purposes of Literary Education in Contemporary China
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作者 Yinglin Dai 《Journal of Contemporary Educational Research》 2024年第8期296-301,共6页
The purposes of education,both immediate and in the future,are an issue to be pondered.A number of scholars have responded that education has different aims,including the cultivation of citizenship,a flourishing life,... The purposes of education,both immediate and in the future,are an issue to be pondered.A number of scholars have responded that education has different aims,including the cultivation of citizenship,a flourishing life,and powerful knowledge.This paper aims to explore whether these different general goals accurately fit literary education and attest to them in the form of questions.Under each section,the paper begins by outlining the theoretical analysis and proceeds to present the author’s judgment and reflections based on experiences related to the context of contemporary China. 展开更多
关键词 Literary education purpose Contemporary China
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Identity Study of English for Specific Purposes Teachers in the Context of Shifts in Public English Teaching Positioning
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作者 Xiaochao Yao 《Journal of Contemporary Educational Research》 2024年第7期138-142,共5页
This study investigates the identity of English for Specific Purposes(ESP)teachers within the dynamic landscape of shifts in public English teaching positioning.Adopting a mixed-methods approach,qualitative and quanti... This study investigates the identity of English for Specific Purposes(ESP)teachers within the dynamic landscape of shifts in public English teaching positioning.Adopting a mixed-methods approach,qualitative and quantitative analyses were employed to explore the complexities of ESP teacher identity construction and adaptation.Qualitative findings revealed key themes including strong professional identity grounded in specialized expertise,the impact of changing educational policies and curriculum reforms,and the importance of cultural competence and intercultural communication.Quantitative analysis of survey data indicated high levels of job satisfaction among ESP teachers,with significant correlations between variables such as professional development participation,perceived efficacy in technology integration,and self-perceptions of identity as ESP educators. 展开更多
关键词 English for Specific purposes teachers IDENTITY Public English teaching POSITIONING
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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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Trip Purposes of Automobile Users Inference Using Multi-day Traffic Monitoring Data
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作者 Wen Zheng Wenquan Li +2 位作者 Qian Chen Yan Zheng Chenhao Zhang 《Journal of Harbin Institute of Technology(New Series)》 CAS 2023年第5期1-11,共11页
Determining trip purpose is an important link to explore travel rules. In this paper,we takea utomobile users in urban areas as the research object,combine unsupervised learning and supervised learningm ethods to anal... Determining trip purpose is an important link to explore travel rules. In this paper,we takea utomobile users in urban areas as the research object,combine unsupervised learning and supervised learningm ethods to analyze their travel characteristics,and focus on the classification and prediction of automobileu sers’trip purposes. However,previous studies on trip purposes mainly focused on questionnaires and GPSd ata,which cannot well reflect the characteristics of automobile travel. In order to avoid the multi-dayb ehavior variability and unobservable heterogeneity of individual characteristics ignored in traditional traffic questionnaires,traffic monitoring data from the Northern District of Qingdao are used,and the K-meansc lustering method is applied to estimate the trip purposes of automobile users. Then,Adaptive Boosting(AdaBoost)and Random Forest(RF)methods are used to classify and predict trip purposes. Finally,ther esult shows:(1)the purpose of automobile users can be mainly divided into four clusters,which includeC ommuting trips,Flexible life demand travel in daytime,Evening entertainment and leisure shopping,andT axi-based trips for the first three types of purposes,respectively;(2)the Random Forest method performss ignificantly better than AdaBoost in trip purpose prediction for higher accuracy;(3)the average predictiona ccuracy of Random Forest under hyper-parameters optimization reaches96.25%,which proves the feasibilitya nd rationality of the above clustering results. 展开更多
关键词 trip purpose automobile users traffic monitoring data K-means clustering ADABOOST random forest
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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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The Powerful Role of Mothers in Adolescent Purpose Development
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作者 Lily Konowitz Terese Lund +5 位作者 Shao Wei Chew Chia Madeline Reed Willow Wood Belle Liang David Blustein Mike Barnett 《Journal of Psychological Research》 2023年第1期1-16,共16页
Adolescence is a critical time for the cultivation of life purpose,also known as a meaningful long-term aim focused on contribution to others.Youth with purpose,especially marginalized youth,report a number of positiv... Adolescence is a critical time for the cultivation of life purpose,also known as a meaningful long-term aim focused on contribution to others.Youth with purpose,especially marginalized youth,report a number of positive outcomes.Relationships with caring adults appear to be particularly helpful in guiding young people on their path to purpose,but little work has focused specifically on the role of mothers.This qualitative study,approved by a Institutional Review Board,examines how twenty adolescents from marginalized communities describe their sense of purpose and its relationship to their caregivers.The sample size was determined based on saturation,a process in qualitative research when the researchers begin to observe redundancy in the data.Through content analysis,a major theme emerged:the role of mothers and their impact on purpose development on their children.Results showed that mothers helped their adolescents develop their sense of purpose through serving as a sense of inspiration,providing the adolescents with support,sparking a desire for the adolescents to make their mothers proud,and through the mothers and adolescents in engaging in conversations about one’s future. 展开更多
关键词 Adolescents Positive youth development purpose Marginalized youth Mothers
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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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Using the Delphi method to propose foods for special medical purposes health effect evaluation indicators
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作者 Peng Ren Hai-Yue Wang Zeng-Ning Li 《Journal of Nutritional Oncology》 2023年第1期47-52,共6页
Objective:The Delphi method was used to propose health effect evaluation indicators to assess foods for special medical purposes(FSMPs).This lays the foundation for the formation of a big data model for human health t... Objective:The Delphi method was used to propose health effect evaluation indicators to assess foods for special medical purposes(FSMPs).This lays the foundation for the formation of a big data model for human health testing,as well as a big data platform for the health and safety evaluation of special medical foods.Methods:The Delphi method was used to conduct two rounds of expert consultation on the constructed FSMP health effect evaluation indicators.Results:Ten major items were identified after two rounds of expert consultation.Among these,there were 10 primary entries,32 secondary entries,50 tertiary entries,and 28 quaternary entries.Conclusion:The complete list of evaluation indicators contains 10 entries,which can comprehensively and systematically monitor adverse reactions to the use of FSMPs.The present findings lay the foundation for a big data platform to evaluate the health and safety of special foods. 展开更多
关键词 Food for special medical purpose(FSMP) Delphi Health effect Expert consultation Evaluation indicators
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Purpose融合:基于风险purpose的隐私查询访问控制 被引量:4
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作者 刘逸敏 周浩峰 +1 位作者 王智慧 汪卫 《计算机学报》 EI CSCD 北大核心 2010年第8期1339-1348,共10页
基于purpose的查询技术是关系数据库对隐私数据访问控制的基础,目前大多数研究都仅仅关注在独立隐私保护数据库环境下,如何建立有效的基于purpose的隐私数据访问控制模型.但随着分布应用整合和数据共享需求的日益增长,如何合并独立应用... 基于purpose的查询技术是关系数据库对隐私数据访问控制的基础,目前大多数研究都仅仅关注在独立隐私保护数据库环境下,如何建立有效的基于purpose的隐私数据访问控制模型.但随着分布应用整合和数据共享需求的日益增长,如何合并独立应用下基于purpose访问控制模型的问题就应运而生.为解决这一问题,文章提出了多应用系统集成环境下基于融合purpose的隐私数据访问控制实现机制.文章首先分析了由于合并独立purpose模型而引起的潜在隐私数据查询泄漏,提出了合并后的purpose树是一棵隐私泄漏风险树,并给出了树结点隐私风险度的计算模型.其次,将隐私泄漏风险树分解成一棵所有结点风险度为0的风险平衡树以及一组由风险度不为0的结点组成的风险路径.这样,一个查询可被改写为先对风险平衡purpose树的查询,再对风险路径查询,以此达到隐私泄漏风险最小的安全查询结果.文章给出了3组实验的结果:(1)对于同一用户同一查询,在不同purpose模型下的查询时间比较.文章提出的模型并没有在查询时间上带来更大的开销.(2)对RPPAAC模型防止隐私数据泄漏的有效性验证.文中的模型可降低由应用整合引起访问控制机制不平衡所带来的隐私数据泄漏风险.(3)不同情况下purpose融合的执行时间比较.文章与相关研究的不同之处是将purpose作为隐私数据的载体、purpose树的路径作为隐私数据的传递通道,引入了显性隐私度和隐性隐私度的计算模型,评估基于一个purpose查询可能带来的隐私泄漏风险,进而提出了多应用系统集成环境下基于融合purpose的隐私数据访问控制实现机制. 展开更多
关键词 隐私 隐私保护数据库 purpose 隐私度 访问控制
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Integral Operator Solving Process of the Boundary Value Problem of Abstract Kinetic Equation with the First Kind of Critical Parameter and Generalized Periodic Boundary Conditions
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作者 YU De-jian 《Chinese Quarterly Journal of Mathematics》 CSCD 2010年第1期110-117,共8页
In this paper the concepts of the boundary value problem of abstract kinetic equation with the first kind of critical parameter γ 0 and generalized periodic boundary conditions are introduced in a Lebesgue space whic... In this paper the concepts of the boundary value problem of abstract kinetic equation with the first kind of critical parameter γ 0 and generalized periodic boundary conditions are introduced in a Lebesgue space which consists of functions with vector valued in a general Banach space, and then describe the solution of these abstract boundary value problem by the abstract linear integral operator of Volterra type. We call this process the integral operator solving process. 展开更多
关键词 abstract kinetic equation with the first kind of critical parameter boundary value problem of abstract kinetic equation generalized periodic boundary conditions abstract linear integral operator of Volterra type integral operator solving process
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关于MEDLINE-Abstracts文献的语法规则的构建与实现 被引量:1
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作者 王剑辉 姜龙滨 穆宝良 《西安科技大学学报》 CAS 北大核心 2007年第1期111-114,共4页
以MEDLINE-Abstracts为研究对象,对其语言特点进行了统计和分析,采用计算机语言学方法,使用XDOC工具,构建并实现了对MEDLINE-Abstracts文献处理有效的英语语法规则。本文作者所开发的应用程序软件对减少文献分析中的多态性问题也是非常... 以MEDLINE-Abstracts为研究对象,对其语言特点进行了统计和分析,采用计算机语言学方法,使用XDOC工具,构建并实现了对MEDLINE-Abstracts文献处理有效的英语语法规则。本文作者所开发的应用程序软件对减少文献分析中的多态性问题也是非常有效和实用的。XDOC是一个处理德文和英文文献有效的工具,对汉语文献的处理也具有积极的借鉴意义。 展开更多
关键词 语言处理 MEDLINE—abstracts语言 实现 语法规则
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CAB ABSTRACTS光盘数据库中的中国文献研究 被引量:3
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作者 张永红 《情报杂志》 CSSCI 北大核心 2000年第5期58-60,共3页
运用文献统计学和文献计量学的方法,对世界第一大国际权威农业文献检索系统CAB AB-STRACTS光盘数据库在1972-1998年4月间收录的中国农业科技论文的数量、原文语种以及英文摘要附有率进行了研究,并就如何提高我国农业文献在国际权威检索... 运用文献统计学和文献计量学的方法,对世界第一大国际权威农业文献检索系统CAB AB-STRACTS光盘数据库在1972-1998年4月间收录的中国农业科技论文的数量、原文语种以及英文摘要附有率进行了研究,并就如何提高我国农业文献在国际权威检索系统中的收录量提出了建议。 展开更多
关键词 CAB abstractS CAB文摘数据库 中国 农业文献
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Experimental and Theoretical Study of Hydrogen Atom Abstraction from C2H6 and C4H10 by Zirconium Oxide Clusters Anions 被引量:1
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作者 马嘉璧 吴晓楠 +2 位作者 赵艳霞 丁迅雷 何圣贵 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2010年第2期133-137,I0001,共6页
The reactions of anionic zirconium oxide clusters ZrxOy- with C2H6 and C4H10 are investi-gated by a time of flight mass spectrometer coupled with a laser vaporization cluster source.Hydrogen containing products Zr2O5H... The reactions of anionic zirconium oxide clusters ZrxOy- with C2H6 and C4H10 are investi-gated by a time of flight mass spectrometer coupled with a laser vaporization cluster source.Hydrogen containing products Zr2O5H- and Zr3O7H- are observed after the reaction. Den-sity functional theory calculations indicate that the hydrogen abstraction is favorable in the reaction of Zr2O5- with C2H6, which supports that the observed Zr2O5H- and Zr3O7H- are due to hydrogen atom abstraction from the alkane molecules. This work shows a newpossible pathway in the reaction of zirconium oxide cluster anions with alkane molecules. 展开更多
关键词 Time of flight mass spectrometry Zirconium oxide cluster anion Reactivity Density functional theory Hydrogen atom abstraction
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Photochemical Hydrogen Abstraction and Electron Transfer Reactions of Tetrachlorobenzoquinone with Pyrimidine Nucleobases
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作者 刘坤辉 吴丽丹 +3 位作者 邹笑然 杨文 杜谦 苏红梅 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2011年第5期580-585,I0004,共7页
Pentachlorophenol, a widespread environmental pollutant that is possibly carcinogenic to humans, is metabolically oxidized to tetrachloroquinone (TCBQ) which can result in DNA damage. We have investigated the photoc... Pentachlorophenol, a widespread environmental pollutant that is possibly carcinogenic to humans, is metabolically oxidized to tetrachloroquinone (TCBQ) which can result in DNA damage. We have investigated the photochemical reaction dynamics of TCBQ with two pyrimidine type nucleobases (thymine and uracil) upon UVA (355 ran) excitation using the technique of nanosecond time-resolved laser flash photolysis. It has been found that 355 nm excitation populates TCBQ molecules to their triplet state 3TCBQ*, which are highly reactive towards thymine or uracil and undergo two parallel reactions, the hydrogen abstraction and electron transfer, leading to the observed photoproducts of TCBQH. and TCBQ.- in transient absorption spectra. The concomitantly produced nucleobase radicals and radical cations are expected to induce a series of oxidative or strand cleavage damage to DNA afterwards. By characterizing the photochemical hydrogen abstraction and electron transfer reactions, our results provide potentially important molecular reaction mechanisms for understanding the carcinogenic effects of pentachlorophenol and its metabolites TCBQ. 展开更多
关键词 Tetrachlorobenzoquinone THYMINE URACIL Triplet state Hydrogen abstraction Electron transfer Laser flash photolysis
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