Zeolite-loaded noble metal catalysts have demonstrated excellent performance in addressing cold-start automotive exhaust NOx emissions and catalytic oxidation of VOCs applications.Pd and Pt are the most commonly used ...Zeolite-loaded noble metal catalysts have demonstrated excellent performance in addressing cold-start automotive exhaust NOx emissions and catalytic oxidation of VOCs applications.Pd and Pt are the most commonly used active metals in PNA and VOC catalysts,respectively.However,despite the same metal/zeolite composition,the efficient active sites for PNA and VOC catalysts have been viewed as mainly Pd2t and Pt0,respectively,both of which are different from each other.As a result,various methods need to be applied to dope Pd and Pt in zeolitic support respectively for different usages.No matter which type of metal species is needed,the common requirement for both PNA and VOC catalysts is that the metal species should be highly dispersed in zeolite support and stay stable.The purpose of this paper is to review the progress of synthetic means of zeolite-coated noble metals(Pd,Pt,etc.)as effective PNA or VOC catalysts.To give a better understanding of the relationship between efficient metal species and the introduced methods,the species that contributed to the NOx adsorption(PNA)and VOCs deep catalytic oxidation were first summarized and compared.Then,based on the above discussion,the detailed construction strategies for different active sites in PNA and VOC catalysts,respectively,were elaborated in terms of synthetic routes,precursor selection,and zeolite carrier requirements.It is hoped that this will contribute to a better understanding of noble metal adsorption/catalysis in zeolites and provide promising strategies for the design of adsorption/catalysts with high activity,selectivity and stability.展开更多
The Moon,as the closest celestial body to the Earth,plays a pivotal role in the progression of deep space exploration,and the establishment of research outposts on its surface represents a crucial step in this mission...The Moon,as the closest celestial body to the Earth,plays a pivotal role in the progression of deep space exploration,and the establishment of research outposts on its surface represents a crucial step in this mission.Lunar lava tubes are special underground caves formed by volcanic eruptions and are considered as ideal natural shelters and scientific laboratories for lunar base construction.This paper begins with an in-depth overview of the geological origins,exploration history,and distribution locations of lunar lava tubes.Subsequently,it delves into the presentation of four distinctive advantages and typical concepts for constructing bases within lava tubes,summarizing the ground-based attempts made thus far in lunar lava tube base construction.Field studies conducted on a lava tube in Hainan revealed rock compositions similar to those found during the Apollo missions and clear lava tube structures,making it a promising analog site.Lastly,the challenges and opportunities encountered in the field of geotechnical engineering regarding the establishment of lunar lava tube bases are discussed,encompassing cave exploration technologies,in-situ testing methods,geomechanical properties under lunar extreme environments,base design and structural stability assessment,excavation and reinforcement techniques,and simulated Earth-based lava tube base.展开更多
Completing the principal engineering components of a pumped storage power station spans between 50 and 60 months,from the inception of construction to the commencement of power generation by the first unit.The filling...Completing the principal engineering components of a pumped storage power station spans between 50 and 60 months,from the inception of construction to the commencement of power generation by the first unit.The filling of the penstock with water represents a critical phase preceding the production of electricity by the first unit.During this interval,the construction of the diversion shaft presents multiple challenges,including intricate construction procedures,considerable construction difficulty,elevated safety risks,and quality control issues.To address this issue,this study uses CFD software to analyze the flow field,pressure gradient,and head loss of shaft curved section with different curvature radius,and examines several key technologies by drawing on the practice of diversion shaft construction at the Meizhou pumped storage power station.These technologies include optimizing the curvature radius of the curved section of diversion shaft,reverse-well excavation for the shaft,and sliding-up for the lining concrete.It is found that as the curvature radius of shaft curved section reduces from 4 to 2 times the shaft diameter,the hydraulic characteristic index does not change much,and the increase of head loss accounts for about 0.18%of the total head loss of the water conveyance system.The result show that optimizing the curvature radius from 4 times to 2 times the shaft diameter is feasible and reasonable,and several improved technical measures have been proposed,such as stabilizing drill rods,mechanical scraper systems,and control technology of the relationship between concrete setting time and formwork sliding.Their implementation effectively mitigates difficulties and safety risks during shaft construction,expedites the project schedule,enhances engineering quality,and creates a 41-month timeline for the principal engineering schedule for the first power unit generation in China.展开更多
The development and utilization of lunar resources are entering a critical stage.Immediate focus is needed on key technologies for in-situ resource utilization(ISRU)and lunar base construction.This paper comparatively...The development and utilization of lunar resources are entering a critical stage.Immediate focus is needed on key technologies for in-situ resource utilization(ISRU)and lunar base construction.This paper comparatively analyzes the basic characteristics of lunar regolith samples returned from Chang'e-5(CE-5),Apollo,and Luna missions,focusing on their physical,mechanical,mineral,chemical,and morphological parameters.Given the limited availability of lunar regolith,more than 50 lunar regolith simulants are summarized.The differences between lunar regolith and simulants concerning these parameters are discussed.To facilitate the construction of lunar bases,this article summarizes the advancements in research on construction materials derived from lunar regolith simulants.Based on statistical results,lunar regolith simulant-based composites are classified into 5 types by their strengthening and toughening mechanisms,and a comprehensive analysis of molding methods,preparation conditions,and mechanical properties is conducted.Furthermore,the potential lunar base construction forms are reviewed,and the adaptability of lunar regolith simulant-based composites and lunar base construction methods are proposed.The key demands of lunar bases constructed with lunar regolith-based composites are discussed,including energy demand,in-situ buildability,service performance,and structural availability.This progress contributes to providing essential material and methodological support for future lunar construction.展开更多
OBE theory focuses on students’learning outcomes and application ability,which is consistent with the requirements of the new curriculum standard.The paper attempts to apply OBE theory to innovate the construction of...OBE theory focuses on students’learning outcomes and application ability,which is consistent with the requirements of the new curriculum standard.The paper attempts to apply OBE theory to innovate the construction of English classroom teaching mode in senior high schools from aspects of teaching aims,teaching activities,teaching assessments and application activities.Results show that the application of OBE in high schools is beneficial to the development of English teaching and students'learning.展开更多
As the extension and supplement of explicit curriculum,the English hidden curriculum in higher vocational colleges plays animportant role in cultivating students' behaviors,stimulate their interest and arouse thei...As the extension and supplement of explicit curriculum,the English hidden curriculum in higher vocational colleges plays animportant role in cultivating students' behaviors,stimulate their interest and arouse their enthusiasm,initiative and creativity in learningEnglish.This paper analyzes the problems of English hidden curriculum construction in higher vocational colleges under the back-ground o"fInternet plus",and puts forward some corresponding countermeasures to bring the role of college English hidden curriculuminto full play.展开更多
There have been heated discussions onthere-be construction in the field of linguistics,and linguists have made numerous attempts to explore it in syntax,semantics,and pragmatics.However,researchers have not reached an...There have been heated discussions onthere-be construction in the field of linguistics,and linguists have made numerous attempts to explore it in syntax,semantics,and pragmatics.However,researchers have not reached any consensus.There is a review of the mainstream of the studies to explore what can be done to promote unanimity.展开更多
According to the definition of tense,English has no actual future tense.The ways to express future time in English vary with the specific situation.We should avoid frequently using the same way to express the future.I...According to the definition of tense,English has no actual future tense.The ways to express future time in English vary with the specific situation.We should avoid frequently using the same way to express the future.It is important to study the different construction of the future time in English and its implications in order to make it clear that the appropriate construction to cope with the specific situation should be noticed.展开更多
In the circle of linguistics,numerous attempts have been made to explore there-be construction in the fields of syntax,semantics,and pragmatics,but in the by-now researches there is little touching on the derivation o...In the circle of linguistics,numerous attempts have been made to explore there-be construction in the fields of syntax,semantics,and pragmatics,but in the by-now researches there is little touching on the derivation of the word there.In consequence,herein the focus and effort are put on the derivation of there.It explores the motivation behind the derivation of there based on the cognitive study on there constructions.It is demonstrated that there-be construction derivates to meet the need of the development of human cognitive capacities of expressing abstract mental space.It is mainly motivated by gestalt law,figure-ground theory.展开更多
M.Butterfly,written by David Henry Hwang,is one of the most influential plays in contemporary American dramatic his-tory.Hwang incorporates a stereotypical fantasy into his play,involving conflicts and misunderstandin...M.Butterfly,written by David Henry Hwang,is one of the most influential plays in contemporary American dramatic his-tory.Hwang incorporates a stereotypical fantasy into his play,involving conflicts and misunderstandings between the East and theWest,between men and women.Through the analysis of the construction of the Orientalist"Madame Butterfly Fantasy"in M.Butterfly,this paper analyzes sexual prejudice and racial bias embedded in the"Fantasy".展开更多
In order to assess college students'overall language proficiency,a new format,banked cloze,is included in the revised CET-4.Based on the previous studies on banked cloze in China,this paper discusses on how to con...In order to assess college students'overall language proficiency,a new format,banked cloze,is included in the revised CET-4.Based on the previous studies on banked cloze in China,this paper discusses on how to construct highly valid CET-4 banked cloze in line with the revised CET Syllabus(2006).展开更多
Empty categories,which lack phonological form and hence are not visible in the phonetic representation of the sentence,have both syntactic and semantic properties.Null subjects PRO and pro are base-generated empty cat...Empty categories,which lack phonological form and hence are not visible in the phonetic representation of the sentence,have both syntactic and semantic properties.Null subjects PRO and pro are base-generated empty categories.This thesis,based on Chomsky's theory about empty categories and research achievements made by Chinese scholars,attempts to analyze the liandong(Serial Verb) construction from Figure and Ground perspective.展开更多
The observation of girls and boys study in college for many years elicits there is a key to construct students' gender which affect their study and job choosing after graduation. In order to make teaching more eff...The observation of girls and boys study in college for many years elicits there is a key to construct students' gender which affect their study and job choosing after graduation. In order to make teaching more effective and efficient, understanding what constructs genders becomes necessary for designing the curriculum. Some literatures tell that gender stereotypes exist ineradicably in our society. The gender stereotypes construct children's gender through their parents, mass media and their peer groups.The stereotypes believe boys wear blue and girls wear pink; boys always choose astronaut, lawyer, dentist as their job and girls prefer to be a nurse or a teacher. Gender stereotypes occur some negative phenomenon such as sex discrimination, restriction on personality development, and inefficient cooperation between male and female in our society. Educators should show a correct direction to students in their gender construction. There are 4 teaching approaches introduced to educator in the essay to reduce the influence of gender stereotypes on students. They are"access and equity""valuing girls' and boys' skills and experiences""acknowledging differences among girls and boys", and"challenging and critically examining the social structures". Students can understand themselves objectively and clearly, shape their personality positively, and develop their interests appropriately through the approaches in education.展开更多
In the era of"Internet Plus",emphasis has been placed on construction of teaching resources by utilizing internet platform andtechnologies.It is of great significance to discuss the construction of English t...In the era of"Internet Plus",emphasis has been placed on construction of teaching resources by utilizing internet platform andtechnologies.It is of great significance to discuss the construction of English teaching resources in higher vocational colleges from theperspective of ecopedagogy which is characterized by openness and diversity.We can achieve high efficiency and effectiveness in con-structing English teaching resources for higher vocational college students through abiding by following principles such as diversity,de-velopment,adaptation and openness.展开更多
An assessment index system including environment, socio-culture, economy and technology was established for evaluating environmental construction level of community （objective construction）, and questionnaire was de...An assessment index system including environment, socio-culture, economy and technology was established for evaluating environmental construction level of community （objective construction）, and questionnaire was designed according to paper review for evaluating residential satisfaction （subjective satisfaction）. The index system was divided into four layers： system （A）, subsystems （B）, categories （C）, and indicators （D）, and in total of 38 indicators was established. The Xihe community, affiliated to Nanfen district, Benxi City, Liaoning Province, China was selected as a case study. Results indicated that the community sustainability index related to objective environmental construction was 0.4355 and was classified as class Ⅲ （moderate）; the community sustainability index related to the residential satisfaction was 0.4255, belonging to class Ⅲ. In conclusion, the sustainability of Xihe community was moderate and needed to be improved. Residential satisfaction was lower than objective environmental construction. The assessment index system established in this study is able to reflect the comprehensive sustainability of community and can be used to evaluate other similar communities＇ sustainability.展开更多
The recent research progress of structure- and size-controlled micro/nano-energetic materials is reviewed, which properties are fundamentally different from those of their corresponding bulk materials. The development...The recent research progress of structure- and size-controlled micro/nano-energetic materials is reviewed, which properties are fundamentally different from those of their corresponding bulk materials. The development of the construction strategies for achieving zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) micro/nanostructures from energetic molecules is introduced. Also, an overview of the unique properties induced by micro/nanostructures and size effects is provided. Special emphasis is focused on the size-dependent properties that are different from those of the conventional micro-sized energetic materials, such as thermal decomposition, sensitivity, combustion and detonation, and compaction behaviors. A conclusion and our view of the future development of micro/nano-energetic materials and devices are given.展开更多
A novel particle/metal-based monolithic catalysts dual-bed reactor with beds-interspace supplementary oxygen is constructed comprising of the upper-layer 5 wt%Na2WO4-2 wt%Mn/SiO2 particle catalyst and the under-layer ...A novel particle/metal-based monolithic catalysts dual-bed reactor with beds-interspace supplementary oxygen is constructed comprising of the upper-layer 5 wt%Na2WO4-2 wt%Mn/SiO2 particle catalyst and the under-layer 3 wt%Ce-5 wt%Na2WO4-2 wt%Mn/SBA-15/Al2O3/FeCrA1 metal-based monolithic catalyst as well as a side tube in the interspaces of two layers for supplementing 02. The reaction performance of oxidative coupling of methane （OCM） in the dual-bed reactor system is evaluated. The effects of the reaction parameters such as feed CH4/O2 ratio, reaction temperature and side tube feed 02 flowrate on the catalytic performance are investigated. The results indicate that the suggested mode of dual-bed reactor exhibits an excellent performance for OCM. CH4 conversion of 33.2%, C2H4 selectivity of 46.5% and C2 yield of 22.5% could be obtained, which have been increased by 6.4%, 4.1% and 5.5%, respectively, as compared with 5 wt%Na2WO4-2 wt%Mn/SiO2 particle catalyst in a single-bed reactor and increased by 10.7%, 31.9% and 17.7%, respectively, as compared with 3 wt%Ce-5 wt%Na2WO4-2 wt%Mn/SBA-15/Al2O3/FeCrA1 metal-based monolithic catalyst in a single-bed reactor. The effective promotion of OCM performance in the reactor would supply a valuable reference for the industrialization of OCM process.展开更多
构式语法研究的新趋势很多,涉及构式的建构过程、构式从词素到分句到更大单位的拓展路径、构式视角下的语言习得与认知,以及构式的历史比较研究等。这些关于构式研究的新问题在牛津大学出版社出版的The Oxford Handbook of Construction...构式语法研究的新趋势很多,涉及构式的建构过程、构式从词素到分句到更大单位的拓展路径、构式视角下的语言习得与认知,以及构式的历史比较研究等。这些关于构式研究的新问题在牛津大学出版社出版的The Oxford Handbook of Construction Grammar一书中得到了充分关注。本文将从内容结构、理论特色、研究局限三个方面详细阐述构式语法研究的新发展。展开更多
PtLFY, a LEAFY （LFY） gene, was cloned from Populus tomentosa （LM50） by PCR. Sequencing analysis indicated that PtLFY was 2629 bp long, composed of three exons and two introns and encoded 378 amino acids. The splic...PtLFY, a LEAFY （LFY） gene, was cloned from Populus tomentosa （LM50） by PCR. Sequencing analysis indicated that PtLFY was 2629 bp long, composed of three exons and two introns and encoded 378 amino acids. The splice donor sites and the splice acceptor sites were in identical positions to the LFY and its homologues. The amino acid sequence inferred was 68%-99% homologous to those of LFY and its homologues by blast analysis in GenBank. The Southern blot analysis indicated that there was a single copy of the PtLFY gene in genomic DNA of male and female P. tomentosa （LM50 and 5082）. The pBI121-Ptalfy （reverse）-intron-Ptlfy-GUS-nos was constructed using RNA interference （RNAi） technique and verified by PCR and digestion identification and transformed into tobacco. Some transgenic tobacco plants were obtained by PCR and PCR-Southern identification. The growth was generally repressed in transgenic tobacco plants compared with wild-type ones and some phenotypic differences were observed.展开更多
Attribute-based encryption is drawing more attention with its inherent attractive properties which are potential to be widely used in the newly developing cloud computing. However, one of the main obstacles for its ap...Attribute-based encryption is drawing more attention with its inherent attractive properties which are potential to be widely used in the newly developing cloud computing. However, one of the main obstacles for its application is how to revoke the attributes of the users, though some ABE schemes have realized revocation, they mostly focused on the user revocation that revokes the user＇s whole attributes, or attribute revocation under the indirect revocation model such that all the users＇ private keys will be affected by the revocation. In this paper, we define the model of CP-ABE supporting the attribute revocation under the direct revocation model, in which the revocation list is embed in the ciphertext and none of the users＇ private keys will be affected by the revocation process. Then we propose a generic construction, and prove its security with the decision q-BDHE assumption.展开更多
基金supported by Zhongtian Iron and Steel-University of Science and Technology Beijing Youth Science and Technology Innovation Fund(No.FZTNTC2024050005)National Engineering Laboratory for Mobile Source Emission Control Technology,China(No.NELMS2020A07)The Fundamental Research Funds for the Central Universities,China(No.FRF-AT-20-12)。
文摘Zeolite-loaded noble metal catalysts have demonstrated excellent performance in addressing cold-start automotive exhaust NOx emissions and catalytic oxidation of VOCs applications.Pd and Pt are the most commonly used active metals in PNA and VOC catalysts,respectively.However,despite the same metal/zeolite composition,the efficient active sites for PNA and VOC catalysts have been viewed as mainly Pd2t and Pt0,respectively,both of which are different from each other.As a result,various methods need to be applied to dope Pd and Pt in zeolitic support respectively for different usages.No matter which type of metal species is needed,the common requirement for both PNA and VOC catalysts is that the metal species should be highly dispersed in zeolite support and stay stable.The purpose of this paper is to review the progress of synthetic means of zeolite-coated noble metals(Pd,Pt,etc.)as effective PNA or VOC catalysts.To give a better understanding of the relationship between efficient metal species and the introduced methods,the species that contributed to the NOx adsorption(PNA)and VOCs deep catalytic oxidation were first summarized and compared.Then,based on the above discussion,the detailed construction strategies for different active sites in PNA and VOC catalysts,respectively,were elaborated in terms of synthetic routes,precursor selection,and zeolite carrier requirements.It is hoped that this will contribute to a better understanding of noble metal adsorption/catalysis in zeolites and provide promising strategies for the design of adsorption/catalysts with high activity,selectivity and stability.
基金supported by the National Natural Science Foundation of China(Nos.52125903 and 52339001).
文摘The Moon,as the closest celestial body to the Earth,plays a pivotal role in the progression of deep space exploration,and the establishment of research outposts on its surface represents a crucial step in this mission.Lunar lava tubes are special underground caves formed by volcanic eruptions and are considered as ideal natural shelters and scientific laboratories for lunar base construction.This paper begins with an in-depth overview of the geological origins,exploration history,and distribution locations of lunar lava tubes.Subsequently,it delves into the presentation of four distinctive advantages and typical concepts for constructing bases within lava tubes,summarizing the ground-based attempts made thus far in lunar lava tube base construction.Field studies conducted on a lava tube in Hainan revealed rock compositions similar to those found during the Apollo missions and clear lava tube structures,making it a promising analog site.Lastly,the challenges and opportunities encountered in the field of geotechnical engineering regarding the establishment of lunar lava tube bases are discussed,encompassing cave exploration technologies,in-situ testing methods,geomechanical properties under lunar extreme environments,base design and structural stability assessment,excavation and reinforcement techniques,and simulated Earth-based lava tube base.
文摘Completing the principal engineering components of a pumped storage power station spans between 50 and 60 months,from the inception of construction to the commencement of power generation by the first unit.The filling of the penstock with water represents a critical phase preceding the production of electricity by the first unit.During this interval,the construction of the diversion shaft presents multiple challenges,including intricate construction procedures,considerable construction difficulty,elevated safety risks,and quality control issues.To address this issue,this study uses CFD software to analyze the flow field,pressure gradient,and head loss of shaft curved section with different curvature radius,and examines several key technologies by drawing on the practice of diversion shaft construction at the Meizhou pumped storage power station.These technologies include optimizing the curvature radius of the curved section of diversion shaft,reverse-well excavation for the shaft,and sliding-up for the lining concrete.It is found that as the curvature radius of shaft curved section reduces from 4 to 2 times the shaft diameter,the hydraulic characteristic index does not change much,and the increase of head loss accounts for about 0.18%of the total head loss of the water conveyance system.The result show that optimizing the curvature radius from 4 times to 2 times the shaft diameter is feasible and reasonable,and several improved technical measures have been proposed,such as stabilizing drill rods,mechanical scraper systems,and control technology of the relationship between concrete setting time and formwork sliding.Their implementation effectively mitigates difficulties and safety risks during shaft construction,expedites the project schedule,enhances engineering quality,and creates a 41-month timeline for the principal engineering schedule for the first power unit generation in China.
基金supported by National Natural Science Foundation of China(No.42172319)the Fundamental Research Funds for the Central Universities(No.2023ZKPYLJ01)。
文摘The development and utilization of lunar resources are entering a critical stage.Immediate focus is needed on key technologies for in-situ resource utilization(ISRU)and lunar base construction.This paper comparatively analyzes the basic characteristics of lunar regolith samples returned from Chang'e-5(CE-5),Apollo,and Luna missions,focusing on their physical,mechanical,mineral,chemical,and morphological parameters.Given the limited availability of lunar regolith,more than 50 lunar regolith simulants are summarized.The differences between lunar regolith and simulants concerning these parameters are discussed.To facilitate the construction of lunar bases,this article summarizes the advancements in research on construction materials derived from lunar regolith simulants.Based on statistical results,lunar regolith simulant-based composites are classified into 5 types by their strengthening and toughening mechanisms,and a comprehensive analysis of molding methods,preparation conditions,and mechanical properties is conducted.Furthermore,the potential lunar base construction forms are reviewed,and the adaptability of lunar regolith simulant-based composites and lunar base construction methods are proposed.The key demands of lunar bases constructed with lunar regolith-based composites are discussed,including energy demand,in-situ buildability,service performance,and structural availability.This progress contributes to providing essential material and methodological support for future lunar construction.
文摘OBE theory focuses on students’learning outcomes and application ability,which is consistent with the requirements of the new curriculum standard.The paper attempts to apply OBE theory to innovate the construction of English classroom teaching mode in senior high schools from aspects of teaching aims,teaching activities,teaching assessments and application activities.Results show that the application of OBE in high schools is beneficial to the development of English teaching and students'learning.
文摘As the extension and supplement of explicit curriculum,the English hidden curriculum in higher vocational colleges plays animportant role in cultivating students' behaviors,stimulate their interest and arouse their enthusiasm,initiative and creativity in learningEnglish.This paper analyzes the problems of English hidden curriculum construction in higher vocational colleges under the back-ground o"fInternet plus",and puts forward some corresponding countermeasures to bring the role of college English hidden curriculuminto full play.
文摘There have been heated discussions onthere-be construction in the field of linguistics,and linguists have made numerous attempts to explore it in syntax,semantics,and pragmatics.However,researchers have not reached any consensus.There is a review of the mainstream of the studies to explore what can be done to promote unanimity.
文摘According to the definition of tense,English has no actual future tense.The ways to express future time in English vary with the specific situation.We should avoid frequently using the same way to express the future.It is important to study the different construction of the future time in English and its implications in order to make it clear that the appropriate construction to cope with the specific situation should be noticed.
文摘In the circle of linguistics,numerous attempts have been made to explore there-be construction in the fields of syntax,semantics,and pragmatics,but in the by-now researches there is little touching on the derivation of the word there.In consequence,herein the focus and effort are put on the derivation of there.It explores the motivation behind the derivation of there based on the cognitive study on there constructions.It is demonstrated that there-be construction derivates to meet the need of the development of human cognitive capacities of expressing abstract mental space.It is mainly motivated by gestalt law,figure-ground theory.
文摘M.Butterfly,written by David Henry Hwang,is one of the most influential plays in contemporary American dramatic his-tory.Hwang incorporates a stereotypical fantasy into his play,involving conflicts and misunderstandings between the East and theWest,between men and women.Through the analysis of the construction of the Orientalist"Madame Butterfly Fantasy"in M.Butterfly,this paper analyzes sexual prejudice and racial bias embedded in the"Fantasy".
文摘In order to assess college students'overall language proficiency,a new format,banked cloze,is included in the revised CET-4.Based on the previous studies on banked cloze in China,this paper discusses on how to construct highly valid CET-4 banked cloze in line with the revised CET Syllabus(2006).
文摘Empty categories,which lack phonological form and hence are not visible in the phonetic representation of the sentence,have both syntactic and semantic properties.Null subjects PRO and pro are base-generated empty categories.This thesis,based on Chomsky's theory about empty categories and research achievements made by Chinese scholars,attempts to analyze the liandong(Serial Verb) construction from Figure and Ground perspective.
文摘The observation of girls and boys study in college for many years elicits there is a key to construct students' gender which affect their study and job choosing after graduation. In order to make teaching more effective and efficient, understanding what constructs genders becomes necessary for designing the curriculum. Some literatures tell that gender stereotypes exist ineradicably in our society. The gender stereotypes construct children's gender through their parents, mass media and their peer groups.The stereotypes believe boys wear blue and girls wear pink; boys always choose astronaut, lawyer, dentist as their job and girls prefer to be a nurse or a teacher. Gender stereotypes occur some negative phenomenon such as sex discrimination, restriction on personality development, and inefficient cooperation between male and female in our society. Educators should show a correct direction to students in their gender construction. There are 4 teaching approaches introduced to educator in the essay to reduce the influence of gender stereotypes on students. They are"access and equity""valuing girls' and boys' skills and experiences""acknowledging differences among girls and boys", and"challenging and critically examining the social structures". Students can understand themselves objectively and clearly, shape their personality positively, and develop their interests appropriately through the approaches in education.
文摘In the era of"Internet Plus",emphasis has been placed on construction of teaching resources by utilizing internet platform andtechnologies.It is of great significance to discuss the construction of English teaching resources in higher vocational colleges from theperspective of ecopedagogy which is characterized by openness and diversity.We can achieve high efficiency and effectiveness in con-structing English teaching resources for higher vocational college students through abiding by following principles such as diversity,de-velopment,adaptation and openness.
基金This study was supported by the National Key Tech-nologies R & D Program of China (2006BAD03A09)Agrifund of China’s Ministry of Science and Technology (2006GB24910472)
文摘An assessment index system including environment, socio-culture, economy and technology was established for evaluating environmental construction level of community （objective construction）, and questionnaire was designed according to paper review for evaluating residential satisfaction （subjective satisfaction）. The index system was divided into four layers： system （A）, subsystems （B）, categories （C）, and indicators （D）, and in total of 38 indicators was established. The Xihe community, affiliated to Nanfen district, Benxi City, Liaoning Province, China was selected as a case study. Results indicated that the community sustainability index related to objective environmental construction was 0.4355 and was classified as class Ⅲ （moderate）; the community sustainability index related to the residential satisfaction was 0.4255, belonging to class Ⅲ. In conclusion, the sustainability of Xihe community was moderate and needed to be improved. Residential satisfaction was lower than objective environmental construction. The assessment index system established in this study is able to reflect the comprehensive sustainability of community and can be used to evaluate other similar communities＇ sustainability.
基金Sponsored by National Natural Science Foundation of China (21231002,21276026,21271023,21173021,91022006,11202193,11172276,and 11072225)the 111 Project ( B07012)+1 种基金the Program of Cooperation of the Beijing Education Commission ( 20091739006)Specialized Research Fund for the Doctoral Program of Higher Education ( 20101101110031)
文摘The recent research progress of structure- and size-controlled micro/nano-energetic materials is reviewed, which properties are fundamentally different from those of their corresponding bulk materials. The development of the construction strategies for achieving zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) micro/nanostructures from energetic molecules is introduced. Also, an overview of the unique properties induced by micro/nanostructures and size effects is provided. Special emphasis is focused on the size-dependent properties that are different from those of the conventional micro-sized energetic materials, such as thermal decomposition, sensitivity, combustion and detonation, and compaction behaviors. A conclusion and our view of the future development of micro/nano-energetic materials and devices are given.
基金supported by the National Basic Research Program of China (Project No. 2005CB221405)
文摘A novel particle/metal-based monolithic catalysts dual-bed reactor with beds-interspace supplementary oxygen is constructed comprising of the upper-layer 5 wt%Na2WO4-2 wt%Mn/SiO2 particle catalyst and the under-layer 3 wt%Ce-5 wt%Na2WO4-2 wt%Mn/SBA-15/Al2O3/FeCrA1 metal-based monolithic catalyst as well as a side tube in the interspaces of two layers for supplementing 02. The reaction performance of oxidative coupling of methane （OCM） in the dual-bed reactor system is evaluated. The effects of the reaction parameters such as feed CH4/O2 ratio, reaction temperature and side tube feed 02 flowrate on the catalytic performance are investigated. The results indicate that the suggested mode of dual-bed reactor exhibits an excellent performance for OCM. CH4 conversion of 33.2%, C2H4 selectivity of 46.5% and C2 yield of 22.5% could be obtained, which have been increased by 6.4%, 4.1% and 5.5%, respectively, as compared with 5 wt%Na2WO4-2 wt%Mn/SiO2 particle catalyst in a single-bed reactor and increased by 10.7%, 31.9% and 17.7%, respectively, as compared with 3 wt%Ce-5 wt%Na2WO4-2 wt%Mn/SBA-15/Al2O3/FeCrA1 metal-based monolithic catalyst in a single-bed reactor. The effective promotion of OCM performance in the reactor would supply a valuable reference for the industrialization of OCM process.
文摘构式语法研究的新趋势很多,涉及构式的建构过程、构式从词素到分句到更大单位的拓展路径、构式视角下的语言习得与认知,以及构式的历史比较研究等。这些关于构式研究的新问题在牛津大学出版社出版的The Oxford Handbook of Construction Grammar一书中得到了充分关注。本文将从内容结构、理论特色、研究局限三个方面详细阐述构式语法研究的新发展。
文摘PtLFY, a LEAFY （LFY） gene, was cloned from Populus tomentosa （LM50） by PCR. Sequencing analysis indicated that PtLFY was 2629 bp long, composed of three exons and two introns and encoded 378 amino acids. The splice donor sites and the splice acceptor sites were in identical positions to the LFY and its homologues. The amino acid sequence inferred was 68%-99% homologous to those of LFY and its homologues by blast analysis in GenBank. The Southern blot analysis indicated that there was a single copy of the PtLFY gene in genomic DNA of male and female P. tomentosa （LM50 and 5082）. The pBI121-Ptalfy （reverse）-intron-Ptlfy-GUS-nos was constructed using RNA interference （RNAi） technique and verified by PCR and digestion identification and transformed into tobacco. Some transgenic tobacco plants were obtained by PCR and PCR-Southern identification. The growth was generally repressed in transgenic tobacco plants compared with wild-type ones and some phenotypic differences were observed.
文摘Attribute-based encryption is drawing more attention with its inherent attractive properties which are potential to be widely used in the newly developing cloud computing. However, one of the main obstacles for its application is how to revoke the attributes of the users, though some ABE schemes have realized revocation, they mostly focused on the user revocation that revokes the user＇s whole attributes, or attribute revocation under the indirect revocation model such that all the users＇ private keys will be affected by the revocation. In this paper, we define the model of CP-ABE supporting the attribute revocation under the direct revocation model, in which the revocation list is embed in the ciphertext and none of the users＇ private keys will be affected by the revocation process. Then we propose a generic construction, and prove its security with the decision q-BDHE assumption.
