This study contests the prevalent perception of graffiti writing,especially tagging and bombing,as meaningless vandalism.It contends that graffiti is a form of expression with intrinsic political implications.Leveragi...This study contests the prevalent perception of graffiti writing,especially tagging and bombing,as meaningless vandalism.It contends that graffiti is a form of expression with intrinsic political implications.Leveraging the notion of spatial justice and Jacques Ranciere's philosophy,I demonstrate how graffiti reclaims urban visibility against the commercial monopoly of visibility in public spaces and challenges the inequitable allocation of opportunities for self-expression in modern cities.Despite writers'common denial of political motives,their actions may be interpreted as manifestations of resistance within wider sociospatial conflicts.This study situates grffti within discussions of political art,spatial commodification,and everyday resistance,proposing a normative framework for viewing the art of the urban signature as an activity that redefines"the community that speaks."展开更多
Polyvinylidene fluoride/lead zirconate titanate(PVDF/PZT)composite films have been prepared by direct ink writing and the effect of PZT content on crystallization behavior and electrical properties of film were system...Polyvinylidene fluoride/lead zirconate titanate(PVDF/PZT)composite films have been prepared by direct ink writing and the effect of PZT content on crystallization behavior and electrical properties of film were systematically investigated.The composite films were characterized by scanning electron microscope(SEM),X-ray diffractometer(XRD),Flourier transform infrared spectroscope(FTIR)and differential scanning calorimeter(DSC).The results show that,surface modified PZT powder(PZT@PDA)is successfully coated by polydopamine(PDA),resulting in a large number of polar groups that interact with the-CF_(2)-groups in PVDF,inducing the generation of polarβphase due to hydrogen bonding formed in the interaction.Theβphase content in composite film increases with increasing PZT@PDA content,up to 28.09%as with 5 wt.%PZT@PDA.PZT@PDA plays a role of nucleating agent to promote the generation of polar phases in the film and also acts as an impurity hindering the growth of nuclei to reduce crystallinity.Moreover,the presence of PZT@PDA in interfaces provides more sites for the occurrence of interfacial polarization and thus improving the electrical properties of films.The composite film with 5 wt.%PZT@PDA possesses the highest dielectric constant(8.61)and residual polarization value(0.6803μC/cm^(2)).展开更多
This paper presents an alternative design of postgraduate English writing course to meet the requirement of the current postgraduate English teaching reform.The author believes that efficiently-organized writing activ...This paper presents an alternative design of postgraduate English writing course to meet the requirement of the current postgraduate English teaching reform.The author believes that efficiently-organized writing activities based on practical needs could refresh teaching frame- work and consequently assist postgraduates in English writing.展开更多
A new laser direct writing system is introduced and the potential application of the diffractive optical elements (DOE’s) fabricated by applying laser direct writing system are presented. The fabrication techniques b...A new laser direct writing system is introduced and the potential application of the diffractive optical elements (DOE’s) fabricated by applying laser direct writing system are presented. The fabrication techniques by applying the laser direct writing are developed. Experimental results have been obtained by applying laser direct writing machine with line width of 5μm and 10μm.展开更多
As an important productive ability, writing is superiorly regarded nowadays. Many students are still unable to achieve the writing goals as required. Some feasible and effective writing strategies are recommended in t...As an important productive ability, writing is superiorly regarded nowadays. Many students are still unable to achieve the writing goals as required. Some feasible and effective writing strategies are recommended in the paper, which can help students in a beneficial way.展开更多
The booming development of DIW technology present an unprecedented prospect in energetic materials field and has attracted great interest due to its relative simplicity and high flexibility of manufacturing.Herein,a n...The booming development of DIW technology present an unprecedented prospect in energetic materials field and has attracted great interest due to its relative simplicity and high flexibility of manufacturing.Herein,a novel CL-20 based explosive ink formulation have been developed successfully for MEMS initiation systems via DIW technology.We designed PVA/GAP into an oil-in-water(O/W)emulsion,in the way that the aqueous solution of PVA as water phase,the ethyl acetate solution of GAP as oil phase,the combination of Tween 80 and SDS as emulsifier,BPS as a curing agent of GAP.The ideal formulation with good shear-thinning rheology properties and clear gel point was prepared using only 10 wt%emulsion.The dual-cured network formed during the curing process made the printed sample have good mechanical properties.The printed samples had satisfactory molding effect without cracks or fractures,the crystal form of CL-20 not changed and the thermal stability have improved.Deposition of explosive inks via DIW in micro-scale grooves had excellent detonation performances,which critical detonation size was 1×0.045 mm,detonation velocity was 7129 m/s and when the corner reaching 150°can still detonated stably.This study may open new avenues for developing binder systems in explosive ink formulations.展开更多
3D-Honeycombed CL-20 structures with low critical size of detonation have been fabricated successfully for intelligent weapon systems using a micro-flow direct ink writing(DIW) technology.The CL-20-based explosive ink...3D-Honeycombed CL-20 structures with low critical size of detonation have been fabricated successfully for intelligent weapon systems using a micro-flow direct ink writing(DIW) technology.The CL-20-based explosive ink for DIW technology was prepared by a two-component adhesive system with waterborne polyurethane(WPU) and ethyl cellulose(EC).Not only the preparation of the explosive ink but also the principle of DIW process have been investigated systematically.The explosive ink displayed stro ng shea rthinning behavior that permitted layer-by-laye r deposition from a fine nozzle onto a substrate to produce complex shapes.The EC content was varied to alter the pore structure distribution and rheological behavior of ink samples after curing.The deposited explosive composite materials are of a honeycombed structure with high porosity,and the pore size distribution increases with the increase of EC content.No phase change was observed during the preparation process.Both WPU and EC show good compatibility with CL-20 particles.Apparently high activation energy was realized in the CL-20-based composite ink compared with that of the refined CL-20 due to the presence of non-energetic but stable WPU.The detonation performance of the composite materials can be precisely controlled by an adjustment in the content of binders.The 3D honeyco mbed CL-20 structures,which are fabricated by DIW technology,have a very small critical detonation size of less than 69 μm,as demonstrated by wedge shaped charge test.The ink can be used to create 3D structures with complex geometries not possible with traditional manufacturing techniques,which presents a bright future for the development of intelligent weapon systems.展开更多
Here we report a femtosecond laser direct writing(a precise 3D printing also known as two-photon polymerization lithography) of hybrid organic-inorganic SZ2080^(TM)pre-polymer without using any photo-initiator and app...Here we report a femtosecond laser direct writing(a precise 3D printing also known as two-photon polymerization lithography) of hybrid organic-inorganic SZ2080^(TM)pre-polymer without using any photo-initiator and applying ~100 fs oscillator operating at 517 nm wavelength and 76 MHz repetition rate. The proof of concept was experimentally demonstrated and benchmarking 3D woodpile nanostructures, micro-scaffolds, free-form micro-object “Benchy” and bulk micro-cubes are successfully produced. The essential novelty underlies the fact that non-amplified laser systems delivering just 40-500 p J individual pulses are sufficient for inducing localized cross-linking reactions within hundreds of nanometers in cross sections. And it is opposed to the prejudice that higher pulse energies and lower repetition rates of amplified lasers are necessary for structuring non-photosensitized polymers. The experimental work is of high importance for fundamental understanding of laser enabled nanoscale 3D additive manufacturing and widens technology’ s field of applications where the avoidance of photo-initiator is preferable or is even a necessity, such as micro-optics, nano-photonics, and biomedicine.展开更多
John Clare is widely known as a nature poet in British romantic literature.Critics often focus quite exclusively on his poetic works therefore,most of his natural prose writings have been constantly neglected.In fact,...John Clare is widely known as a nature poet in British romantic literature.Critics often focus quite exclusively on his poetic works therefore,most of his natural prose writings have been constantly neglected.In fact,in addition to presenting the artistic values,Clare' s poems and prose also jointly contribute to the scientific values from the aspect of natural history studies.Through comparative studies with the contemporary nature writers,one can grasp Clare' s contribution concerning botanical and zoological aspects respectively,This paper aims at demonstrating the linking role between scientific studies and homeland protection in the typical "Clarean" nature writing.展开更多
The frequently used concept of "global reaction" is discussed and the reason for the confusion behind explained. The misconception is cleared by formula writing based on the donor–acceptor(donac) reaction c...The frequently used concept of "global reaction" is discussed and the reason for the confusion behind explained. The misconception is cleared by formula writing based on the donor–acceptor(donac) reaction concept and by applying the Grand Rule of Formula Writing that is based on it.展开更多
The key point of college English teaching in China is to train students’ comprehensive language using competence. There are many ways that teachers use to improve English levels of their students. This paper provides...The key point of college English teaching in China is to train students’ comprehensive language using competence. There are many ways that teachers use to improve English levels of their students. This paper provides a successful approach of English language teaching to attain this purpose. Two classes with approximately the same grasp of English were chosen before the college English class began. For two years, both classes had the following: the same teacher, the same requirements of English, the same textbooks and teaching hours, etc; however, one class was better than the other in almost every aspect such as listening, writing and comprehensive use of English due to a different style of teaching: “listening writing approach".展开更多
In view of the fact that most college English teachers in China invest a great deal of time and effort responding to students’ writing, but find students improve so little in their writing skills, I venture to put fo...In view of the fact that most college English teachers in China invest a great deal of time and effort responding to students’ writing, but find students improve so little in their writing skills, I venture to put forward an alternative way of teaching writing in the paper, that is, teaching writing through small group conferencing. Compared with the traditional teaching methods small group conferencing has following advantages: (1) Saving evaluation time; (2) Providing better feedback; (3) Helping students critique their writing, etc. Since many empirical studies and teaching practices demonstrate that small group conferencing is an effective and efficient way of teaching writing, we have good reason to believe that it will become widespread in the college English teaching in China. \;展开更多
The types of teachers’ written feedback and their effects have been the focuses of researches on feedback in EFL writing. This paper aims at providing some references and suggestions on the effective feedback types i...The types of teachers’ written feedback and their effects have been the focuses of researches on feedback in EFL writing. This paper aims at providing some references and suggestions on the effective feedback types in EFL writing in China through reviewing the recent ten-year researches on teachers’ written feedback in EFL writing in China from the perspectives of feedback source, content, types and comments, and exploring the future development of the researches from research design, feedback types, and research perspectives and so on.Literature research shows that the answers remain controversial on which kind of feedback source, feedback content, feedback type, and feedback comments are the best to students in EFL writing. However, the supplementary roles of peer feedback and electronic feedback are well recognized; form-focused feedback combined with content-focused feedback is popular with the students; the demand for the degree of feedback directness and feedback comments varies with the level of students. Compared to the past, recent domestic researches on teachers’ feedback are more various in research methods, more diversified in research perspectives and extended more in research content. Future domestic research on teachers’ feedback needs to make efforts on designing the experiment, expanding the feedback content, combining different feedback types and broadening research perspectives in order to further verify the effectiveness of teachers’ written feedback.展开更多
Almost everyone faces a variety of writing tasks whether in school or on the job.People have to write reports,lectures,speeches,papers,ease studies,examinations,directions,summaries,job application letters and a host ...Almost everyone faces a variety of writing tasks whether in school or on the job.People have to write reports,lectures,speeches,papers,ease studies,examinations,directions,summaries,job application letters and a host of other assignments.In fact,there is not a field of professional or business life in the world today that does notdemand the ability to write well.Yet,the fact should be faced squarely that good writ-ing is and has always been extremely rare.By good writing I mean just the simple,clear kind that everyone always demands from others.The truth is that simple。展开更多
Ⅱ.Anaphoric RepetitionAccording to Otto Jespersen,anaphoric repetition means that a wordis repeated and for emphasis given front position:a.There was to be no outrage,and no outrage there was.(noun repeated)Charles K...Ⅱ.Anaphoric RepetitionAccording to Otto Jespersen,anaphoric repetition means that a wordis repeated and for emphasis given front position:a.There was to be no outrage,and no outrage there was.(noun repeated)Charles Kengsley,Hypatiab.She signed delicately and delicately she panted.(adverb repeated)Anthony Hope,Dolly Dialoguesc.She found him perfect,and perfect in her sight he remained.(adjectiverepeated)展开更多
文摘This study contests the prevalent perception of graffiti writing,especially tagging and bombing,as meaningless vandalism.It contends that graffiti is a form of expression with intrinsic political implications.Leveraging the notion of spatial justice and Jacques Ranciere's philosophy,I demonstrate how graffiti reclaims urban visibility against the commercial monopoly of visibility in public spaces and challenges the inequitable allocation of opportunities for self-expression in modern cities.Despite writers'common denial of political motives,their actions may be interpreted as manifestations of resistance within wider sociospatial conflicts.This study situates grffti within discussions of political art,spatial commodification,and everyday resistance,proposing a normative framework for viewing the art of the urban signature as an activity that redefines"the community that speaks."
基金Project(22020JJ4729)supported by the Natural Science Foundation of Hunan Province,China。
文摘Polyvinylidene fluoride/lead zirconate titanate(PVDF/PZT)composite films have been prepared by direct ink writing and the effect of PZT content on crystallization behavior and electrical properties of film were systematically investigated.The composite films were characterized by scanning electron microscope(SEM),X-ray diffractometer(XRD),Flourier transform infrared spectroscope(FTIR)and differential scanning calorimeter(DSC).The results show that,surface modified PZT powder(PZT@PDA)is successfully coated by polydopamine(PDA),resulting in a large number of polar groups that interact with the-CF_(2)-groups in PVDF,inducing the generation of polarβphase due to hydrogen bonding formed in the interaction.Theβphase content in composite film increases with increasing PZT@PDA content,up to 28.09%as with 5 wt.%PZT@PDA.PZT@PDA plays a role of nucleating agent to promote the generation of polar phases in the film and also acts as an impurity hindering the growth of nuclei to reduce crystallinity.Moreover,the presence of PZT@PDA in interfaces provides more sites for the occurrence of interfacial polarization and thus improving the electrical properties of films.The composite film with 5 wt.%PZT@PDA possesses the highest dielectric constant(8.61)and residual polarization value(0.6803μC/cm^(2)).
文摘This paper presents an alternative design of postgraduate English writing course to meet the requirement of the current postgraduate English teaching reform.The author believes that efficiently-organized writing activities based on practical needs could refresh teaching frame- work and consequently assist postgraduates in English writing.
文摘A new laser direct writing system is introduced and the potential application of the diffractive optical elements (DOE’s) fabricated by applying laser direct writing system are presented. The fabrication techniques by applying the laser direct writing are developed. Experimental results have been obtained by applying laser direct writing machine with line width of 5μm and 10μm.
文摘As an important productive ability, writing is superiorly regarded nowadays. Many students are still unable to achieve the writing goals as required. Some feasible and effective writing strategies are recommended in the paper, which can help students in a beneficial way.
基金This work was supported by the Graduate Education Innovation Project of Shanxi Province(2020SY401)No.55 Research Institute of China North Industries Group Corporation Open Innovation Fund(WDZC2020JJ017).
文摘The booming development of DIW technology present an unprecedented prospect in energetic materials field and has attracted great interest due to its relative simplicity and high flexibility of manufacturing.Herein,a novel CL-20 based explosive ink formulation have been developed successfully for MEMS initiation systems via DIW technology.We designed PVA/GAP into an oil-in-water(O/W)emulsion,in the way that the aqueous solution of PVA as water phase,the ethyl acetate solution of GAP as oil phase,the combination of Tween 80 and SDS as emulsifier,BPS as a curing agent of GAP.The ideal formulation with good shear-thinning rheology properties and clear gel point was prepared using only 10 wt%emulsion.The dual-cured network formed during the curing process made the printed sample have good mechanical properties.The printed samples had satisfactory molding effect without cracks or fractures,the crystal form of CL-20 not changed and the thermal stability have improved.Deposition of explosive inks via DIW in micro-scale grooves had excellent detonation performances,which critical detonation size was 1×0.045 mm,detonation velocity was 7129 m/s and when the corner reaching 150°can still detonated stably.This study may open new avenues for developing binder systems in explosive ink formulations.
基金This research work was financially supported by the Advantage Disciplines Climbing Plan of Shanxi Province and Graduate Education Innovation Project in Shanxi Province(2016BY119).
文摘3D-Honeycombed CL-20 structures with low critical size of detonation have been fabricated successfully for intelligent weapon systems using a micro-flow direct ink writing(DIW) technology.The CL-20-based explosive ink for DIW technology was prepared by a two-component adhesive system with waterborne polyurethane(WPU) and ethyl cellulose(EC).Not only the preparation of the explosive ink but also the principle of DIW process have been investigated systematically.The explosive ink displayed stro ng shea rthinning behavior that permitted layer-by-laye r deposition from a fine nozzle onto a substrate to produce complex shapes.The EC content was varied to alter the pore structure distribution and rheological behavior of ink samples after curing.The deposited explosive composite materials are of a honeycombed structure with high porosity,and the pore size distribution increases with the increase of EC content.No phase change was observed during the preparation process.Both WPU and EC show good compatibility with CL-20 particles.Apparently high activation energy was realized in the CL-20-based composite ink compared with that of the refined CL-20 due to the presence of non-energetic but stable WPU.The detonation performance of the composite materials can be precisely controlled by an adjustment in the content of binders.The 3D honeyco mbed CL-20 structures,which are fabricated by DIW technology,have a very small critical detonation size of less than 69 μm,as demonstrated by wedge shaped charge test.The ink can be used to create 3D structures with complex geometries not possible with traditional manufacturing techniques,which presents a bright future for the development of intelligent weapon systems.
基金Project(S-MIP-20-17) supported by the Research Council of LithuaniaProject(871124) supported by the EU Horizon 2020, Research and Innovation program LASERLAB-EUROPE JRA。
文摘Here we report a femtosecond laser direct writing(a precise 3D printing also known as two-photon polymerization lithography) of hybrid organic-inorganic SZ2080^(TM)pre-polymer without using any photo-initiator and applying ~100 fs oscillator operating at 517 nm wavelength and 76 MHz repetition rate. The proof of concept was experimentally demonstrated and benchmarking 3D woodpile nanostructures, micro-scaffolds, free-form micro-object “Benchy” and bulk micro-cubes are successfully produced. The essential novelty underlies the fact that non-amplified laser systems delivering just 40-500 p J individual pulses are sufficient for inducing localized cross-linking reactions within hundreds of nanometers in cross sections. And it is opposed to the prejudice that higher pulse energies and lower repetition rates of amplified lasers are necessary for structuring non-photosensitized polymers. The experimental work is of high importance for fundamental understanding of laser enabled nanoscale 3D additive manufacturing and widens technology’ s field of applications where the avoidance of photo-initiator is preferable or is even a necessity, such as micro-optics, nano-photonics, and biomedicine.
文摘John Clare is widely known as a nature poet in British romantic literature.Critics often focus quite exclusively on his poetic works therefore,most of his natural prose writings have been constantly neglected.In fact,in addition to presenting the artistic values,Clare' s poems and prose also jointly contribute to the scientific values from the aspect of natural history studies.Through comparative studies with the contemporary nature writers,one can grasp Clare' s contribution concerning botanical and zoological aspects respectively,This paper aims at demonstrating the linking role between scientific studies and homeland protection in the typical "Clarean" nature writing.
文摘The frequently used concept of "global reaction" is discussed and the reason for the confusion behind explained. The misconception is cleared by formula writing based on the donor–acceptor(donac) reaction concept and by applying the Grand Rule of Formula Writing that is based on it.
文摘The key point of college English teaching in China is to train students’ comprehensive language using competence. There are many ways that teachers use to improve English levels of their students. This paper provides a successful approach of English language teaching to attain this purpose. Two classes with approximately the same grasp of English were chosen before the college English class began. For two years, both classes had the following: the same teacher, the same requirements of English, the same textbooks and teaching hours, etc; however, one class was better than the other in almost every aspect such as listening, writing and comprehensive use of English due to a different style of teaching: “listening writing approach".
文摘In view of the fact that most college English teachers in China invest a great deal of time and effort responding to students’ writing, but find students improve so little in their writing skills, I venture to put forward an alternative way of teaching writing in the paper, that is, teaching writing through small group conferencing. Compared with the traditional teaching methods small group conferencing has following advantages: (1) Saving evaluation time; (2) Providing better feedback; (3) Helping students critique their writing, etc. Since many empirical studies and teaching practices demonstrate that small group conferencing is an effective and efficient way of teaching writing, we have good reason to believe that it will become widespread in the college English teaching in China. \;
文摘The types of teachers’ written feedback and their effects have been the focuses of researches on feedback in EFL writing. This paper aims at providing some references and suggestions on the effective feedback types in EFL writing in China through reviewing the recent ten-year researches on teachers’ written feedback in EFL writing in China from the perspectives of feedback source, content, types and comments, and exploring the future development of the researches from research design, feedback types, and research perspectives and so on.Literature research shows that the answers remain controversial on which kind of feedback source, feedback content, feedback type, and feedback comments are the best to students in EFL writing. However, the supplementary roles of peer feedback and electronic feedback are well recognized; form-focused feedback combined with content-focused feedback is popular with the students; the demand for the degree of feedback directness and feedback comments varies with the level of students. Compared to the past, recent domestic researches on teachers’ feedback are more various in research methods, more diversified in research perspectives and extended more in research content. Future domestic research on teachers’ feedback needs to make efforts on designing the experiment, expanding the feedback content, combining different feedback types and broadening research perspectives in order to further verify the effectiveness of teachers’ written feedback.
文摘Almost everyone faces a variety of writing tasks whether in school or on the job.People have to write reports,lectures,speeches,papers,ease studies,examinations,directions,summaries,job application letters and a host of other assignments.In fact,there is not a field of professional or business life in the world today that does notdemand the ability to write well.Yet,the fact should be faced squarely that good writ-ing is and has always been extremely rare.By good writing I mean just the simple,clear kind that everyone always demands from others.The truth is that simple。
文摘Ⅱ.Anaphoric RepetitionAccording to Otto Jespersen,anaphoric repetition means that a wordis repeated and for emphasis given front position:a.There was to be no outrage,and no outrage there was.(noun repeated)Charles Kengsley,Hypatiab.She signed delicately and delicately she panted.(adverb repeated)Anthony Hope,Dolly Dialoguesc.She found him perfect,and perfect in her sight he remained.(adjectiverepeated)
