With the rapid development of modern technology and all-round reform in national college English teaching,Internet-Based teaching mode has become a new trend of college English teaching.Therefore,in the new teaching m...With the rapid development of modern technology and all-round reform in national college English teaching,Internet-Based teaching mode has become a new trend of college English teaching.Therefore,in the new teaching mode,the teacher should turn an inculcator into an instructor,facilitator and participant in teaching;a passive user of textbook into a dominant and modeler of courses;a planner of teaching specific tasks into an organizer of teaching process,a helper and shepherd of learning knowledge.展开更多
In order to develop the photodetector for effective blue-green response, the 18-mm-diameter vacuum image tube combined with the transmission-mode Alo.7Gao.3Aso.9Po.1/GaAso.9Po.1 photocathode grown by molecular beam ep...In order to develop the photodetector for effective blue-green response, the 18-mm-diameter vacuum image tube combined with the transmission-mode Alo.7Gao.3Aso.9Po.1/GaAso.9Po.1 photocathode grown by molecular beam epitaxy is tentatively fabricated. A comparison of photoelectric property, spectral characteristic and performance parameter be- tween the transmission-mode GaAsP-based and blue-extended GaAs-based photocathodes shows that the GaAsP-based photocathode possesses better absorption and higher quantum efficiency in the blue-green waveband, combined with a larger surface electron escape probability. Especially, the quantum efficiency at 532 nm for the GaAsP-based photocathode achieves as high as 59%, nearly twice that for the blue-extended GaAs-based one, which would be more conducive to the underwater range-gated imaging based on laser illumination. Moreover, the simulation results show that the favorable blue-green response can be achieved by optimizing the emission-layer thickness in a range of 0.4 μm-0.6 μm.展开更多
In photonie integrated circuits, information is usually encoded in the optical path. In this work, based on the multi-mode dielectric-loaded surface plasmon polariton waveguide, we numerically design a directional cou...In photonie integrated circuits, information is usually encoded in the optical path. In this work, based on the multi-mode dielectric-loaded surface plasmon polariton waveguide, we numerically design a directional coupler, which can divide the different waveguide eigenmodes into different optical paths. The results show a possibility to encode information onto different waveguide modes. We also experimentally demonstrate that the splitting ratio of this directional coupler structure can be tuned without changing its size.展开更多
The application of language,to a great extant,requires learners to understand the inputted information quickly as well as automatically,and combine verbal fragments into meaningful outputted language. This type of spo...The application of language,to a great extant,requires learners to understand the inputted information quickly as well as automatically,and combine verbal fragments into meaningful outputted language. This type of spontaneous mechanism depends on the effective input of language and long-rang internalization of language structure,which helps to form the implicit knowledge in students' conceptual system,thus to realize the automatic use of language. Therefore,the article intends to combine implicit learning theory with the output teaching mode with a purpose of working out a practical teaching mode to enhance the teaching effect and college students' applied abilities to use English.展开更多
信息技术的飞速发展深刻影响着教育领域,传统教学模式难以满足“计算机应用基础”课程对学生实践与创新能力培养的要求。文章聚焦于基于成果导向型教育(Outcome Based Education,OBE)理念的混合式教学模式在“计算机应用基础”课程的应...信息技术的飞速发展深刻影响着教育领域,传统教学模式难以满足“计算机应用基础”课程对学生实践与创新能力培养的要求。文章聚焦于基于成果导向型教育(Outcome Based Education,OBE)理念的混合式教学模式在“计算机应用基础”课程的应用,阐述了OBE理念的核心概念与特征,分析了“计算机应用基础”课程当前的教学现状。基于OBE理念的混合式教学模式设计思路,文章提出了教学模式构建、教学内容重组及整合教学资源等环节的改进措施,从而实现提升教学质量和学生综合能力的目标,为“计算机应用基础”课程教学模式改革提供了新思路,对其他课程教学改革具有借鉴作用。展开更多
Landslides are one of the key problems for stability analysis of pipelines in the western region of China where the geological conditions are extremely complicated. In order to offer a theoretical basis for the pipe-s...Landslides are one of the key problems for stability analysis of pipelines in the western region of China where the geological conditions are extremely complicated. In order to offer a theoretical basis for the pipe-soil interaction, the general finite element program ABAQUS is used to analyze the distribution of pipe strain caused by landslide through which the pipeline passes. In this paper the Ramberg-Osgood constitutive equation is used to study the strain-based mechanical characteristics of pipelines. Different calculation schemas are designed by considering the change of spatial relationship between pipeline and landslide, and the change of D/t, diameter-thickness ratio of pipeline. The results indicate that the pipeline is primarily subjected to tension stress when the landslide crosses the pipeline perpendicularly, the pipe strain is a maximum along the central axis of the landslide, and reverse bending occurs on pipeline at both edges of the landslide. The pipeline is primarily subjected to friction force caused by the downward movement of the landslide, and the friction force is relatively small when the landslide is parallel to the pipeline. The pipe strain is in proportional to D/t, and this means decreasing D/t can help to improve security of pipelines subjected to the landslide.展开更多
We report electronic Raman scattering measurements on Ba（Fei1-xCox）2As2（x = 0.065 and 0.2） single crystals with Raman shifts from 9 cm^-1 up to 600 cm^-1 in the symmetry of Blg with respect to 1 Fe unit cell.When ...We report electronic Raman scattering measurements on Ba（Fei1-xCox）2As2（x = 0.065 and 0.2） single crystals with Raman shifts from 9 cm^-1 up to 600 cm^-1 in the symmetry of Blg with respect to 1 Fe unit cell.When the crystals are cooled down,the evident quasielastic peaks of Raman spectra occur only in the crystal with x = 0.065,which is due to the contribution of orbital ordering between xz and yz Fe 3d orbitals,as we reported in another work.Here,we analyze the Eg phonon at 128 cm^-1,which has the same function form of its Raman tensors as those of xz and yz Fe 3d orbitals in these two crystals respectively.Unlike their electronic continuums,no anomalies are found in the Eg phonons of these two samples,which simply follows the expressions corresponding to the anharmonic phonon decay into acoustic phonons with the same frequencies and opposite momenta.Our results indicate that the structural and magnetic phase transition might be completely suppressed by chemical doping and there is not any indication of coupling between charge nematicity and Eg phonon mode from our experimental results,which is consistent with the results in our previous work.展开更多
The far-infrared optical reflectivity of an optimaUy doped Ba1-xKxFe2As2 （x = 0.4） single crystal is measured from room temperature down to 4 K. We study the temperature dependence of the in-plane infrared-active ph...The far-infrared optical reflectivity of an optimaUy doped Ba1-xKxFe2As2 （x = 0.4） single crystal is measured from room temperature down to 4 K. We study the temperature dependence of the in-plane infrared-active phonon at 251 em-1. This phonon exhibits a symmetric line shape in the optical conductivity, suggesting that the coupling between the phonon and the electronic background is weak. Upon cooling down, the frequency of this phonon continu- ously increases, following the conventional temperature dependence expected in the absence of a structural or magnetic transition. The intensity of this phonon is temperature independent within the measurement accuracy. These observa- tions indicate that the structural and magnetic phase transition might be completely suppressed by chemical doping in the optimally doped Bao.6Ko.4Fe2As2 compound.展开更多
A non-recessed-gate quasi-E-mode double heterojunction A1GaN/GaN high electron mobility transistor （quasi-E- DHEMT） with a thin barrier, high breakdown voltage and good performance of drain induced barrier lowering ...A non-recessed-gate quasi-E-mode double heterojunction A1GaN/GaN high electron mobility transistor （quasi-E- DHEMT） with a thin barrier, high breakdown voltage and good performance of drain induced barrier lowering （DIBL） was presented. Due to the metal organic chemical vapor deposition （MOCVD） grown 9-nm undoped A1GaN barrier, the effect that the gate metal depleted the two-dimensiomal electron gas （2DEG） was greatly impressed. Therefore, the density of carriers in the channel was nearly zero. Hence, the threshold voltage was above 0 V. Quasi-E-DHEMT with 4.1%tm source-to-drain distance, 2.6-μm gate-to-drain distance, and 0.5-μm gate length showed a drain current of 260 mA/mm. The threshold voltage of this device was 0.165 V when the drain voltage was 10 V and the DIBL was 5.26 mV/V. The quasi-E-DHEMT drain leakage current at a drain voltage of 146 V and a gate voltage of -6 V was below 1 mA/mm. This indicated that the hard breakdown voltage was more than 146 V.展开更多
This research aims to study the relationship between content-based instruction and secondary vocational English learners.Two classes in one secondary vocational school were chosen as participants.The result shows that...This research aims to study the relationship between content-based instruction and secondary vocational English learners.Two classes in one secondary vocational school were chosen as participants.The result shows that CBI teaching has a negative correlation with English learning anxiety and has an impact on alleviating students' anxiety.展开更多
Without the assumption that the private keys are kept secure perfectly, cryptographic primitives cannot be deployed in the insecure environments where the key leakage is inevitable. In order to reduce the damage cause...Without the assumption that the private keys are kept secure perfectly, cryptographic primitives cannot be deployed in the insecure environments where the key leakage is inevitable. In order to reduce the damage caused by the key exposure in the identity-based（ID-based） signature scenarios efficiently, we propose an ID-based key-insulated signature scheme in this paper, which eliminates the expensive bilinear pairing operations. Compared with the previous work, our scheme minimizes the computation cost without any extra cost. Under the discrete logarithm（DL） assumption, a security proof of our scheme in the random oracle model has also been given.展开更多
文摘With the rapid development of modern technology and all-round reform in national college English teaching,Internet-Based teaching mode has become a new trend of college English teaching.Therefore,in the new teaching mode,the teacher should turn an inculcator into an instructor,facilitator and participant in teaching;a passive user of textbook into a dominant and modeler of courses;a planner of teaching specific tasks into an organizer of teaching process,a helper and shepherd of learning knowledge.
基金supported by the National Natural Science Foundation of China(Grant No.61301023)the Science and Technology on Low-Light-Level Nigh Vision Laboratory Foundation,China(Grant No.BJ2014001)
文摘In order to develop the photodetector for effective blue-green response, the 18-mm-diameter vacuum image tube combined with the transmission-mode Alo.7Gao.3Aso.9Po.1/GaAso.9Po.1 photocathode grown by molecular beam epitaxy is tentatively fabricated. A comparison of photoelectric property, spectral characteristic and performance parameter be- tween the transmission-mode GaAsP-based and blue-extended GaAs-based photocathodes shows that the GaAsP-based photocathode possesses better absorption and higher quantum efficiency in the blue-green waveband, combined with a larger surface electron escape probability. Especially, the quantum efficiency at 532 nm for the GaAsP-based photocathode achieves as high as 59%, nearly twice that for the blue-extended GaAs-based one, which would be more conducive to the underwater range-gated imaging based on laser illumination. Moreover, the simulation results show that the favorable blue-green response can be achieved by optimizing the emission-layer thickness in a range of 0.4 μm-0.6 μm.
基金Supported by the National Basic Research Program of China under Grant Nos 2011CBA00200 and 2011CB921200the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant No XDB01030200+2 种基金the National Natural Science Foundation of China under Grant No 11374289the Fundamental Research Funds for the Central Universities under Grant No K2470000012the Program for New Century Excellent Talents in University
文摘In photonie integrated circuits, information is usually encoded in the optical path. In this work, based on the multi-mode dielectric-loaded surface plasmon polariton waveguide, we numerically design a directional coupler, which can divide the different waveguide eigenmodes into different optical paths. The results show a possibility to encode information onto different waveguide modes. We also experimentally demonstrate that the splitting ratio of this directional coupler structure can be tuned without changing its size.
文摘The application of language,to a great extant,requires learners to understand the inputted information quickly as well as automatically,and combine verbal fragments into meaningful outputted language. This type of spontaneous mechanism depends on the effective input of language and long-rang internalization of language structure,which helps to form the implicit knowledge in students' conceptual system,thus to realize the automatic use of language. Therefore,the article intends to combine implicit learning theory with the output teaching mode with a purpose of working out a practical teaching mode to enhance the teaching effect and college students' applied abilities to use English.
文摘信息技术的飞速发展深刻影响着教育领域,传统教学模式难以满足“计算机应用基础”课程对学生实践与创新能力培养的要求。文章聚焦于基于成果导向型教育(Outcome Based Education,OBE)理念的混合式教学模式在“计算机应用基础”课程的应用,阐述了OBE理念的核心概念与特征,分析了“计算机应用基础”课程当前的教学现状。基于OBE理念的混合式教学模式设计思路,文章提出了教学模式构建、教学内容重组及整合教学资源等环节的改进措施,从而实现提升教学质量和学生综合能力的目标,为“计算机应用基础”课程教学模式改革提供了新思路,对其他课程教学改革具有借鉴作用。
基金supported by the National Natural Science Foundation of China (Grant No. 50774090)
文摘Landslides are one of the key problems for stability analysis of pipelines in the western region of China where the geological conditions are extremely complicated. In order to offer a theoretical basis for the pipe-soil interaction, the general finite element program ABAQUS is used to analyze the distribution of pipe strain caused by landslide through which the pipeline passes. In this paper the Ramberg-Osgood constitutive equation is used to study the strain-based mechanical characteristics of pipelines. Different calculation schemas are designed by considering the change of spatial relationship between pipeline and landslide, and the change of D/t, diameter-thickness ratio of pipeline. The results indicate that the pipeline is primarily subjected to tension stress when the landslide crosses the pipeline perpendicularly, the pipe strain is a maximum along the central axis of the landslide, and reverse bending occurs on pipeline at both edges of the landslide. The pipeline is primarily subjected to friction force caused by the downward movement of the landslide, and the friction force is relatively small when the landslide is parallel to the pipeline. The pipe strain is in proportional to D/t, and this means decreasing D/t can help to improve security of pipelines subjected to the landslide.
基金supported by the Agence Nationale de la Recherche through Grant PNICTIDES
文摘We report electronic Raman scattering measurements on Ba（Fei1-xCox）2As2（x = 0.065 and 0.2） single crystals with Raman shifts from 9 cm^-1 up to 600 cm^-1 in the symmetry of Blg with respect to 1 Fe unit cell.When the crystals are cooled down,the evident quasielastic peaks of Raman spectra occur only in the crystal with x = 0.065,which is due to the contribution of orbital ordering between xz and yz Fe 3d orbitals,as we reported in another work.Here,we analyze the Eg phonon at 128 cm^-1,which has the same function form of its Raman tensors as those of xz and yz Fe 3d orbitals in these two crystals respectively.Unlike their electronic continuums,no anomalies are found in the Eg phonons of these two samples,which simply follows the expressions corresponding to the anharmonic phonon decay into acoustic phonons with the same frequencies and opposite momenta.Our results indicate that the structural and magnetic phase transition might be completely suppressed by chemical doping and there is not any indication of coupling between charge nematicity and Eg phonon mode from our experimental results,which is consistent with the results in our previous work.
基金Project supported by the National Natural Science Foundation of China （Grant Nos. 11104335 and 91121004）, the National Basic Research Program of China （Grant Nos. 2011CBA00107, 2012CB821400, and 2009CB929102）, and the ANR, France （Grant No. BLAN07-1-183876 GAPSUPRA）.
文摘The far-infrared optical reflectivity of an optimaUy doped Ba1-xKxFe2As2 （x = 0.4） single crystal is measured from room temperature down to 4 K. We study the temperature dependence of the in-plane infrared-active phonon at 251 em-1. This phonon exhibits a symmetric line shape in the optical conductivity, suggesting that the coupling between the phonon and the electronic background is weak. Upon cooling down, the frequency of this phonon continu- ously increases, following the conventional temperature dependence expected in the absence of a structural or magnetic transition. The intensity of this phonon is temperature independent within the measurement accuracy. These observa- tions indicate that the structural and magnetic phase transition might be completely suppressed by chemical doping in the optimally doped Bao.6Ko.4Fe2As2 compound.
基金supported by the National Natural Science Foundation of China(Grant No.61334002)the Opening Project of Science and Technology on ReliabilityPhysics and Application Technology of Electronic Component Laboratory,China(Grant No.ZHD201206)
文摘A non-recessed-gate quasi-E-mode double heterojunction A1GaN/GaN high electron mobility transistor （quasi-E- DHEMT） with a thin barrier, high breakdown voltage and good performance of drain induced barrier lowering （DIBL） was presented. Due to the metal organic chemical vapor deposition （MOCVD） grown 9-nm undoped A1GaN barrier, the effect that the gate metal depleted the two-dimensiomal electron gas （2DEG） was greatly impressed. Therefore, the density of carriers in the channel was nearly zero. Hence, the threshold voltage was above 0 V. Quasi-E-DHEMT with 4.1%tm source-to-drain distance, 2.6-μm gate-to-drain distance, and 0.5-μm gate length showed a drain current of 260 mA/mm. The threshold voltage of this device was 0.165 V when the drain voltage was 10 V and the DIBL was 5.26 mV/V. The quasi-E-DHEMT drain leakage current at a drain voltage of 146 V and a gate voltage of -6 V was below 1 mA/mm. This indicated that the hard breakdown voltage was more than 146 V.
文摘This research aims to study the relationship between content-based instruction and secondary vocational English learners.Two classes in one secondary vocational school were chosen as participants.The result shows that CBI teaching has a negative correlation with English learning anxiety and has an impact on alleviating students' anxiety.
基金supported by the National Natural Science Foundation of China under Grant No.61003230,No.61370026,No.61103206,and No.61300191Chongqing Key Lab of Computer Network and Communication Technology under Grant No.CY-CNCL-2012-02
文摘Without the assumption that the private keys are kept secure perfectly, cryptographic primitives cannot be deployed in the insecure environments where the key leakage is inevitable. In order to reduce the damage caused by the key exposure in the identity-based（ID-based） signature scenarios efficiently, we propose an ID-based key-insulated signature scheme in this paper, which eliminates the expensive bilinear pairing operations. Compared with the previous work, our scheme minimizes the computation cost without any extra cost. Under the discrete logarithm（DL） assumption, a security proof of our scheme in the random oracle model has also been given.
