A high open-circuit voltage betavoltaic microbattery based on a GaN p-i-n diode is demonstrated.Under the irradiation of a 4×4 mm^(2) planar solid 63Ni source with an activity of 2 mCi,the open−circuit voltage Vo...A high open-circuit voltage betavoltaic microbattery based on a GaN p-i-n diode is demonstrated.Under the irradiation of a 4×4 mm^(2) planar solid 63Ni source with an activity of 2 mCi,the open−circuit voltage Voc of the fabricated single 2×2 mm^(2) cell reaches as high as 1.62 V,the short−circuit current density Jsc is measured to be 16nA/cm^(2).The microbattery has a fill factor of 55%,and the energy conversion efficiency of beta radiation into electricity reaches to 1.13%.The results suggest that GaN is a highly promising potential candidate for long-life betavoltaic microbatteries used as power supplies for microelectromechanical system devices.展开更多
目的:探讨翻转课堂结合以团队为基础的教学模式(Team-based learning,TBL)在口腔瓷贴面教学中的应用效果。方法:2019年11月-2019年12月,选择第四军医大学口腔医学院2016级五年制口腔医学专业40名本科生作为研究对象,随机分为试验组20人...目的:探讨翻转课堂结合以团队为基础的教学模式(Team-based learning,TBL)在口腔瓷贴面教学中的应用效果。方法:2019年11月-2019年12月,选择第四军医大学口腔医学院2016级五年制口腔医学专业40名本科生作为研究对象,随机分为试验组20人和对照组20人。试验组采用翻转课堂结合TBL教学方法;对照组采用传统讲授结合多媒体教学方法。教学结束后,比较两组学生的学习成绩及问卷调查结果。结果:试验组的瓷贴面修复课程的理论成绩、实践成绩分别为(18.4±1.2)分、(8.8±0.8)分,均优于对照组的(16.8±1.7)分、(7.7±0.7)分,差异均具有统计学意义(P<0.05)。问卷调查结果显示,与对照组相比,试验组学生对教学模式满意度方面高于对照组(9.1±0.6 vs 7.8±0.7),差异具有统计学意义(P<0.05)。试验组所有学生均了解并满意翻转课堂+TBL教学模式,认为理论与实践结合效果更好,愿意继续使用该教学模式进行学习。同时95%的学生认为通过该模式学习后能够很快掌握所学知识,90%的学生认为可以提升学习主动性和学习兴趣。结论:翻转课堂结合TBL教学模式应用于瓷贴面修复教学,可以激发学生自主学习的积极性,提高学生的临床思维能力,提高教学效果。展开更多
The valence band offset(VBO)of an Al_(0.17)Ga_(0.83)N/GaN heterojunction is determined to be 0.13±0.07 eV by x-ray photoelectron spectroscopy.From the obtained VBO value,the conduction band offset(CBO)of~0.22 eV ...The valence band offset(VBO)of an Al_(0.17)Ga_(0.83)N/GaN heterojunction is determined to be 0.13±0.07 eV by x-ray photoelectron spectroscopy.From the obtained VBO value,the conduction band offset(CBO)of~0.22 eV is obtained.The results indicate that the Al_(0.17)Ga_(0.83)N/GaN heterojunction exhibits a type-Ⅰ band alignment.展开更多
A nano-channel array(NCA)structure is applied to realize enhancement-mode(E-mode)AlGaN/GaN high-electron mobility transistors(HEMTs).The fabricated NCA-HEMT,consisting of 1000 channels connected in parallel with a cha...A nano-channel array(NCA)structure is applied to realize enhancement-mode(E-mode)AlGaN/GaN high-electron mobility transistors(HEMTs).The fabricated NCA-HEMT,consisting of 1000 channels connected in parallel with a channel width of 64 nm,shows a threshold voltage of 0.15 V and a subthreshold slope of 78 mV/dec,compared to−3.92 V and 99 mV/dec for a conventional HEMT(C-HEMT),respectively.Both the NCA-HEMT and C-HEMT show similar gate leakage current,indicating no significant degradation in gate leakage characteristics for the NCA-HEMT.The surrounding-field effect and relieved polarization contribute to the very large positive threshold voltage shift,while the work function difference makes it positive.展开更多
Wafer-scale graphene field-effect transistors are fabricated using benzocyclobutene and atomic layer deposition Al_(2)O_(3) as the top−gate dielectric.The epitaxial-graphene layer is formed by graphitization of a 2-in...Wafer-scale graphene field-effect transistors are fabricated using benzocyclobutene and atomic layer deposition Al_(2)O_(3) as the top−gate dielectric.The epitaxial-graphene layer is formed by graphitization of a 2-inch-diameter Si-face semi-insulating 6H-SiC substrate.The graphene on the silicon carbide substrate is heavily n-doped and current saturation is not found.For the intrinsic characteristic of this particular channel material,the devices cannot be switched off.The cut-off frequencies of these graphene field-effect transistors,which have a gate length of 1µm,are larger than 800 MHz.The largest one can reach 1.24 GHz.There are greater than 95% active devices that can be successfully applied.We thus succeed in fabricating wafer-scale gigahertz graphene field-effect transistors,which paves the way for high-performance graphene devices and circuits.展开更多
基金by the National Natural Science Foundation of China(No 51075344)Natural Science Foundation of Fujian Province(No 2010J01015).
文摘A high open-circuit voltage betavoltaic microbattery based on a GaN p-i-n diode is demonstrated.Under the irradiation of a 4×4 mm^(2) planar solid 63Ni source with an activity of 2 mCi,the open−circuit voltage Voc of the fabricated single 2×2 mm^(2) cell reaches as high as 1.62 V,the short−circuit current density Jsc is measured to be 16nA/cm^(2).The microbattery has a fill factor of 55%,and the energy conversion efficiency of beta radiation into electricity reaches to 1.13%.The results suggest that GaN is a highly promising potential candidate for long-life betavoltaic microbatteries used as power supplies for microelectromechanical system devices.
文摘目的:探讨翻转课堂结合以团队为基础的教学模式(Team-based learning,TBL)在口腔瓷贴面教学中的应用效果。方法:2019年11月-2019年12月,选择第四军医大学口腔医学院2016级五年制口腔医学专业40名本科生作为研究对象,随机分为试验组20人和对照组20人。试验组采用翻转课堂结合TBL教学方法;对照组采用传统讲授结合多媒体教学方法。教学结束后,比较两组学生的学习成绩及问卷调查结果。结果:试验组的瓷贴面修复课程的理论成绩、实践成绩分别为(18.4±1.2)分、(8.8±0.8)分,均优于对照组的(16.8±1.7)分、(7.7±0.7)分,差异均具有统计学意义(P<0.05)。问卷调查结果显示,与对照组相比,试验组学生对教学模式满意度方面高于对照组(9.1±0.6 vs 7.8±0.7),差异具有统计学意义(P<0.05)。试验组所有学生均了解并满意翻转课堂+TBL教学模式,认为理论与实践结合效果更好,愿意继续使用该教学模式进行学习。同时95%的学生认为通过该模式学习后能够很快掌握所学知识,90%的学生认为可以提升学习主动性和学习兴趣。结论:翻转课堂结合TBL教学模式应用于瓷贴面修复教学,可以激发学生自主学习的积极性,提高学生的临床思维能力,提高教学效果。
基金the Knowledge Innovation Program of the Chinese Academy of Sciences under Grant No YYY-0701-02the National Natural Science Foundation of China under Grant Nos 60890193 and 61106014+2 种基金the National Basic Research Program of China under Grant Nos 2010CB327503 and 2012CB619303the High-Technology Research and Development Program of China under Grant No 2011AA050514the National Science and Technology Major Project of China。
文摘The valence band offset(VBO)of an Al_(0.17)Ga_(0.83)N/GaN heterojunction is determined to be 0.13±0.07 eV by x-ray photoelectron spectroscopy.From the obtained VBO value,the conduction band offset(CBO)of~0.22 eV is obtained.The results indicate that the Al_(0.17)Ga_(0.83)N/GaN heterojunction exhibits a type-Ⅰ band alignment.
基金by the National Basic Research Program of China under Grant No G2009CB929300.
文摘A nano-channel array(NCA)structure is applied to realize enhancement-mode(E-mode)AlGaN/GaN high-electron mobility transistors(HEMTs).The fabricated NCA-HEMT,consisting of 1000 channels connected in parallel with a channel width of 64 nm,shows a threshold voltage of 0.15 V and a subthreshold slope of 78 mV/dec,compared to−3.92 V and 99 mV/dec for a conventional HEMT(C-HEMT),respectively.Both the NCA-HEMT and C-HEMT show similar gate leakage current,indicating no significant degradation in gate leakage characteristics for the NCA-HEMT.The surrounding-field effect and relieved polarization contribute to the very large positive threshold voltage shift,while the work function difference makes it positive.
基金Supported by the National Science and Technology Major Project of China(2011ZX02707)the National Natural Science Foundation of China under Grant Nos 61136005 and 110761006063.
文摘Wafer-scale graphene field-effect transistors are fabricated using benzocyclobutene and atomic layer deposition Al_(2)O_(3) as the top−gate dielectric.The epitaxial-graphene layer is formed by graphitization of a 2-inch-diameter Si-face semi-insulating 6H-SiC substrate.The graphene on the silicon carbide substrate is heavily n-doped and current saturation is not found.For the intrinsic characteristic of this particular channel material,the devices cannot be switched off.The cut-off frequencies of these graphene field-effect transistors,which have a gate length of 1µm,are larger than 800 MHz.The largest one can reach 1.24 GHz.There are greater than 95% active devices that can be successfully applied.We thus succeed in fabricating wafer-scale gigahertz graphene field-effect transistors,which paves the way for high-performance graphene devices and circuits.
