研究了一种新型非对称栅隧穿场效应晶体管(AG-TFET),新型结构结合了隧穿场效应晶体管陡峭的亚阈值摆幅与无结器件较大的开态电流的优点,其总电流大小受控于底部沟道势垒和p+区与本征沟道区形成的反偏p-i隧穿结处的带隙宽度以及电场强度...研究了一种新型非对称栅隧穿场效应晶体管(AG-TFET),新型结构结合了隧穿场效应晶体管陡峭的亚阈值摆幅与无结器件较大的开态电流的优点,其总电流大小受控于底部沟道势垒和p+区与本征沟道区形成的反偏p-i隧穿结处的带隙宽度以及电场强度。使用Silvaco TCAD软件对器件性能进行了仿真,并对p+区厚度以及底栅栅介质二氧化铪的长度进行了优化。仿真结果表明:新型AG-TFET具有良好的电学特性,在室温下开关电流比可以达到3.3×1010,开态电流为302μA/μm,陡峭的亚阈值摆幅即点亚阈值摆幅为35 m V/dec,平均亚阈值摆幅为54 m V/dec。因此,该新型AG-TFET有望被应用在未来低功耗电路中。展开更多
The current paper presents experimental and computational results to assess the effectiveness of non-axisymmetric endwall contouring in a compressor linear cascade. The endwaU was designed by an endwall design optimi-...The current paper presents experimental and computational results to assess the effectiveness of non-axisymmetric endwall contouring in a compressor linear cascade. The endwaU was designed by an endwall design optimi- zation platform at 0° incidence （design condition）. The optimization method is based on a genetic algorithm. The design objective was to minimize the total pressure losses. The experiments were carried out in a compressor cascade at a low-speed test facility with a Mach number of 0.15. Four nominal inlet flow angles were chosen to test the performance of non-axisymmetric Contoured Endwall （CEW）. A five-hole pressure probe with a head diameter of 2 mm was used to traverse the downstream flow fields of the flat-endwall （FEW） and CEW cascades. Both the measured and predicted results indicated that the implementation of CEW results in smaller comer stall, and reduction of total pressure losses. The CEW gets 15.6% total pressure loss coefficient reduction at design condition, and 22.6% at off-design condition （＋7° incidence）. And the mechanism of the improvement of CEW based on both measured and calculated results is that the adverse pressure gradient （APG） has been reduced through the groove configuration near the leading edge （LE） of the suction surface （SS）.展开更多
A novel dual-wavelength fiber laser with asymmetric fiber Bragg grating(FBG) Fabry-Perot(FP) cavity is proposed and experimentally demonstrated. A couple of uniform FBGs are used as the cavity mirrors, and the third F...A novel dual-wavelength fiber laser with asymmetric fiber Bragg grating(FBG) Fabry-Perot(FP) cavity is proposed and experimentally demonstrated. A couple of uniform FBGs are used as the cavity mirrors, and the third FBG is used as intracavity wavelength selector by changing its operation temperature. Experimental results show that by adjusting the operation temperature of the intracavity wavelength selector, a tunable dual-wavelength laser emission can be achieved. The results demonstrate the new concept of dual-wavelength lasing with asymmetric FBG FP resonator and its technical feasibility.展开更多
A novel optical microfiber asymmetric Fabry-Perot interferometric （MAFPI） sensor is developed for simultaneous measurement of force and temperature. The MAFPI structure is formed by a weak fiber Bragg grating （FBG...A novel optical microfiber asymmetric Fabry-Perot interferometric （MAFPI） sensor is developed for simultaneous measurement of force and temperature. The MAFPI structure is formed by a weak fiber Bragg grating （FBG）, a section of the microfiber, and a cleaved fiber end surface. The narrowband beam reflected from the low-reflectivity FBG and the broadband beam from the Fresnel reflection interfere lead to its unique sensing performance. The force sensing is performed by detecting the bending-loss induced fringe contrast changes, while the Bragg wavelength shift is employed for temperature measurement. Sensitivities of 9.8pm/℃ and 0.025dB/μN were obtained experimentally for temperature and force measurements, respectively.展开更多
文摘研究了一种新型非对称栅隧穿场效应晶体管(AG-TFET),新型结构结合了隧穿场效应晶体管陡峭的亚阈值摆幅与无结器件较大的开态电流的优点,其总电流大小受控于底部沟道势垒和p+区与本征沟道区形成的反偏p-i隧穿结处的带隙宽度以及电场强度。使用Silvaco TCAD软件对器件性能进行了仿真,并对p+区厚度以及底栅栅介质二氧化铪的长度进行了优化。仿真结果表明:新型AG-TFET具有良好的电学特性,在室温下开关电流比可以达到3.3×1010,开态电流为302μA/μm,陡峭的亚阈值摆幅即点亚阈值摆幅为35 m V/dec,平均亚阈值摆幅为54 m V/dec。因此,该新型AG-TFET有望被应用在未来低功耗电路中。
基金supported by National Natural Science Foundation of China(51236001)National Basic Research Program of China(2012CB720201)Beijing Natural Science Foundation(No.3151002)
文摘The current paper presents experimental and computational results to assess the effectiveness of non-axisymmetric endwall contouring in a compressor linear cascade. The endwaU was designed by an endwall design optimi- zation platform at 0° incidence （design condition）. The optimization method is based on a genetic algorithm. The design objective was to minimize the total pressure losses. The experiments were carried out in a compressor cascade at a low-speed test facility with a Mach number of 0.15. Four nominal inlet flow angles were chosen to test the performance of non-axisymmetric Contoured Endwall （CEW）. A five-hole pressure probe with a head diameter of 2 mm was used to traverse the downstream flow fields of the flat-endwall （FEW） and CEW cascades. Both the measured and predicted results indicated that the implementation of CEW results in smaller comer stall, and reduction of total pressure losses. The CEW gets 15.6% total pressure loss coefficient reduction at design condition, and 22.6% at off-design condition （＋7° incidence）. And the mechanism of the improvement of CEW based on both measured and calculated results is that the adverse pressure gradient （APG） has been reduced through the groove configuration near the leading edge （LE） of the suction surface （SS）.
基金supported by the National Natural Science Foundation of China(No.60777020)the Hubei Provincial Natural Science Foundation of China(No.2008CDB317)the Innovation Project of Hubei Provincial Department of Education of China(No.2012344/104892013043)
文摘A novel dual-wavelength fiber laser with asymmetric fiber Bragg grating(FBG) Fabry-Perot(FP) cavity is proposed and experimentally demonstrated. A couple of uniform FBGs are used as the cavity mirrors, and the third FBG is used as intracavity wavelength selector by changing its operation temperature. Experimental results show that by adjusting the operation temperature of the intracavity wavelength selector, a tunable dual-wavelength laser emission can be achieved. The results demonstrate the new concept of dual-wavelength lasing with asymmetric FBG FP resonator and its technical feasibility.
基金This work is supported by the National Natural Science Foundation of China （61107073, 61107072 and 61290312）, Fundamental Research Funds for the Central Universities （ZYGX2011J002）, Research Fund for the Doctoral Program of Higher Education of China （20110185120020）, Program for Changjiang Scholars and Innovative Research Team in University （PCSIRT, IRT1218）, and the 111 Project （B 14039）. Open Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author（s） and source are credited.
文摘A novel optical microfiber asymmetric Fabry-Perot interferometric （MAFPI） sensor is developed for simultaneous measurement of force and temperature. The MAFPI structure is formed by a weak fiber Bragg grating （FBG）, a section of the microfiber, and a cleaved fiber end surface. The narrowband beam reflected from the low-reflectivity FBG and the broadband beam from the Fresnel reflection interfere lead to its unique sensing performance. The force sensing is performed by detecting the bending-loss induced fringe contrast changes, while the Bragg wavelength shift is employed for temperature measurement. Sensitivities of 9.8pm/℃ and 0.025dB/μN were obtained experimentally for temperature and force measurements, respectively.
