Pressure effect study on the I－V property of the GaAs-based resonant tunnelling structure by photoluminescence measurement

This paper discusses the I-V property of the GaAs-based resonant tunnelling structure （RTS） under external uniaxial pressure by photoluminescence studies. Compressive pressure parallel to the [110] direction, whose value is determined by Hooke＇s law, is imposed on the sample by a helix micrometer. With the increase of the applied external uniaxial compressive pressure, the blue shift and splitting of the luminescence peaks were observed, which have some influence on the I-V curve of RTS from the point of view of the energy gap, and the splitting became more apparent with applied pressure. Full width at half maximum broadening could also be observed.     

A novel micro accelerometer with adjustable sensitivity based on resonant tunneling diodes

Resonant tunnelling diodes (RTDs) have negative differential resistance effect, and the current--voltage characteristics change as a function of external stress, which is regarded as meso-piezoresistance effect of RTDs. In this paper, a novel micro-accelerometer based on AlAs/GaAs/In_0.1Ga_0.9As/GaAs/AlAs RTDs is designed and fabricated to be a four-beam-mass structure, and an RTD-Wheatstone bridge measurement system is established to test the basic properties of this novel accelerometer. According to the experimental results, the sensitivity of the RTD based micro-accelerometer is adjustable within a range of 3 orders when the bias voltage of the sensor changes. The largest sensitivity of this RTD based micro-accelerometer is 560.2025 mV/g which is about 10 times larger than that of silicon based micro piezoresistive accelerometer, while the smallest one is 1.49135 mV/g.     

HA/GCPU复合多孔支架的可控制备及细胞相容性

以脂肪族异佛尔酮二异氰酸酯(IPDI)作为硬段、蓖麻油甘油酯(GCO)作为软段,通过原位聚合法制备了羟基磷灰石/蓖麻油甘油酯基聚氨酯(HA/GCPU)复合多孔支架.利用红外光谱和扫描电子显微镜对复合支架进行表征,并测试其力学性能及孔隙率.研究结果表明,HA/GCPU复合多孔支架的孔隙率和抗压强度依赖羟基磷灰石的含量,并具有明显的可控性.HA质量分数分别为0,20%和40%时,HA/GCPU复合多孔支架孔隙率分别为(61±3)%,(68±2)%和(57±3)%,抗压强度分别为(605±61),(2125±58)和(4588±260)k Pa,可见HA质量分数为20%时,HA/GCPU复合多孔支架具有与松质骨较为匹配的孔隙率和抗压强度.将MG63细胞与多孔支架共培养,通过倒置显微镜和扫描电子显微镜观察,用噻唑蓝(MTT)法表征HA/GCPU复合多孔支架的细胞相容性,结果表明,HA/GCPU复合多孔支架表面细胞黏附,生长良好,无细胞毒性,在骨组织工程领域具有一定的应用前景.     

Pressure effect study on the Ⅰ-Ⅴ property of the GaAs-based resonant tunnelling structure by photoluminescence measurement

This paper discusses the Ⅰ-Ⅴ property of the GaAs-based resonant tunnelling structure(RTS) under external uniaxial pressure by photoluminescence studies.Compressive pressure parallel to the [110] direction,whose value is determined by Hooke's law,is imposed on the sample by a helix micrometer.With the increase of the applied external uniaxial compressive pressure,the blue shift and splitting of the luminescence peaks were observed,which have some influence on the I-V curve of RTS from the point of view of the energy gap,and the splitting became more apparent with applied pressure.Full width at half maximum broadening could also be observed.