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Effects of contact shape on ballistic phonon transport in semiconductor nanowires
Jing-Jing Yao,Wei-Qing Huang,Gui-Fang Huang,Yuan Chen,Ling-Ling Wang,Wangyu Hu,Anlian Pan 한국물리학회 2012 Current Applied Physics Vol.12 No.2
We study the effects of contact shape on ballistic phonon transport in semiconductor nanowires at low temperatures using an approximative scalar model of continuum elasticity. Five different contacts connected to two semiconductor nanowires with different transverse widths are discussed. Numerical results show that the contact shape acts as an ‘acoustic impedance adaptor’, playing a crucial role on the ballistic phonon transmission and thermal conductance. The phonon coupling in the contacts with certain length facilitates ballistic phonon transmission compared to the abrupt interface, in which the phonon scattering is the strongest. It is found that the more the contact is abrupt, the smaller the thermal conductance is. The catenoidal contact rather than the abrupt interface is also the competitive candidate to obtain bigger thermal conductance. These results indicate that choosing an appropriate contact shape is one of the most critical factors to accurately measure the thermal conductance with a very high precision and reliability in different temperature ranges at low temperatures.
Membrane surface charge and morphological and mechanical properties of young and old erythrocytes
Xing-Yao Chen,Yao-Xiong Huang,Wen-jing Liu,Zhi-jian Yuan 한국물리학회 2007 Current Applied Physics Vol.7 No.s1
ditions were studied as a function of cell age. The young and old cells were separated from fresh rabbit blood by using Percoll densitygradients. A novel multi-dimensional microscope was employed to perform real-time, non-invasivein situmeasurements on the mem-brane bending elastic modulus and the cell shape and size. A phase-analysis micro-electrophoresis laser scattering technique was usedto measure the surface charge density. The results show that the membrane Zeta potential of red blood cells is reduced when they become.
E.S Kannan,Gil Ho Kim,D. H. Youn,Chi-Te Liang,Jing-Han Chen,Jyun-Ying Lin,Kuang Yao Chen,Kwang-Yong Kang,Li-Hung Lin,N.C. Chen,Zhi-Yao Zhang 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.6
We report comparative magnetoresistance measurements of the two-dimensional electron gas formed in two different GaN/AlGaN quantum well structures with different starting disorder. The longitudinal magnetoresistance measurements for both the samples exhibited temperature-independent crossing points, evidence for a weak insulator - quantum Hall transition. Our data suggest that the onset of Landau quantization does not correspond to the crossing point. Moreover, the effect of the electron-electron interaction must be taken into account because the Hall resistivity shows a strong temperature dependence in the more disordered sample. Our experimental results, therefore, urge further studies on the low-field weak insulator - quantum Hall transition
Jing Li,Song-You Wang,Ming Xu,Shen-Jin Wei,Song Wu,Fei Pei,Liang-Yao Chen,Yu Jia 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.4
Ge2Sb2Te5 (GST) is widely used as an excellent data recording material based on its fast and reversible amorphous-to-crystalline phase transformation that is accompanied by changes in the optical reflectivity and the electrical conductivity. It was demonstrated that GST can be transformed reversibly between the amorphous and the cubic phases, and, under certain conditions, it can be transformed between the cubic and the hexagonal phases as well. Thus, if we can take advantage of the differences in the optical and the electrical properties among the amorphous, the cubic, and the hexagonal states, we could use GST as a multi-state storage material, and its storage density would be improved remarkably. In this study, we investigate the electronic and the optical properties of crystalline GST by using both ab-initio and experimental analyses. The results show that the cubic GST is semi-conductive while the hexagonal GST may exhibit much higher conductivity. The reflectivity contrast of the two crystalline states is above 8 % in the range from 400 nm to 700 nm, indicating a potential for applications of GST in multi-state optical data storage.
Investigation on Preparation of Ge Quantum Dots in $SiO_2$ Thin Films
Chen, Jing,Wu, Xuemei,Jin, Zongming,Yao, Weiguo The Korean Vacuum Society 1998 Applied Science and Convergence Technology Vol.7 No.1
Ge quantum dots in $SiO_2$ thin films were prepared by r.f. magnetron co-sputtering using a Ge, $SiO_2$ composite target. The size of quantum dots was modulated by controlling of substrate temperature during depositing and annealing of samples deposited at certain substrate temperature. A series of work was done on the influence of preparing parameters on the growth of quantum dots, and a discussion on the formation and growth of quantum dots under different preparation parameters is given.
Yao Zhang,Sheng Chen,Miao He,Jing Wu,Jian Chen,Qiang Wang 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.4
Previously, we presented a novel approach for increasing Thermobifida fusca cutinase adsorption on cotton fibers by fusing cutinase with a carbohydrate-binding module (CBM). A preliminary study showed that two fusion proteins,namely cutinase-CBM_(Cel6A) and cutinase-CBM_(CenA),with similar stabilities and catalytic properties, had potential applications in bioscouring. In the present study, an indepth analysis of both cutinase-CBMs in bioscouring was explored. Effects of cutinase-CBMs on cotton bioscouring were investigated by characterizing the chemical and physical surface changes in enzyme-treated cotton fabrics. Gas chromatography/mass spectrometry was used to analyze the degradation of the cotton fabric cuticle; Fourier transform infrared microspectroscopy was used to study changes in the chemical composition of the cotton fabric epidermal layer; and scanning electron microscopy was used to monitor minor changes in the morphology of the fiber surface. Our results indicated that cutinase-CBMs in combination with pectinase had a greater effect on cotton fabric than did cutinase. Following scouring with cutinase-CBMs and pectinase, the performance of cotton fabric in terms of its wettability and dyeability was similar to that following alkali scouring. Our study provides a foundation for the further application of cutinase-CBM to bioscouring.
Li, Chen-Long,Chang, Liang,Guo, Lin,Zhao, Dan,Liu, Hui-Bin,Wang, Qiu-Shi,Zhang, Ping,Du, Wen-Zhong,Liu, Xing,Zhang, Hai-Tao,Liu, Yang,Zhang, Yao,Xie, Jing-Hong,Ming, Jian-Guang,Cui, Yu-Qiong,Sun, Ying Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.23
Background: ${\beta}$-elemene, extracted from herb medicine Curcuma wenyujin has potent anti-tumor effects in various cancer cell lines. However, the activity of ${\beta}$-elemene against glioma cells remains unclear. In the present study, we assessed effects of ${\beta}$-elemene on human glioma cells and explored the underlying mechanism. Materials and Methods: Human glioma U87 cells were used. Cell proliferation was determined with MTT assay and colony formation assay to detect the effect of ${\beta}$-elemene at different doses and times. Fluorescence microscopy was used to observe cell apoptosis with Hoechst 33258 staining and change of glioma apoptosis and cell cycling were analyzed by flow cytometry. Real-time quantitative PCR and Western-blotting assay were performed to investigated the influence of ${\beta}$-elemene on expression levels of Fas/FasL, caspase-3, Bcl-2 and Bax. The experiment was divided into two groups: the blank control group and ${\beta}$-elemne treatment group. Results: With increase in the concentration of ${\beta}$-elemene, cytotoxic effects were enhanced in the glioma cell line and the concentration of inhibited cell viability ($IC_{50}$) was $48.5{\mu}g/mL$ for 24h. ${\beta}$-elemene could induce cell cycle arrest in the G0/G1 phase. With Hoechst 33258 staining, apoptotic nuclear morphological changes were observed. Activation of caspase-3,-8 and -9 was increased and the pro-apoptotic factors Fas/FasL and Bax were upregulated, while the anti-apoptotic Bcl-2 was downregulated after treatment with ${\beta}$-elemene at both mRNA and protein levels. Furthermore, proliferation and colony formation by U87 cells were inhibited by ${\beta}$-elemene in a time and does-dependent manner. Conclusions: Our results indicate that ${\beta}$-elemene inhibits growth and induces apoptosis of human glioma cells in vitro. The induction of apoptosis appears to be related with the upregulation of Fas/FasL and Bax, activation of caspase-3,-8 and -9 and downregulation of Bcl-2, which then trigger major apoptotic cascades.