Search Results - (Author, Cooperation:H. Z. Chen)
-
1Latest Papers from Table of Contents or Articles in PressX. C. Yao ; T. X. Wang ; H. Z. Chen ; W. B. Gao ; A. G. Fowler ; R. Raussendorf ; Z. B. Chen ; N. L. Liu ; C. Y. Lu ; Y. J. Deng ; Y. A. Chen ; J. W. Pan
Nature Publishing Group (NPG)
Published 2012Staff ViewPublication Date: 2012-02-24Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsPublished by: -
2Latest Papers from Table of Contents or Articles in PressG P Li, C L He, R Li, J M Shi, G F Ma, X Y Fu, H Z Chen and J M Wang
Institute of Physics (IOP)
Published 2018Staff ViewPublication Date: 2018-02-03Publisher: Institute of Physics (IOP)Print ISSN: 1757-8981Electronic ISSN: 1757-899XTopics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision MechanicsPublished by: -
3Latest Papers from Table of Contents or Articles in PressJ M Shi, C L He, G P Li, H Z Chen, X Y Fu, R Li, G F Ma and J M Wang
Institute of Physics (IOP)
Published 2018Staff ViewPublication Date: 2018-02-03Publisher: Institute of Physics (IOP)Print ISSN: 1757-8981Electronic ISSN: 1757-899XTopics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision MechanicsPublished by: -
4Latest Papers from Table of Contents or Articles in PressZ H Chen, M Z Wei, X M Zhang, D P Wang, K Sun, J Zhou and F Xue
Institute of Physics (IOP)
Published 2018Staff ViewPublication Date: 2018-10-24Publisher: Institute of Physics (IOP)Print ISSN: 1757-8981Electronic ISSN: 1757-899XTopics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision MechanicsPublished by: -
5Latest Papers from Table of Contents or Articles in PressM Z Wei, Z H Chen, X M Zhang, D P Wang, K Sun, J Zhou and F Xue
Institute of Physics (IOP)
Published 2018Staff ViewPublication Date: 2018-10-24Publisher: Institute of Physics (IOP)Print ISSN: 1757-8981Electronic ISSN: 1757-899XTopics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision MechanicsPublished by: -
6Latest Papers from Table of Contents or Articles in PressStaff View
Publication Date: 2012-08-07Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsKeywords: Biological Assay ; *Cell Differentiation ; Cyclic GMP/*analogs & derivatives/metabolism ; Dictyostelium/*cytology/genetics/growth & development/*metabolism ; Fruiting Bodies, Fungal/metabolism ; Guanosine Triphosphate/metabolism ; Molecular Sequence Data ; Prokaryotic Cells/*metabolism ; Protozoan Proteins/metabolism ; RNA, Messenger/genetics/metabolism ; *Second Messenger SystemsPublished by: -
7Articles: DFG German National LicensesChen, H. Z. ; Ghaffari, A. ; Wang, H. ; Morkoç, H. ; Yariv, A.
Woodbury, NY : American Institute of Physics (AIP)
Published 1987Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: Low-threshold graded-refractive-index GaAs/AlGaAs laser structures were grown on Si (100) by molecular beam epitaxy and tested at room temperature under a probe station. Broad area devices having widths of 110–120 μm and cavity lengths of ∼500–1210 μm exhibited threshold current densities as low as 600 A/cm2 and total slope efficiencies of as high as 0.75 W/A. The thresholds fell in the range of 600–1000 A/cm2 in three different wafers, and it is assumed that the quality of the facets accounts for most of the spread in results.Type of Medium: Electronic ResourceURL: -
8Articles: DFG German National LicensesChen, H. Z. ; Wang, H. ; Ghaffari, A. ; Morkoç, H. ; Yariv, A.
Woodbury, NY : American Institute of Physics (AIP)
Published 1987Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: A new hetero-Schottky structure for the study of Schottky barriers and heterojunctions is discussed. Photoelectric measurements have revealed a correlation between Au/GaAs and Au/AlxGa1−xAs Schottky barrier heights and GaAs/AlxGa1−xAs heterojunction band offsets. The conduction-band discontinuity ΔEc in the GaAs/AlxGa1−xAs system is determined, and the ratio ΔEc:ΔEg is found to vary between 69±5% and 58±5% for x=0.15–0.48.Type of Medium: Electronic ResourceURL: -
9Articles: DFG German National LicensesPaslaski, J. ; Chen, H. Z. ; Morkoç, H. ; Yariv, A.
Woodbury, NY : American Institute of Physics (AIP)
Published 1988Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: We present results on high-speed GaAs p-i-n photodiodes grown on Si substrates by molecular beam epitaxy. In addition to the dc operating characteristics, we also report the first impulse response and microwave frequency response measurements of GaAs-on-Si photodiodes. Results include an impulse response pulse width of 45 ps and a modulation corner frequency 〉4 GHz at a reverse bias of −3 V.Type of Medium: Electronic ResourceURL: -
10Articles: DFG German National LicensesChen, H. Z. ; Ghaffari, A. ; Morkoç, H. ; Yariv, A.
Woodbury, NY : American Institute of Physics (AIP)
Published 1987Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: Single quantum well, graded refractive index separate confinement heterostucture (SQW GRINSCH) lasers with well thicknesses in the range of 65–480 A(ring) have been grown by molecular beam epitaxy (MBE) on (100) and off of (100) by 4° toward (111) A substrates. The threshold current density appears to be independent of the well thickness in the range of 65–165 A(ring) due to the compensating effects of volume of inversion and optical confinement. Under optimum growth conditions, the tilted substrates led to lower threshold current densities, the lowest value being 93 A/cm2 for a 520-μm-long cavity laser with a 125-A(ring)-thick well. To our knowledge, this is by far the best ever reported threshold current density obtained in a semiconductor injection laser. Deviations from optimum growth conditions drastically increased the threshold current density on (100) substrates whereas the degradation for those on the tilted substrates was much less pronounced.Type of Medium: Electronic ResourceURL: -
11Articles: DFG German National LicensesXiong, Fulin ; Tombrello, T. A. ; Wang, H. ; Chen, T. R. ; Chen, H. Z. ; Morkoç, H. ; Yariv, A.
Woodbury, NY : American Institute of Physics (AIP)
Published 1989Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: Single quantum well AlGaAs/GaAs graded-index separate-confinement heterostructure lasers have been fabricated using MeV oxygen ion implantation plus optimized subsequent thermal annealing. A high differential quantum efficiency of 85% has been obtained in a 360-μm-long and 10-μm-wide stripe geometry device. The results have also demonstrated that excellent electrical isolation (breakdown voltage of over 30 V) and low threshold currents (22 mA) can be obtained with MeV oxygen ion isolation. It is suggested that oxygen ion implantation induced selective carrier compensation and compositional disordering in the quantum well region as well as radiation-induced lattice disordering in AlxGa1−xAs/GaAs may be mostly responsible for the buried layer modification in this fabrication process.Type of Medium: Electronic ResourceURL: -
12Articles: DFG German National LicensesChen, H. Z. ; Paslaski, J. ; Yariv, A. ; Morkoç, H.
Woodbury, NY : American Institute of Physics (AIP)
Published 1988Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: We report on the frequency response of quantum well lasers on Si substrates grown by molecular beam epitaxy. Ridge waveguide lasers of 10 μm×380 μm having threshold currents as low as 40 mA were used in this study. Measurements were performed up to a frequency of 4.5 GHz with a resultant modulation corner frequency of 2.5 GHz when the laser was operated about 20% above the threshold.Type of Medium: Electronic ResourceURL: -
13Articles: DFG German National LicensesChou, Hsiung ; Chen, H. Z. ; Chen, Y. C. ; Lin, T. L. ; Chow, T. C. ; Wang, T. P.
Woodbury, NY : American Institute of Physics (AIP)
Published 1996Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: Three Y1Ba2Cu3O7−δ superconducting thin films with 20%, 60%, and 100% coverage of precipitates were fabricated into microbridges of 25×650 μm2 by a conventional photolithography method. These microbridges exhibit a Tco(R=0) from 83.6 to 87.2 K and a transition width of about 1.8 K. These also have (dR/dt)max values of about 71–78 Ω/K. We find that the fewer the precipitates on the film, the better the thermal conduction, and a larger responsivity (S) can be achieved. The best responsivity of 783 V/W measured at Ib=8 mA, Top=86.8 K, and f=2 Hz for various wavelengths of light sources is obtained from the film with 20% precipitation. The photoresponse signals decay exponentially with the precipitation coverages, which indicates that these precipitates behave as thermal resistance layers that smooth out the ac incident signal, suppress the rise in microbridge temperature, and result in a smaller photoresponse signal for the bolometer. © 1996 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
14Articles: DFG German National LicensesChou, Hsiung ; Chen, H. Z. ; Hong, M. T. ; Chen, Y. C. ; Chow, T. C.
Woodbury, NY : American Institute of Physics (AIP)
Published 1996Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: A photodetector with high responsivity has been fabricated with a high quality Y1Ba2Cu3O7−δ film on a regular SrTiO3 (100) substrate that has no thinning or etching. The film exhibits a precipitation-free morphology and has an extremely smooth surface having a rms roughness smaller than 5 nm. The film was patterned into a 25×650 μm2 long microbridge by a conventional photolithography technique. The Tco of the microbridge can be tuned by applying different bias currents, which results in a tunable operation temperature of the photodetector at 77.35±1 K. This makes it operationally more practical and economical. The noise voltage at 10 mA bias current is less than the resolution of our setup, 15 nV Hz−0.5. A high responsivity of 2.3×103 V/W was obtained when a bias current of 8 mA and a low power density He–Ne laser of 0.08 J/cm2 s chopped at 2 Hz were applied on the microbridge at 77.35 K. Under the same condition, the noise equivalent power (NEP) and detectivity (D*) have been measured to be 4.34×10−12 W Hz−0.5 and 3×109 cm Hz0.5 W−1, respectively. © 1996 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
15Articles: DFG German National LicensesGeng, J.-G. ; Chen, H.-Z. ; Yang, Y.-F. ; Jian, C.-Y. ; Qian, Z.-H. ; Han, Q.-Q. ; Yao, Y.-M.
Amsterdam : ElsevierStaff ViewISSN: 0009-8981Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: MedicineType of Medium: Electronic ResourceURL: -
16Articles: DFG German National LicensesStaff View
ISSN: 1010-6030Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: Chemistry and PharmacologyType of Medium: Electronic ResourceURL: -
17Articles: DFG German National LicensesStaff View
ISSN: 1010-6030Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: Chemistry and PharmacologyType of Medium: Electronic ResourceURL: -
18Articles: DFG German National LicensesStaff View
ISSN: 1010-6030Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: Chemistry and PharmacologyType of Medium: Electronic ResourceURL: -
19Articles: DFG German National LicensesStaff View
ISSN: 1435-1536Keywords: Aging ; surfactant ; titanium gelsSource: Springer Online Journal Archives 1860-2000Topics: Chemistry and PharmacologyMechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision MechanicsNotes: Abstract Titanium hydrogels prepared without and with different amounts of surfactant (sodium dodecylbenzene sulfonate) have been examined for their behavior during aging for more than 100 days (some for more than 200 days) at different temperatures. By means of XRD semi-quantitative analyses and SEM observations with high magnification (100 K), the effects of the surfactant on the crystalline structure and content, on the morphology and the size of the particles, and on the aggregation phenomena have been investigated. It was also found that aging somewhat decreases the adsorption capacity of the gels.Type of Medium: Electronic ResourceURL: