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  • 1
    Electronic Resource
    Electronic Resource
    Extremely low non-alloyed specific contact resistance ρc (10−8 Ω cm2) to metalorganic molecular beam epitaxy grown super heavily C-doped (1021 cm−3) p++GaAs (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 8227-8232 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The specific contact resistance ρc of non-alloyed ohmic metals (Mo/Au and WSix) to p-type GaAs is evaluated by transmission line method (TLM) patterns for various doping concentrations from 8×1018 to 1021 cm−3. The obtained specific contact resistance ρc, less than 10−8 Ω cm2, to metalorganic molecular beam epitaxy grown C-doped ( 1021 cm−3) GaAs is the lowest reported value. From the application point of view for the emitter electrodes of PNp type (two-dimensional electron gas base) heterojunction bipolar transistors, the specific contact resistance of a refractory metal, or the sputter-deposited WSix (x=0.45), is also studied. By reducing the growth temperature of molecular beam epitaxy from 600 to 450 °C and enhancing the As4/Ga flux ratio to 15, a nondiffusive heavily Be doped (1020 cm−3) GaAs is obtained. The specific contact resistance of the WSix to this sample is less than 10−6 Ω cm2. The obtained specific contact resistance can be well explained by a simple modeling based on the tunneling transport of light holes. Secondary ion mass spectroscopy analysis of the depth profile under heat acceleration shows a small diffusion of dopants for Be doped (1020 cm−3) GaAs and C-doped (1021 cm−3) GaAs. In addition, the specific contact resistance ρcISO of the isoheterojunction (p+GaAs/p+AlxGa1−xAs) is also evaluated by TLM patterns.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.347427
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  • 2
    Electronic Resource
    Electronic Resource
    Ionization by electron impact in an indirectly heated Penning source (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 151-154 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: ion-production mechanism in an indirectly heated Penning source has been studied at NIRS. Taking the number of primary electron passages between two cathodes into account, we calculated the effective electron current density, Ji ; it is the order of kA/cm2 for Ar, where the index "i'' is the charge state. In a pulsed arc condition of 2.6 A and 1300 V with a neutral atom density of 4×1013/cm3(cw), the calculated ionization times for Ar5+→Ar6+ and Ar6+→Ar7+ are 18 and 28 μs if their production process is step-by-step. These values agree well with the experimental value of 20 μs. Ji is proportional to the arc voltage and inversely proportional to the neutral-atom density N. The yield of multiply charged ions is in proportion to 1/Ni−2. This expression agrees well with the experimental results, which suggest that multiply charged ions are produced from Ar2+ through step-by-step ionization by primary electrons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.347736
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  • 3
    Electronic Resource
    Electronic Resource
    Application of low-temperature ions in the nonequilibrium state plasma of a Penning source (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 7933-7935 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present the high-output properties during the early 100–200 μs of a pulsed Penning source. The peak intensity, I, is higher than that of a dc source by a factor of more than 10. This phenomenon is due to the long confinement time of ions, τ, at the rising of the plasma, since within such a short time the ion temperature, T, does not reach thermal equilibrium and is still low. These characteristics are expressed as I∝τ∝T−1/2. The ratio of T−1/2 before and after equilibrium has a maximum of 1/18.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.347487
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  • 4
    Electronic Resource
    Electronic Resource
    Development of the National Institute of Radiological Sciences electron cyclotron resonance ion source for the heavy ion medical accelerator in Chiba : Proceedings of the 5th international conference on ion sources (1994)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 1087-1089 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The development of an electron cyclotron resonance ion source for the heavy ion medical accelerator in Chiba (HIMAC) injector is reported. The HIMAC is a heavy ion medical accelerator for cancer therapy. The electron cyclotron resonance (ECR) ion source is expected to provide a long lifetime, easy operation, and easy maintenance for medical use. The NIRS-ECR ion source has a single closed ECR stage, and a microwave frequency of 10 GHz is applied. Under the present performance, the output electrical currents of the ions are 2500 eμA for He1+, 300 eμA for C2+, 480 eμA for Ne3+, and 110 eμA for Ar6+. Stability of the intensity is better than 2%. The transmission efficiency through a low-energy beam-transport line with an acceptance of 200 πmm mrad is more than 70%; the typical 50% and 90% emittances of the injection beam with 8 keV/u are 20 and 80 πmm mrad, respectively. These performances satisfy the requirements for radiotherapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145071
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  • 5
    Electronic Resource
    Electronic Resource
    Retrospective review of 41 patients with endodermal sinus tumor of the ovary (1993)
    238 Main Street, Cambridge, Massachusetts 02142, USA : Blackwell Scientific Publications
    International journal of gynecological cancer 3 (1993), S. 0 
    Details
    ISSN: 1525-1438
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Forty-one patients with endodermal sinus tumors of the ovary (EST) (23: pure EST, nine: EST with dysgerminoma; and nine: EST with immature teratoma) were treated with cytoreductive surgery, with or without subsequent adjuvant chemotherapy including VAC or PVB. Clinical staging of these patients showed 23 in stage I, six in stage II and 12 in stage III and IV. The outcome was good in the patients with stage I or II disease, with 5- and 10-year survival rates of around 80%. In contrast, all except two patients with stage III or IV disease died within 2 years. Aggressive surgery did not change the outcome of patients with stage I disease. In addition, postoperative chemotherapy was necessary, but the choice of vincristine, actinomycin-D and cyclophosphamide (VAC) or cis-platin, vinblastine and bleomycin (PVB) did not make any difference. Based on the results of the present study, VAC or PVB chemotherapy, after cytoreductive surgery, is essential for cure and conservative surgery followed by VAC or PVB regimen should be recommended for young patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1525-1438.1993.03050329.x
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  • 6
    Electronic Resource
    Electronic Resource
    Causes of low seed set in white clover (Trifolium repens L.) (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 48 (1993), S. 0 
    Details
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: A field experiment was conducted to clarify the factors responsible for poor seed set in four white clover (Trifolium repens L.) cultivars. Although the mean number of ovules per floret was 5·18–5·29, the average number of seeds per floret was found to be only 1·23-1·82. A stainclearing technique was used to examine the cytoplasmic state of the embryo sac in intact, unfertilized, mature ovules and it was found that 28–33% of ovules per carpel were sterile. The abortion rate of fertilized ovules and immature seeds (7 days after pollination) ranged between 32 and 34%. Beyond this period, it was observed that only a very small proportion of the total seeds were lost. The observation of high pollen fertility and a high pollen load strongly suggests that poor pollination does not account for the reduced number of seeds per floret. A ‘nutrient competition’ hypothesis was proposed for high ovule sterility and post-fertilization abortion of developing seeds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2494.1993.tb01839.x
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  • 7
    Electronic Resource
    Electronic Resource
    Direct observation of glide dislocations in a KCl crystal by the light scattering method (1990)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 56 (1990), S. 1317-1319 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The edge-like dislocations in a KCl single crystal produced by plastic deformation have been observed successfully by a 90° angle light scattering method using a scanning type microscope constructed with a high-power Ar-ion laser (2 W for a wavelength of 514 nm) and a conventional optical microscope. The image of glide dislocations was very sharp and uniform compared with that of grown-in dislocations. The orientation dependence of light scattering agreed with Moriya–Ogawa's theory [Philos. Mag. A 41, 191 (1980)].
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.102504
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  • 8
    Electronic Resource
    Electronic Resource
    Design of a compact storage ring for industrial research : Proceedings of the 4th international conference on synchrotron radiation instrumentation (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 770-773 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An 800-MeV compact storage ring is under construction for development of the technology of a compact ring and for research of x-ray lithography and material analysis. Synchrotron radiation with a critical wavelength of 0.65 nm is emitted from a pair of superconducting bending magnets. A straight section of the ring has only one quadrupole magnet to make the smaller ring. An injection efficiency with a single kicker magnet is optimized by computer simulation. The kicker field strength and an injection angle are determined. A beam tracking with a numerical integration method shows this ring has a sufficiently wide dynamic aperture of ||x||(approximately-equal-to)30 mm and ||y||(approximately-equal-to)50 mm at the center of the bending magnet, which has βxmin and βymax. A 1-GeV synchrotron is used as an injector, which has accelerated a beam up to 1 GeV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1142658
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  • 9
    Electronic Resource
    Electronic Resource
    Low-duty pulsed PIG source in HIMAC : International conference on ion sources (1990)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 61 (1990), S. 466-468 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A low-duty pulsed PIG source has been developed for the injector (e/m= (1)/(7) – 1/4 ) of HIMAC. This source is of an indirectly heated PIG type. The requirement for this source is a high current with a low repetition rate and a low-duty factor. To obtain good stability during pulsed operation, the source is operated in a positive arc impedance range. Pulsed operation also allows the arc voltage to be high (1.4 kV), resulting in a high yield of multiply charged ions. With an arc pulse width of 500 μs (1 Hz and a duty of 0.05%), a useful beam pulse width of 200 μs with a peak intensity of 120 μA for Ar6+ has been obtained at an optimum gas pressure of 10−3 Torr. This intensity is higher than for cw mode by a factor of 5. A 90% emittance has also been measured to be 250π mm mrad in both the X and Y directions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1141275
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  • 10
    Electronic Resource
    Electronic Resource
    Double-wavelength laser array with InGaAsP/InGaAsP multiple quantum well grown by Ar ion laser-assisted metalorganic molecular beam epitaxy (1992)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 61 (1992), S. 2449-2451 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: This letter reports a laser diode array of InGaAsP/InGaAsP multiple quantum well (MQW) lasers, emitting at different wavelengths, grown by Ar ion laser assisted metalorganic molecular beam epitaxy. A separate confinement heterostructure MQW laser film was locally irradiated during well growth with an Ar ion laser and processed into a laser diode array having a 6 μm stripe width and 300 μm pitch. The laser diode with an irradiated MQW active layer operated at 1.40 μm; the laser diodes with nonirradiated MQW active layers operated at 1.28 μm. The threshold currents of the 300 μm-long laser diodes were 23 mA for the irradiated diode and 55 mA for the nonirradiated diodes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.108148
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