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We designed and manufactured a high current ion source for ion beam applications. As an industrial application, we studied the relation between bombarding nitrogen fluence and surface resistivity on MPPO (modified polyphenylene oxide) material, which is used for the IC tray, using the high current ion implantation technology. During the transportation, electrical charge is induced on the tray surface and it generates an electrical shock into the IC chip. To prevent such damage, we developed an implantation process for IC tray surface modification, which was carried out at an accelerating energy of 50 keV and an ion beam current of 50 mA. The surface resistivity of the MPPO IC tray that is normally insulating was decreased in the range of 10/sup 12/ to 10/sup 6/ /spl Omega//sq by increasing the total dose from 7/spl times/10/sup 14/ ions/cm/sup 2/ to 8/spl times/10/sup 16/ ions/cm/sup 2/.

A 1MV Tandem Proton Accelerator is being developed for the industrial applications such as high-energy implantation and explosive detection. The proton accelerator consists of a 10 mA negative hydrogen ion source, two Einzel lenses, accelerating tubes, a gas stripper, a 1MV 30 mA Cockroft-Walton high voltage power supply, vacuum pumping system, and a high pressure insulating gas system. The large current proton beam can be accelerated into the optical system, which is designed with simulation which includes space charge effects. The simple optical geometry is adapted for the optics design for the accelerator. The 2 MV/m accelerating tube is being developed for this accelerator, and the detail of the accelerator development is reported.

KOMAC (Korea Multipurpose Accelerator Complex) Test Facility (KTF) has been prepared to develop accelerator technologies and low energy proton beam applications with a 20MeV proton accelerator. For the KTF accelerator, a conventional DTL (Drift Tube Linac) from 3MeV to 20MeV has been designed with 10% duty. It consists of 350MHz DTL cavities with permanent quadrupole magnet and a I MW RF source. The details of the DTL design are reported.

Summary form only given, as follows. The Korea Atomic Energy Research Institute (KAERI) has been developing a multipurpose proton accelerator with an energy of 1 GeV and a current of 20 mA.. Hanyang Univ. is developing an ion beam probe. Using four magnetic probes we measured the magnitude and position of a pulsing ion current in the ion beam simulator. The improvement and a method for the DC proton beam are addressed.

Summary form only given. The dependence of pump wavelength for the amplification characteristics of a Er/sup 3+/-doped fiber amplifier (EDFA) has been reported for 0.8, 0.98, or 1.48 /spl mu/m band, to date now most of long-wavelength-band (L-band) EDFA are using these pump bands. In this paper, 1.53 /spl mu/m band is proposed and intensively investigated as new pump wavelength of L-band EDFA for the fist time. Power conversion efficiency (PCE), gain coefficient and noise figure (NF) for pumping efficiency were measured and compared with 1.48 /spl mu/m pumped L-band EDFA.

We present an exoskeletal haptic device called SKK Hand Master. The device is semi-directly driven by linkages with ultrasonic motors, which has characteristic features close to cybernetic actuators. In the control of the device, we propose a method of measuring the joint positions and joint torques of the finger and a control method called PWM/PS is presented to overcome the intrinsic disadvantages of ultrasonic motors such as hysteresis. Construction of the device is addressed and several results of experiments for performance evaluation are included.

GDNF expression was examined immunocytochemically in developing human fetal brains obtained from aborted fetuses ranging from 7 to 39 weeks in gestational age. At 7-8 weeks, strong immunoreactivity was noted within radial glial processes, glia limitans and choroid plexus of the telencephalic vesicle. By 10 weeks, ependymal cells, primitive matrix cells and early developing cortical plate neurons showed positive staining. By 15-16 weeks, migrating neurons in the subventricular and intermediate zones and in the cortical plate were strongly positive for GDNF. The glia limitans of the cerebral cortex and subependymal astrocytes remained positive at this time. As fetal age increased, GDNF expression shifted to neurons and glial cells in the deeper structures of the brain. The most prominent GDNF staining was observed in the cytoplasm and dendrites of Purkinje cells of the cerebellum by 25 weeks and thereafter. Pyramidal neurons of the CA1 region and granule cells of the dentate fascia of the hippocampus, neurons of the entorhinal cortex, and scattered neurons within the brain stem, medulla and spinal cord all showed strong GDNF staining by 25-35 weeks. Widespread GDNF expression in neuronal and non-neuronal cells with distinct developmental shifts suggests that GDNF may play a critical role in the survival, differentiation and maintenance of neurons at different stages of development in the developing human fetal brain.

We have been developing a mine detection system coupled with a 1 MV compact tandem accelerator. This system will consist of a compact high current tandem accelerator, a target system, a detection system, a power generator system and a transportation system for mine field applications. The tandem accelerator is designed to accelerate protons with energies of 1.75 MeV up to a 10 mA beam current. We have developed a new mine detection method for a scattered 9.17 MeV gamma-ray produced from the /sup 14/N(/spl gamma/,/spl gamma/)/sup 14/N photo-resonant reaction. The incident gamma-rays are produced by a 1.75 MeV proton beam bombarding at a /sup 13/C target. A new detection method is described which separates the scattered gamma-rays from the /sup 13/C target gamma-rays to within a 0.1% energy resolution using the Doppler effect from the nucleus recoil mechanism.

A new scheme for beam extraction is presented to partially extract a negative hydrogen ion beam at 260 MeV from the main linac where both protons and negative hydrogen ions are accelerated up to 1 GeV. The negative hydrogen ions are extracted by a stripper magnet and the un-extracted ions are returned to the linac. The main feature of this extractor is its ability to regulate the intensity of the extracted beam with the stripper magnet. This extraction scheme will be utilized for the KOMAC (Korea Multi-purpose Accelerator Complex) linear accelerator of 1 GeV cw proton (H/sup +/)/negative-hydrogen (H/sup -/) beams with an intensity of 20 mA.

For the first phase of the KOMAC (Korea Multi-purpose Accelerator Complex) project, a CCDTL (Coupled Cavity Drift Tube Linac) which accelerates a 20 mA cw proton beam from 3 MeV to 20 MeV is designed. An Al cold model is fabricated to check the design, the tuning method, and the coupling coefficients. To check the engineering design, a Cu cold model is fabricated. The design and the test results are presented.

Intraoral negative pressure during bottle feeding with two kinds of teats (a regular Nuk and a cleft Nuk) was measured in 7 infants with cleft lip and palate, 8 infants with cleft palate, 2 infants with cleft lip, 4 infants with operated cleft lip and palate and 7 normal infants. Infants with cleft lip and palate or cleft palate were unable to generate negative pressure before cleft lip and palate closure. The presence or absence of an early orthopaedic plate did not make any difference. In infants with unoperated cleft lip and with operated cleft lip and palate, peak negative pressure during feeding differed little from that of normal infants.

Ionization probabilities of the hydrogenic ions, with atomic number between 4 and 9, impinging upon a crystal at grazing angle are calculated. It is found that the transition probability from the ground state nlm = (100) to the continuum states is negligible. For incident ions at near-resonance velocity, transition probabilities from 2 lm and 3 lm states to the continuum states exhibit high peaks. As a result of ionization, the efficiency of coherent excitation of the ions by a crystal is greatly reduced. Based on the present ionization data, we point out some possible methods to enhance stimulated emission of soft X-rays by a crystal surface.

Coherent excitation of fast hydrogenic ions with velocity near 10 9 cm/s by a periodic crystal surface is investigated. Electronic transitions of the ion induced by the crystal potential are calculated for both the cases that nucleus of the ion travels above and below the surface. It is found that the transition matrix elements between the hydrogenic (1, 0, 0) and (3, l, m ) states depend strongly on whether the nucleus of the ion is above or below the surface and on the value of l and m . It is estimated that the Rabi distance for complete excitation of the Be 3+ ion lies between 1 and 300 A and the fractional energy loss ΔE loss / E ion is of the order of 10 −6 to 10 −4 . From estimating the collision time between ions, the excitation time of ionic electrons, the spontaneous and the stimulated lifetimes, we calculate the upper and lower limits of the incident ion current density for which stimulated emission of soft X-ray occurs. The distance beyond which the surface effect becomes insignificant and the confinement of ions over the crystal are discussed.

A quantum mechanical approach is used to calculate the cross sections and rate constants of D+H/sub 2/(v/sub ..cap alpha../=1,0) ..-->.. DH(v/sub ..beta../=0,1)+H. With v/sub ..cap alpha../=0, present results are in agreement with classical calculation. With v/sub ..cap alpha../=1, cross sections for the vibrational adiabatic transition (v/sub ..cap alpha../=1 to v/sub ..beta../=1) is an order of magnitude larger than that for the vibrational nonadiabatic transition (v/sub ..cap alpha../=1 to v/sub ..beta../=0). This result is in agreement with recent experiments but in disagreement with classical-trajectory calculation.

The total ionization rates R 100 → k μ from the ground state to the continuum, via coherent excitation to the first excited state, of a fast hydrogenic ion impinging upon a thin film of gold are computed for ions with atomic number between 6 and 9. Since the inclusion of the relativistic factor makes the analytical manipulation of the total ionization rate and the numerical computations extremely difficult, we adopt the approximation of treating the crystal as one-dimensional in the numerical computations. For incident ions at the calculated resonance velocity, R 100 → k μ exhibits a narrow peak. Further, we found that the resonances are asymmetric with respect to the velocity of the ions and the total ionization rate decreases as the atomic and/or harmonic number increases. These results are qualitatively in agreement with the experiments. Since the ions do not follow exactly the same paths in the channel, they experience different electrostatic potentials. As a result the energy levels of the ions are broadened by approximately 1 eV, The effect of this broadening on the total ionization rate is also discussed.

The East China Sea is a broad continental shelf over which there are large tides and tidal currents. During the joint China-U.S.A. Marine Sedimentation Dynamics Study, a large number of current measurements were made across the continental shelf along approximately 30°N. There is general agreement between these observations and Choi's (1980) tidal model of the area, which supports his assumed boundary conditions and numerical procedures. The semi-diurnal tidal current near the mouth of the Changjiang transports water southward at maximum ebb and northward following maximum flood. Because the tides rotate clockwise, southward flow is followed by shoreward flow, confining the initial river plume and sediment deposition to the coastal region south of the river mouth. Six hours later the remnants of the initial plume move to the north and seaward. The southward discharge on ebb results in initial and greatest sedimentation rates on the south sides of the river mouths.

The selectively adsorbed compound states for H2 + Cu rigid surface scattering, which are the quasibound states embedded in the continuum, are computed employing quantum mechanical method. With a semi-empirical molecule-flat surface interaction potential, we diagonalize the total Hamiltonian of the system including the rotational and vibrational states of the molecular projectile. Our emphases here are to study the vib-rotational and vibrational components that are proportional to the scattering amplitude of the Feshbach type internal excitation associated with selectively adsorbed resonance states, to study the relative importance between the rotational and vibrational mediations for selective adsorption, and to make comparison with quasiclassical trajectory results obtained in the preceeding paper. For incident energy below ∼ 0.3 eV, rotation mediations are found to be dominant in the resonance scattering, whereas the resonance states that arise from the vibrational mediation often appear above that energy. Good agreement between the quantal and the classical trajectory results is obtained regarding the energies of the selectively adsorbed quasibound states and other related physical quantities in the energy region above the potential barrier. Below this barrier, the quantum mechanical tunneling effect is important.

Two typhoon surges generated during July–August 1978 are investigated numerically with the use of a vertically-integrated finite-difference model of the Yellow Sea and the East China Sea. The hindcast scheme involves processing pressure data from weather charts to provide the necessary meteorological forcing to a sea model that computes the response in terms of water levels and currents. Computed residuals are compared with hourly records from selected tide gauges (Inchon, Kunsan, Mokpo, Jeju and Yeosu) along the coast of Korea. Some of the preliminary results are presented and discussed.

Formation of an intracranial aneurysm as a result of aspergillus infection, a rare occurrence, typically develops in patients who have not received immunosuppressive therapy but on whom an operation has been performed in the recent past. This report describes the first instance of formation of an aspergillotic cerebral arterial aneurysm in a patient on chronic hemodialysis, which occurred in the absence of a prior operation or immunosuppressive therapy.

It has been suggested that primary traumatic lesions of the brainstem do not occur in the absence of widespread injury to other parts of the brain. We describe a patient who suffered a severe head injury that left him with paralysis of three extremities and weakness in the fourth. Intellectual function was entirely preserved. Neuropath-ological examination 39 years after the injury disclosed the presence of a cavitary lesion within the basis pontis. There was no pathological evidence of traumatic injury to any other part of the central nervous system.

Correlative immunocytochemical and electron-microscopic studies of the subpial region of the human fetal spinal cord between 12-18 weeks of ovulation age revealed immature oligodendroglial cells showing immunoreactive GFAP within both the cytoplasm and its processes. By 17-18 weeks, however, GFAP immunoreactivity is no longer evident within such cells. The expression of GFAP by immature oligodendroglial cells in the developing human fetal spinal cord prior to the formation of compact myelin sheaths supports the hypothesis that oligodendrocytes, along with astrocytes, are ultimately derived from radial glial cells.

A three-dimensional numerical model of the Yellow Sea and the East China Sea has been developed to investigate the M 2 tidal current distribution, expecially the vertical variation of horizontal current in the region. Results have been compared with current meter data acquired from AMTEX-75 and recent joint USA-China Marine Sedimentation Dynamics Study Program. Some of the preliminary results are presented and discussed.