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The purpose of this study is to devise a bending fatigue strength evaluation method that can be widely used for any machine component under the consideration that bending fatigue breakage depends on the initiation of a surface fatigue crack, namely, the conditions for the initiation of a fatigue crack can be used as the criteria for bending fatigue strength design. The specially designed and manufactured three-point bending specimens with crowned round notches are used in bending fatigue experiments. The obtained bending fatigue strengths are expressed as the maximum actual stress at the critical point, which increases with decreasing notch radius. Considering the effects of the stress distribution on the bending fatigue strength, we present a method for estimating the tension fatigue strength of a smooth specimen, which is shape-independent fatigue strength and can be applied to bending fatigue strength design for machine components with complex geometries.

We develop a monitor system to control a parallel-type superconducting (SC) level sensor and to indicate the level of liquid hydrogen in a container. The parallel-type level sensor is composed of an MgB2 wire and non-SC wire, which are vertically located in parallel and electrically connected in series. We assemble the monitor unit using a power supply, central processing unit (CPU), analog-to-digital (AD)/digital-to-analog (DA) converter, touch panel, voltage dividers and isolators. The terminal voltages of the MgB2 wire and non-SC wire with a constant current produced by the power supply are stored in the memory of CPU through the isolators, voltage dividers and AD converter. The liquid level is calculated in the CPU according to a pre-written program code. The obtained result is displayed on the touch panel and also output externally via the DA converter and isolator. Furthermore, the normal operation of the developed monitor system is validated using dummy voltages from an oscillator.

This research investigates the stress distribution of the three types of implanted femurs using the finite element method analysis. The comparisons of the stress distribution between the implanted femursand the healthy femur were performed and the characteristics in the stress shielding of each casewere clarified. Since the load is transferred on the contact surface between the implant and the inner surface of the femur in the case of the total hip arthroplasty, the stress in the intertrochanteric zone (Gruen zone 7) become very small, and the phenomenon of the stress shielding is confirmed obviously. The stress distributions of the femurs afterthe resurfacing hiparthroplasty and the thrust plate prosthesis are about the same with that of the healthy femur, so, the possibility of the stress shielding is considered lower compared with the femur after the total hip arthroplasty. However, considering the stress concentration thatwill increase the risk of femoral fracture caused by the screws for the fixation of the implant in the thrust plate prosthesis, the resurfacing hiparthroplastymay beconcluded as the best method among these three types of implants to avoid stress shielding.

Pulse-mode operation was realized in spin-polarized transmission electron microscopy (SP-TEM) using a laser-driven electron gun with a GaAs-GaAsP strained-layer-superlattice photocathode. TEM images were acquired with a pulsed electron beam with a 5-μs pulse duration. Phase locking of wobbling TEM images was demonstrated using a pulsed beam with a 1-kHz repetition frequency, which matched the image wobbling frequency. It was found that in composite images formed by superimposing 2 × 10(4) separate single-pulse exposures, the amount of image blurring due to wobbling was a linear function of the pulse duration. These results suggest the possibility of pump-probe measurements in SP-TEM using the pulsed electron beam as a probe, allowing nanometer-scale time-resolved spin mapping.

A metal nanomesh electrode has the potential to realize a low-resistive, rare-metal-free transparent electrode. However, the electrical resistivity has not been measured as yet. We fabricated metal nanomesh electrodes and their electrical resistivity was obtained by measuring the current–voltage characteristics. Comparing with the calculated values of the microapertures, the electrical resistivity of the nanomesh electrode tended to deviate from the calculated values with reduction of the aperture interval and increase of the aperture density. This deviation was considered to be the effect of narrowing the conduction path of electrons and increasing the electron scattering probability by the nanoapertures. The order of the resistivity of the nanomesh electrodes was 10−6–10−5 Ω cm, one order of magnitude lower than that of conventional transparent oxides such as indium tin oxide.

The purpose of this research is to evaluate the effects of surface roughness in normalized steel and the effects of abnormal surface layer in carburized steel on the fatigue strength that is considered as the limit of no crack initiation. Normalized and Carburized test pieces with crowned round notches were used in the fatigue tests, the normalized test pieces have different surface roughnesses and the carburized test pieces have different surface microstructures on the notch surface. The changes in fatigue strength due to the differences in the notch surface roughness and surface microstructure were investigated. As the conclusions, fatigue strength will be certainly increased by decreasing the surface maximum height, and removing the abnormal surface layer formed during carburized treatment leads to a marked increase in fatigue strength.

The strains in GaAs/GaAsP superlattices used in spin-polarized photocathodes grown on GaAs and GaP (001) substrates were determined by X-ray diffraction. The thicknesses of the GaAs wells and GaAsP barrier layers were also determined. The band structures of the superlattices were calculated on the basis of these experimentally determined strains and layer thicknesses. The thicknesses and band structures were in good agreement with those observed by transmission electron microscopy and photoluminescence, respectively. The strains induced in the GaAs well layers were approximately linearly dependent upon the phosphorous fraction in the GaAsP layer, and the splitting between the heavy hole band and the light hole band of the superlattices grown on GaP substrates was larger than that of superlattices grown on GaAs substrates. In photocathodes grown on GaP substrates, low polarizations were observed, not due to a lack of band splitting, but to depolarization scattering caused by crystal defects, which were different from that induced in superlattices grown on GaAs substrates. [DOI: 10.1380/ejssnt.2010.125]

The crystalline structure of GaAsP layers grown on GaAs and GaP (001) substrates, used for spin polarized photocathodes, has been investigated by X-ray diffraction. The layers on the GaAs substrate possess a mosaic structure observable by X-ray topography and consist of many large blocks. The mosaicity anisotropic and the distribution of the mosaic is restricted within the (110) plane, and the blocks zigzag around the [110] direction. The layer grown on the GaP substrate was uniform and no mosaic was observed in the topographs. The results indicate that different mechanisms of strain release occur in GaAsP layers for tensile and compressive strains.

To get high performance, downsizing and weight saving of the power transmission systems, the improvement of machine elements has been required. In this study, case-carburized gear materials for a high load-carrying capacity were developed. Low-alloyed steels with 1%Cr-0.2%Mo, 1%Cr-0.2%Mo-1%Si and 1%Cr-0.2%Mo-2%Ni (Cr-Mo steel, Cr-Mo-Si steel and Cr-Mo-Ni steel) were melted in a hypoxia vacuum. Test rollers were made of the developed steels, and they were carburized (Type A and Type B), hardened and tempered. Heating retention tests were carried out to investigate the softening behavior of hardness at high heating temperatures in the case of the developed steels. Roller tests were conducted under the rolling-sliding contact and high-load conditions to study the surface fatigue of the developed steels. From the obtained test results, it was found that the softening behavior of surface hardness at high temperatures in the cases of Cr-Mo-Si steel (Type A) and Cr-Mo-Ni steel (Type B) is lower than that in the cases of Cr-Mo steel (Type A) and Cr-Mo steel (Type B). In the cases of Cr-Mo-Si steel (A) and Cr-Mo-Ni steel (B), micro- and small-pitting area ratios are smaller and large-pitting life is longer than those in the cases of Cr-Mo steel(A) and Cr-Mo steel(B) under the same carburizing treatment method and high-load conditions. Furthermore, the relationship between the softening behavior of surface hardness on the heating pattern and the surface fatigue on the rolling-sliding contact of the developed alloy steels was clarified.

We successfully developed a transmission-type photocathode, and a high polarization (90%) with a super-high brightness (1.3×10 7 A cm −2 sr −1 ) of electron beam was achieved. In this research, we found that the polarization of electrons from the GaAs–GaAsP superlattice on the GaP substrate was lower than that from the same superlattice on the GaAs substrate, and that a GaAs inter-layer deposition on the GaP substrate recovered that from the GaAs–GaAsP superlattice. Mechanism of the polarization degradation was investigated from a viewpoint of strain-relaxation process in the GaAsP buffer layer that was adopted between the superlattice and the substrates. The buffer layer with in-plain tensile strain was relaxed by inducing cracks, but that with in-plain compressive strain was relaxed by inducing dislocations. The dislocations may disturb the spin-polarization of electrons more effectively than the cracks do.

This research presents a practicable method to investigate the characteristics of the microcrack growth in brittle materials. The crack length measurement method using an ion-sputtered film was applied to measure the length of the microcrack growing in soda-lime glass and alumina ceramics in four-point bending tests. Since the measurement system can measure the crack length at a sampling frequency of 125 kHz, the crack length was measured almost continually, and the relation-ship between the crack growth rate and the stress intensity factor was obtained in the whole regions from low crack growth rate to brittle fracture. If the relationship between crack growth rate and stress intensity factor follows the Paris law, the n values of the soda-lime glass and alumina ceramics are obtained in the region I and region II that are very important to the fatigue life estimation for these materials.

To develop case-carburized gears with high loading capacity, the surface durability of a developed Cr-Mo-Si steel (with 1 mass% Si added in the chemical composition) was studied. Initially, the fatigue tests of case-carburized Cr-Mo-Si steel and Cr-Mo steel melted in a hypoxia vacuum were carried out using a two-roller contact fatigue tester. Next, the changes in the surface failure, surface roughness and sectional hardness distribution of the test rollers were examined using a scanning electron microscope, a surface roughness measuring instrument and a penetrometer, respectively. In the case of Cr-Mo-Si steel test rollers under rolling-sliding contact, the following results are obtained in comparison with Cr-Mo steel test rollers: micro pitting area ratio is lower under a medium load, the pits do not occur under a heavy load, and the value of surface variation is lower. Therefore, it is clear that the developed Cr-Mo-Si steel can be applied to case-carburized gear materials under a heavy load.

This research developed a simple and high precision method to measure the length of a fatigue crack using an extremely thin ion sputtered metal film based on that the electric resistance of the film changes with the increase of the crack. The electric resistance of a cracked film was calculated by the electrothermal FEM analysis. Based on the FEM analysis results, the relationship between the electric resistance and crack length is expressed by a practical formula. Fatigue crack length measurements for acrylic and metal test specimens were performed on the three-points fatigue test equipment. Based on the good agreements between the measurement results by the ion sputtered film and that by the optical microscope, it is clarified that the crack length measurement method with an ion sputtered metal film has a very high precision. In addition that the measurement system is very simple, this method can be said to have a high practical usability.

A new nano-fabrication technique using a self-assembled nano-particle monolayer as an etch mask is presented. We developed the embedded particle monolayer (EPM) method that forms a homogeneous particle monolayer over a large area with a high throughput. By transferring the pattern of the particle monolayer onto the substrate, nano-structures were fabricated over the entire surface on the substrate. The moth-eye antireflection surface, which has a nano-cone array, was fabricated on the fused silica substrate using this nano-fabrication technique. The reflectivity of the patterned substrate was reduced more than 40% compared to the flat substrate in the visible light wavelength region.

Crack length measurement and crack initiation detection in a fatigue process are extremely important techniques in the researches for the investigation of crack growth characteristics and the fatigue strength evaluation of machine elements. The purpose of this research is to show a simple and high precision method to measure the length of a crack as well as a micro crack using an extremely thin ion sputtered film. A grid pattern ion sputtered film was proposed to measure the crack length for a bending test specimen. Based on the comparisons between the measurement results and that by a microscope, it was clarified that the grid pattern ion sputtered film has a very high measurement precision. This method should be invaluable and practicable for the crack length measurement of insulating materials such as ceramics. Meanwhile, a rectangle ion sputtered film was used on a metal bending specimen, the possibility to apply the film in the crack length measurement of a metal machine element was confirmed by the change of the electric resistance of the film with crack growth.

Molybdenum, in many cases, is chosen as a substrate of cesium telluride thin film photocathode for a radio frequency electron gun (RF-Gun), which shows high performance. Therefore, in this study, we chose molybdenum as a substrate for cesium telluride thin film. The dependence of quantum efficiency on the kinds of metals for substrate has not been measured entirely and not been well understood. In this report, showing the result of measurements, we report on the dependence of the quantum efficiency on substrate for the cesium telluride thin film photocathode. In addition to molybdenum, we use tungsten and copper for substrate. We also report on the dependence of the quantum efficiency on the average surface roughness of substrate for cesium telluride thin film when using tungsten and copper as well as molybdenum for the substrate. The rate in the measurement of the dependence of quantum efficiency on the kinds of metals for substrate to incident light wavelength 250 nm was 20% on molybdenum, on tungsten 8.6% and on copper 4.8%, when the tellurium thickness is 10 nm. In the measurement of the dependence of quantum efficiency on the average surface roughness Ra of the substrates, the rate a sample on a substrate of which Ra is less than 0.1 μm shows was 20%, on a substrate of which Ra is 50 μm was 15%. Thus, the quantum efficiency of cesium telluride thin film photocathode depends on the kind of metals for the substrate, and also on the roughness of the surface of substrates.

Dispersion of metal particles into polymer materials by the plasticizing effect of supercritical fluids was investigated. Using supercritical carbon dioxide, a metal precursor of Ag (AgFOD) was infused into polymer materials such as poly (methylmethacrylate) (PMMA), polystyrene (PS) and poly (ethylene terephthalate) (PET). The heat treatment reduced the infused precursor into Ag metal, leading to the formation of a fine particle dispersion layer near the surface of the polymer sample. To investigate the relationship between the infused amount of Ag and sorption of carbon dioxide into these samples, AgFOD was infused in each sample in the temperature range of 35 to 70°C, pressure range of 10 to 30MPa, and infusion time of 0.5 to 4h. It was found that the amount of metal particles infused into polymers via supercritical carbon dioxide had a strong relationship with the sorption of carbon dioxide. Moreover, addition of small amount of acetone as an entrainer to supercritical carbon dioxide could increase the infusion of Ag particles into the inner layer of the samples. It should be noted that metal particle infusion into polymers using supercritical CO2 might be controlled by manipulating temperature, pressure, infusion time, and amount of entrainer.

An unusual penta-peptide nanotube was synthesized by a solid-phase method using Fmoc chemistry. This nanotube consists of the natural homo-L-amino acid sequence (cyclo[-(L-Gln)5]), which is different from the already-known dl-peptide nanotubes having an even number of residues. We also observed the morphology by atomic force microscope (AFM) and found meandering tubular structures on the substrate. This result is consistent with our ab initio energy calculations, which show that the penta-peptide nanorings stabilize by breaking the C5 symmetry and stack themselves to form a meandering nanotube through the inter-ring hydrogen bonds.

Since the manufacturing methods of gears were improved, the failure of case-carburized gears has changed to the surface fatigue of the tooth flank from the fatigue breakage at the tooth fillet. The objective of this work is to develop the case-carburized gears for the high load-carrying capacity. Then, the factors of influence on the surface durability of the hypoxia vacuum melting case-carburized alloy steel were investigated by using a backup-roller-type two-roller fatigue test rig. As a result of examining the rolling-sliding contact surface of the test roller under the high load condition. the following were clarified :(1)The surface failure with various features occurs. (2) The surface temperature rises above tempering temperature of heat treatment process. (3) The surface asperities become very smooth. (4) The surface profiles are greatly deformed. (5) The surface hardness decreases. In addition, (6) The outside diameter of the test roller increases.

This research is to develop a new method to enhance the bending load capacity of gear tooth using asymmetric tooth profiles. For many power transmission devices operate in one direction, only one side of the tooth surfaces (the front of tooth) is in mesh. So the tooth is not necessary to be a symmetric form. The dimensions of the front and back profiles of the tooth could be designed individually. The back profile of the tooth that does not contact in running could be decided to decrease the maximum tensile stress at the root of tooth. Different standard pressure angles are used in the front and back profiles of an asymmetric tooth. Tooth root stress and bending stiffness of the asymmetrical tooth for several combinations of standard pressure angles were calculated by the use of finite element method. Based on the results of calculations, it is clarified that a larger standard pressure angle in the back profile of tooth makes the tooth root stress decrease remarkably and bending stiffness of tooth increase, but dose not change the load sharing ratio.

In recent years, power transmission gears for vehicles run at higher speeds and loads and are accompanied by very high surface temperatures. Under such a high surface temperature condition, the surface strength cannot be evaluated correctly only by the use of Hertzian stress. This research attempts to introduce a new surface strength evaluation method considering the surface temperature rise. First, the surface temperatures of rollers under different rolling and sliding conditions are measured using a thermocouple. The effects of load P, mean tangential velocity Vm and sliding velocity Vs on surface temperature are investigated and analyzed. Then, an experimental equation is presented which shows the linear relationship between surface temperature and GRP0.86Vs1.31Vm−0.83 value. Based on the comparisons between calculated and measured tooth surface temperatures, this equation is confirmed applicable to gear tooth surface temperature evaluation as well. A surface temperature index is proposed for surface strength evaluation. The relationship between the surface temperature index and the number of load cycles of the rollers is investigated. The results indicate the possibility to evaluate the surface strength based on the surface temperature.

Surface temperature is considered to be an integrated index that is dependent on not only the load and the dimensions at the contact point but also the sliding velocity, rolling velocity, surface roughness, and lubrication conditions. Therefore, the surface durability of rollers and gears can be evaluated more exactly and simply by the use of surface temperature rather than Hertzian stress. In this research, surface temperatures of rollers under different rolling and sliding conditions are measured using a thermocouple. The effects of load P, mean velocity Vm and sliding velocity Vs on surface temperature are clarified. An experimental formula, which expresses the linear relationship between surface temperature and the P0.86Vs1.31Vm-0.83 value, is used to determine surface temperature. By comparing calculated and measured temperature on the tooth surface of a gear, this formula is confirmed to be applicable for gear tooth surface temperature calculation.

We have developed a new thin film pyroelectric IR sensor with micro cavity structure, which consists of infra-red absorption layer using carbon-modified resin membrane on the infra-red detecting azea. And we were able to find the best sensor design rule or thermal conductance: G for micro cavity size, and Pt electrode width and thickness. The developing sensor has realized a high-performance of sensing characteristic that responsivity: Rv, and detectivity: D* were 2400V/W, and 6.6×107cm√Hz/W at 20Hz, respectively.In the future, the developing sensor is expected the wide applications for high accurate human detection and non-contact temperature detection.

This study is to develop a new method to enhance the bending capacity of gear tooth by the use of asymmetric tooth profile. Considering that many power transmission devices operate in one direction, where only one tooth surface (the front of tooth) is practically used. Therefore, it is not necessary to make tooth profile symmetrically, the back profile of tooth, which does not mesh in operation, can be designed to decrease tooth root stress. Different standard pressure angles are used to the front and back tooth profiles. Finite element method was used to calculate the tooth root stress and the bending stiffness of the asymmetrical tooth in several standard pressure angle combinations. Based on the results of calculations, it is clarified that tooth root stress decreases and bending stiffness increases remarkably by the use of a large standard pressure angle in the back profile of tooth, but no clear change in load sharing ratio appears during meshing period.

Luminescence polarization was measured on strained GaAs samples fabricated as a spin polarized photocathode. Photoluminescence (PL) spectrum of the strained GaAs layer showed large polarization at the band edge in comparison with that of the GaAs substrate. The increase of the band gap and the splitting of the valence band were observed in luminescence polarization spectra of photoluminescence excitation (PLE) although they are not clear in the PLE intensity spectra. Spin relaxation time and lifetime of electrons in the strained GaAs layer were measured by using a mode-locked Ti: sapphire laser and a streak camera. The spin relaxation time and the electron lifetime were 105 ps and 45 ps at room temperature, respectively. From the temperature dependence of spin relaxation time, the spin relaxation of our strained GaAs photocathode was found to be mainly caused by electron scattering by holes with simultaneous exchange interaction.

A thin metal film with nano-apertures, called “nano-mesh electrode,” generates near-field lights near the electrode. We investigated carrier excitations in semiconductors by the near-field light. Finite-difference time-domain (FDTD) method revealed that when the infrared light irradiates the Au nano-mesh electrode on Ge, near-field lights are generated and absorbed in the surface region of the Ge. In order to measure the photocurrent involved by near-filed lights, we fabricated a Schottky cell and applied a Au nano-mesh electrode on the n-type Ge. The efficiency of the Schottky cell with the Au nano-mesh electrode improved in infrared region compared to plain the Au-film Schottky cell. The agreement between theoretical simulations and experiments indicates that near-field lights enhance the carrier excitation in the semiconductor.

A crack length measurement method is very important in the investigation of the fatigue crack growth characteristics of a material and in the evaluation of the fatigue strength of a machine element. Many crack length measurement methods have been proposed. Brown et al. (1966) and Nishitani et al. (1985) measured crack length through the changes in the displacement and compliance of the test piece. Ashida et al. (1996) and Nakai et al. (1989) investigated the changes in electrical properties around a crack during its growth. Lee et al. (1985) and JSME (1986) recommended estimating the crack length from the opening or closing displacement of a crack. In addition, crack length can also be measured by using an optical microscope, an optical grid technology (Bucci et al., 1972, Maustz et al., 1976, James et al., 1981), an acoustic emission method (Masuyama et al., 1994) and an ultrasonic method (Shimada et al., 1983). However, the methods proposed up to now require specific measuring apparatuses and complex calculation processes for crack length, and are applicable to long cracks several millimeters in length, not to small cracks shorter than 1mm in length or cracks with a high growth rate. In addition to the above-mentioned methods, a thin metal film, such as a crack gauge (e.g., KV-25B manufactured by Kyowa Co.), has been used for crack length measurement and fatigue crack initiation detection in some machine elements, such as gears, where cracks are up to several millimeters in length (Deng et al., 1991). Since this metal film is formed on a plastic base film with a thickness of about several tens of micrometers, there is a relatively large error between the actual and measured crack lengths. Increasing the measurement accuracy of the film can only be achieved by decreasing the thicknesses of the metal and plastic base films. An ion-sputtering device, widely used in a scanning electron microscopy system, is a coating device used to form a nanoscale-thickness metal film on a surface. In this chapter, we introduce methods for crack length measurement using an ion-sputtered film, which are considered as ideal and practical methods applicable to micro-cracks or small cracks in glass

The effects of the combination of tooth flank hardness and tooth surface roughness on the surface durability of medium-hardness gears are investigated using a disk machine. The meaning of the difference in hardness between a pair of gears is discussed. In the case where the surface roughnesses differ between contact surfaces with the same initial hardness, severe wear and pitting occur on the smooth surface because the asperities on the rough surface are highly hardeneddue to the repetition of contact. Therefore, it is necessary that the initial hardness of the smooth surface is higher than that of the rough surface in a combination of different sufface roughnesses. This means that the hardness combination between a pair of gears should be determined in consideration of the final condition of the finished tooth surfaces of the gears., JSME international journal. Ser. 3, Vibration, control engineering, engineering for industry. 1992, 35(4), p.633-640

The light extraction efficiency of top-emitting organic light-emitting diodes (OLEDs) was improved by insertion of a two-dimensional (2D) diffraction layer. The 2D diffraction layer was fabricated by our original nanofabrication technique, the embedded particle monolayer method, which could form a self-assembled particle monolayer. As a result, the electroluminescence intensity of the device with the 2D diffraction layer was improved by 1.67 times (in total luminous flux) and 2.07 times (in peak wavelength). High luminance top-emitting OLEDs were fabricated using the potentially low-cost self-assembling technique.

A transmission photocathode was fabricated based on GaAs‐GaAsP strained superlattice layers on a GaP substrate and a 20 kV‐gun was built to generate the polarized electron beams with the diameter of a few micro‐meter. As the results, the reduced brightness of 1.3×107 A/cm2/sr and the polarization of 90% were achieved.

The development of fatigue in a machine element can be divided into the fatigue crack initiation stage and the crack growth stage. The effects of the surface conditions, such as roughness and surface qualities, on the fatigue strength are considered to be restricted to the fatigue crack initiation stage. Thus, these effects can be evaluated exactly by the investigation on the fatigue crack initiation life. In this research a practical method is presented for detecting fatigue crack initiation during fatigue tests using an ion-sputtered film. Ion-sputtered films were formed on acrylic and steel test pieces having a specially designed round notch. Three-point bending fatigue tests were performed and the instants of fatigue crack initiation on the notched surface of both acrylic and steel test pieces during the tests were identified clearly; thus the fatigue crack initiation life can also be determined experimentally using the presented method. In addition, since the system used to measure the electric resistance of the film, which indicates the crack initiation, is extremely simple, that is, it consists of a variable resistor, a DC power source, and a data recorder, this method is considered very practical for monitoring crack initiation.

The purpose of this research is to show a simple and high precision method to measure the length of a crack as well as a micro crack using an extremely thin ion sputtered film. An ion sputtered grid film was proposed to measure the crack length for a bending test specimen. Based on the comparisons between the measurement results and that by an optical microscope, the ion sputtered gird film has a very high measurement precision. This method is considered convenient and practicable for the crack length measurement of insulating materials such as ceramics. Meanwhile, an one-piece ion sputtered film was used on a metal bending specimen, the possibility to apply the ion sputtered film in the crack length measurement of a metal machine element was confirmed by the change of the electric resistance of the film with crack growth.

A 200-keV gun has been developed for generation of bunch charge of 2 3.2 nC, bunch length of 5 2 ns multi-bunch polarized electron beam that is required for International Linear Collider. In this paper, the beam simulations using General Particle Tracer (GPT) code for such space-charge dominated regions, and a fabrication method of electrode for higher electric field (2 3 MV/m) at the photocathode surface by using a titanium anode and a molybdenum cathode are described.