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Filtering based on blacklists is a major countermeasure against malicious websites. However, blacklists must be updated because malicious URLs tend to be short-lived, and they can be partially mutated to avoid blacklisting. Due to these characteristics, it can be assumed that unknown malicious URLs exist in the neighborhood of known malicious URLs created by the same adversary. The authors propose an effective blacklist URL generation method that discovers URLs in the neighborhood of a malicious URL by using a search engine. This article is part of a special issue on security.

Nitrogen-doped ZnO layers grown on C-sapphire at 400°C by plasma-assisted epitaxy in oxygen and nitrogen mixed gas plasma were studied by photoluminescence measurements comparing to undoped ZnO layers grown in pure oxygen plasma. A new luminescence was observed around 3.27 eV with phonon-replicas at 20 K and we concluded that they are due to shallow donor–acceptor pair emission by excitation power dependence of the peak energy. The donor and acceptor levels were assigned as shallow levels located at 40 meV below conduction bandedge and 135 meV above valence bandedge, respectively. It was also indicated that Zn-rich condition should be given for efficient nitrogen-acceptor doping.

The K L → π 0 η η decay is one of the most attractive phenomena for the study of the CP violation. The branching ratio can be calculated with a small theoretical ambiguity, which will provide a clean determination of a basic parameter of the present particle physics. It will also play an important role for the search of the new physics as well as for the fundamental unerstanding of the CP-violation. We will start a kind of pilot experiment using a present 12-GeV proton synchrotron (PS) at KEK from early 2004, which is the first dedicated experiment searching for the K L → π 0 η η decay.

Zinc oxide thin films were epitaxially grown at 400°C on C-sapphire substrates by plasma-assisted epitaxy in which elemental zinc is supplied through oxygen plasma excited by radio frequency power at 13.56 MHz. The intensity of bound exciton emission was strongly dependent on the growth rate and was drastically increased with decreasing the growth rate. Surface morphology was also roughened with increasing the growth rate. An initial layer grown with low growth rate around 1.7 nm/min at 400°C is quite effective in preventing the unfavorable growth and then to improve the successive growth of a thick ZnO layer with high growth rate. Photoluminescence property and surface morphology were also very much improved with suppressing poly-crystallization in this way in the thick layer grown at high growth rate around 17 nm/min on the initial layer thicker than 300 nm.

Experiments of gate leakage current in a double-channel n-AlGaAs/GaAs FET with SiN/sub x/ film passivation indicated that the gate leakage current and its stability depend critically on the stoichiometry of the surface. The content of NH/sub 4/ OH in the etching solution prior to the SiN/sub x/ film deposition and the NH/sub 3//SiH/sub 4/ gas content ratio, particularly at the initial stage of plasma-CVD SiN, deposition, should be selected to minimize the surface state density of possible antisite defects. Extremely low gate leakage currents of 50 nA/mm have been obtained with an improved process, which is useful to realize low-distortion FETs.

Plasma-assisted epitaxial growth of ZnO layers were achieved on C- and R-plane sapphire substrates in oxygen plasma excited by radio frequency power at 13.56 MHz with evaporation of pure elemental Zn. The ZnO layers were grown at 300–400°C with high growth rate around 1.7 μm/h. Surface cleaning of sapphire substrates using Ar-plasma was crucial for good quality ZnO growth. Photoluminescence spectra at 10 K were dominated by band-edge emission due to bound excitons without deep level emission in green-light region. The intensity of band-edge emission was strongly dependent on applied radio frequency power to excite Ar- and O 2 -plasma for sapphire surface cleaning and ZnO growth, respectively, and was about 50 times larger on the layer grown in oxygen plasma than that grown in non-excited oxygen gas. The ZnO layer grown on R-plane sapphire was epitaxially grown above 300°C in oxygen plasma, however, on C-plane sapphire the ZnO layer was easily polycrystallized for thick films even at 400°C. Growth mode and surface morphology of ZnO layers were drastically changed with the substrate orientation.

The conventional charged device model (CDM) test methods for large-scale integrated (LSI) circuits have not prescribed the device capacitance; furthermore, the CDM sensitivity has been represented by the withstand voltage. Also, a method for measuring the voltage of small objects such as LSI circuits has not been established. For these reasons, the failure voltages obtained with every kind of tester have varied, and it could not be judged whether the charged LSI circuit would fail or not in CDM events. To solve these problems, we defined the failure factor as the excess mobile charge which could be measured by the newly developed coulomb meter. In addition, we developed a new CDM tester with the coulomb meter and obtained the excess mobile charge and the device capacitance. The CDM tester showed that several logic MOS LSI circuits failed at their inherent constant charge. However, when the charge in low capacities was measured by the coulomb meter, the internal circuit showed a step transient response. This problem could be alleviated considerably by replacing the metal probe with a ceramic one. By using this coulomb meter, we investigated the basic characteristics of the device capacitance. Consequently, the device capacitance versus the distance between the LSI circuit and the ground plane and the relationship between each pin's capacitance and the applied voltage became clear. In conclusion, the basic failure factors in the CDM could be made clear; then it could be judged by the coulomb meter whether the charged LSI circuits would fail or not in CDM events.

In the charged device model (CDM) test, the relationship between the failure voltage, the capacitance of LSIs and the failure charge was made clear by a new CDM tester. The mobile charge measurement apparatus was fabricated in the tester, and the capacity and the charge could be measured simultaneously in the CDM test. The CDM sensitivity of the logic MOS LSIs was represented as an inherent quantity of charge for each LSI. Furthermore, using the experimental results, a basic protection circuit to withstand the high quantity of charge in the CDM test was described. The practical use of the data gives us methods to prevent electrostatic discharge (ESD) trouble for quarter-micron LSIs.

In a recent human body model (HBM) test for non-wired pins of large-scale integrated circuits (LSIs), the LSIs have failed at lower voltage in comparison with the test for wired pins. The failure voltage agreed with the sparking voltage between the non-wired and the adjacent pins. A transient response simulation with a sparking gap showed that the low failure voltage was caused by the low parasitic capacitance on the nodes of non-wired pins. Although these data indicate the electrostatic discharge (ESD) sensitivity of LSIs, the conventional HBM tester could not control the low capacitance. We conclude that the charged device model (CDM) test with variable capacitance or the machine model (MM) test with low capacitance should be carried out besides the HBM test. Application of these data gives us a method to protect quarter-micron LSIs from ESD troubles.

The nanosecond transient response between a pin of a large-scale integrated circuit (LSI) held by a charged person and the ground plane showed a very sharp impulse and high peak current. This response could not be represented using the human body model (HBM), and it was caused by the parasitic capacity between an inner conductor in the LSI and the ground plane. However, the conventional HBM tester could not control the low capacitance. Consequently, the machine model (MM) using a low capacitance or the charged device model (CDM) with low device capacitance should be used. Moreover, the capacitanc of charged objects including LSIs can be determined by a Coulomb meter. Practical use of these data will give us the methods to prevent electrostatic discharge troubles for quarter-micron LSIs.

Hydrogen plasma surface cleaning of Si at 600°C and the surface stabilization with arsenic-vapor at lower temperature were employed for heteroepitaxial growth of InSb on Si with large lattice mismatch of 19%. The passivated Si surface showed 1×1 structure and was stable even in air. InSb was successively grown in hydrogen plasma on the Si surface at 450°C with controlled Sb/In supply ratio. Initial buffer layer grown at 210°C with four average monolayers was found to be optimum with suppressed three-dimensional nucleation and strain with the longitudinal lattice mismatch around 12–13%. Hall mobility of 2 μm thick heteroepitaxial InSb film on Si successively grown by the total plasma process was 1.2×10 4 cm 2 /Vs at room temperature, compared to the lower value of 3×10 3 cm 2 /Vs for the polycrystalline film.

Optical emission spectroscopy (OES) has been applied to detect the excited species in plasma‐assisted epitaxial growth of (In, Ga) (As, Sb) compound semiconductors. The plasma cracking of evaporated group V molecules into atoms, which is an important advantage in plasma‐assisted epitaxy (PAE), and the excitation of all the source elements were confirmed both in hydrogen plasma and argon plasma. The effect of V/III supply ratio on the growth behaviors observed in PAE can be well explained by the change of group V atomic densities caused by this plasma cracking. OES is also useful for detecting and monitoring residual impurities such as moisture in the growth atmosphere.

Recently, demand for mobile computing environments has been increasing greatly, and easy access from remote sites has become desirable. To meet this requirement, NTT has proposed a "Logical Office" service, which enables terminal plug & play, multiprotocol, and ubiquitous communication. NTT has already done some Logical Office service experiments, in LAN and Internet environments, which focused on the service offered in the early stages. The paper investigates our proposed Logical Office service over international ATM networks, which focuses on the future stage international ATM test beds between Japan and the US, provided by AT&T, KDD, and NTT, are used for this experiment. It was verified that the Logical Office service worked correctly in the international ATM environments, and that it provided sufficiently practical performance even there.

Dynamic cardiomyoplasty (DCMP) has been performed in more than seven hundreds cases world wide. However, despite symptomatic improvement in the majority of patients surviving the procedure, objective hemodynamic effects have not been consistently demonstrated. Previous studies reported that left ventricular function deteriorated and returned to preoperative level in the chronic phase. We previously reported that atrophy of the latissimus dorsi muscular flap (LDMF) was responsible for the effect of DCMP on improvement of cardiac function in the chronic phase. Ischemia of the muscle flap was proved to induce peripheral muscular atrophy of the flap, and thus preservation of the blood flow is important in preventing muscular atrophy. In the present study, we applied omental flap to LDMF, and postulated that the omentum would improve vascularity and perfusion of latissimus dorsi and prevent peripheral muscle atrophy. In dogs, the right and left latissimus dorsi muscles were dissected free from all attachment except for its thoracodorsal pedicles, and omental flap was wrapped around peripheral part of the left LDMF. Tissue blood flow, maximal muscle isotonic strength, morphologic features, and tissue vascular endothelial growth factor (VEGF) were examined in left LDMF with omental flap (OM group) and in the right LDMF served as the control (Control group). In the distal part of the LDMF, tissue blood flow of OM was significantly preserved than Control (86.4 +/- 6.5% in OM and 33.6 +/- 3.4% in Control, p0.05). Maximal isotonic tension was significantly higher in OM as compared to Control. Microscopic findings of H and E stained specimen from distal part of LDMF showed that muscle fibers were preserved in OM. And in the distal part, VEGF expression of OM was 49.6 +/- 7.9 pg/100 micrograms protein and significantly higher than that of Control. Our results indicated that induced endogenous VEGF expression in the LDMF by the omental flap preserved blood perfusion and muscular strength of the LDMF, and suggested that dynamic cardiomyoplasty might not lose its long-term direct cardiac assistance when an omental flap applied for the latissimus dorsi muscle flap.

A new DLTS analysis was proposed to derive the distribution of surface states in MIS structures. The interface of ZnSe/GaAs heterostructures was characterized with reduced surface state density when ZnSe layers were grown after the native oxide was removed and the surface was successively treated with N- or Se-containing hydrogen plasma.

GaSb Schottky barrier photodiodes are shown to have quantum efficiency higher than 35 percent over a broad band of infra-red light wavelength shorter than 1.6 µm. Theoretical calculations of current voltage characteristics including tunneling current are compared with the experiment and it is suggested that surface leakage current, tunneling current, and avalanche breakdown, respectively, dominate the reverse characteristics with increasing voltage. Epitaxial growth of an n-type layer with carrier density 1015cm-3and suitable surface passivation are key technologies for the application of this material to infra-red detectors.

ZnSe thin films have been epitaxially grown on GaAs substrates by plasma-assisted epitaxy in a hydrogen plasma at a substrate temperature in the range of 170–440°C. It was confirmed that the plasma is effective in increasing the growth rate, decreasing the temperature for epitaxial growth by about 100°C with the growth rate around 1.5 μm h−1 and also in improving the crystallographic and photoluminescent properties. Photoluminescence measurement showed clear and improved exciton emission spectra according to the optimization of the supply ratio ZnSe and the substrate temperature.

The measurements of low-frequency dielectric dispersion properties of evaporated silicon oxide films under high DC biasing voltage are reported. The results show that the total conductance consists of frequency-dependent and independent parts. The latter part agrees with the differential conductance derived from the DC I-V characteristics and it increases with increasing DC biasing voltage. The former part, which contributes to the relaxation phenomena, decreases with increasing DC biasing voltage. The results of the DC-bias-dependent relaxation phenomena are interpreted by using the two-site hopping model, which is consistent with the results of an electrically excited thermally stimulated current (ETSC) and an absorption current.

Plasma-assisted epitaxy has been successfully applied to grow device-quality GaAs and GaSb layers on semi-insulating GaAs at relatively low substrate temperatures. Nondoped GaAs layers deposited in argon and hydrogen plasma showed p- and n-type conduction, respectively. The mobility in As-grown nondoped n-layers deposited in hydrogen plasma at a substrate temperature of 550°C is 3200 cm2/V . s. Nondoped GaSb layers deposited in argon and hydrogen plasma both showed p-type conduction. Hole concentration and Hall mobility of an undoped GaSb layer deposited in hydrogen plasma at a substrate temperature of 410°C are about 6 \times 10^{16} cm-3and 750 cm2/V . s, respectively, which are comparable to those obtained by other methods like MBE, MOCVD, etc., in spite of a lower substrate temperature in PAE. As the substrate temperature is decreased, optimum plasma power for the growth of good epitaxial layers shifts to higher value. PAE in hydrogen plasma was found to give much better results than in argon plasma, as indicated by lower carrier concentration, higher Hall mobility, and clear edge emission in photoluminescence.

The conditions for the production of stationary anode Gunn-effect domains have been clarified by both experimental and computational results. The stationary domains have been observed in both sandwich and planar device structures and it is proposed that this effect is due to the balancing of drift and diffusion currents at the doping gradient of the anode contact.

Details of the design and experimental result of a new monolithic planar reflection-insensitive Gunn-effect pulse regenerator arc presented. The device is based on three purely ohmic electrodes and is suitable for pulse rates well above one Gigapulse/sec.

Nitrogen-doped epitaxial ZnSe layers were successfully grown on (100) GaAs in a mixed gas plasma of H 2 + N 2 excited by RF power at 13.56 MHz. The supply rate of Se relative to Zn determines not only the growth rate of ZnSe layers, but also affects the photoluminescent properties of N-doped ZnSe. The optimum supply rate of Se is about 10 times the Zn supply rate for maximum donor-acceptor pair emission intensity.

A unified view of the latge-signal behavior of transit-time-effect diodes under cartier injection in-phase with the cathode field is given by modeling the injection characteristic as an exponential dependence on cathode field. The concept consists of an extension of a unified view of small-signal behavior by introducing another parameter which expresses the nonlinearity of injection in addition to small-signal injection conductance, and by assuming velocity saturation. Phase advance and suppression of injection current due to space-charge effect are influential factors which dominate the large-signal behavior and which impose a limitation on output power. The present treatment gives a way for optimizing the device and circuit as well as for estimation of the ultimate available power for a given carrier-injection characteristic.

To prevent regurgitation esophagitis in esophagogastrostomy after proximal gastrectomy, valvuloplasty plus fundoplasty was carried out in 17 patients with stomach cancer or cancer of the abdominal esophagus. For this purpose, an equilateral triangular flap of 2.5 cm per side was formed at the upper margin of the remaining stomach along the greater curvature. The flap was inverted into the stomach only to serve as a valve. After the esophagogastrostomy was properly performed, fundoplasty was carried out, lifting and suturing the uppermost edge of the stomach to the esophagus along the greater curvature. To prevent pylorospasm as a result of reduced gastric volume, pyloromyotomy was also performed. The results were excellent in those followed for more than 1 year. The technique is simple and effective and, we believe, deserves further clinical evaluation.

Dielectric dispersion properties of evaporated silicon oxide films sandwiched between Al electrodes are reported for the frequency range from 0.1 Hz to 20 kHz and the results are analysed by comparing them with the ETSC (electrically excited thermally stimulated current) and the DC current-voltage characteristics. It is shown that the total conductance measured by the AC bridge method is constructed of DC and AC conductivities, as expressed by the empirical relation sigma ( omega )= sigma dc+ sigma ac( omega ). Only the AC conductivity is related to the dielectric dispersion properties, which are Debye-like. The activation energy and the frequency factor of the relaxation frequency are in good agreement with those deduced from the ETSC results. At a frequency moderately higher than the relaxation frequency, the AC conductivity obeys the empirical relation sigma ac varies as omega 0.66. The frequency range over which the empirical relation holds is about four decades, which is much narrower than the results of Frost and Jonscher (1975).

A first theoretical analysis is given based on a new model of GaAs MESFET's which considers the inherent effects of a free-surface depletion layer between source and gate as well as between gate and drain. Change of surface potential according to the input gate voltage causes variable series resistance and variable gate capacitance to be added to the intrinsic FET. The parasitic effects are now quantitatively estimated and an improved guideline for the design and the fabrication process is given. Detailed calculation of the effects of device parameters for recessed gate structure and some comments on the optimization of n+-layers in self-aligned structure are included. The effects of the interfacial depletion layer between active layer and substrate is also estimated in terms of drain voltage and the ratio of total deep levels density in the substrate to donor density in the active layer.

Static and transient current characteristics in the saturated‐velocity regime under arbitrary dependence of injection on the field were analyzed. The expressions for the transient behavior were derived analytically and were found to be determined uniquely by the ratio of the transit time to the injection‐controlling time constant τc=e/σc where σc is the contact conductance. These are useful for the characterization of devices operating in this regime, especially for the derivation of the contact characteristic.

The spread of the total energy distribution of thermal field-emitted electrons from LaB6 is calculated and compared with that from W. The results show that the energy spread of electrons emitted from LaB6 has a maximum at a certain temperature, and that the spread of those from W is smaller than those from LaB6. This suggests that a low work-function material do not necessarily show a good performance for a temperature field-emitted electron source.

The assumptions required for the transient method of measuring Gunn-diode conductance are shown to be valid if either the diode susceptance or the characteristic admittance of the resonator transmission line are larger than the modulus of the negative conductance of the device.

Nitride-based passivation of GaAs has been intended. Gallium oxy-nitride film was deposited by reactive sputtering with optimum oxygen incorporation into the film for the non-dispersive behavior of capacitance of the insulator film itself. The removal of native oxide from GaAs surface by sputter-etching with nitrogen resulted in the disappearance of anomalous frequency dispersion in the accumulation region of n-GaAs MIS structure, which is observed with native oxide deposited by anodic oxidation in electrolyte or gas plasma, and in the interface state density of the order of 1011cm-2eV-1.

Mass screening for breast cancer which was commenced by Miyagi Cancer Society in 1977 has been carried out on 94953 examinees. The main activities comprise itinerant screening in the communities and group screening at the workplaces. In addition to two types of mass screening, examination was also performed at the detection center. The overall breast cancer detection rate was 0.12% in mass screening. In contrast it was 3.1% at the center. Early breast cancer, however, was more frequently found in mass screening than at the center examination. The cytologic studies of nipple discharge were performed on 14314 subjects as first screening. Positive finding was seen in 5 (0.005%). In high risk group, which also underwent mammography at first screening, the detection rate was higher than that among general examinees. Method for effective procedures for detecting early breast cancer are now under study.

Pathological features of duodenal papillitis relative to cholelithiasis were analyzed in terms of dilatation of the bile duct, intracholedochal pressure, and histopathological pictures of papillitis, and the following conclusions were drawn: The principal causes of bile duct dilatation appeared to be pathological changes in the papilla per se; Papillitis accompanying choledocholithiasis with cholesterol stone were secondary to those gallstones evacuated from the gallbladder; Calcium bilirubinate stones seemed to be formed primarily as the result of papillitis. In some cases, ascariasis in their past history was thought responsible for the papillitis; and 4. It is suggested that as the papillitis advances, papillary incompetence will emerge.

Bias sputtering is an effective method for improvement of step coverage. However, the electromigration lifetime of bias-sputtered Al films is inferior to unbiased film. The lifetime of Al-Cu(2-wt.%)/Ti layered films is improved when Al-Cu layer is deposited at high temperature (500 degrees C) and with substrate bias (-600 V). Here, the influence of the substrate temperature and bias lifetimes is studied and the effect of the impinged Ar atoms on the Al-Cu film lifetimes is discussed. >

GaSb, InSb and InAs epitaxial layers with mirror surface were grown on GaSb, GaAs, InP, Si and sapphire substrates at relatively low temperatures by plasma-assisted epitaxy (PAE) in hydrogen plasma. Carrier concentrations and Hall mobilities of undoped PAE layers at room temperature are p=6×O16 cm−3; μp=750cm2/Vs, n=1×1016cm−3; μn=39,000cm2/Vs and n=7×1017 cm−3; μn=21,000cm2/Vs for GaSb on GaAs, InSb on GaAs and InAs on InP, respectively. As the first application of PAE layers to optoelectronic devices, p-GaSb/n-GaAs heterojunction photodiodes have been demonstrated to result in remarkable reduction of dark current with photoresponse in the wavelength region between 0.85 and 1.7μm for the light incident from GaAs.

A modification of cholangiomanometry in which the papilla of Vater was stimulated by hydrochloric acid was devised as a means to evaluate the papillary function. Manometric tracings could be classified into four patterns according to the mode of response to hydrochloric acid of the papilla. Pattern I was the type in which a group of regular, high-amplitude spikes appeared within 60 seconds after the onset of perfusion. This represented a normally functioning papilla. Pattern II was characterized by rhythmic occurrence of low-amplitude waves. This represented a reversible papillitis as evidenced by the fact that postoperatively such cases exhibited pattern I results as examined through T tube. In pattern III the perfusion pressure remained flat, showing no reaction waves. This represented an incompetent papilla. The pattern III patients with conditions which were reversible responded to intravenous pentazocine. In pattern IV the perfusion pressure continued to increase without reaction waves, representing cicatricial stenosis of the papilla or incarcerated stone in the papilla. This method of cholangiomanometry was thus found to be useful for selecting candidates for sphincteroplasty.

Possible ways of controlling Schottky barrier height for a given material are discussed. The values of doping density and thickness of the high-doped layer in metal-n+(thin)-n structure for the required barrier height are given.

Amorphous gallium nitride was deposited onto various substrates by reactive sputtering of gallium in nitrogen ambient. Higher pressure up to 2×10−1 Torr is effective in making films closer to the stoichiometric composition. Annealing at 350 °C improves the insulating property of as‐deposited films by decreasing dc and ac conductance. The surface‐state density and time constant of a GaAs MIS structure, corrected for the dispersive behavior of the insulator, was derived as 7.6×1011 cm−2 eV−1 and 1.9×10−4 sec, respectively. This surface‐state density is much lower than that for the native oxide.

Transient behavior of switching diodes based on space-charge overlapping has been analyzed. The delay time was derived analytically and compared satisfactorily with experiments on amorphous threshold switches.