Search

The internal temperature of a gas bubble caused by a fault arc is a key basic parameter for investigating the bubble behavior and the pressure rise inside oil-filled power equipment. Due to the constraints imposed by the measurement methods and experimental conditions, this temperature has always been estimated as a constant value of 2000 K in past decades. In this letter, we present direct experimental evidence of the gas bubble temperature around an arc. A large oil-filled transformer was reformed and used to conduct arcing fault tests. A sapphire fiber optic infrared thermometer was established and used to detect the internal gas bubble temperature. The experimental results confirm that this internal temperature is not constant but rather varies over a wide range from 2100 K to 1500 K, plummeting with rapid bubble growth and then exhibiting small variations until arc extinction. Furthermore, the bubble growth process throughout the arc duration can be approximately regarded as first polytropic and then isothermal.

This work has launched a comprehensive investigation on the macro performance and micro structure of mass concrete produced with alkali-active sand slate powder (ASSP) for use as the mineral admixture and a thorough analysis on its technical and economic effects is also conducted. Results indicated ternary blend with hybrid of 5–8 wt.% silica fume (SF) and 15–20 wt.% ASSP has the optimal compressive and flexural strength. ASSP particle participates in hydration, accelerates hydration of cement clinker within 8.5 hours, and reduces the autogenous strain of pastes by 164 × 10−6 in case of dosage less than 25% by mass. Improvement in the mechanical and deformation properties of concrete produced with the hybrid of SF and ASSP is attributed to better particles gradation, compactness enhancement, and transformation in products of hydration. On the whole, it provides another new approach for use of alkali-active rock after second processing as mineral admixture in hydraulic concrete in terms of good performance and economic effects.

Firstly, the suitable forming method of graphite ring was screened according to compression deformation test, considering the characteristics of radial clearance seal. Then, the compression resilience, radial contact stress and axial sealing performance of graphite packing rings with different density were researched by testing. Research shows: 25% compressibility is the limit of radial clearance compensation ability of graphite packing ring; And the radial contact stress of graphite packing ring on the pipe wall is linearly positively correlated with the axial load, density has little effect on it. Based on the porous media model of gaskets, axial leakage models of three kinds of graphite rings with different density were obtained by experimental fitting and the influence of external working conditions on leakage mode was analyzed, which provide a theoretical basis for the design of graphite ring seal based on leakage rate.

The inner shell process produced by the collision of highly charged ion with medium atoms near the Bragg peak is an important frontier area of atomic physics under extreme conditions such as celestial plasmas and controlled nuclear fusion plasmas. Because of the special complexity of the inner shell process produced by the collision of ions with atoms in the Bragg peak energy region and the relevant experimental research is less, limited by the experimental conditions, there remain some interesting and unanswered questions.We report the experimental data of X-ray spectra produced by the impact of Xe20+ with 6.0 MeV kinetic energy on V, Fe, Ni, Cu, and Zn surface in the National Laboratory of Heavy Ion Research Facility in Lanzhou, China. The generation mechanism of X-ray with energy of 1.60 keV is analyzed. The results show that when Xe20+ without initial holes interacts with different targets, the Mα X-ray of Xe is not observed, but X-ray with energy twice as great as that of Xe Mα X-ray is observed in the experiment, which is called Xe Mαα X-ray and considered to be generated by the two-electron-one-photon process of Xe on the upper surface of the target. The existence time of the first-generation hollow atoms on the upper surface is calculated by using the classical over-barrier model when Xe20+ interacts with different targets, which is consistent with the variation of Mαα X-ray yield with the atomic number of target, therefore it is further proved that Mαα X-ray is formed by the two-electron one-photon process of Xe on the upper surface of the target. Of course, this conclusion needs further analyzing and verifying with more experimental data.

In this article, a novel microwave photonic filter with negative coefficient using semiconductor optical amplifiers and Fiber Bragg Gratings is proposed. Three major factors, including input current, grating coefficients and the input signal power are analyzed and compared respectively with scrutinize their affects to the filter response. Through the simulation, a better performance of the flat-top microwave photonic filter can be achieved. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 9–13, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24824

Defects in ZnO films grown by radio-frequency reactive magnetron sputtering under variable ratios between oxygen and argon gas have been investigated by using the monoenergetic positron beam technique. The dominate intrinsic defects in these ZnO samples are O vacancies (V-O) and Zn interstitials (Zn-i) when the oxygen fraction in the O-2/Ar feed gas does not exceed 70% in the processing chamber. On the other hand, zinc vacancies are preponderant in the ZnO Elms fabricated in richer oxygen environment. The concentration of zinc vacancies increases with the increasing (2) fraction. For the oxygen fraction 85%, the number of zinc vacancies that could trap positrons will be smaller. It is speculated that some unknown defects could shield zinc vacancies. The concentration of zinc vacancies in the ZnO films varies with the oxygen fraction in the growth chamber, which is in agreement with the results of photoluminescence spectra.

In recent years, the formate ion (HCO2−) as a kind of hole-to-electron converter has attracted much attention of photographic researchers. The formate ions can trap photo-generated holes, eliminate or reduce the electron loss caused by electron–hole recombination in latent image formation process. Through the hole-to-electron conversion, it can also release an extra electron or electron carrier, improving photosensitivity. In this paper the microwave absorption and dielectric spectrum detection technique is used to detect the time evolution behaviour of free photoelectrons generated by 35ps laser pulses in cubic AgCl emulsions doped with formate ions. The influence of different doping conditions of formate ions on the photoelectron decay kinetics of AgCl is analysed. It is found that when the HCO2− content is 10−3mol/mol Ag and the doping position is 90% the electron decay time and lifetime reach their maxima due to the efficient trap of holes by formate ions.

The defect changes in 6H-SiC after annealing and 10MeV electron irradiation have been studied by using a variable-energy positron beam. It was found that after annealing, the defect concentration in n-type 6H-SiC decreased due to recombination with interstitials. When the sample was annealed at 1400°C for 30min in vacuum, a 20-nm thickness Si layer was found on the top of the SiC substrate, this is a direct proof of the Si atoms diffusing to surface when annealed at high temperature stages. After 10MeV electron irradiation, for n-type 6H-SiC, the S parameter increased from 0.4739 to 0.4822, and the relative positron-trapping rate was about 27.878 times of the origin sample, this shows that there are some defects created in n-type 6H-SiC. For p-type 6H-SiC, it is very unclear, this may be because of the opposite charge of vacancy defects.

The investigations of interaction processes between ion beams and gas and between ion beams and plasma play important roles in atomic physics, astrophysics, high energy density physics, and inertial confinement fusion.The atomic density of target is one of the key experimental parameters which may determine the interaction mechanism and experimental results.How to precisely diagnose the atomic density of target in different matter states, like gas phase and plasma phase, is challenging work on the experiments in laboratory.Conventionally the vacuum gauges are used to measure the pressure inside the gas target, but the accuracy is limited for a complex target system and they can hardly work in a strong radiation surrounding, especially in plasma where the high temperature can physically damage the gauges.Therefore we propose a new method to measure the atomic densities for both gas target and plasma target based on the heavy ion beam accelerator facility at the Institute of Modern Physics, Chinese Academy of Sciences.In our experiment the protons are extracted from an electron cyclotron resonance ion source (ECRIS) and accelerated to 100 keV then transmitted to the target.A two-stage differential pumping system is constructed to keep 10-7 mbar order of magnitude in beam line when the gas is filled into the target area where the pressure could increase to higher than 1 mbar.A 45 dipole magnet is used to bend the protons which have passed through the gas.The energy is determined by the different positions of protons at the position-sensitive detector which is placed at the end of magnet.Consequently the energy losses of protons at different pressures are obtained.There have been proposed many theories for calculating the energy loss of protons in gas, and we chose the very popular code named SRIM to simulate the experimental case. Finally the effective linear atomic density of target along the ion beam trajectory in the target area is obtained.For comparison, the conventional vacuum gauges (one is the hot cathode gauge-IonIVac ITR 90 and the other is capacitance diaphragm gauge-Varian CDG-500) are simultaneously used in the experiment.The results show that the recalibrated effective pressure obtained by the energy loss is close to the pressure measured by Varian CDG-500 but much lower than the pressure from IonIVac ITR 90.Only after the detection efficiency correction, could the corrected results of IonIVac ITR 90 be coincident with the effective pressure obtained according to energy loss.Moreover we find that the effective atomic density determined by the protons energy loss shows that these advantages over the conventional gauges are not only the high accuracy and reliability but also the in-situ measurement, high temporal resolution and the ability to work in the complex radiation and hot plasma environment.These properties may play a great role in the experimental researches and relevant topics.

We report the experimental data of characteristic X-ray spectra produced by the impact of H+, Ar8+, Ar12+, Kr13+ and Eu20+ ions with different kinetic energies on Au surface in the National Laboratory of Heavy Ion Research Facility in Lanzhou, China. The energy shifts of X-ray spectra are analyzed and the ratio of X-ray yield is calculated. The results show that H+ can excite the characteristic X-ray spectra of Mζ and Mα of Au, while Ar8+, Ar12+, Kr13+ and Eu20+ can excite the characteristic X-ray spectra of Mζ, Mα, Mγ and Mδ of Au, because the inner shells of target atom are multiply ionized by heavy ions impact, so that the relative intensity ratio of the X-rays changes when the heavy ions are incident. There are different energy shifts of Au M X-ray due to multiple ionization effect in collision. When the ion incident energy is lower, the degree of multiple ionization of the inner shells of the target atom is almost independent of the incident energy, when the ion energy is higher, the degree of multiple ionization increases with incident ion energy increasing. At the same time, the degree of multiple ionization also depends on the number of holes in the outer shell of the ion and its atomic number. That the ratio of X-ray yield increases with the increase of the atomic number of the incident ion further indicates that the degree of multiple ionization increases with atomic number of the incident ion increasing. The multiple ionization and electron configuration of the inner shells of the atom can be determined by the energy shift and spectra broadening. These measurements provide basic data for further studying the multiple ionization mechanism of the inner shells of the atom. But due to the limitation of the resolution of the detector, the spectral broadening data cannot be measured. It is necessary to use a higher-resolution detector to further study the multi-ionization effect of the inner shells of the atom.

Integration of novel functional material with fiber optic components is one of the new trends in the field of novel sensing technologies. The combination of fiber optics with functional materials offers great potential for realizing the novel sensors. Typically in optical fibre sensing technology, fibre itself acts as sensing element and also transmitting element, such as fiber Bragg grating (FBG), Brillouin or Raman optical time domain reflectometer. However such sensing components can only detect limited physical parameters such as temperature or strain based on the principle of characteristic wavelength drifts. While the idea of optical fiber sensing technology with functional materials is quite different from that of the traditional technology, functional materials can be employed as sensing components, therefore many parameters, including chemical or biological parameters, can be detected, depending on the designs of different sensing films. When compared with the common fiber sensing technologies such as FBG and optical time domain reflectometer, fiber optic sensors based on functional materials show advantages in the diversity of measurement parameters. However, functional materials can be realized by many techniques including e-beam evaporation, magnetron sputtering, spin-coating, electro-chemical plating, etc. The mechanical stability of tiny optical fibers is still problematic, which could be a challenge to industrial applications. In this work, a femtosecond laser fabricated fiber inline micro Mach-Zehnder interferometer with deposited palladium film for hydrogen sensing is presented. Simulation results show that the transmission spectrum of the interferometer is critically dependent on the microcavity length and the refractive index of Pd film, and a short microcavity length corresponds to a high sensitivity. The experimental results obtained in a wavelength region of 1200-1400 nm, and in a hydrogen concentration range of 0-16%, accord well with those of the simulations. The developed system has high potential in hydrogen sensing with high sensitivity. Three-dimensional multitrench microstructures, femtosecond laser ablated in fiber Bragg grating cladding, TbDyFe sputtering are proposed and demonstrated for magnetic field sensing probe. Parameters such as the number of straight microtrenches, translation speed (feed rate), and laser pulse power of laser beam have been systematically varied and optimized. A 5-m-thick giant Terfenol-D magnetostrictive film is sputtered onto FBG microtrenches, and acts as a magnetic sensing transducer. Eight microtrench samples produce the highest central wavelength shift of 120 pm, nearly fivefold more sensitive than nonmicrostructured standard FBG. An increase in laser pulse power to 20 mW generates a magnetic sensitivity of 0.58 pm/mT. Interestingly, reduction in translational speed contributes dramatically to the rise in the magnetic sensitivity of the sample. These sensor samples show magnetic response reversibility and have great potential in the magnetic field sensing domain. Furthermore hydrogen sensors based on fiber Bragg gratings micro-machined by femtosecond laser to form microgrooves and sputtered with Pd/Ag composite film are proposed and demonstrated. The atomic ratio of the two metals is controlled at Pd:Ag=3:1. At room temperature, the hydrogen sensitivity of the sensor probe micro-machined by 75 mW laser power and sputtered with 520 nm of Pd/Ag film is 16.5 pm/%H. Comparably, the standard FBG hydrogen sensitivity becomes 2.5~pm/%H for the same 4% hydrogen concentration. At an ambient temperature of 35℃, the processed sensor head has a dramatic rise in hydrogen sensitivity. Besides, the sensor shows good response and repeatability during hydrogen concentration test.

Accurate measurement of the ionization cross section of the target atom induced by collision between ions and atoms is of great significance for studying the atomic shell process and establishing a suitable theoretical model. The experimental data and the theoretical models mostly concentrate on the cases in the low energy region at present. Only a few experimental data of high energy region are reported due to the limitation of experimental conditions. Which theory is more suitable to describe the ionization cross section of the inner shell of the target atom caused by the high energy heavy ions, is necessarily studied experimentally. The C6+ ions provided by the Heavy Ion Research Facility in Lanzhou Electron Cooling Storage Ring, are used to bombard the Ni target, in which the K-shell X-ray of Ni is measured. The incident energies of C6+ ions are 165, 300, 350 and 430 MeV/u respectively. Through analyzing the intensity ratio of K/K X-ray of Ni, it is found that the influence of incident energy on the intensity ratio of K/K X-ray is not obvious. The intensity ratios of this experiment are greater than the experimental values of incident proton and the calculated values based on the Hartree-Slater theory, which may be caused by the multiple-ionization of the L shell. The production cross sections of Ni K-shell X-ray are calculated by the binary encounter approximation (BEA) model, the plane wave Born approximation (PWBA) model and the energy-loss coulomb-repulsion perturbed-stationary-state relativistic (ECPSSR) theory respectively, which are compared with the experimental results in this paper. It is found that the experimental cross section increases with the increasing incident energy, which is consistent with the trend of BEA model estimation, but the experimental value is obviously lower than the theoretical value. We think that BEA model needs to be modified when describing the ionization process in the high energy region.

In this paper it is reported that the measurement of the bulk positron lifetime as a function of substitution content x in the temperature range from 70 to 220 K was performed in two high-Tc superconducting systems, Y1-xCaxBa2Cu3-x FexO7-? and Y1-xCaxBa2Cu3O7-?. It was found that ?B of both systems decreases significantly with x and the temperature dependence of ?B is very weak in normal state. In lower temperature region (T?Tc), a dramatic x-dependent temperature variation of ?B was observed in the Ca-substituted system: from a decrease of ?B with decreasing T to an increase of ?B. With increasing x, the temperature dependence of ?B remains weak in the Ca- and Fe- substituted systems. Compared with the experimental data of positron lifetime in other substituted systems and the calculation of the positron density distribution, the authors suggest that positron bulk lifetime spectra behaviour can be interpreted by the physical model based on the transfer of electron density between the CuO2 planes and Cu-O chains. Therefore, the study of positron lifetime spectra provides a useful means to detect the local charge density and to study the correlation between the electronic structure and the high-Tc superconductivity.

Sound velocities in shock-loaded solids are not only important to determine bulk moduli of solids at high pressures, but are also crucial to inform the shock melting of solids upon loading. In this letter, we first report on shock melting of porous solids at high pressures by measuring sound velocities in the porous iron of average density 6.90 g/cm3 in the pressure range of 110-180 GPa. The measured sound velocity softens at pressures from 122 to 156 Gpa, which may be attributed to shock melting of the porous iron.

Energy loss of protons with energy 100 keV penetrating the partially ionized hydrogen plasma target was measured. The plasma target was created by electric discharge in the hydrogen gas, the state of the plasma target was diagnosed by using the laser interferometry method: the free electron density is up to 1016 cm-3, temperature is about 1-2 eV, and the plasma target may exist at the microsecond level. It is found that the energy loss of protons is closely related to the free electron density, and the energy loss data enable us to infer the value of the Coulomb logarithm (10.8) for the stopping power of the free electrons. This agrees well with the theoretical prediction which is 4.3 times higher than that given by the Bethe formula for neutral hydrogen, which is a little bigger than Hoffmann's result but much smaller than Jacoby's result. Comparing our result with Hoffmann's, the energy we used is only 100 keV, much lower than 1.4 MeV/u, and the low-energy regime we applied could be the cause of the increase in the enhancement factor. However, in the comparison between our result and the Jacoby's, the effective charge for protons is almost constant, unlike the Kr+ impact in wihch the enhanced ion charge state induces the giant enhancement factor. Compared to the gas target, the energy loss enhancement factor in plasma target is 2.9.

We report the experiment data of X-ray spectra produced by the impact of Xeq+ (q=10, 15, 20, 26) with 2.4 MeV kinetic energy on Au surface in the National Laboratory of Heavy Ion Research Facility in Lanzhou. Results show that there is different broadening of Au M X-ray owing to multiply ionized effect in the collision with heavy ions, the degree of ionization mainly depends on the distribution of the electronic states in the ions' outer shell. The yield of X-ray is calculated and compared with BEA (binary encounter approximation) model, and the effect of ion charge state on the X-ray yield is also discussed.

As the C6+ ion beam pulses, provided by the Heavy Ion Research Facility in Lanzhou-Cooling Storage Rings, impact on Au taget surface, the Lα-and Lβ-X spectra of Au atom are measured. Results show that the production cross section of Lα is larger than that of Lβ. The production cross sections increase with the kinetic energies of the projectiles. The PWBA and ECPSSR theoretical models are compared with the experimental resulms. The significant difference between experimental data and theoretical models was discussed.

We have measured secondary electron emission yields in forward and backward directions from the carbon foils with different thicknesses, which are penetrated by Ne2+ ion of an energy from 2 to 25 keV/u. In the experiment, the contributions of projectile potential energy deposition, electronic energy loss and recoil atom to the forward and backward electron emission yields have been studied systematically by changing the projectile ions energy. Results show that the ions potential energy deposition only have the impact on the backward electron emission yield, while the forward and backward electron emission yields increase approximately linearly with the increase of the electron energy loss at the exit and entrance surfaces of the thin film respectively. When the electron energy loss is low, the impact of recoil atoms on the electron emission cannot be neglected.

X-ray emission induced by 300 MeV/u C ions impacting on copper was investigated at the Heavy Ion Research Facility in Lanzhou (HIRFL). The results showed a very high yield of K hyper-satellite emission comparing to the satellite emission.

The X-ray emission due to the impact of 129Xe30+ ions of 1.07.0 MeV kinetic energies on Au surface is detected. The experimental result shows that when ion kinetic energy is larger the incident ion excits not only Au M X-ray but also Xe L X-ray. The X-ray yield and the ion kinetic energy have a strong correlation with each other. The relationship between the X-ray yield with ion kinetic energy is analyzed.

Using ab initio plane-wave pseudo-potential density functional theory method, the elastic constants and band structures of stishovite were calculated. The calculated elastic constants under ambient conditions agree well with previous experimental and theoretical data. C13, C33, C44, and C66 increase nearly linearly with pressure while C11 and C12 show irregularly changes with pressure over 20 GPa. The shear modulus (C11-C12)/2 was observed to decrease drastically between 40 GPa and 50 GPa, indicating acoustic mode softening in consistency with the phase transition to CaCl2-type structure around 50 GPa. The calculated band structures show no obvious difierence at 0 and 80 GPa, being consistent with the high incompressibility of stishovite. With a quasi-harmonic Debye model, thermodynamic properties of stishovite were also calculated and the results are in good agreement with available experimental data.

Plate impact experiments are conducted on high density glass (HDG) with an initial density of ～4.817g/cm3 (Brand ZF6) at a two-stage light gas gun facility. A copper flyer plate is used as a standard sample. Experimental shock pressure is between 52.1GPa and 167.8GPa. A multi-wavelength pyrometer and optical analyzer technique are used to determine the Hugoniot curve, sound velocity and shock temperature of HDG. The experiment results reveal that polymorphism phase transitions occur in HDG under compression, and the onset pressures are ～23, ～78 and ～120GPa, respectively. The measured sound velocity first increases and arrives at about 78GPa, then decreases rapidly, and increases again with pressure increasing. Beyond ～120 GPa, the longitudinal sound velocity turns in to bulk sound velocity, indicating the melting of HDG. Measured shock temperatures also show discontinuities at ～78 and ～120GPa, after which its increase rate becomes small and consistent with the calculated Lindemann melting line, confirming the above HDG phase transformation behaviors. Our Hugoniot data are consistent well with LASL shock Hugoniot data of HDG, which shows discontinuity only at about 23GPa, indicating that the phase transitions at 78 and 120GPa are not first-order ones. Our shock data and the gained knowledge of dynamic response behavior of HDG are valuable for improving the accuracies in sound velocity measurements for metals and non-metals at pressures over a megabar range.

On the basis of of local density approximation (LDA) and general gradient approximation (GGA), positron annihilation information has been calculated for five types of compound semiconductors, which are ZnO, GaN, GaAs, SiC and InP. The calculated information includes distribution of positron density, distribution of positron annihilation rate density, positron bulk lifetime, positron monovacancy lifetime and positron divacancy lifetime.

This paper presents the positron study on carbon-Fe3O4 coaxial nanofibers, which is one kind of new promising functional materials. According to the positron annihilation lifetime spectra and the coincidence Doppler broadening spectra, we find in this material that positrons annihilate partly in monovacancies of Fe3O4, partly in microcavities of Fe3O4 and partly in shelled carbon nanotubes. We also estimate the annihilation proportion in each part, which reveals the nanofibers’ microstructure to a certain extent.

In this paper, reverse-impact method for measuring release sound velocities was improved through special treatment of the impacted face of the window, and using time-resolved velocity interferometer system for any reflector. Our experimental technique solved the problem that bulk and longitudinal sound velocities can not be obtained simultaneously using the original method reported in the literature, due to the effect of release behaviors in the buffer. With the modified reverse-impact method, sound velocities of tin were measured with higher accuracy (measuring errors of longitudinal and bulk sound velocities being about 2% and 5%, respectively) in the range of 37—80 GPa. The experimental results are consistent with thermodynamic theoretical values.

In this paper, a comparative experimental study on optical transparency of z-cut LiF, sapphire and LiTaO3 under 1011 Pa shock compression at our two-stage light-gas gun facility is presented. In our experiments, intensity contrast variation of light emitted from a modified experimental setup of Mallory-type was monitored by a high-speed electronic camera. The results demonstrated that the LiF under the shock pressure of 102 GPa retains its initial transparency in the whole observation time interval, which is in good agreement with the common view of good sustained transparency of LiF. The LiTaO3 became basically opaque at 139 GPa. Sapphire at 131 GPa shock pressure showed a continuous transparency degradation till became completely darkened when the shock wave was arriving at the free-surface.

A novel back-gate reduced bulk field concept which makes a breakthrough in improving the vertical breakdown voltage of high voltage SOI transistors is proposed. The mechanism of the improved breakdown characteristics is that the electric field distributions of the active region are modulated by the interface charges induced by the back-gate voltage. The bulk electric field at the drain side is reduced, the bulk electric field at the source side is increased, and the breakdown voltage of the high voltage SOI device is improved. The impact of the back-gate bias on thick film SOI LDMOS (over 600 V) is discussed via two-dimensional simulations. When the back-gate bias is 330V, the breakdown voltage of the three-zone SOI double RESURF LDMOS is 1020V, which is 47.83% greater than that of a conventional LDMOS. The novel concept presents a new method for realizing over 600 V high voltage power device and high voltage integrated circuit.

Small Angle X-ray Scattering(SAXS), Field Ion Microscopy(FIM) and Large Angle X-ray Diffraction(LAXD) were used to study the structure of the metallic glass Zr 78 Co 22 . The results indicate that the amorphous phase separation exists obviously in the as-qenched state of the metallic glass Zr 78 Co 22 . The compositions of two segregation amorphous phases tend to α - Zr and Zr 4 Co respectively. All amorphous phases are superconducting.

A multivalued Ic-H characteristic of the superconducting metallic glass Zr78Co22 has firstly been observed in the as quenched state under transverse fields at T⩽Tc. Namely, there are several critical currents for a given field and a number of magnetic field peaks appear on the Ic-H curves. Based on the analysis of the microstructure and crystalline phases of samples, a model of superconducting phase separation has been proposed and the observed experimental phenomena have been explained qualitatively.

The fission cross sections of Pu-239 in the neutron energy ranges 1.0–1.6 MeV and 3.4–5.6 MeV are measured absolutely. The monoenergetic neutrons are produced from T(p,n)3He and D(d,n)3He reactions on a 2.5 MV Van de Graaff accelerator. The neutrn fluence is determined with recoil proton telescope system and the number of fission events with fission ionization chamber filled with methan gas.The deposit of Pu-239 and the polyethylene film are put in a back-to-back geometry and the neutron fluence and fission fragments are measured simultaneously. The absolute values of fission cross section of Pu-239 are obtained and compared with other experimental and compiled results.

The structure, structural relaxation and crystallization of metallic glass Zr78Co22 are investigated by the small angle X-ray diffraction, the wide angle X-ray diffraction and the field ion microscopy, together with the measurements of the superconducting critical temperature and the microhardness. The results indicate that there exists obviously the amorphous phase separation in the as-quenched state of the metallic glass Zr78Co22. The compositions of two segregated amorphous phases are similar to pure Zr and Zr4Co respectively. In the process of structural relaxation, the changes of the toplogical short range order are essential and controlled by the nucleation-growth mechanism. When the number of nucleation is sufficient, the segregation grow homogenously and identically.

The 1 hour isochronal annealing treatment has been made on amorphous alloy Zr87.7Si12.3. The changes of the superconducting critical parameters, Tc and H(C2) and their transition width have been measured for different annealing temperatures. The different change laws of metal-metal type amorphous alloys were observed. The experimental results-were discussed in connection with the toplogical short range order and the chemical short range order in the process of structural relaxation and the corresponding crystallization mechanism.

In this paper, we have studied systematically the l-V characteristic of the superconducting metallic glass Zr78Co22 without applied magnetic fields. It is observed that the transition from superconducting states to normal states is completed in steps as the current increasing. The properties of steps are localized and depend on current scanning rate. It is shown that the occurence of resistive steps is because of the inhomogenity of materials which leads to the ap-pearence of hot-spots. The equation of one-dimensional thermal flow may be used to described the localized resistive state of superconducting metallic glass Zr78Co22, in case of considering the effecs of interaction between hot-spots, selfabsorbing-heat of the sample itself, and so on.

When the temperature is far below Tc, a set of electric voltage steps appear on the H-V or I-V curves of the metallic glass Zn78Co22 under longitudinal magnetic fields. The oc-curing conditions and the structural characteristic of steps have been compared systematically with the steps existing in homogeneous superconductors of quasi-one or quasi-two dimension systems. A model of superconducting phase separation and the idea of phase slip centers have been used to explain the observed phenomena.

Measurements of magnetoresistance of upper critical magnetic field have been made on superconducting metallic glass Zr78Co22. The results correspond qualitatively with the weak localization theory including spin-orbit scattering for three demensional system. Quantitatively, there exists an obvious deviation, which originates mainly from superconducting fluctuations. In the measuring temperature range, the value of upper critical field Mc2 varies linearly with temperature, and we obtain the inelastic scattering rate τi-1=1.3×1O10T2, which can be atributed to the electron-phonon processes in disordered metals This value is slightly lower than that predicted by Bergmann theory.