Search

Aluminum honeycomb framework reinforced Al/PTFE material is a kind of high inert energetic material, which has higher strength and structure advantages than that of pure Al/PTFE material. In order to meet the requirements of special penetration/blasting performance, this paper adds aluminum honeycomb framework with arm length of 1.5 mm into the traditional formula Al/PTFE (mass percentage of Al and PTFE is 26.5% and 73.5%). The energetic material reinforced by aluminum honeycomb framework (20.5% Al/73.5% PTFE/6% aluminum honeycomb) is obtained by cold pressing sintering，and the experimental evaluation of release energy generated by high velocity impact in vacuum was performed by using two-stage light gas gun loading system, transient optical fiber pyrometer measurement system, overpressure measurement system and infrared thermal imager measurement system. Experimental results show that the impact reaction temperature is about 700 °C in vacuum in the velocity range of 0.96–1.5 km/s, and the energy release of the specimen increases with the increase of impact velocity. When the impact velocity is greater than 1.5 km/s, the specimen fully reacts, and the energy released by the complete reaction of the specimen does not exceed 8.3 kJ/g.

On-orbit filling is one of the important technologies for long-period space exploration. Filling without moving components and with low mass loss has obvious advantage for on-orbit fillings, especially for small volume filling. For such purpose, a no-pump no-vent filling system was proposed, and the working principle of the filling and the criterion to end the filling in microgravity were equivalently verified on ground. In such filling system, two distinct filling phases were witnessed: a fast and effective liquid transfer phase followed by a slow and ineffective vapor transfer phase. The vapor in this phase came from the evaporation of the remaining liquid in the capillary structure, which has to be evaporated by heating in microgravity. The heating power determines the period of the vapor transfer phase for a given system with certain capillary structure. It was found that the transition point of the system pressure from increase to decrease can be used as a criterion to end the filling. Experiment that simulated such vapor transfer phase on ground provides data supports for optimizing the filling control scenario.

To find a cool storage phase-change materials (PCM) with large storage capacity, high heat transfer efficiency, and low supercooling, we investigated a water-based composite by using foam copper as the framework, which has been proved to enhance the thermal conductivity remarkably. We investigated the supercooling of water icing in pure foam copper with the help of differential scanning calorimetry, and found it was suppressed from 20.6 °C to 6.8 °C. By introducing AgI as the nucleation agent onto the foam copper coated with gold layer to prevent chemical reaction between the AgI and the copper, the supercooling was further suppressed down to 2.1 °C. Mechanism of the suppression of the supercooling was also discussed. Potential applications are expected for such PCM with high latent heat, relatively high thermal conductivity, and low supercooling, especially in the field required instantly high cold release power.

Hypergravity-assisted chemical liquid deposition (HACLD) is an effective method to increase the density of and improve the flatness of the films prepared using chemical reaction. Here, we have demonstrated the entire HACLD film deposition process and explained the film deposition mechanism, which had not been shown before. In this paper, HACLD method was utilized to deposit silver (Ag) films on the inner surface of quartz tubes for exploring the film formation process. One of the obtained Ag films exhibited a structure of uniformly distributed nanoparticles (NPs) with the mean size of about 50 nm. The film-forming mechanism of the single-layer nano-granular film prepared with HACLD method was revealed by studying the film-forming process, the effects of the hypergravity and the temperature distribution on the growth process of Ag NPs. This attempt may provide an understanding of the film-forming mechanism in hypergravity.

Higgs boson production in association with a photon ($H$+$\gamma$) offers a promising channel to test the Higgs boson to photon coupling at various energy scales. Its potential sensitivity to anomalous couplings of the Higgs boson has not been explored with the proton-proton collision data. In this paper, we reinterpret the latest ATLAS $H$+$\gamma$ resonance search results within the Standard Model effective field theory (EFT) framework, using 36.1 fb$^{-1}$ of proton-proton collision data recorded with the ATLAS detector at $\sqrt{s}=13$ TeV. Constraints on the Wilson coefficients of dimension-six EFT operators related to the Higgs boson to photon coupling are provided for the first time in the $H$+$\gamma$ final state at the LHC., Comment: 10 pages, 3 figures

The insufficient dynamic compressive strength of the Al/PTFE energetic material with traditional ingredients has seriously restricted its application in the field of national defence. However, the improvement of strength must be at the expense of activity. In view of the contradiction, this paper pioneers aluminum honeycomb skeleton reinforcement method to achieve both strength and activity. On the basis of traditional ingredients Al/PTFE (mass percentage of 26.5%/73.5%), three types of energetic materials were prepared by cold pressing sintering process by adding different aluminum honeycomb skeletons with arm lengths of 1 mm, 1.5 mm and 2 mm, respectively. The dynamic compressive strengths of the specimen are obtained by using self-built Split Hopkinson Pressure Bar (SHPB) loading system and high-speed camera acquisition system. Meanwhile, the impact reaction release energies are also evaluated experimentally by using the one-stage light gas gun loading system combined with the transient optical fiber pyrometer measurement system, the overpressure measurement system and the infrared thermal imager measurement system. In term of dynamic compressive strength and impact reaction release energy, the performances of three types of Aluminum honeycomb reinforced energetic material were compared with those of traditional ingredients energetic material. The experimental results show that compared with the strength (25.17 MPa) of traditional ingredients Al/PTFE energetic material, the strengths of three kinds of energetic materials reinforced by aluminum honeycomb framework with arm lengths of 1 mm, 1.5 mm and 2 mm are 1.5, 3.1 and 2.2 times that of the traditional ingredients Al/PTFE, respectively; Especially, at the impact velocity of 510 m/s, the release energy of three kinds of Al/PTFE energetic materials reinforced by aluminum honeycomb framework with arm lengths of 1 mm, 1.5 mm and 2 mm were 2.52 kJ/g, 1.94 kJ/g and 2.40 kJ/g, respectively. However, the release energy of traditional ingredients Al/PTFE energetic material was only 1.85 kJ/g. Compared with the traditional ingredients Al/PTFE, the compressive strengths and release energies of three kinds of energetic materials reinforced by different arm lengths of Aluminum honeycomb were significantly improved under the same impact conditions.

Flow boiling in micro-channels and mini-channels has received significant attention due to its capability for dissipating highflux heat, especially in the thermal management of high precision electronics. A heat sink with narrow rectangular mini-channels is designed to investigate flow boiling in the mini-channels, including the effect of gravity. It contains 14 parallel channels with a cross section, of 1×4mm 2, of which the hydraulic diameter is 1.6mm. The cooling capability, the temperature uniformity, and the temperature stability of the flow boiling in minichannels are investigated with R22, with total mass flow flux ranges from 35 to 70kg/m 2s. The results show that the cooling capability of the heat- sink is up to 340W(∼ 3.0W/cm 2), and the temperature difference is below 4 ∘C(even down to 2 ∘C) on the heat sink. The temperature uniformity isn’t quite sensitive to heat flux. The instability has not been observed in the present researches.

The accumulation of neutral lipids in intracellular lipid droplets has been associated with the formation and progression of many cancers, including prostate cancer (PCa). Alpha-beta Hydrolase Domain Containing 5 (ABHD5) is a key regulator of intracellular neutral lipids that has been recently identified as a tumor suppressor in colorectal cancer, yet its potential role in PCa has not been investigated. Through mining publicly accessible PCa gene expression datasets, we found that ABHD5 gene expression is markedly decreased in metastatic castration-resistant PCa (mCRPC) samples. We further demonstrated that RNAi-mediated ABHD5 silencing promotes, whereas ectopic ABHD5 overexpression inhibits, the invasion and proliferation of PCa cells. Mechanistically, we found that ABHD5 knockdown induces epithelial to mesenchymal transition, increasing aerobic glycolysis by upregulating the glycolytic enzymes hexokinase 2 and phosphofrucokinase, while decreasing mitochondrial respiration by downregulating respiratory chain complexes I and III. Interestingly, knockdown of ATGL, the best-known molecular target of ABHD5, impeded the proliferation and invasion, suggesting an ATGL-independent role of ABHD5 in modulating PCa aggressiveness. Collectively, these results provide evidence that ABHD5 acts as a metabolic tumor suppressor in PCa that prevents EMT and the Warburg effect, and indicates that ABHD5 is a potential therapeutic target against mCRPC, the deadly aggressive PCa.

For experiments of flow boiling, a window with the functions of heating and temperature measurement of the heater is an ideal tool to observe flow patterns and measure the heat transfer coefficient at the same time. In the present work, we prepared a translucent tube typically 90 mm in length and 7.0 mm in inner diameter (i.d.) with the functions of directly heating fluid flowing through and measuring the temperature of the heating surface for the purpose. Conductive platinum (Pt) film was prepared on the inner surface of a quartz tube by using the precursor solution having a resistance of 50 to 70 Ω and a good linear relationship between resistance and temperature. We demonstrated the processes of nucleation, evaporation, and boiling of water at different temperatures with the heating window. This attempt may provide a tool for the accurate measurement of heat transfer coefficient during the boiling process.

MgO films were prepared by using pulsed cathodic vacuum arc deposition technique. The substrate bias voltage was in the range of −150 to −750 V. Film structure was investigated by X-ray diffraction (XRD). The annealing effect of thermal spike produced by the impacting of energetic ions was analyzed. The calculated results showed that the lifetime of a thermal spike generated by an energetic ion with the energy of 150 eV was less than one picosecond and it was sufficient to allow Mg2+ or O2- to move one bond length to satisfy the intrinsic stress relief in the affected volume. The MgO(200) lattice spacings of the films deposited at different bias voltages were all larger than the ideal value of 2.1056 A. As the bias amplitude increased the lattice spacing decreased, which indicated that the compressive stress in the film was partially relieved with increasing impacting ion energy. The stress relief also could be reflected from the film orientation with bias voltage. The biaxial elastic modulus for MgO(100), MgO(110) and MgO(111) planes were calculated and they were M(100) = 199 GPa, M(110) = 335 GPa and M(111) = 340 GPa, respectively. The M values indicated that the preferred orientation will be MgO(200) due to the minimum energy configuration when the lattice strain was large. It was confirmed by the XRD results in our experiments.

Modification of hydrogen-free diamond-like carbon (DLC) is presented, with acrylic acid (AA) vapor carried into a vacuum chamber by argon and with the in situ assistance of low-power radio frequency (RF) plasma at a temperature below 100°C. Measured by atomic force microscopy (AFM) technique, the roughness (Ra) of the DLC was 1.063±0.040 nm. XPS and FT-IR spectra analysis showed that carboxyl groups were immobilized on the surface of the DLC films, with about 40% of carboxyl group area coverage. It was found that the RF plasma and reaction time are important in enhancing the modification rate and efficiency.

MgO thin films, as the protective layers for plasma display panels (PDP), were prepared by using cathodic vacuum arc deposition technique. The influences of deposition angle between −60° and 60° on film structure and properties were investigated. X-ray diffraction (XRD), ellipsometer, thermal field emission environment scanning electron microscopy (SEM) and UV-Visible spectrophotometry were used to study the properties of MgO thin films like crystallization, surface structures, thicknesses and refraction indices. Our results show that the thickness of MgO thin film decreases with the increase of incidence angle. This is confirmed by the transmittance spectra as well. The film deposited at 0° shows sharper diffraction peaks and smaller FWHMs (full width at half maximum) of both MgO (200) and (220), which means better crystallization quality of the film. The higher packing density is achieved on the 0° deposited film as well.

MgO thin films with high optical transmittances (more than 90%) were prepared by cathodic vacuum arc deposition technique. With the increase of arc current from 40 to 80 A, the deposition pressure decreases and the film thickness increases; the atomic ratio of Mg/O in MgO thin films (obtained by RBS) increases from 0.97 to 1.17, giving that deposited at 50 A most close to the stoichiometric composition of the bulk MgO; the grains of MgO thin films grow gradually as shown in SEM images. XRD patterns show that MgO (1 1 0) orientation is predominant for films prepared at the arc currents ranged from 50 to 70 A. The MgO (1 0 0) orientation is much enhanced and comparable to that of MgO (1 1 0) for films prepared at the arc current of 80 A. The secondary electron emission coefficient of MgO thin film increases with arc current ranged from 50 to 70 A.

A model based on localized partition function and master equation was set up to calculate the zero-field-cooled (ZFC) and field-cooled (FC) curves of a non-interacting magnetic nanoparticle assembly with randomly oriented anisotropy. The peak temperature of the ZFC curve corresponds to the highest energy barrier that acts against the unblocking process, and could be described well by an equation covering the heating rate effect. The predicted H 2/3 field dependence of the peak temperature is in good agreement with published results.

By means of experiment and simulation, we investigated the coupling between the accumulator and the loop in the Tracker Thermal Control System (TTCS) system, which is a typical mechanically pumped carbon dioxide two-phase loop, by studying the system behaviors under the disturbance of the temperature boundary of the condensers, and the step change of the evaporator heat load. We found that the disturbance of the loop affects the accumulator, and in turns, affects the loop itself. If the heat compensation of the accumulator is large enough, e.g., by using the accumulator heater with enough heating power and with a thermal conductance good enough between the heater and the two-phase CO2 inside the accumulator, the loop is controllable over the disturbance. The coupling is a fundamentally important factor to be considered for the design of a stable and controllable two-phase system, such as a mechanically pumped two-phase loop.

The tracker thermal control system (TTCS) is an active-pumped two-phase carbon dioxide cooling loop, which is developed for the Alpha Magnetic Spectrometer (AMS) tracker front-end electronics. The evaporators in parallel, gathering waste heat from, and providing stable and uniform thermal boundary condition to the electronics, are the key components of the loop. Any abnormities to the parallel evaporators is unacceptable. In this paper, we observed self-sustained temperature oscillations at the outlet of the evaporators when the cooling loop is operated at low temperature with the pump rotation speed lower than 3,300 rpm. Analysis shows that the oscillation could be of density-wave origin, and the flow rate redistribution between the two parallel evaporators may result in the self-sustained temperature oscillations.

A general acid vapor oxidation (AVO) strategy has been developed to grow highly oriented hierarchically structured rutile TiO(2) nanoarrays with tunable morphologies from titanium thin films. This is a simple one-pot synthesis approach involving the reaction of a titanium surface with the vapor generated from a hydrochloric acid solution in a Teflon lined autoclave. To the best of our knowledge, this is the first successful attempt to grow ordered tree-like titania nanoarrays. A possible formation mechanism for the interesting architectures has been proposed based on series of time-dependent experiments. By adjusting the initial HCl concentration, films of different rutile structures including nanotrees, dendritic nanobundles, and nanorods can be selectively obtained. Subsequently, the surface morphologies and wettability can be readily tuned.

We use Monte Carlo simulations to study the influence of dipolar interaction on the equilibrium magnetic properties of monodisperse single-domain ferromagnetic nanoparticles. Low field magnetizations simulated in zero field cooling (ZFC)/field cooling (FC) procedures and field-dependent magnetization curves above the blocking temperatures show strong dependence on the concentration and the spatial arrangement (cubic or random) of the magnetic particles. The field-dependent magnetizations can not be simply described by the T* model at relative low temperatures due to the interplay between anisotropy and dipolar interactions, as well as the spatial arrangement effect.

Tracker thermal control system (TTCS) is an active-pumped two-phase carbon dioxide cooling loop, which is developed for the Alpha Magnetic Spectrometer tracker front-end electronics. The maintenance-free centrifugal pump is a critical component in the design mainly due to the limited pressure head with small mass flows. Therefore a correct pressure drop is required to predict the pressure drop for dynamic modeling. As the normal operational temperature of the carbon dioxide in the TTCS is from − 15°C to +15°C, which is very close to its critical point, 33°C, and many two-phase pressure drop correlations may not fit well here. In this paper, we attempt to correlate the pressure drops between the calculations and the experiment of the two-phase CO2 loop. The comparison will focus on one evaporator. Here, the Lockhart/Martinelli correlation is recorrelated with different definition C value for CO2 according to the test results. Comparison shows that, the new correlation can fit the test results well.

A phenomenological model is employed to explain the departure of H/T scaling of tunneling magnetoresistance (TMR) in Co 0.43 (ZrO 2 ) 0.57 granular films (see [B.J. Hattink, M. Garcia del Muro, Z. Konstantinovic, X. Batlle, A. Labarta, Phys. Rev. B 73 (2006) 045418]). The model bases on the modification of Langevin function by taking into account the field-dependent correlation length, in the framework of Inoue–Maekawa model. Both TMR –H and TMR –H/T curves can be reproduced very well by this model, indicating that the interparticle coupling plays an important role on TMR in the interacting superparamagnetic systems. The influence of anisotropy and spin polarization of the magnetic particles on TMR –H/T curves is also discussed.

Single crystals of MgO with (100), (110) and (111) orientations were implanted with 64 keV Fe ions at a dose of 1.9×1017 ions/cm2 by using metal-vapor vacuum arc ion source (MEVVA). The magnetic properties were investigated by a superconducting quantum interference device magnetometer and Rutherford backscattering spectrometry (RBS) was used to analyze the Fe concentration and distribution. The presence of Fe nanoparticles in MgO matrix was verified by magnetization measurements. Results show that all the samples behave with ferromagnetism at 5 K and 300 K, and the coercive field, H C , follow well the relation: H C ( 110 ) H C ( 100 ) H C ( 111 ) at measured temperatures. The orientation dependence of the coercive field may result from the different distribution of Fe nanoparticle size.

Tetrahedral amorphous hydrogenated carbon (ta-C:H) films with various substrate bias voltages were prepared using a magnetic-field-filter plasma stream deposition system. The microstructural and optical properties were studied using ellipsometric spectra. The refractive index n of each sample was obtained by simulating their ellipsometric spectral using Tauc–Lorentz oscillator model, and then the relative sp3 C ratio of each sample was calculated using Bruggeman effective medium approximation. The sp3 C fraction of each sample was quantified by using electron energy-loss spectroscopy (EELS). The blood compatibility of the samples was evaluated by tests of platelet adhesion, kinetic clotting time and thrombin time. The quantity and morphology of the adherent platelets on the surface of these samples were investigated using scanning electron microscopy. Results show that the spectroscopic ellipsometry is a helpful method to evaluate the sp3 carbon fraction of the carbon films. The substrate bias voltage has an obvious effect on sp3 content and blood compatibility of ta-C:H films. The sample prepared with substrate bias voltage of − 20 V showed the best blood compatibility. A simple bio-physical hypothetical model was proposed to explain the experiment results.

MgO thin films with high optical transmittance were prepared by cathodic vacuum arc deposition technique. Rutherford backscattering spectroscopy, atomic force microscopy and X-ray diffraction were used to investigate the influences of the negative pulse bias voltage on the composition, the morphology and the crystal structure of MgO thin films, respectively. AFM images show that the grain growth is influenced by high energy ions under bias voltage and that the grains deposited at the pulse bias voltage with set value of | V p | = 600 V stack densely and look the largest as compared to those prepared at different set V p . The RBS spectra indicate that the Mg/O ratio is about 0.95–1.00 in MgO thin films which is nearly the stoichiometric composition of bulk MgO. The Mg/O ratio increases with set | V p | until | V p | is 450 V, and then keeps almost unchanged with set | V p | up to 750 V. The MgO thin films have a combined orientation of (100) and (110). Below − 150 V, the (100) orientation is predominant and the intensity ratio of I 220 / I 200 increases with set | V p |.

Based on the ubiquitous existence of phase separation in the A 1− x B x MnO 3 system, using Mn(CH 3 COO) 2 ·4H 2 O to react with SrCO 3 and La 2 O 3 , we obtained multi-phase nanocrystalline manganese perovskites with nominal composition of La 1− x Sr x MnO 3 by a low temperature synthesis approach. The grain size of the as-prepared samples is estimated to be about 70 nm by using Scherrer formula and the full width at half maximum (FWHM) of X-ray diffraction lines. And two magnetic transitions were observed in AC susceptibility measurement, which should be related to the coexistence of the two phases in the fine grains. Through modulating the synthesis temperature, the grain size of the composites can be controlled from 70 to 240 nm, and the magnetic transition temperature varies from 273 K to 373 K, correspondingly. The inter-diffusion between the two phases was under control, and a broad temperature range of flat resistance and magnetoresistance near room temperature were obtained.

Magnesium-oxide (MgOx) films have been prepared by a cathodic-vacuum-arc ion deposition system operated in an intermediate frequency pulse mode of substrate bias voltage at a mixed atmosphere of O2 and Ar. The O2 flow was adjusted in a range of 180-240 sccm at a fixed O2/Ar flow rate of 20. The structure, composition, morphology, and optical properties of the samples were analyzed by X-ray diffraction, Rutherford backscattering technique, atomic force microscopy, and UV-visible absorption spectra, respectively. Results show that the crystal orientation and grain size of the samples strongly depends on O2 flow rate. Growth of Magnesium-oxide films prefers MgO (200) and MgO (220) orientation at a smaller and larger O2 flow rate of 180 and 220 sccm, respectively. Transparent MgOx films used as the protective layer for alternating-current plasma display panel are obtained at optimal deposition conditions

J. van Es, A. Pauw, H.J. van Gerner, Thermal Control Group, Space Division, National Aerospace Laboratory, 8316 PR Marknesse Johannes.van.Es@nlr.nl, The Netherlands and E. Laudi Laboratory Study of Radiation Effect on Materials for Space application, 05100 Terni, Italy and C.Gargiulo Instituto Nazionale di Fisica Nucleare Sezione di Roma c/o Dipartimento di Fisica Universita' degli Studi di Roma 00185 Roma – Italy and Z.He Center of Space Technology, Sun Yat-Sen University, 519082 Zhuhai, People’s Republic of China and B. Verlaat NIKHEF, National Institute for Subatomic Physics, 1098 XG Amsterdam, The Netherlands

Stability is a key factor that limits the application of liquid-vapor two-phase loop. in this paper, we investigated the two-phase flow stability boundaries of two evaporators in parallel in a mechanically pumped CO2 two-phase loop(MPTL), which distinguish steady flow, flow oscillations at the inlet, and temperature oscillations at the outlets of the evaporators. We inferred that the instability is the result of density wave oscillation (DWO), and found that the periods of the flow oscillations are comparable with the residence time of CO2 fluid particle in the evaporator.

Giant magnetoresistance spin-valve based biosensors are becoming more prevalent for sensitive biomolecular detection. However, there is little attention to the application of the commercial spin-valve sensors in bio-detection. In this paper, we present an integrated multi-channel detection platform for commercial spin-valve sensors. For the implementation, we propose a new detection method named scanning magnetic field that takes the magnetoresistance transfer curve shift caused by the magnetic beads. The reproducibility of this new method in detection is confirmed by the single channel experiment. Lastly, to demonstrate the concentration resolution of our detection platform, we performed a concentration calibration. The result indicates that concentration resolution can be achieved when applying the scanning magnetic field method with the commercial spin-valve sensors and magnetic beads.

We investigated experimentally the start-up characteristics of a mechanically pumped two-phase loop (MPTCL), with CO2 as working fluid, and a single evaporator that consists of a bent inner ring and an outer ring constructed by stainless tubes with hydraulic diameter of 2.6 mm and length of 9 m, along which totally 54 pieces of heating element are distributed. Experiments were performed in the following conditions: mass flow rates of 1.1, 2.1, and 3.3g/s; heat loads ranged from 50 to 300W, with the heat-load ratios of the inner ring to the outer ring 2.2:1, 1:1, and 1:2.2 at the operational temperature of −15°C, respectively. During the start-up cases, we detected a reverse flow accompanying with pressure spike, which can be understood as explosive boiling, and a subsequent temporal dry-out phenomenon at the outlet of the evaporator, as a result of explosive boiling. The back flow together with the pressure spike is helpful to set up a two-phase flow all along the evaporator, though it may have negative effect on the loop, especially, when coincident explosive boiling happens. However, such a pressure spike that depends on initial superheating should be controlled to avoid possible harm to the loop.

Through silicon vias (TSV) as used in 3D integrated electronic packages were inspected non-destructively by highly resolving nanofocus computed tomography (nanoCT). In particular, in the TSVs plating voids were visualised and quantitatively evaluated by numerical processing of the resulting volumetric data. The nanoCT technology is outlined and further applications such as interposers etc. are considered.

Nanofocus tube technology and high resolution CT are the future inspection tools for IC packages. The elementary principles and techniques of latest 2D and 3D nanofocus techniques are briefly outlined and typical results of highest resolution failure analysis including bond wire defects, copper bond wire inspection, Flip Chip solder interconnection and microvia inspection are presented.

I – V characteristics of epitaxial, c-axis-oriented GdBa 2 Cu 3 O y film was measured between 70 K and 90 K. A magnetic field of 3 T was applied parallel to the basal plane (a – b plane), the angle between the field and one side of the substrate being 0° or 60°. We found that there were differences between the I – V characteristics for the 0° and 60° cases due to the anisotropy of the superconductivity in the a – b plane.

Measurements of the Hall coefficient (RH) were carried out for a polycrystalline YBa2Cu3O7-y film, a well oriented YBa2Cu3O7-y film and an oriented GdBa2Cu3O7-y film. Sign change of RH was observed for the two YBa2Cu3O7-y films near Tc, but not for the GdBa2Cu3O7-y film which contains partly the component of (110) orientation. The RH anisotropy model proposed previously turns out to be incorrect. Why the YBa2Cu3O7-y films experience sign change of RH while the GdBa2Cu3O7-y film does not is tentatively investigated.

Nanofocus tube technology in combination with high resolution CT are the driving forces in X-ray and the leading future technologies for the inspection of IC packages. The paper shows different results of highest resolution failure analysis performed with latest 2D and 3D nanofocus techniques like the first 180 kV nanoCT system.

Etude de la serie orthorhombique de ces composes en mesurant leur coefficient de Hall. L'interaction entre les orbites de Cu et de O et la concentration en porteurs de charge est supposee importante a la supraconductivite a haute T c dans les composes de phase 123

Les caracteristiques courant-tension de ces films sont dues au fluage de flux. Certaines differences dans les resultats peuvent etre dus a l'anisotropie. Ainsi ces caracteristiques peuvent etre liees a l'anisotropie des supraconducteurs a haute T c

The relations of a.c. susceptibility, a.c. resistance, remanent resistance (under a magnetic field) versus temperature and Hall coefficient (RH) in transition region have been investigated for 123 phase YBa2Cu3−xSnxO7+δ system. In normal state,RH is positive for the single phase samples with x=0.05, 0.1, 0.2 and 0.3, but negative for that with x=0.4 which contains impyrity phases. In superconducting transition region, a negativeRH peak is found for each of the single phase samples. Several situations are considered in the discussion of the origin of such anomalousRH, and it is suspected to be closely related to the anisotropy of the grain and itsRH.

Nonlinear I–V characteristics of YBa2Cu3O y epitaxial film at different temperatures in a magnetic field of up to 5T and angles between the direction of the field and the a–b plane of 0°, 30°, 45°, 60°, and 90° were measured. We find that there are the vortex glass phase and vortex liquid phase in the mixed state. The flux creep exists in the vortex glass phase, and it obviously appears in the area around the boundary between the vortex glass phase and the vortex liquid phase.

Single phase samples (Bi, Pb)2Sr2Ca2Cu3Oy have been prepared under different heat treatments. The midpoint transition temperature (Tc) is determined by both AC susceptibility and resistance measurement. The resistance-temperature coefficient is found changed from positive to negative when the sample is fast cooled. The Hall coefficient measurement shows that Tc increases monotonically with the effective carrier concentration (nH) and that nH increases with temperature linearly. The authors draw the conclusion that the reduction of the carrier concentration is caused not by the reduction of the oxygen content, but by the weak localization of the carriers which is unfavorable to High Tc.