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Synthetic hydroxyapatite (HA) and its related materials have made great progress in basic research and clinical application in spinal repair and reconstruction. However, the effect of HA and its composites used in spinal fusion still remained controversial. This meta-analysis aimed at evaluating the efficacy and safety of HA compared with autologous bone.A systematic search in PubMed, MEDLINE, China National Knowledge Internet, EMBASE, and the Cochrane Library was conducted for relevant studies from inception until May 2021. Studies investigating the application of HA and its related composites in spinal fusion were selected for analysis.The operation time of patients treated with artificial bone containing HA was less than that of patients with autologous bone (p = 0.02). The amount of operative blood loss in patients in the HA group was less than that in the autograft group (p = 0.007). Patients treated with autologous bone got a more significant advantage in fusion rate at 6 months (p = 0.009). Nevertheless, there was no significant difference in the fusion rate between patients in the two groups at 12 months or no less than 24 months postoperatively (p = 0.24; p = 0.87). Compared to the autograft group, the HA group significantly decreased postoperative adverse events (p = 0.03). Furthermore, there was no significant difference in the Oswestry Disability Index (p = 1.00) nor the Visual Analogue Scale score (p = 0.94) between the two groups.This meta-analysis suggests that the clinical application of HA and its related composite materials in spinal reconstruction is comparable to that of autologous bone, with satisfactory efficacy and safety.

Osteosarcoma is a common bone sarcoma that often occurs in childhood and adolescence. In recent years, the efficacy of osteosarcoma treatments has been improved by adjuvant chemotherapies and surgical approaches. However, poor prognosis often occurs among osteosarcoma patients due to recurrence, metastasis, or drug resistance problems. Cancer stem cells (CSCs), a specific type of tumor malignant cells with stem cell-like properties, have been reported to be responsible for tumor origination, aggression, metastasis, recurrence, and drug resistance. CSCs have been identified in osteosarcomas treatment, which exhibits self-renewal, multi-potency, and enhanced drug resistance. Therefore, in the present narrative review, we intend to summarize the role of lncRNAs in regulating CSCs and their effectiveness in the treatment of osteosarcoma.The databases PubMed (Medline), Web of Science, Embase, Scopus, and Cochrane Library, were used for the presented study. The keywords we used to complete our search are 'lncRNA', 'Stem cell', and 'osteosarcoma'. A total of over 800 relevant articles, with a time limit from 2010 to 2021, were identified according to search strategy. Duplicate records and review articles were excluded by their titles and abstracts. Finally, we found about 80 articles matching our inclusion criteria, which included about 13 relevant studies focusing on both the mechanism and effectiveness of osteosarcomas treatment among osteosarcoma patients.CD133, CD117, ALDH, and Stro-1 are validated as the stem cell biomarkers in osteosarcoma CSCs. Accumulating evidence has revealed that lncRNAs, containing HIF2PUT, SOX2-OT, MALAT1, THOR, B4GALT1-AS1, H19, PVT1, FER1L4, LINK-A, DANCR, and DLX6-AS1, play a potential role in regulating CSCs in osteosarcoma. The drug resistance, inhibition of the relapse, and metastasis in osteosarcoma could be avoided via regulating lncRNAs of targeting CSCs.Multiple lncRNAs regulate CSCs in osteosarcoma via various molecular mechanisms. This review demonstrated that the method of eliminating CSCs by targeting these lncRNAs is a safe, effective, and a well-tolerated way for osteosarcoma patients, which shows a broad research prospect in tumor diagnoses and therapies. However, this method should be further demonstrated by better animal models and more clinical experiments.

In this work, the failure behavior of a commercial chip size packaging (CSP) with flip chip solder joint was investigated under the coupling condition of thermal cycling and electrical current. The damage behavior of solder joint was real-time monitored through the electrical resistance response. The microstructure evolution under the coupling condition were observed. The failure was classified as three modes, i.e., the cracking within solder on the PCB side (mode I), the cracking along the solder/IMC interface (mode II) and the detachment between the solder and chip due to the complete dissolving of Cu UBM layer (mode III). At low current density the mode I accounted for a large percentage while the mode II and mode III accounted for a large percentage at high current density. Based on the Weibull distribution of failure life, it was found that the mean time to failure sharply decreased with the increasing current density. A lifetime prediction model was constructed for the reliability test under coupling condition of thermal cycling and electrical current.

MicroRNAs are small non-coding RNAs that regulate gene expression at the post-transcriptional level which have been reported to be involved in the pathogenesis of various cancers. In the present study, we found that miR-497 was downregulated in osteosarcoma tissues. Gain and loss of function studies were carried out to investigate the effect of miR-497 on the growth of osteosarcoma cells. The results indicated that miR-497 inhibited the growth of osteosarcoma cells. Furthermore, bioinformatics analysis predicted plexinA4 and CDK6 as targets of miR-497, which was afterward confirmed by luciferase activity assay and rescue experiments. These findings suggested that miR-497, plexinA4 and CDK6 may serve as novel potential makers for osteosarcoma diagnostics and therapy.

本文系统回顾和总结颈椎后路减压术后颈椎后凸改变的危险因素及预防措施，为颈椎手术治疗策略的选择和制定提供有益的参考。.

The three optical absorption bands and EPR parameters of the [CuO

The electromigration (EM) lifetime of copper pillars were investigated by orthogonal tests. According to the Black’s mean-time-to-failure equation, the activation energy and exponent of current density were calculated to be 0.88 eV and 1.64, respectively. The microstructure evolution of the joints under current stressing was observed. It was found that the Sn solder was usually depleted before the joint failed, which means the joint was only composed of Cu6Sn5 and Cu3Sn phases as a Cu/Cu3Sn/Cu6Sn5/Cu3Sn/Cu structure after a period of EM test. Three failure modes were observed: failure along the Cu/Cu3Sn interface at the cathode side, failure along the Cu/Cu3Sn interface at the anode side and brittle fracture through the IMCs. The percentages of these three failure modes are 55, 24 and 21 %, respectively. The formation of Kirkendall voids was suggested to be the key factor for the EM failure of the Cu pillar joints. Before the Sn solder was depleted, voids were mainly formed at the Cu6Sn5/Sn interface at the cathode, which is dominated by the Cu flux induced by current; while after the Sn solder was depleted, voids formation is dominated by the chemical diffusion.

Sn–Ag–Cu solder interconnects were made by solidifying the solder balls in a magnetic field and subsequently tested for their electromigration behavior. The orientation of the tin grains was analyzed by electron backscattered diffraction. It was found that the c-axis of Sn grain tended to rotate away from the direction of the magnetic field during solidification, resulting in an enhanced electromigration resistance for the solder joint when the current was applied along the direction of the magnetic field, as evidenced by a smaller electromigration-induced polarity effect in the growth of the interfacial intermetallic compound. Such a reduced polarity-effect of electromigration is shown to agree well with the anisotropy in the diffusivity of the active diffusion species, Cu, in the tetragonal Sn. The difference of free energy change caused by the anisotropy in the magnetic susceptibility of the tetragonal Sn during solidification is suggested to be the main factor for this phenomenon.

BiFeO 3 ferrite ceramics were synthesized by spark plasma sintering (SPS) and conventional solid-state synthesis in conjunction with high-energy ball milling. They were evaluated by different characterization techniques such as X-ray diffraction, scanning electron microscopy, and dielectric, ferroelectric and magnetic measurements. The 750 °C-SPS prepared ceramic samples possessed a single perovskite structure and they were compared with the conventionally synthesized ones. The relative density and average grain size were approximately 95% and 300 nm for the conventionally prepared ones. In comparison with the conventionally synthesized ceramics, the SPS-prepared ones exhibited improved dielectric, ferroelectric and magnetic properties. These should be associated with high-density, fine-grained and uniform microstructure created by SPS in conjunction with high-energy ball milling, which could be a promising technique for fabricating high-quality BiFeO 3 multiferroic ceramics.

The liquid oxidation behaviors of Sn–40Bi–2Zn and Sn–40Bi–2Zn–0.005Al solders were investigated from thermal dynamics and kinetics analysis. The characteristics of surface oxidation film at 170 °C were studied by thermo gravimetric analysis and X-ray photoelectron spectroscopy (XPS). Sn–40Bi–2Zn solder performed inferiorly in oxidation prevention performance, due to the formation of ZnO, which exhibits lower Gibbs free energy of formation and higher growth rate. Trace amount of Al addition, however, alleviated the oxidation behavior of Zn. XPS depth profile results indicated that the surface layer of Sn–40Bi–2Zn–0.005Al consisted of oxides of Al and Zn formed on the outer surface of the solder film and in the subsequent layer, mainly formed by the oxides of Sn, Bi. Al, basically formed as Al2O3, segregated towards the outer surface, seemed to deter the Zn oxidation on the solder surface.

Effects of electromigration on microstructure and tensile property were studied in the Sn–1Ag–0.5Cu and Sn–1Ag–0.5Cu–1Zn solder interconnects. While the polarity effect and strength reduction from electromigration occurred in the Sn–1Ag–0.5Cu solder interconnects, they were suppressed by the Zn addition in the Sn–1Ag–0.5Cu–1Zn solder interconnects. Such a strong effect of Zn was explained by the strong binding of Zn with Cu, which prevented the dissolution of the IMC at the cathode, and by the reverse migration of the Zn elements, which counteracted the increase in the vacancy concentration so that the strength reduction was successfully inhibited.

Morphological changes from electromigration were examined on microsized Sn-Ag-Cu, pure Sn, and single-crystal Sn solder interconnects. It was found that both grain structure and alloying had a strong influence on the form of electromigration damage. In polycrystal Sn, grain boundary grooves were the primary form of electromigration damage, while in single-crystal Sn interconnects wavy surface relief appeared following electromigration. Alloying with Ag and Cu encouraged formation of Sn hillocks and Cu6Sn5 intermetallic compound (IMC) segregation. The grain boundary grooves were related to the divergence of the vacancy concentration at grain boundaries, which induced Sn grain tilting or sliding. Removal of the grain boundaries in the single-crystal interconnect made surface diffusion the primary electromigration mechanism, resulting in wavy surface relief after long electromigration time. In Sn-Ag-Cu alloy, directional flow of Cu caused Cu6Sn5 IMC segregation, which produced large compressive stress, driving the stressed grains to grow into hillocks.

The effect of electromigration on stress relaxation behavior of pure tin solder joints was investigated. It was found that the stress relaxation rate was accelerated significantly after the sample was subjected to current stressing. The accelerating effect increased with the current stressing time. Measurements of the activation energy and stress exponent suggested that the dominant mechanism of the stress relaxation of pure tin solder joint went from dislocation climb to grain boundary diffusion after electromigration. As a result of grain boundary diffusion and sliding, grain boundary grooves were observed on the surface of the tin solder joints after electromigration. The groove was associated with the divergence of vacancy concentration at the grain boundaries. The vacancy concentration at the grain boundaries, which increased with the current stressing time, promoted the atomic diffusion along the grain boundaries, resulting in a higher stress relaxation rate. (C) 2010 Elsevier B.V. All rights reserved.

In this study the authors present and discuss the results of the investigation on the fatigue fracture behaviors in a series of as-soldered and thermal-aged copper/lead-free solder joints deformed under both monotonic and cyclic loadings. The observation results showed that fatigue cracks generally initiate around the IMC/solder interface when the loading axis is vertical to the interface. The intrinsic deformation behaviors are little different for different solder joints resulting from strain localization induced by the stain mismatch. Fracture surface observations revealed the crack propagation path and fatigue resistance of the solder joints to be affected by the yield strength and mechanical property of the solder. When the copper/solder interface is parallel to the loading axis, the interfacial IMC layer failed approximately perpendicular to the interface when the cumulative strain exceeded the fracture strain, then the cracks propagated to the IMC/solder interface, leading to the fracture along the interface. The failure mechanisms and factors influencing interfacial fatigue are discussed.

Effects of Zn addition on microstructure and tensile properties of Sn-1Ag-0.5Cu alloy were investigated. It was found that after the Zn addition, the Cu(6)Sn(5) and Ag(3)Sn phases were gradually replaced by the Cu(5)Zn(8), Ag(5)Zn(8) and AgZn(3) phases and the amount of them were increased with increasing Zn content. The tensile tests showed that while the elongation of the alloy decreased with increasing Zn content, the strength was increased by Zn additions for Zn content

Effects of electromigration on microstructure, shear strength, and fracture behavior of solder joints were investigated by single-ball shear samples of eutectic Sn-3.8Ag-0.7Cu (SAC) joined by Cu plates at two sides. The electromigratipn tests were conducted at a current density of about 1.1x10(3) A/cm(2) and a working temperature of about 83 degrees C. The results showed that the shear strength and flow stress decreased greatly after current stressing. Such a decrease was associated with no significant loss of the fracture strain at short electromigration but a great reduction in the fracture strain after long-term current stressing. The variation of the fracture strain with the electromigration time was shown to result from the shift of the fracture surface from the center of the solder towards the intermetallic compound (IMC) interface at the cathode.

X-ray photoelectron spectroscopy has been used to measure the valence band offset (VBO) of the w-InN/h-BN heterojunction. We find that it is a type-II heterojunction with the VBO being −0.30 ± 0.09 eV and the corresponding conduction band offset (CBO) being 4.99 ± 0.09 eV. The accurate determination of VBO and CBO is important for designing the w-InN/h-BN-based electronic devices.

Tensile stress–strain response of an equal channel angularly pressed (ECAPed) Sn–3.8Ag–0.7Cu alloy was investigated to seek a mechanistic understanding of the time-dependent deformation in Sn-rich alloys. It was found that the deformation behavior of the ECAPed alloy had a stronger rate-dependence than the as-cast alloy. At low strain rates, the ECAPed alloy exhibited a higher ductility but a lower flow stress. During tensile deformation, the equiaxed Sn grains were stretched into thin strips. In comparison, the slip steps were primary feature within single grain at high strain rates. The enhanced rate-dependence of the ECAPed alloy was related to greater tendency for grain boundary diffusion due to the increase in the grain boundary density.

Cyclic stress–strain response of an equal channel angularly pressed Sn-3.8Ag-0.7Cu alloy was investigated to seek a mechanistic understanding of cyclic softening in Sn-rich alloys. The equal channel angular pressing (ECAP) was applied to modify the microstructure of the solder alloy by breaking up the needlelike Ag3Sn intermetallic phase into fine granules and by reducing the large β-Sn dendrites into smaller and equiaxed grains. The extruded alloys were subjected to strain-controlled fatigue test at various strain amplitudes. It was found that the extruded alloy exhibited a sharp decrease of the stress amplitude within the initial few cycles compared with the as-cast alloy. After only a few cycles, the alloy suffered from noticeable surface damage. In situ scanning electron microscopy observations of the cyclic bending specimens revealed an approximately logarithmic relationship between crack density and the number of cycles. A theoretical model of microcrack accumulation was constructed to explain the rapid cyclic softening behavior. The predicted results, based on the model, agreed well with the experimental data and indicated that the rapid softening had resulted from an increased tendency for grain boundary cracking in the ECAPed microstructure due to the increase in the grain boundary area per unit volume and the reduced resistance of Ag3Sn to grain boundary sliding.

Electrodeposited Ag film was explored as a potential interfacial barrier to Bi segregation for suppressing the interfacial embrittlement of Cu/SnBi interconnects. The presence of Ag film introduced Ag3Sn intermetallic layer at the interface, which effectively prevented Bi from reaching the Cu/intermetallic interface. When the persistent slip bands (PSBs) in the Cu single crystal were driven to impinge the Cu/Cu3Sn interface, interfacial cracking was averted and instead superceded by cracking of intermetallic compounds (IMCs) at the interface.

On the metalorganic chemical vapour deposition growth of AlN, by adjusting H-2+N-2 mixture gas components, we can gradually control island dimension. During the Volmer - Weber growth, the 2-dimensional coalescence of the islands induces an intrinsic tensile stress. Then, this process can control the in-plane stress: with the N-2 content increasing from 0 to 3 slm, the in-plane stress gradually changes from 1.5 GPa tensile stress to - 1.2GPa compressive stress. Especially, with the 0.5 slm N-2 + 2.5 slm H-2 mixture gas, the in-plane stress is only 0.1 GPa, which is close to the complete relaxation state. Under this condition, this sample has good crystal and optical qualities.

ZnO thin films were grown by metal-organic chemical vapour deposition using methanol as oxidant. Rapid thermal annealing (RTA) was performed in an ambient of one atmosphere oxygen at 900 degrees C for 60 s. The RTA properties of the films have been characterized using scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, photoluminescence spectra and Hall measurement. The grains of the film were well coalesced and the surface became denser after RTA. The full-width at half maximum of rocking curves was only 496 arcsec. The ZnO films were also proved to have good optical quality. The Hall mobility increased to 43.2 cm(2) V-1 s(-1) while the electron concentration decreased to 6.6 x 10(16) cm(-3). It is found that methanol is a potential oxidant for ZnO growth and the quality of ZnO film can be improved substantially through RTA.

Recent fatigue studies of Sn-rich Pb-free solder alloys are reviewed to provide an overview of the current understanding of cyclic deformation, cyclic softening, fatigue crack initiation, fatigue crack growth, and fatigue life behavior in these alloys. Because of their low melting temperatures, these alloys demonstrated extensive cyclic creep deformation at room temperature. Limited amount of data have shown that the cyclic creep rate is strongly dependent on stress amplitude, peak stress, stress ratio and cyclic frequency. At constant cyclic strain amplitudes, most Sn-rich alloys exhibit cycle-dependent and cyclic softening. The softening is more pronounced at larger strain amplitudes and higher temperatures, and in fine grain structures. Characteristic of these alloys, fatigue cracks tend to initiate at grain and phase boundaries very early in the fatigue life, involving considerable amount of grain boundary cavitation and sliding. The growth of fatigue cracks in these alloys may follow both transgranular and intergranular paths, depending on the stress ratio and frequency of the cyclic loading. At low stress ratios and high frequencies, fatigue crack growth rate correlates well with the range of stress intensities or J-integrals but the time-dependent C* integral provides a better correlation with the crack velocity at high stress ratios and low frequencies. The fatigue life of the alloys is a strong function of the strain amplitude, cyclic frequency, temperature, and microstructure. While a few sets of fatigue life data are available, these data, when analyzed in terms of the Coffin–Mason equation, showed large variations, with the fatigue ductility exponent ranging from −0.43 to −1.14 and the fatigue ductility from 0.04 to 20.9. Several approaches have been suggested to explain the differences in the fatigue life behavior, including revision of the Coffin–Mason analysis and use of alternative fatigue life models.

Valence-band type Auger lines in Al doped and undoped ZnO were comparatively studied with the corresponding core level x-ray photoelectron spectrography (XPS) spectra as references. Then the shift trend of energy levels in the valence band was that p and p-s-d states move upwards but e and p-d states downwards with increasing Al concentration. The decreased energy of the Zn 3d state is larger than the increased energy of the 0 2p state, indicating the lowering of total energy. This may indicate that Al doping could induce the enhancement of p-d coupling in ZnO, which originates from stronger Al-O hybridization. The shifts of these states and the mechanism were confirmed by valence band XPS spectra and 0 K-edge x-ray absorption spectrography (XAS) spectra. Finally, some previously reported phenomena are explained based on the Al doping induced enhancement of p-d coupling.

This study was to test the hypothesis that the interaction between abscisic acid (ABA) and ethylene may be involved in mediating the effects of water stress on grain filling. Two high lodging-resistant rice (Oryza saliva L.) cultivars were pot-grown. Three treatments, well-watered, moderate water-stressed (MD), and severe water-stressed (SD), were imposed from 9 d post-anthesis until maturity. Grain filling rate and grain weight were significantly increased under MD but decreased under SD. The two cultivars behaved the same. ABA concentration in the grains was very low during the grain filling stage, reaching a maximum when the grain filling rate was highest. Both the grain filling rate and ABA concentration were substantially enhanced by water stress. In contrast to ABA, concentrations of ethylene and 1-aminocylopropane -1-carboxylic acid (ACC) in the grains were very high at early grain filling stage and sharply decreased during the linear period of grain growth. MD reduced, whereas SD remarkably increased, their accumulation. The ratio of ABA to ACC was increased in MD grains but decreased in SD grains, indicating that there was a greater enhancement of A BA concentration than ethylene production in the MD treatment only. Application of cobalt ion (inhibitor of ethylene synthesis) or ABA at the early grain filling stage significantly increased grain filling rate. Spraying with ethephon (ethylene-releasing agent) or fluridone (inhibitor of ABA synthesis) had the opposite effect. The results suggest that antagonistic interactions between ABA and ethylene mediate the grain filling rate, and a high ratio of ABA to ethylene enhances grain filling rate.

This study investigated the possibility that abscisic acid (ABA) and cytokinins may mediate the effect of water deficit that enhances plant senescence and remobilization of pre-stored carbon reserves. Two high lodging-resistant wheat (Triticum aestivum L.) cultivars were field grown and treated with either a normal or high amount of nitrogen at heading. Well-watered (WW) and water-stressed (WS) treatments were imposed from 9 d post-anthesis until maturity. Chlorophyll (Chl) and photosynthetic rate (Pr) of the flag leaves declined faster in WS plants than in WW plants, indicating that the water deficit enhanced senescence. Water stress facilitated the reduction of non-structural carbohydrate in the stems and promoted the re-allocation of prefixed 14C from the stems to grains, shortened the grain filling period and increased the grain filling rate. Water stress substantially increased ABA but reduced zeatin (Z) + zeatin riboside (ZR) concentrations in the stems and leaves. ABA correlated significantly and negatively, whereas Z + ZR correlated positively, with Pr and Chl of the flag leaves. ABA but not Z + ZR, was positively and significantly correlated with remobilization of pre-stored carbon and grain filling rate. Exogenous ABA reduced Chl in the flag leaves, enhanced the remobilization, and increased grain filling rate. Spraying with kinetin had the opposite effect. The results suggest that both ABA and cytokinins are involved in controlling plant senescence, and an enhanced carbon remobilization and accelerated grain filling rate are attributed to an elevated ABA level in wheat plants when subjected to water stress.

Two Mg-doped GaN films with different doping concentrations were grown by a metalorganic chemical vapor deposition technique. Photoluminescence (PL) experiments were carried out to investigate the optical properties of these films. For highly Mg-doped GaN, the PL spectra at 10 K are composed of a blue luminescence (BL) band at 2.857 eV and two excitonic luminescence lines at 3.342 eV and 3.282 eV, in addition to a L2 phonon replica at 3.212 eV. The intensity of the L1 line decreases monotonously with an increase in temperature. However, the intensity of the L2 line first slowly increases at first, and then decreases quickly with an increase in temperature. The two lines are attributed to bound excitonic emissions at extended defects. The BL band is most likely due to the transition from deep donor Mg–VN complex to Mg shallow acceptor. From the temperature dependence of the luminescence peak intensity of the BL band, the activation energy of acceptor Mg was found to be 290 meV.

In this paper, we present a high-resolution wet etching technology of 1.5 μm-thick electroless nickel alloy film. The minimum feature size was successfully reduced to about 10 μm. The developed etching technology is well compatible to conventional micro-electro-mechanical systems (MEMS) processes, and has been successfully utilized on the 4-inch wafer as well. It could be expected more practical application of electroless nickel alloy film in not only MEMS but also electronic packaging.

Mobility limited by the scattering of a phosphorous vacancy‐induced deep center in In0.5Ga0.5P alloy grown by liquid‐phase epitaxy on a (100) GaAs substrate has been investigated by means of Hall mobility and deep‐level transient spectroscopy measurements. Two kinds of scattering potentials, Gaussian well type and square‐well type, were considered. It was found that the scattering potential can be better described by the Gaussian‐type potential than the square‐well one. The mobility limited by deep center scattering has been fully calculated and analyzed. As a result, the mobility is characterized by a temperature dependence of T−1/2 in the temperature range from 77 to 400 K. The point defect scattering severely reduces the total mobility as its concentration increases. In addition, the scattering case when there is an electron trapped in the Gaussian potential well was also quantitatively investigated.

The [Formula: see text] system of 80Se2 has been observed from a discharge flow system where [Formula: see text] molecules were excited by electronic energy transfer from metastable oxygen, O2(a1Δg), to ground state Se2. Emission spectra of the 0–0, 0–1, 0–2, 1–1, 1–2, 1–3, and 2–3 bands have been recorded at high resolution with a Bomem Fourier-transform spectrometer. The rotational structures of the bands are determined by magnetic dipole selection rules. Detailed analysis has yielded accurate molecular constants for the [Formula: see text] and X21g states of 80Se2.

Results are reported of electric‐field dependence on thermal emission of electrons from the 0.40 eV level at various temperatures in InGaP by means of deep‐level transient spectroscopy. The data are analyzed according to the Poole–Frankel emission from the potentials which are assumed to be Coulombic, square well, and Gaussian, respectively. The emission rate from this level is strongly field dependent. It is found that the Gaussian potential model is more reasonable to describe the phosphorus‐vacancy‐induced potential in InGaP than the Coulombic and square‐well ones.

With the miniaturization of the solder joint, the dependence of the property on the microstructure orientation has become increasingly notable. In this work, a lead-free Sn3.8Ag0.7Cu solders with certain microstructure orientation were processed by the Bridgman method in a horizontal furnace. After tensile tests at different strain rates, it was found that the tensile strengths of the materials were strongly dependent on the growth direction. The strength of the sample with a gauge perpendicular to the growth direction was much lower than that parallel to the growth direction. While the radial Cu6Sn5 and Ag 3 Sn IMCs were distributed uniformly around the equiaxed tin grains perpendicular to the growth direction, the well-arranged needle shaped IMCs were oriented along the growth direction. At an applied tensile strain of 20%, the cross-slip lines were found throughout the polished surface and then impinged to the IMCs, resulting in the breaking of the IMCs. The variation of the tensile property with microstructural orientation may be attributed to the modification of the mobile slip system and the interaction of the slip lines with the IMC phase.

A wideband high CMRR instrumentation amplifier is described. Based on a previously reported current-mode design, the improved amplifier features excellent CMRR performance of better than 60 dB up to 200 kHz with unity differential gain.

Zn was added into Sn-Bi solder to investigate the effect of Zn on the microstructure of the alloy. Zn addition was found to refine and redistribute the Bi-rich phase. With Zn addition, a different intermetallic compound, Cu 5 Zn 8 was formed at the Sn-Bi-Zn/Cu interface upon reflow. After aging, the Bi segregation was not observed at the Sn-Bi-Zn/Cu interface while a continuous Bi segregation layer appeared in the Sn-Bi/Cu interface. The Zn addition into the solder freed Sn near the interface from interfacial reaction, which suppressed the occurrence of Bi segregation layer.

Hole trap levels in a Mg-doped GaN grown by metalorganic vapor phase epitaxy (MOVPE) are studied with deep level transient spectroscopy (DLTS). The Mg concentration of the sample was 4.8 x 10(19) cm(-3), but the hole concentration was as low as 1.3 x 10(17) cm(-3) at room temperature. The DLTS spectrum has a dominant peak D-1 with activation energy of 0.41+/-0.05 eV, accompanied by two additional peaks with activation energies of 0.49+/-0.09 eV (D-2) and 0.59+/-0.05 eV (D-3). It was found that the dominant peak D-1 consists of five peaks, each of which has different activation energy and capture cross section. A relevant model for these levels is presented in relation to the Mg-N-H complexes. (C) 1998 American Institute of Physics. [S0003-6951(98)04340-X].

We have observed an extremely narrow absorption spectrum due to bound-to-continuum transition in GaAs/AlxGa1-xAs multiple quantum wells (MQWs). Its linewidth is only about one tenth of the values reported previously. Our calculation indicates that the broadening of the excited state in the continuum has little contribution to the absorption linewidth. We have grown a sample whose MQW region contains two kinds of wells with a minor thickness inhomogeneity. Its resultant absorption linewidth is six times as large as that of homogeneous well sample, which is in good agreement with our theoretical analysis. Thus we can suggest that the wider absorption spectra reported by many authors may be due to the well width inhomogeneity. (C) 1998 American Institute of Physics. [S0003-6951(98)03430-5]

Using deep level transient spectroscopy (DLTS) the conduction-subband energy levels in a V-shaped potential well induced by Si-delta doping in GaAs were determined. Self-consistent calculation gives four subbands in the well below the Fermi level. Experimentally, two DLTS peaks due to electron emission from these subbands were observed. Another two subbands with low electron concentration are believed to be merged into the adjacent DLTS peak. A good agreement between self-consistent calculation and experiment was obtained. (C) 1994 American Institute of Physics.

We estimated associations between polymorphisms in the gene encoding microsomal epoxide hydrolase (mEH) among 464 cases diagnosed with first occurrence of colorectal adenoma and 510 matched controls. In an analysis controlling only for the matching variables, we found little or no association between adenoma and mEH genotypes defined by polymorphisms at either codon 113 and 139 or mEH activity predicted by both polymorphisms. However, in subsequent analyses, high predicted mEH activity was significantly associated with adenoma among certain subgroups defined by smoking history [odds ratio (OR), 4.27; 95% confidence interval (CI), 1.68-10.81 among current smokers; interaction, P = 0.11], meat consumption (OR, 2.47; CI, 0.99-6.19 among individuals who regularly eat well-done meat; interaction, P = 0.03), and genotypes for the *A/*B polymorphism in the gene encoding glutatione S-transferase M3 (OR, 2.60; CI, 1.28-5.28 among individuals with *A*A genotype; interaction, P = 0.03). These findings are consistent with causal roles for environmental polycyclic aromatic hydrocarbons and genetically encoded variants in enzymes whose actions lead to the production of activated polycyclic aromatic hydrocarbon metabolites.

In this work, we present one flexible 3D micro-coil. This 3D micro-coil is successfully prepared in a thin polymer film with a thickness of 120μm. The flexible coil is expected to be used in current sensing and energy harvesting MEMS those require a large deformation degree to wrap target object. A typical micro-machined 3D coil is composed of bottom, vertical and top windings. We firstly adopt through polymer vias (TPVs) and metal filling technology to fabricate the vertical windings. A high-speed copper electrodeposition technology of TPVs is developed to obtain void-free vertical windings.

In the present study transcriptional activities has been measured with different fragments of the 5′-flanking sequence of the human monoamine oxidase (MAO) genes linked to human growth hormone which was used as a reporter gene. SH-SY5Y neuroblastoma cells and 1242 MG glioma cells were compared under basal conditions as well as after treatments with different drugs. Under basal conditions, the relative reporter activities of the different promoter fragments were similar for both cell lines. No changes in promoter activities, were observed when cells were treated with L-deprenyl, lithium chloride or raclopride. In contrast, increases (2–3-fold) in both reporter gene expression and enzyme activity were observed after ethanol treatment of cells transfected with MAO-B fragments. Gel retardation analysis showed that ethanol caused changes in transcription factor binding to the MAO-B core promoter in both the SH-SY5Y and 1242 MG cell lines in a cell-type specific fashion.