Search

We designed a versatile analog front-end chip, called LTARS, for TPC-applications, primarily targeted at dual-phase liquid Ar-TPCs for neutrino experiments and negative-ion $\mu$-TPCs for directional dark matter searches. Low-noise performance and wide dynamic range are two requirements for reading out the signals induced on the TPC readout channels. One of the development objectives is to establish the analog processing circuits under low temperature operation, which are designed on function block basis as reusable IPs (Intellectual Properties). The newly developed ASIC was implemented in the Silterra 180~nm CMOS technology and has 16 readout channels. We carried out the performance test at room temperature and the results showed an equivalent noise charge of 2695$\pm$71~e$^-$ (rms) with a detector capacitance of 300~pF. The dynamic range was measured to be 20--100~fC in the low-gain mode and 200--1600~fC in the high-gain mode within 10\% integral nonlinearity at room temperature. We also tested the performance at the liquid-Ar temperature and found a deterioration of the noise level with a longer shaper time. Based on these results, we also discuss a unique simulation methodology for future cold-electronics development. This method can be applicable to design the electronics used at low temperature., Comment: 15 pages, 13 figures, accepted by Jour. Instr

Exon 20 insertion (Ex20Ins) mutations are the third most prevalent epidermal growth factor receptor (EGFR) activating mutation and the most prevalent HER2 mutation in non-small cell lung cancer (NSCLC). Novel therapeutics for the patients with Ex20Ins mutations are urgently needed, due to their poor responses to the currently approved EGFR and HER2 inhibitors. Here we report the discovery of highly potent and broadly effective EGFR and HER2 Ex20Ins mutant inhibitors. The co-crystal structure of compound 1 b in complex with wild type EGFR clearly revealed an additional hydrophobic interaction of 4-fluorobenzene ring within a deep hydrophobic pocket, which has not been widely exploited in the development of EGFR and HER2 inhibitors. As compared with afatinib, compound 1 a exhibited superior inhibition of proliferation and signaling pathways in Ba/F3 cells harboring either EGFR or HER2 Ex20Ins mutations, and in the EGFR P772_H773insPNP patient-derived lung cancer cell line DFCI127. Our study identifies promising strategies for development of EGFR and HER2 Ex20Ins mutant inhibitors.

This study presents a novel variable stiffness oscillator for vibration energy harvesting with resonant frequency tunability. Methods of tuning frequency include changing dimensions, moving center of gravity of the proofmass, and adding positive or negative stiffness in electrostatic ways, piezoelectric ways, or magnetic ways. In this study, an EPM-based variable stiffness mechanism for a vibration energy harvester was proposed and applied to a cantilever oscillator to examine its basic performance. It was described that the holding force of the EPM significantly depended on the activation process, and it was important to realize the full activation to exploit the potential performance of the EPM. Then, it was shown that the resonance frequency of the cantilever oscillator can be changed from 26Hz to 42 Hz when the EPM placed in the middle of the beam was fully activated, while the partially activated EPM could not maintain the resonance because of its weak holding force.

Insertion mutations in EGFR and HER2 both occur at analogous positions in exon 20. Non–small cell lung cancer (NSCLC) patients with tumors harboring these mutations seldom achieve clinical responses to dacomitinib and afatinib, two covalent quinazoline–based inhibitors of EGFR or HER2, respectively. In this study, we investigated the effects of specific EGFR and HER2 exon 20 insertion mutations from NSCLC patients that had clinically achieved a partial response after dacomitinib treatment. We identified Gly770 as a common feature among the drug-sensitive mutations. Structural modeling suggested that this mutation may facilitate inhibitor binding to EGFR. Introduction of Gly770 into two dacomitinib-resistant EGFR exon 20 insertion mutants restored sensitivity to dacomitinib. Based on these findings, we used afatinib to treat an NSCLC patient whose tumor harbored the HER2 V777_G778insGSP mutation and achieved a durable partial response. We further identified secondary mutations in EGFR (T790M or C797S) and HER2 (C805S) that mediated acquired drug resistance in drug-sensitive EGFR or HER2 exon 20 insertion models. Overall, our findings identified a subset of EGFR and HER2 exon 20 insertion mutations that are sensitive to existing covalent quinazoline–based EGFR/HER2 inhibitors, with implications for current clinical treatment and next-generation small-molecule inhibitors. Cancer Res; 77(10); 2712–21. ©2017 AACR.

We prepared a block copolymer composed of polythiophene (PT) with cinnamate groups and poly(ethylene oxide) (PEO), which are connected through a cleavable acetal bond, aiming at constructing donor/acceptor heterostructures through post deposition of acceptor molecules into donor template networks. The block copolymer films showed phase-separated structures with domain sizes of 10–100 nm. Irradiation with UV light afforded crosslinked films through [2+2] cyclodimerization of cinnamate groups. Then, PEO was removed by acidic cleavage of the acetal bond, yielding PT template networks. Taking advantage of the insoluble networks, a fullerene derivative was deposited into the PT templates through a spin-coating process to form donor/acceptor heterostructures. The introduction of the fullerene derivative was confirmed by UV-Vis absorption and fluorescence spectroscopy. This strategy of depositing acceptor molecules into donor template networks, instead of spin-coating from donor/acceptor blend solutions, could be applied to improve the phase-separated structures and power conversion efficiencies of polymer solar cells.

Purpose: Efforts to discover drugs that overcome resistance to targeted therapies in patients with rare oncogenic alterations, such as NTRK1 and ROS1 rearrangements, are complicated by the cost and protracted timeline of drug discovery. Experimental Design: In an effort to identify inhibitors of NTRK1 and ROS1, which are aberrantly activated in some patients with non–small cell lung cancer (NSCLC), we created and screened a library of existing targeted drugs against Ba/F3 cells transformed with these oncogenes. Results: This screen identified the FDA-approved drug cabozantinib as a potent inhibitor of CD74–ROS1-transformed Ba/F3, including the crizotinib-resistant mutants G2032R and L2026M (IC50 = 9, 26, and 11 nmol/L, respectively). Cabozantinib inhibited CD74–ROS1-transformed Ba/F3 cells more potently than brigatinib (wild-type/G2032R/L2026M IC50 = 30/170/200 nmol/L, respectively), entrectinib (IC50 = 6/2,200/3,500 nmol/L), and PF-06463922 (IC50 = 1/270/2 nmol/L). Cabozantinib inhibited ROS1 autophosphorylation and downstream ERK activation in transformed Ba/F3 cells and in patient-derived tumor cell lines. The IGF-1R inhibitor BMS-536924 potently inhibited CD74–NTRK1-transformed compared with parental Ba/F3 cells (IC50 = 19 nmol/L vs. > 470 nmol/L). A patient with metastatic ROS1-rearranged NSCLC with progression on crizotinib was treated with cabozantinib and experienced a partial response. Conclusions: While acquired resistance to targeted therapies is challenging, this study highlights that existing agents may be repurposed to overcome drug resistance and identifies cabozantinib as a promising treatment of ROS1-rearranged NSCLC after progression on crizotinib. Clin Cancer Res; 23(1); 204–13. ©2016 AACR.

Background The axillary reverse mapping (ARM) procedure was developed to identify and preserve arm lymphatic drainage during axillary lymph node dissection (ALND), thereby theoretically reducing the incidence of arm lymphedema. However, the oncological safety of this procedure has not yet been determined. Methods Two hundred ninety-two patients with clinically negative nodes (cN0) underwent both sentinel lymph node (SLN) biopsy and ARM. SLN was identified by dye and gamma probe methods, and ARM nodes were identified using a fluorescence imaging system. If SLN was histologically positive, ALND was performed with removal of ARM nodes. Otherwise, identified ARM nodes were preserved unless they coincided with SLN. Postoperatively, SLN as well as ARM nodes were histologically examined with H&E staining. Results SLN was identified in 286 of 292 patients, and ARM nodes were identified in 90 patients. In 54 patients with positive SLN, SLN was the same as the ARM node in 19 patients (the concordance type), whereas it was not an ARM node in the remaining 35 patients (the separate type). Non-SLN and ARM node was not involved in 51 of 54 patients with positive SLN, while it was involved in 3 patients of the concordance type. Conclusions When ARM nodes were involved in patients with cN0, these were most often the SLN-ARM nodes. Therefore, it may be concluded that ARM nodes that do not coincide with SLNs might be preserved during ALND in SLN-positive patients.

Objectives Oncogenic HER2 mutations are present in 2–4% of lung adenocarcinomas, but the relevant clinical trials are unsatisfactory. The novel HER2 inhibitor poziotinib was recently developed and clinical trials are ongoing. We compared poziotinib with nine tyrosine kinase inhibitors (TKIs), and derived poziotinib-resistant clones to investigate the resistant mechanism. Materials and methods We introduced three common HER2 mutations A775_G776insYVMA (YVMA), G776delinsVC (VC) and P780_Y781insGSP (GSP), which account for 94% of HER2 exon 20 insertions in the literature, into Ba/F3 cells. We then compared the activity of poziotinib with that of nine TKIs (erlotinib, afatinib, dacomitinib, neratinib, osimertinib, AZ5104, pyrotinib, lapatinib, and irbinitinib), determined the 90% inhibitory concentration (IC90) through a growth inhibition assay, and defined a sensitivity index (SI) as IC90 divided by the trough concentration at the recommended dose as a surrogate for drug activity in humans. We also generated resistant clones by exposure to poziotinib in the presence of N-ethyl-N-nitrosourea, and HER2 secondary mutations that might serve as a resistance mechanism were searched. Results YVMA showed resistance to all tested drugs except neratinib, poziotinib and pyrotinib. Poziotinib was the only drug with an SI less than 10 for YVMA, the most common HER2 exon 20 insertion. We established 62 poziotinib-resistant clones, and among these, only C805S of HER2, which is homologous to C797S of the EGFR, was identified as a secondary mutation in 19 clones. We also revealed that heat shock protein (HSP) 90 inhibitors show potent anti-growth activity to the C805S secondary mutant clone. Conclusions Poziotinib showed the most potent activity against HER2 exon 20 mutations. We identified the secondary C805S at the covalent binding site of HER2 to poziotinib as a potential mechanism of acquired resistance. HSP90 inhibitors might be a therapeutic strategy for the C805S secondary mutation.

In recent years, flux switching machines (FSMs) have been an attractive research topic owing to their tremendous advantages of robust rotor structure, high torque, and high power capability suitable for intensive applications. However, most of the investigations are focusing on the inner-rotor structure, which is incongruous for direct drive applications. In this study, high torque and power densities of a new 12S-14P outer-rotor permanent magnet (PM) FSM with a DC excitation coil was investigated based on two-dimensional finite element analysis for in-wheel direct drive electric vehicle (EV). Based on some design restrictions and specifications, design refinements were conducted on the original design machine by using the deterministic optimization approach. With only 1.0 kg PM, the final design machine achieved the maximum torque and power densities of 12.4 Nm/kg and 5.93 kW/kg, respectively, slightly better than the inner-rotor HEFSM and interior PM synchronous machine design for EV.

In recent years, the occurrence in steel deck welds of fatigue cracks caused by deformation arising from vehicle travel has become conspicuous, and costs required for maintenance such as inspection and repair are rising. In response to this situation, the authors developed waffle-type slabs that use ultra high strength fiber reinforced concrete (UFC) for high durability and light weight on a par with that of steel slabs. Thus far, stress verification by finite element method (FEM) analysis and verification of safety against fatigue through wheel load running tests have been conducted. In the present study, load testing was performed on test specimens after subjecting them to the wheel load running test, for the purpose of identifying the failure mode and verifying safety in terms of fracture strength. As a result, the failure mode was identified as flexural failure, and the specimens were confirmed to have load-bearing capacity 7.5 times the design wheel load.近年，鋼床版の溶接部に車両の走行に伴う変形に起因する疲労き裂の発生が顕在化しており，点検や補修など維持管理に必要なコストが増加する傾向にある。そこで，筆者らは超高強度繊維補強コンクリート（UFC）を用い，耐久性が高く，しかも鋼床版並みに軽量なワッフル型UFC床版を開発している。これまでに，FEM解析による応力度の照査や輪荷重走行試験による疲労に対する安全性の検証を行っている。本研究では，破壊モードの確認および破壊耐力に対する安全性の検証を目的として，輪荷重走行試験後の試験体を用いた載荷実験を行った。その結果，破壊モードは曲げ破壊であり，設計輪荷重の7.5倍の耐力を有することを確認した。

High Glasgow Prognostic scores (GPSs) have been associated with poor outcomes in various tumors, but the values of GPS and modified GPS (mGPS) in patients with advanced esophageal cancer receiving chemoradiotherapy (CRT) has not yet been reported. We have evaluated these with respect to predicting responsiveness to CRT and long-term survival. Between January 2002 and December 2011, tumor responses in 142 esophageal cancer patients (131 men and 11 women) with stage III (A, B and C) and IV receiving CRT were assessed. We assessed the value of the GPS as a predictor of a response to definitive CRT and also as a prognostic indicator in patients with esophageal cancer receiving CRT. We found that independent predictors of CRT responsiveness were Eastern Cooperative Oncology Group (ECOG) performance status, GPS and cTNM stage. Independent prognostic factors were ECOG performance status and GPS for progression-free survival and ECOG performance status, GPS and cTNM stage IV for disease-specific survival. GPS may be a novel predictor of CRT responsiveness and a prognostic indicator for progression-free and disease-specific survival in patients with advanced esophageal cancer. However, a multicenter study as same regime with large number of patients will be needed to confirm these outcomes.

Background: The axillary reverse mapping (ARM) procedure is based on the hypothesis that the lymphatic drainage from the upper arm is different from that of the breast. However, the oncologic safety of the procedure has not yet been determined. Methods: The ARM nodes were identified using a fluorescence imaging system. Sentinel lymph node (SLN) biopsy was performed in patients with clinically uninvolved nodes. If the SLN was positive, ALND was performed with removal of ARM nodes. Otherwise, the identified ARM nodes were preserved unless they were the same as the SLN. Results: The ARM node was identified in 30 of 91 patients who underwent SLN biopsy, and it was the same as the SLN in 23 patients. However, in 13 patients with a positive SLN who subsequently underwent ALND, ARM nodes were tumor-free when they were not the same as the positive SLN. Conclusions: There are limits to the principle of non-overlap between breast and arm nodes. However, it may be feasible to spare ARM nodes during ALND in patients with clinically negative nodes. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-07-44.

Background: An inappropriate skin incision on the breast reduces the cosmetic benefit of breast-conserving surgery (BCS). Methods: To improve the cosmetic outcome, we have performed “Moving window” operation in which BCS can be performed via a periareolar incision (periareolar approach) and/or axillary incision (axillary approach) under direct visualization. Axillary lymph node dissection is also performed via an axillary incision. Results: Periareolar approach was performed in 65 patients and axillary approach in 43 patients. Average operation time was 130 minutes in periareolar approach and 131 minutes in axillary approach. Average blood loss was 37 mL and 50 mL, respectively. Postoperatively, the surgical margin of breast tissue was histologically confirmed to be negative in 107 (99%) of 108 patients, while two patients underwent reoperation because of positive surgical margin. Fifty-two patients (85%) in periareolar approach and 37 patients (86%) in axillary approach had excellent or good cosmetic results. With a mean follow-up of 36 months, one patient with DCIS developed in-breast recurrence, while 3 patients who had neoadjuvant chemotherapy developed in-breast recurrence. Conclusion: The moving window operation can improve a cosmetic outcome of the conserved breast without compromising the oncological safety. Moreover, it can reduce operating time and blood loss when compared with the endoscope-assisted BCS. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-15-13.

Bi2.5Y0.5Fe5O12 and Bi3Fe5O12 thin films were prepared on Gd3Ga5O12 substrates using a metal organic decomposition (MOD) method as magneto-optical indicators (MOI) to visualize the distribution of magnetic flux. Their structural and magneto-optical properties were studied. The Faraday rotations of Bi2.5Y0.5Fe5O12 and Bi3Fe5O12 thin films were 15.5 μm/degrees at a wavelength of 524 nm for the former and 23.0 μm/degrees at 530 nm for the latter. We found that these films prepared by MOD were suitable for MOI, because of their large Faraday rotation, in-plane magnetic anisotropy, and extinct magnetic domain structures.

Advanced sol–gel methods using a secondary solvent addition into (Pb, La)(Zr, Ti)O 3 (PLZT) sol–gel solution and a methanol pre-treatment of sapphire substrates are demonstrated. For the secondary solvent addition, the additive affected the crystallinity and electro-optic (EO) property of PLZT films and only methanol addition can improve them. In addition, the methanol pre-treatment is also appeared to be effective to improve film characteristics. Through these optimizations, epitaxially grown PLZT thin films on r-cut sapphire are obtained and a high Pockels coefficient which is comparable to those of bulk PLZTs is achieved. It is believed that these PLZT thin films are applicable for integrated EO devices and open the door for the future data communication systems.

CS-670 is a non-steroidal anti-inflammatory agent with an alpha,beta-unsaturated ketone structure. It exerts its pharmacological activity after being transformed to the active metabolite (2S,1'R,2'S)-trans-alcohol. Two consecutive reductions are needed for the formation of the active metabolite, reduction of the double-bond of the alpha,beta-unsaturated ketone moiety, followed by reduction of the resulting saturated ketone. The objective of the current study was to identify the enzyme responsible for reduction of the double-bond. An enzyme purified from rat liver cytosol as a single band on sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE) was analysed by a Mascot database search of nano-LC tandem mass spectrometry (MS/MS) data and the enzyme was identified as 2-alkenal reductase (EC 1.3.1.74), which is known as an beta-nicotinamide adenine dinucleotide phosphate (NADPH)-dependent alkenal/one oxidoreductase and has a role for leukotriene B(4) 12-hydroxydehydrogenase/15-ketoprostaglandinDelta13-reductase (LTB(4) 12-HD/PGR). The identification was confirmed by cloning LTB(4) 12-HD/PGR cDNA from rat liver, expressing it in Escherichia coli, and characterizing the properties of the enzyme. The identity was further supported by the subcellular localization in cytosol, a cofactor requirement for NADPH, substrate specificity, and substantial inhibition by 15-ketoPGF(2alpha), benzylideneacetophenone, indomethacin, and quercitrin. In addition to catalysing the biological reduction of eicosanoids, including prostaglandins, leukotrienes, and lipoxins, LTB(4) 12-HD/PGR was also determined to function as a xenobiotic-metabolizing enzyme.

The oxidation on nickel silicide (NiSi x ) during plasma etching and oxygen ashing is investigated for stable contact resistance on NiSi x . NiSi x exposed by various processes is observed by X-ray photoelectron spectroscopy. The oxidation on NiSi x is promoted by the fluorine that remains during etching and the oxide thickness on n + NiSi x is greater than that on p + NiSi x . The remaining fluorine after etching can be decreased by in-situ nitrogen plasma treatment during the post-etching process. Therefore, the oxidation progress with exposure to air and the difference in oxidation on NiSi x between n + and p + can be suppressed.

Research and development on hybrid excitation flux switching machines (HE-FSM) for various applications have been carried out in the last years. The designed HE-FSM consist of permanent magnet (PM) and DC field excitation coil (DC-FEC) as their main flux sources located on the stator, while a single piece rotor gives the advantages of robust rotor structure. Since most of the designed HE-FSMs utilize three-phase windings, more complicated design and control system are required to run the motor. Thus, a new design of single-phase ECore HE-FSM with several advantages of much simpler converter size and smaller battery package due to small voltage capacity when compared with conventional three-phase system is proposed. Consequently, the size of overall configuration systems will also be reduced resulting in reducing total weight and cost. In this paper, initial performances of 4S-4P, 4S-6P, 4S-8P and 4S-10P E-Core HE-FSM topologies are analyzed. Since 4S-10P design gives highest torque and power performances, deterministic design optimization approach is conducted to enhance much higher and optimum performances. As conclusion, the optimized E-core HE-FSM with 4S-10P topology has low back-emf, acceptable cogging torque with maximum torque and power of 208.857Nm and 47.31 kW, respectively.

Based on the recent requirements, high strength, high damping stainless alloy HIDAS was developed. The chemical compositions are Fe-12%Cr-22%Mn and Fe-12%Cr-22%Mn-2%Co. After solution annealing, microstructure consisting of austenite fcc , martensite hcp and bcc ’. When cold work was given, and increased. Damping capacity increased with the increase of phase. The mechanism of high damping capacity would come from the hysteretic motion of Shockley partial dislocations which are lying at interphase interface of /. This alloy has also high strength. This is due to fine structure of /. Because of these properties, HIDAS can be applied to machinery industries.

A shear horizontal-mode surface acoustic wave (SH-SAW) has the unique characteristic of complete reflection at a free edge normal to the direction of propagation, making it possible to construct a reflective delay line. A passive SAW strain sensor based on such a reflective delay line is presented. The reflective delay line is constructed on a 36° YX LiTaO 3 substrate. The SH-SAW velocity is shown to provide a reliable measure of the strain of a propagation surface, and incorporation of an oscillator circuit is demonstrated to allow wireless remote monitoring of strain using this sensor.

Fluorine incorporated diamond-like carbon (F-DLC) films were deposited by RF magnetron sputtering method using a mixture of argon (Ar) and methane (CH4) and tetrafluoromethane (CF4) gases and a graphite target. The structure of the films changes from a diamond-like structure to polymer-like structure, with reduction of the hardness and Young's modulus of the films. The surface energy is decreased by the fluorine incorporation. The tribological test by a ball-on-disk friction tester in a deionized environment showed that 25 at.% F-DLC films exhibit the low friction. The antibacterial activity of the DLC films and the F-DLC films were also evaluated by bacterial eradication tests with Escherichia coli (E. coli). The percentage eradication of E. coli attached to DLC films and 25 at.% F-DLC films was 40% and 56%, respectively. The antibacterial activity of the fluorine-free DLC films was improved by the fluorine incorporation. © 2006 Elsevier B.V. All rights reserved.

Spherical particles of 0.5mol%Pr3+-doped CaTiO3 were prepared by hydrothermal reaction on dissolved CaCl2, Pr(NO3)3, and ammonium citratoperoxotitanate (IV) complex precursor solution with molar ratio of Ti/CA=1:2 and calcination in ambient atmosphere. The obtained particle exhibited red photoluminescence at 610nm. It is found that several particles have hollow structure. It is required that further investigation is needed to clarify the formation mechanism of these spherical hollow paricles.

To clarify the alterations of tau, amyloid beta protein (A beta) 1-40 and A beta1-42(43) in the cerebrospinal fluid (CSF) that accompany normal aging and the progression of Alzheimer's disease (AD), CSF samples of 93 AD patients, 32 longitudinal subjects among these 93 AD patients, 33 patients with non-AD dementia, 56 with other neurological diseases, and 54 normal control subjects from three independent institutes were analyzed by sensitive enzyme-linked immunosorbent assays. Although the tau levels increased with aging, a significant elevation of tau and a correlation between the tau levels and the clinical progression were observed in the AD patients. A significant decrease of the A beta1-42(43) levels and a significant increase of the ratio of A beta1-40 to A beta1-42(43) were observed in the AD patients. The longitudinal AD study showed continuous low A beta1-42(43) levels and an increase of the ratio of A beta1-40 to A beta1-42(43) before the onset of AD. These findings suggest that CSF tau may increase with the clinical progression of dementia and that the alteration of the CSF level of A beta1-42(43) and the ratio of A beta1-40 to A beta1-42(43) may start at early stages in AD. The assays of CSF tau, A beta1-40, and A beta1-42(43) provided efficient diagnostic sensitivity (71%) and specificity (83%) by using the production of tau levels and the ratio of A beta1-40 to A beta1-42(43), and an improvement in sensitivity (to 91%) was obtained in the longitudinal evaluation.

Grazing incidence X-ray scattering (GIXS) and Auger electron spectroscopy (AES) have been used for characterizing thin polycrystalline titanium and titanium oxide films sputtered on silicon wafers. The critical angle in X-ray reflection curves indicates that the density of sputtered TiO x /Si is higher than the titanium bulk value. The values of thickness of these thin films estimated from a comparison with calculated reflection curves were in good agreement with those obtained by a surface thickness profiler. Diffraction patterns in both GIXS and Seemann-Bohlin geometries show that Ti/Si and TiO x /Si, which are identified as Ti and Ti 2 O 3 , respectively, are oriented to the c-axis. The compositional homogeneity through the films of Ti/Si and TiO x /Si has been recognized by the AES depth profiles.

Manganese which is very often added to steels is known to be significantly enriched to the surface with oxidation even if manganese concentration is less than 1% in iron alloys. Such enrichment of a small amount of manganese on the surface during oxidation in stainless steels is well recognized by glow discharge optical emission spectrometry (GDOS). However, the chemical state of such enriched manganese on the surface of iron and steels has not been understood yet. The objective of this work is to provide information of the structure and compositional distribution of a thin oxide film formed on the Fe-40 mass%Cr alloy using XPS depth profiling, angle resolved XPS (AR-XPS), and GIXS. This includes the chemical state of a small amount of manganese as well as iron and chromium.

The pressure induced semiconductor to metal transition in the rare earth compound TmTe has been investigated with electrical resistivity measurements under high pressure. At room temperature, the resistivity showed an exponential decrease up to 2GPa, indicating a linear closing of the energy gap, followed by an almost pressure independent metallic regime. The resistivity in the metallic regime showed a logarithmic temperature dependence reminiscent of a Kondo effect and a TmSe-like anomaly appeared at low temperature and above 5GPa. At 5.7GPa the resistivity showed an abrupt decrease that corresponded to the structural phase transition. {copyright} {ital 1997} {ital The American Physical Society}

Angle-resolved X-ray photoelectron spectroscopy (AR-XPS) has been used for investigating the effect of the surface segregation of chromium on oxide films formed on the surface of high-purity iron−13% and 25% chromium alloys at room temperature (298 K). The chromium segregation in the surface was confirmed by in-situ heating at 973 K under ultra high vacuum. The effective thickness of its segregated zone was evaluated to be less than 1 nm, from the relationship between the concentration of iron and chromium and the take-off angle in AR-XPS. The effective concentration of segregated chromium was estimated a few times as much as the bulk concentration. The surface with the chromium segregation was subsequently exposed to air, and an oxide film formed on the surface was also characterized. The oxide film formed on the surface with the chromium segregation was found to be thinner than the case without segregation. These results on the surface layer were consistent with spectral information of the chemical state denoted by Fe 2p and Cr 2p.

Thin Fe, Fe2O3 and Cr2O3 films deposited on Si wafers have been investigated by grazing incidence X-ray scattering (GIXS) and the results have been compared with microstructural data by atomic force microscopy (AFM) and transmission electron microscopy (TEM). It is found that changes in density of these films can be estimated from the critical angle in X-ray reflection curves. Measurements in GIXS with two different geometries indicate the preferential orientation of crystalline Fe and Fe2O3 films. AFM and TEM observation shows characteristic features in microstructures of the films, and it is indicate that a ten nanometer order of magnitude of roughness in the surface prevents the oscillations in the X-ray reflection curves.