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We prepared Pb2CrMoO6 under high pressure and high temperature. The sample has a heavily or fully disordered double perovskite structure (Pm-3m, a=3.9472 A). It shows a weak ferromagnetic behavior (TC~33 K) and a significant low magnetization (~0.095 μB/f.u. at 7 T and 5 K), which is discussed based on the cation disorder. The temperature dependence of the electrical resistivity of Pb2CrMoO6 exhibits a semiconducting behavior, which could be well understood by the 3D variable range hopping model. No significant magnetoresistance was observed in this sample.

The relationship between reproductive breast risk factors and breast cancer survival in patients with different breast cancer subtypes is not well known.We examined a large-sized, retrospective study of 23,882 subjects from the Korean Breast Cancer Registry. The breast cancer subtype was determined by immunohistochemical staining for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2). Information regarding reproductive factors, including breastfeeding, age at first birth (AFB), and parity, was gathered. Multivariate Cox regression analysis was used to estimate the association among breast cancer subtypes, such as luminal A, luminal B, Her-2/neu overexpressing, and triple negative breast cancer (TNBC), and breast cancer survival as dependent variables and adjusting for age and stage.High parity (≥ 5) increased the recurrence risk of luminal A and B breast cancer (hazard ratio [HR], 1.95; 95% confidence interval [CI], 0.96-3.97; P = .0055 and HR, 1.12; 95% CI, 0.42-3.02, respectively; P = .0073) in breast cancer-specific survival (BCSS), but 1 to 3 child births decreased the recurrence risk of luminal A breast cancer (HR, 0.56; 95% CI, 0.34-0.91; P = .0055) and luminal B breast cancer (HR, 0.32; 95% CI, 0.17-0.61; P = .0073) in BCSS. Early AFB (20 years) increased the recurrence risk of luminal A breast cancers (HR, 1.61; 95% CI, 0.62-4.26; P = .039) in BCSS and of TNBC (HR, 1.31; 95% CI, 0.78-2.21; P = .0006) in overall survival. Her-2/neu overexpressing breast cancer had no correlation with parity and AFB in breast cancer survival.High parity (≥ 5) and early AFB (20 years) were correlated with worse clinical outcomes in patients with luminal breast cancer, but not with other subtyped breast cancers.

In order to improve the technical specifications of space reflectors, antennas and other payloads on Earth observation, space communication, deep space exploration and other fields of space applications, people urgently need to enhance the surface shape control accuracy of these large complex curvature flexible structures. Based on the photovoltaic effect and converse piezoelectric effect, this paper presents a non-contact shape-adjusting method which adopts a new space energy conversion: using the PLZT photovoltage, which is controlled by the ultraviolet, to activate the PVDF attached on the flexible structure surface, and adjust and control the structure's shape. This paper firstly built up the electric model of the PLZT/PVDF hybrid drive, derived the constitutive relation of light-electric-mechanical energy field conversion, and determined the key parameters inmathematical model by principle experiments. Then, taking aflexiblecantilever beam as thecontrol object, actuation equation of the PVDF bonded structure was built, and actuation properties and influence factors of the cantilever beam actuated by the PLZT/PVDF hybrid drive were simulated and analyzed. After that, the hybrid drive experiment system was built up, and deflecting effect of using ultraviolet illuminated PLZT to actuate PVDF bonded cantilever beam was tested, whose result verified the validity of theoretical modeling and simulation analysis. Lastly, characteristics of the hybrid drive method and conventional PVDF driving were compared, and space application direction of this method was pointed out.

Background Despite mounting interest in combination immunotherapy including immune checkpoint inhibitors (ICIs) to improve anti-tumor responses, clinical translation has been disappointing. To address the significant unmet needs remaining, we designed GI101 comprising the extracellular domain of CD80 acting as a dual checkpoint (CTLA4/PD-L1) inhibitor, together with a long acting IL2v that preferentially binds to the IL2Rβ. Methods Affinity of GI101 for IL2Rs, CTLA4, and PD-L1 was determined by SPR. Immune cell proliferation was analyzed by CFSE assay and in vivo immune profiling. In vivo efficacy of GI101 were performed in a tumor-bearing mouse model. Results GI101 exhibits high affinity to both CTLA4 (Kd, 2.9 nM), PD-L1 (Kd, 8.5 nM), and preferential binding to IL2Rβ (Kd, 28.4 nM). GI101 induces the robust stimulation of in vitro and in vivo CD8+ T and NK cell proliferation without a significant increase in Treg cells. GI101 has high binding affinity to CTLA4 acting as a decoy ligand, thereby enhancing the interaction between endogenous CD80 and CD28, leading to the activation of T cells. GI101 elicits improved restoration of immune functions compared to a CD80-Fc in in vitro settings using human PBMCs co-cultured with PD-L1hi tumor cells. In the CT26 tumor-bearing mice, GI101 was superior at inhibiting tumor growth when compared to a combination of aPD-1/aCLTA4 in association with a profound increase in CD8+ T and NK cells without causing an increase in Tregs in the TME. In addition, a dose-dependent anti-tumor effect was observed in CT26 syngeneic models. Furthermore, isolated mortality was observed in the aPD-1/aCTLA4 combo-treated group whereas GI101-treated group has no evidence for toxicity associated with IL2 activity including vascular leakage syndrome and cytokine storm. Conclusions The complementary modes of action of GI101 via dual checkpoint blockade with IL2 activity to enhance the proliferation and activation of Teff and NK cells is projected to translate into superior clinical efficacy and safety as indicated even in ‘cold tumor’ models. GI101 has promising potential to replace first-generation ICIs as a monotherapy or in combination with chemo/radiotherapies and other immunotherapies. Legal entity responsible for the study GI innovation. Funding GI innovation. Disclosure J.C. Park: Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation. K.H. Pyo: Research grant / Funding (institution): Yonsei Medical Center. Y.J. Song: Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation. W.J. Lee: Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation. J. Kim: Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation. H.N. Ji: Full / Part-time employment: GI innovation. S.S. Park: Full / Part-time employment: GI innovation. Y.J. Koh: Full / Part-time employment: GI innovation. K. Lee: Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation. B. Cho: Research grant / Funding (institution): Yonsei Medical Center. B. Chun: Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation. Y.M. Oh: Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation. B. Yang: Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation. S.Y. Nam: Leadership role, Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation. M.H. Jang: Leadership role, Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation.

Background and purpose To evaluate the potential neuroprotection against subsequent cerebral infarction conferred by a prodromal transient ischaemic attack (TIA). Methods Various measures, including blood pressure, blood serum glucose, serum lipids, cardiovascular imaging and changes to NIHSS scores were evaluated upon admission and discharge for patients presenting with ischaemic stroke with or without prodromal TIA (n = 60 per group). Results When all patients from each group were considered together, no significant group effects emerged. However, when the NIHSS difference scores from the prodromal TIA group were subdivided based on (i) prodromal TIA lasting up to 4 min; (ii) two prodromal TIA attacks and/or; (iii) prodromal TIA-stroke interval within 7 days separately, patients in subgroups 1 and 2 exhibited significantly better outcome on discharge. There was no significant effect found in subgroup three although this TIA group did show better outcome in considering the NIHSS changes. Conclusions Prodromal TIA prior to cerebral infarction may result in an ischaemic tolerance effect. Moreover, the neuroprotection conferred by the TIA may be associated with the duration and the frequency of the TIA, although the relationship between the TIA-stroke interval and prognosis is not clear.

As is pointed out by Gourieroux (1997), the volatility effects in financial time series vary according to the signs of the return rates and therefore asymmetric Threshold-GARCH (TGARCH, henceforth) processes are natural extensions of the standard GARCH toward asymmetric volatility modeling. For preliminary detection of asymmetry in volatility, we suggest graphs of squared-log-returns for various financial time series including KOSPI, KOSDAQ and won-Euro exchange rate. Next, asymmetric TGARCH(1,1) model fits are provided in comparisons with standard GARCH(1.1) models.

The inner and outer car panels for bonnet, door, and trunk lid are assembled by hemming rather than welding. To achieve successful fabrication of these panels, the complicated timing chart of hemming units for pre-and main hemming stages should be made to optimal one. In this study, a design system for automatic timing chart generation is developed. Using AutoCAD VBA and EXCEL data chart, hemming die design parameters and guidelines were put into the program to give hemming unit drawings and consequent timing charts. Then the prepared timing charts were checked and modified. The effectiveness of the system is verified by applying it successfully to hemming unit design for bonnet panel joining.

The KSTAR (Korea Superconducting Tokamak Advanced Research) superconducting magnet system adopts a superconducting CICC(Cable-In-Conduit Conductor) type conductor. It consists of 16 TF (Toroidal Field) coils and 14 PF (Poroidal Field) coils and it also uses two different types of CICCs-Nb3Sn cable with Incoloy 908 conduit and NbTi cable with 316LN stainless-steel conduit. A special CICC jacketing system is developed for the KSTAR CICC fabrication: the tube-mill process, which consists of forming, welding, sizing and squaring procedure. The cabling process for TF and PF superconducting cable and the fabrication process of each CICCs (TF CICC and PF CICC) is described. The welding of conduit materials are also discussed. The fabrication results such as the geometrical specification, micro structure and the void fraction will be discussed

The growth behavior and atomic structure of the Ag wetting layer grown on the W(1 1 0) surface, was studied with scanning tunneling microscopy. Deposited Ag atoms preferentially adsorb at the step edges and reveal a step-flow growth behavior at room temperature. In the Ag wetting layer, a periodic bright ridge structure was observed along the [ 3 ¯ 3 7 ] and [ 3 ¯ 3 7 ¯ ] directions. The atomic registry of the ridge structure is proposed on the basis of atomically resolved images.

Undoped hydrogenated amorphous silicon (a-Si:H)/p-type crystalline silicon (c-Si) structures with and without a microcrystalline silicon (μc-Si) buffer layer have been investigated as a potential low-cost heterojunction (HJ) solar cell. Unlike the conventional HJ silicon solar cell with a highly doped window layer, the undoped a-Si:H emitter was photovoltaically active, and a thicker emitter layer was proven to be advantageous for more light absorption, as long as the carriers generated in the layer are effectively collected at the junction. In addition, without using heavy doping and transparent front contacts, the solar cell exhibited a fill factor comparable to the conventional HJ silicon solar cell. The optimized configuration consisted of an undoped a-Si:H emitter layer (700 A), providing an excellent light absorption and defect passivation, and a thin μc-Si buffer layer (200 A), providing an improved carrier collection by lowering barrier height at the interface, resulting in a maximum conversion efficiency of 10% without an anti-reflective coating.

We have investigated the carrier transport mechanisms in undoped a -Si:H/p-type c-Si heterojunctions with and without a μc-Si buffer layer, as well as their effects on the photovoltaic properties of the junction. The conduction behavior of the junction is strongly affected by the defect state distribution and band offset at the hetero-interface. The recombination process involving the interface states on the thin film silicon (a-Si:H/μc-Si) side dominates at low forward bias ( V V V >0.55 V). The MTCE process seems to be more closely related to the bulk defects in the thin film silicon than the interface states. In addition, the position of a trapping level, where the tunneling process occurs, seems to be determined by the hole energy at the edge of the c-Si and the trap distribution in the thin film silicon. Despite the domination of MTCE in the indicated voltage range, the reduced band offset at the interface increases current levels by the enhanced diffusion and/or emission processes. The insertion of a 200 A thick μc-Si buffer layer between the a-Si:H (700 A)/c-Si increases the solar cell efficiency to 10%, without an antireflective coating, by improving both the carrier transport and the red response of the cell.

We proposed and demonstrated a new concept of switchable multiwavelength erbium-doped fiber ring laser with a multisection high-birefringence fiber loop mirror (HiBi-FLM). The HiBi-FLM results in the laser operating on different allowed wavelengths. The wavelength switching can be achieved by modifying the reflection spectrum of HiBi-FLM through two polarization controllers. The experiment demonstrates the switchable lasing operation within the random combination of three wavelengths, as well as with a large (/spl sim/40 dB) output signal to background noise ratio.

Hypomethylation of the O6-methylguanine-DNA-methyltransferase (MGMT) promoter in glioma cells has been associated with temozolomide resistance. S-adenosylmethionine (SAM), which is produced during folate metabolism, is the main source of methyl groups during DNA methylation. As a key enzyme during folate metabolism, polymorphisms of 5,10-methylenetetrahydrofolate reductase (MTHFR) may regulate folate end-products. We investigated the effect of typical polymorphisms of MTHFR (C677T and A1298C) on MGMT methylation based on different serum folate levels in patients with glioma from Northeast China. A total of 275 patients with glioma and 329 without malignant tumors were tested. Serum folate concentration was assayed by using the electrochemiluminescence immunoassay. MTHFR polymorphisms were detected by Taqman-Fluorescence quantitative polymerase chain reaction (PCR). Methylation-specific PCR was used to assess MGMT methylation. The constituent ratio of glioma patients below the serum folate biological reference value was significantly higher than that of the control population (P0.001). In patients with oligodendroglioma and glioblastoma, heterozygotes for the A1298C mutation were found in higher frequency than homozygotes or wild types (oligodendroglioma, P0.001; glioblastoma, P0.01). When grouped by the median or biological reference value of serum folate, only homozygotes for C677T with low levels of folate were significantly associated with decreased methylation of MGMT (median, P0.001; biological reference value, P = 0.036). These data suggest that, in combination with a negative folate balance in glioma patients, T/T genotypes in MTHFR C677T may be associated with MGMT demethylation.

Transparent indium tin oxide (ITO)/beta-silicon carbide (β-SiC) Schottky barrier and ohmic contact have been successfully fabricated by sputtering ITO films on rapid thermal chemical vapor deposition (RTCVD) prepared β-SiC grown heteroepitaxially on a (111) silicon substrate. The transmission line method (TLM) was used to determine the specific contact resistance of the ITO/n-SiC ohmic contact for varying operation temperatures. It was found that the specific contact resistance is 0.56 ω cm 2 for a temperature of 300 K and decreases with increasing temperature. The indium (In)/n-SiC, NiCr/n-SiC ohmic contact systems were also developed for comparison purposes. In addition, the influence of operating temperature on the C - V characteristics of the ITO/p-SiC Schottky barrier was studied. It reveals that the ideality factor n is in the range of 1.44–2.3 for temperature ranging from 300 to 473 K. The barrier height φ B ( C - V ) is 1.61−1.23 eV with varying operation temperature from 300 to 473 K for C - V measurement.

The effects of oxygen vacancies on the magnetic and electrical properties of Ca-substituted YIG films, Y3−xCaxFe5O12−0.5x−z, have been investigated. Annealing in a reducing atmosphere between 900 and 1000°C produces a significant change in the saturation magnetization over the temperature range from 4 K to the Curie temperature. The change in 4 π M at 4 K under various annealing conditions is proportional to a change in the lattice constant. A microscopic molecular field model is proposed, in which a singly charged oxygen vacancy, VO., mediates a localized ferromagnetic superexchange between the iron ions at adjacent sites, in order to explain the 4 πM(T) for various annealing conditions. The I–V characteristics of the samples were measured between 140 and 300 K and the voltage drop across the surface layer and the bulk was analyzed using a two-layer model. The temperature dependence of the bulk resistivity favors ionized impurity scattering, ρ α T−3exp(EF − Ev/kT). Assuming VO. as the major scattering center, the effective mass of a hole is estimated to be 0.1me. An analysis of the position of the Fermi levels led to an identification of an impurity band of oxygen vacancies, which is centered at 0.3 eV above the valence band edge with a half width of about 0.1 eV.

We demonstrate the generation of 12-wavelength comb with 14.5-nm tunable range in the Brillouin-Erbium fiber laser. This is achieved through tuning the gain profile of Erbium-doped fiber by a Sagnac loop filter with 18-cm polarization-maintaining fiber, in conjunction with modifying the wavelength of Brillouin pump. The experiment also demonstrates that the tunable range is closely equal to the 3-dB bandwidth of Sagnac loop filter due to its periodic transmission profile. Meanwhile, the effect of the 980-nm pump on the tunable multiwavelength generation is investigated. The power of 980-nm pump has a great effect on the wavelength number and the output power of the generated multiwavelength comb, but little on the tunable range. This technique may be applicable to multiwavelength operation lasers with a large tunable range.

The corrosion fatigue propagation behaviours and mechanisms of quenched and tempered AISI 4340 and 4135 steels have been systematically investigated in 3.5% NaCl spray and in 3.5% NaCl solution. The crack closure for AISI 4135 steel has been studied in 3.5% NaCl spray and in air. It is shown that there is a great crack arrest tendency in 3.5% NaCl spray but no crack arrest in 3.5% NaCl solution. The crack closure effect for AISI 4135 steel is higher in 3.5% NaCl spray than in air because of thick oxide deposits within the crack. Through detailed analyses and SEM fractographic examination, it is found that the dominant crack growth mechanism is crack tip anodic dissolution in 3.5% NaCl spray but is hydrogen embrittlement in 3.5% NaCl solution. In this paper, a crack closure blunting model is presented for crack arrest. It is proposed that crack arrest is caused by the combined effects of crack closure and crack tip blunting. The crack arrest tendencies and corrosion fatigue parameters such as frequency, stress ratio and crack tip anodic current density can be predicted and described qualitatively by this model.

Objective To describe clinical features of patients with multiple sclerosis (MS) in Shanghai, China. Methods Prevalent patients with MS were identified and investigated by a network of physicians in 11 districts of Shanghai during the period from 1 September 2004 to 31 August 2005. Admission registries of each hospital in the study area were checked systematically for patients with a diagnosis of MS, neuromyelitis optica or other demyelinating disorders. All patients with collected information were evaluated by four senior neurologists according to the McDonald criteria. Results There were 249 (146 female and 103 male) patients with a confirmed MS diagnosis, at a female-to-male ratio of 1.4. The mean age at onset of MS was 37.4 years for the 249 patients with MS and, on the prevalence day, 42.7 years. The most frequent location of clinical MS lesions in the central nervous system was the spinal cord (61%), followed by the cerebrum (55%) and optic nerves (41%). Nearly all (96%) of the patients with MS had been examined by magnetic resonance imaging, and 226 (94%) patients of those examined were suggestive of MS. No family history of MS was found in any of the patients. Most (86%) of the patients had no or mild disability on the prevalence day (31 December 2004). Almost all (96%) patients with MS had been treated with corticosteroids. Conclusion Clinical features of patients with MS are described based on the information from the largest case series reported among Chinese. Comparisons and discussions are made with findings from the other populations.

Programming with larger current than optimized one is often preferable to ensure a good resistance distribution of high-resistive reset state in high-density phase-change random access memories because it is very effective to increase the resistance of cells to a target value. In this paper, we firstly report that this larger current writing may conversely degrade the reset distribution by reducing the resistance of normal cells via the partial crystallization of amorphous Ge2Sb2Te5 and this degradation can be suppressed by designing a novel cell structure with a heat dissipating layer.

Fully functional 512Mb PRAM with 0.047mum2 (5.8F2) cell size was successfully fabricated using 90nm diode technology in which the authors developed novel process schemes such as vertical diode as cell switch, self-aligned bottom electrode contact scheme, and line-type Ge2Sb2Te5. The 512Mb PRAM showed excellent electrical properties of sufficiently large on-current and stable phase transition behavior. The reliability of the 512Mb chip was also evaluated as a write-endurance over 1E5 cycles and a data retention time over 10 years at 85degC

A wide-band SBS slow light method is achieved by phase-modulating the Brillouin pump. A 1-Gb/s RZ PRBS data is delayed by 600ps with certain pulse distortion using such a technique.

Advanced ring type technology and encapsulating scheme were developed to fabricate highly manufacturable and reliable 256Mb PRAM. Very uniform BEC area was prepared by the advanced ring type technology in which core dielectrics were optimized for cell contact CMP process. In addition, relatively high set resistance was stabilized from encapsulating Ge2Sb2Te5 (GST) stack with blocking layers, thus giving rise to a wide sensing window. These advanced ring type and encapsulating technologies can provide great potentials of developing high density 512Mb PRAM and beyond

Advanced bottom electrode contact (BEC) scheme was successfully developed for fabricating reliable high density 64 Mb PRAM by using ring type contact scheme. This advanced ring type BEC scheme was prepared by depositing very thin TiN films inside a contact hole, and then core dielectrics was uniformly filled into the TiN-deposited contact hole. Using this novel contact scheme, it was possible to reduce a reset current with low set resistance, and also maintain a uniform cell distribution. Thus, it is clearly demonstrated that the ring type BEC technology can exhibit strong feasibility of high density 256 Mb PRAM and beyond.

We have proposed and demonstrated a novel multiwavelength Brillouin-erbium fiber laser (BEFL) with a linear cavity, in which, the Brillouin pump is self-excited within the cavity, doesn't require the injection from the external cavity or direct generation within the intracavity. In this scheme, more than 115 Stokes lines with relatively uniform amplitudes have been generated. The experiment also demonstrates that such a self-seeded BEFL performs good repetition and stability for both the operating wavelengths and the output power of each Stokes line. Meanwhile, the effect of the 980nm pump on the performance of the laser is investigated.

Novel small contact fabrication technologies were proposed to realize reliable high density 256Mb PRAM(phase change memory) product. Introducing the 2-step CMP (chemical mechanical polishing) process and the ring-shaped contact structure, the contact area distribution was greatly improved even at the smallest contact diameter of 50nm node. The validity of this approach was directly confirmed by the evaluation of the functionality for the fabricated 256Mbit PRAM based on 0.10/spl mu/m CMOS technology.

In the paper, the supercontinuum generation in the normal dispersion shifted fiber is investigated using the single-pass and double-pass configurations. The spectral bandwidth of supercontinuum is enhanced from the 90nm with single pass configuration to127nm using the double pass configuration. The enhanced broadening mechanism is mainly due to the collision interaction between counter- traveling pulses, as well as the doubled length of fiber.

In this paper, we propose a text extraction method from camera-captured document style images and propose a text segmentation method based on a color clustering method. The proposed extraction method detects text regions from the images using two low-level image features and verifies the regions through a high-level text stroke feature. The two level features are combined hierarchically. The low-level features are intensity variation and color variance. And, we use text strokes as a high-level feature using multi-resolution wavelet transforms on local image areas. The stroke feature vector is an input to a SVM (support vector machine) for verification, when needed. The proposed text segmentation method uses color clustering to the extracted text regions. We improved K-means clustering method and it selects K and initial seed values automatically. We tested the proposed methods with various document style images captured by three different cameras. We confirmed that the extraction rates are good enough to be used in real-life applications.

We experimentally demonstrate an all-fiber passively Q-switched erbium fiber laser by the symmetrical nonlinear optical loop mirror with nonlinear polarization rotation. And this Q-switched laser has the all-fiber nature. (2 pages)

The mobility of β-SiC thin films grown on (100) Si substrates by low-pressure rapid thermal chemical vapor deposition (LP-RTCVD) has been found to have a 200% improvement over that prepared by conventional low-pressure CVD. The SiC growth is achieved using a C 3 H 8 -SiH 4 -H 2 reaction gas system at a reduced pressure of 2.5 Torr. Both X-ray and transmission electron microscopy patterns show that the grown layer is single-crystal β-SiC. The influence of the growth conditions on the electrical properties of the SiC layer was also investigated. It was found that the maximum electron mobility can reach 254 cm 2 V −1 s −1 for carrier concentrations of (1–4) × 10 17 cm −3 and at substrate temperature of 1 150 °C. The electron mobility is the highest one reported to date for the low-pressure heteroepitaxial SiC films on Si substrates.

A 64 Mb phase change random access memory, based on 0.18 /spl mu/m technology is developed. We proposed several key factors such as BEC and GST cell size, contributing to stabilization of writing current for reversible cell transition. By reducing writing current to 1.1 mA through such optimization, we have developed a 64 Mb PRAM. With memory functions and reliability tests, the feasibility for developing high-density 64 Mb PRAM is presented.

It was discovered that the application of a constant DC field (/spl sim/10/sup 4/ V/cm) at room temperature for several days reversed the changes in the electrical properties produced by thermal annealing in Ca:YIG single crystal films. The electrical conductivity of these films improved by five to seven orders of magnitude during this process to values as much as ten times greater than those of the as-grown state. After the field was removed this new high conduction state was found to be stable. The rate of conductivity increase became exponentially smaller when either the applied field or the temperature were decreased.

The optimization of amorphous silicon/crystalline silicon (a-Si:H/c-Si) heterojunction solar cells was performed in terms of emitter material and heterointerface. Various conditions were explored and monitored by a residual gas analyzer. In addition, a thin microcrystalline (/spl mu/c-Si) buffer layer was inserted into the heterojunction to improve the interface by bandgap grading. The conduction behavior is strongly influenced by the defect distribution and band offset at the hetero-interface. The recombination process dominates at low forward bias (V 0.55 V). The reduced band offset at the interface increases current levels by the enhanced diffusion/emission process. The solar cell with a 700 /spl Aring/ a-Si:H top layer and a 200 /spl Aring/, /spl mu/c-Si buffer layer shows the maximum solar cell efficiency of around 10 %, without an antireflective coating by improving both the carrier transport and the red response of the cell.

In this paper four typical watermarking techniques are compared and tested extensively, which not only include the private system, the semi-private system but also the public schemes. The comparisons mainly focus on the evaluation of robustness and visual image quality. The benchmarking is the popular Stirmark 3.1. Results show that the chosen schemes do not have the same behavior and no method has all the desirable characteristics.

A compact array of multiwavelength vertical-cavity surface-emitting laser (VCSEL) directly-coupled to single multimode fiber can be a promising solution for high data transmission rates. Several techniques have been introduced to fabricate multiwavelength VCSELs. Among them postgrowth wavelength adjustment methods are considered to be more desirable than the growth methods due to relatively good controllability and simplicity. In this reports we present a method to adjust wavelengths by varying the optical thickness of dielectric mirror precisely, which is feasible for fabricating multiwavelength VCSELs.

We propose a general routine, Genetic-Simulated Annealing method (GSA) for the optimal design of quasi-phase matched (QPM) non-uniform grating. Here this method is applied to the design of the flat broadened wavelength conversion bandwidth of 40-mm aperiodically poled lithium niobate (APLN) based on difference-frequency generation (DFG). The flat conversion bandwidth of APLN is broadened from the original 65nm in a 40-mm periodically poled lithium niobate (PPLN) to the pre-designated 130 nm in a 40-mm APLN, which conversion efficiency is 6.7 dB higher than that of 12.4-mm PPLN under the same conversion bandwidth.

Microwave chemical vapor deposition (MCVD) is utilized to deposit nanocrystalline silicon (nc-si) thin films onto a variety of substrates for application to thin film transistors (TFT's) and solar cells. It is especially important to gain reproducible control of the processing. Thus, an in-situ mass spectrometer (MS) records the plasma conditions with variation of process conditions such as gas selection, pressures, partial pressures, and substrate temperature. These data are correlated with electrical and optical properties of the films. Raman spectra show a FWHM of 11/cm with position at 522/cm as desired for crystalline Si. Typical film thickness is 100nm with grain size of 20-30 nm, using standard deposition, and 50-80 nm when the substrate is intensely optically illuminated during deposition, called photon assist (PA). Hydrogen dilution serves to increase the crystallinity of the films. The ratio of photo-to dark conductivity exceeds 10+5 with dark conductivity as low as 1.5 × 10-10 S/cm. Thin film transistors have been fabricated with Ion/Ioff of 10+7. Hetrojunction solar cells were fabricated using amorphous Si/ nc-Si/ crystlline Si giving a conversion efficiency of above 10.5%, without an antireflection coating. The use of MS in device design will be emphasized.