Search

Single-crystal silicon-based solar cells laminated with tempered-glass and ceramic tiles for use in a building's façade have been developed. The optical, thermal, and electrical properties of the proposed PV module are first evaluated, and then a wind-resistance test is carried out to evaluate the feasibility of installing it in Taiwan. The electrical and deflection characteristics of the proposed PV module did not change significantly after a 50 thermal cycling test and a 200-hour humidity-freeze test, based on IEC 61215 and a wind-resistance test. Finally, the electrical power generation ability of the proposed BIPV system with 1 kWp electrical power capacity was examined. Building information modeling software tools were used to simulate the BIPV system and carry out the energy analysis. The simulation results show a very consistent trend with regard to the actual monthly electricity production of the BIPV system designed in this work. The BIPV system was able to produce an accumulative electrical power of 185 kWh during the 6-month experimental period. In addition, the exterior temperature of the demonstration house was about 10°C lower than the surface of the BIPV system, which could reduce indoor temperature. [ABSTRACT FROM AUTHOR]

Timely feedback is considered essential for supporting professional growth and personal development. However, it is difficult to employ such feedback in traditional learning environments. Recently, smartphones are considered as educational tools for supporting instructional activities. Therefore, this study attempts to leverage the advantages of physical textbooks and mobile devices. A pedagogical strategy called constructive feedback was proposed to provide learners with real-time and personalized suggestions according to the results of electronic assessment. Two types of connectivity techniques, namely QR Codes and hyperlinking, were applied for integrating printed materials and digital content. An experiment was conducted in a university course entitled Computer Networks, and a total of 80 students were recruited to participate in this experiment. The findings revealed that the strategy of constructive feedback had a significant influence on learning performance. However, no significant differences on learning performance were found between using QR Codes and using hyperlinking. Finally, implications of the findings were discussed for further research directions and practical applications. [ABSTRACT FROM AUTHOR]

Two contact engineering approaches are proposed and investigated to enhance the breakdown voltage VBK in GaN-on-Si power devices, including the hybrid Schottky-ohmic-drain structure for AlGaN/GaN HEMTs and the selective Si-diffusion structure for AlGaN/GaN SBDs. With the hybrid Schottky-ohmic drain, the devices showed a zero onset voltage and reduced off-state leakage current by one order of magnitude, compared with that of the traditional ohmic-drain devices. The breakdown voltage was also enhanced with comparable on-resistance. For the SBDs with the selective silicon-diffusion layer underneath ohmic metal at the cathode, a low-contact resistance Rc of 0.2 Ω mm and a smooth ohmic metal morphology were obtained. The SBDs with the additional silicon diffusion layer showed enhanced VBK, compared with that of the conventional SBDs. The results demonstrate that the proposed contact engineering approaches are useful for the breakdown voltage enhancement of GaN-on-Si power devices. [ABSTRACT FROM AUTHOR]

The aim of the present study was to elucidate a reasonable model and the efficacy of hepatocellular carcinoma (HCC) screening on an elderly population. Two-stage HCC screening was conducted in a hepatitis C virus (HCV)-endemic area. First, participants underwent blood tests for hepatitis B surface antigen (HBsAg), anti-HCV antibody, serum α-fetoprotein (AFP), aspartate aminotransferase, alanine aminotransferase, and platelet count. Patients who were abnormal for any of the six markers were enrolled for second-stage ultrasonography. Suspected cases were referred for confirmation. HCC cases were followed for 4 years. All patients were linked to national mortality and cancer register databases to identify newly-developed HCC, 30 months after screening. A total of 461 males and 541 females were screened for HCC, with 15.1% testing positive for HBsAg and 44.3% positive for anti-HCV. Among them, 619 (61.8%) met the criteria of ultrasonographic screening; 527 (85.1%) responded, and 16 confirmed HCC (male/female = 8/8, 68.8 ± 8 years) cases were detected. All tumor diameters were less than 5 cm, and six were less than 2 cm. AFP and thrombocytopenia were two independent predictive factors of HCC. The overall survival rates of detected cases were 93.8% and 56.3% was 1 and 4 years, respectively. The only good prognostic predictor was 'underwent curative treatment'. Another seven non-HCC residents developed HCC after screening, and five of these were with either thrombocytopenia or AFP elevation. Under economical consideration, AFP and platelet count should be feasible screening markers of risk identification. Early detection and prompt treatment results in good prognosis in an aged population. [ABSTRACT FROM AUTHOR]

A periodically bunched electron beam is useful for generating high-brightness electron superradiance. This paper studies the generation and acceleration of density-modulated electron beams from a photocathode electron gun driven by a laser beat wave. Computer simulation shows the feasibility of accelerating and preserving the density-modulated electron beam in an accelerator. This paper also details the implementation of a beat-wave laser system with a variable beat frequency for driving a photocathode electron gun. [ABSTRACT FROM AUTHOR]

Chitinases (EC 3.2.1.14) are found in a broad range of organisms, including bacteria, fungi and higher plants, and play different roles depending on their origin. A chitinase from Bacillus cereus NCTU2 (ChiNCTU2) capable of hydrolyzing chitin as a carbon and nitrogen nutrient has been identified as a member of the family 18 glycoside hydrolases. ChiNCTU2 of molecular weight 36 kDa has been crystallized using the hanging-drop vapour-diffusion method. According to the diffraction of chitinase crystals at 1.10 Å resolution, the crystal belongs to space group P21, with unit-cell parameters a = 50.79, b = 48.79, c = 66.87 Å, β = 99.31°. Preliminary analysis indicates there is one chitinase molecule in the asymmetric unit, with a solvent content of 43.4%. [ABSTRACT FROM AUTHOR]

We conducted a series of passively Q-switched Nd:YAG laser pumped optical parametric generation, amplification, and oscillation experiments in monolithic periodically poled lithium niobate (PPLN) crystals. Double-pass optical parametric generation with an effective gain length of 10 cm in a PPLN crystal was performed in comparison with single-pass operation in the same crystal. By seeding a PPLN optical parametric amplifier with a distributed feedback (DFB) diode laser, we produced 200-ps transform-limited laser pulses at 1549.6 nm and observed parametric gain competition at different pump levels. For optical parametric oscillations, we first demonstrated 22% power efficiency from a 2.4-cm intrinsic-cavity PPLN optical parametric oscillator pumped by a 4.2-ns, 10-kW passively Q-switched Nd:YAG laser. Preliminary studies on DFB optical parametric oscillators in PPLN are mentioned. The temporal and spectral properties of these optical parametric generators, amplifiers, and oscillators are characterized and discussed. [ABSTRACT FROM AUTHOR]

We report optical parametric generation from a 532-nm-pumped periodically poled lithium niobate with a wavelength spectrum covering the sodium D[sub 1], D[sub 2] wavelengths 589.6 and 589.0 nm. Despite the 8 cm[sup -1] attenuation at the 5.45 μm idler wavelength, the PPLN generates a 9 μJ/pulse energy near the 589-nm sodium wavelength when pumped by a 130 μJ/pulse frequency-doubled Nd:YAG Q-switched laser. The observed effective nonlinear coefficient is about 40% higher than its value at the visible and near infrared wavelengths. We believe that this is the first observation of ionic susceptibility enhanced parametric gain in the mid-infrared absorption region of lithium niobate. [ABSTRACT FROM AUTHOR]

We report simultaneous frequency conversion and amplitude modulation in an optical second-harmonic generator by electrooptically controlling the relative phase between the 1064-nm fundamental and the 532-nm second-harmonic fields in a dispersion crystal section between two periodically poled lithium niobate (PPLN) sections. Theoretical derivation and experimental demonstration were carried out for two novel crystal configurations, including a linear cascaded configuration in which a 1-cm dispersion section is sandwiched between two 2-cm PPLN sections, and a folding-crystal high-efficiency configuration in which the mixing waves traverse twice in a 2-cm PPLN section through total internal reflections in a 1.5-cm dispersion section. Due to the coherence enhancement in the constructive phase between the two second-harmonic generation (SHG) fields in the two PPLN sections, we measured a 30% increase in conversion efficiency compared to a 4-cm continuous-grating PPLN under the same condition. The measured half-wave voltage for the amplitude modulation is 1.1 V × d (μm)/ld (cm), where d is the separation of the electrodes and ld is the length of the electrodes. [ABSTRACT FROM PUBLISHER]

I present a theoretical and simulation study of a desktop, megawatt (MW), terahertz (THz) superradiance free-electron laser (FEL) driven by a THz-pulse-train photoinjector. With nominal electron parameters from a THz-pulse-train photoinjector, this superradiant FEL is capable of generating more than 5 MW power at THz frequencies from a half-meter, single-pass undulator. Tapering the undulator to a length of 1.5 m can further increase the FEL output power to nearly 15 MW. [ABSTRACT FROM AUTHOR]

The proton-exchanged OH- absorption spectra of congruent and 8.1 mol % Zn-doped LiNbO3 single crystals with and without polarization inversion are presented. The variation in the proton-exchanged OH- spectra for the congruent sample is not affected by polarization inversion. This result confirms the Li-vacancy model. However, the highly doped sample shows stronger increase in intensities with polarization inversion. In our investigation, highly negative charge vacancy model confirms with proton-exchanged OH- absorption spectra and domain inversion etching experiment. Finally, we demonstrated the polarization inversion mechanism with these two samples based on extended x-ray-absorption fine structure experimental results. [ABSTRACT FROM AUTHOR]

The branched-chain amino-acid aminotransferase (BCAT), which requires pyridoxal 5′-phosphate (PLP) as a cofactor, is a key enzyme in the biosynthetic pathway of the hydrophobic amino acids leucine, isoleucine and valine. DrBCAT from Deinococcus radiodurans, which has a molecular weight of 40.9 kDa, was crystallized using the hanging-drop vapour-diffusion method. According to X-ray diffraction data to 2.50 Å resolution from a DrBCAT crystal, the crystal belongs to space group P212121, with unit-cell parameters a = 56.37, b = 90.70, c = 155.47 Å. Preliminary analysis indicates the presence of two DrBCAT molecules in the asymmetric unit, with a solvent content of 47.52%. [ABSTRACT FROM AUTHOR]

Bowman–Birk inhibitors (BBIs) are cysteine-rich proteins with inhibitory activity against proteases that are widely distributed in monocot and dicot species. The expression of rice BBI from Oryza sativa is up-regulated and induced by pathogens or insects during germination of rice seeds. The rice BBI (RBTI) of molecular weight 15 kDa has been crystallized using the hanging-drop vapour-diffusion method. According to the diffraction of rice BBI crystals at a resolution of 2.07 Å, the unit cell belongs to space group P212121, with unit-cell parameters a = 74.37, b = 96.69, c = 100.36 Å. Preliminary analysis indicates four BBI molecules in an asymmetric unit, with a solvent content of 58.29%. [ABSTRACT FROM AUTHOR]

Lectins with sugar-binding specificity are widely distributed in higher plants and various other species. The expression of rice lectin from Oryza sativa is up-regulated in the growing coleoptile when anaerobic stress persists. A rice lectin of molecular weight 15.2 kDa has been crystallized using the hanging-drop vapour-diffusion method. From the diffraction of the lectin crystals at 1.93 Å resolution, the unit cell belongs to space group P31, with unit-cell parameters a = 98.58, b = 98.58, c = 44.72 Å. Preliminary analysis indicates that there are two lectin molecules in an asymmetric unit with a large solvent content, 70.1%. [ABSTRACT FROM AUTHOR]

The use of a TiO2 nanowire (NW) hydrothermally grown on an fluorine-doped tin oxide (FTO) substrate as a separated sensing electrode of an extended-gate field-effect-transistor (SE-EGFET) pH sensor is demonstrated. Sensing responses to the prepared samples in a wide pH range (2–12) are presented and compared with responses of a film-type TiO2 electrode. The pH sensors with the NW-type and film-type electrodes show a sensitivity of 62 and 50 mV/pH, respectively, and a comparably good linearity in the pH range of 2–12. The superiority of the NW-type TiO2 electrode (24% improvement in sensitivity compared with that of the film-type electrode) is attributed mainly to the higher surface-to-volume (SV) ratio and higher conductivity of the hydrogen thermal growth (HTG) nanowires. [ABSTRACT FROM AUTHOR]