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A 1-D plasma model coupled with a well-mixed reactor model was used to simulate the growth properties of hydrogenated microcrystalline silicon film deposited by very high frequency plasma-enhanced chemical vapor deposition from SiH 4 and H 2 gas mixtures. Plasma parameters of the former, such as electron density and electron temperature, were determined and used as input values for the latter, in which concentrations of gas phase species, crystalline orientation, hydrogen content, surface fraction of dangling bonds, and deposition rate were calculated. Simultaneously, a series of in situ optical emission spectroscopy measurements and film depositions were carried out to investigate the correlation between the model and the experiments. Desired agreements between both were achieved.

Horizontal deflection often occurs when a ray propagates in shallow water with an irregular sea bottom, which makes it difficult to determine eigen-ray trajectory and transmission time. A new method for seeking eigen-ray in three dimensions was proposed and sound speed profile (SSP) was inverted in three-dimensional shallow water using the fastest eigen-ray transmission times to form the cost function. In order to satisfy long-time monitoring of SSP, a kind of sonobuoy was developed with the function of DGPS, short wave radio controlling and dada transmission and experiment was implemented in the South China Sea. It is indicated that the sonobuoy has high reliability and stability in rough sea condition. The precision of SSP inversion can be enhanced dramatically by considering horizontal deflections of eigen-ray. In addition, the influence of small mismatch of seabed depth on precision of inversion can be neglected.

In this paper, we have measured the temperature depended growth properties of hydrogenated microcrystalline silicon (μc-Si:H) films, prepared by very high frequency plasma-enhanced chemical vapor deposition (VHF-PECVD) from SiH4 and H2 gas mixtures. And, a 1D plasma model coupled with a well-mixed reactor model is used to simulate the growth process, in which concentrations of gas phase species, the crystalline orientation, the hydrogen content and the deposition rate are calculated. It suggests that the increasing surface fraction of the dangling bonds with the increase of substrate temperatures is responsible for the increase in the grain sizes. At the same time, the observed variations of the X-ray-diffraction intensities and the deposition rates of the films with temperature result from the differences in the growth rates of the facets.

The upconversion (UC) properties of β-NaYF4:Yb3+(10%),Er3+(1%) microprisms synthesized using a hydrothermal method were studied under different excitation conditions. It was found that the UC emission of β-NaYF4:Yb3+(10%),Er3+(1%) was more sensitive to the 980 nm photons than the 1560 nm photons, because of the high mole ratio of Yb3+/Er3+ in crystals. Applying this material at the back of a hydrogenated amorphous silicon (a-Si:H) solar cell, a short-circuit current density of 64 μA/cm2 was measured under 0.53 W/cm2 980 nm laser excitation. This corresponds to an external quantum efficiency of 0.015% of the solar cell. When co-excited with the 980 nm and 1560 nm lasers, a very weak enhancement in the current was shown, which resulted from the slightly increased red emission. This indicates that co-excitation with multiple wavelengths accessible to the β-NaYF4:Yb3+(10%),Er3+(1%) microprisms is not an effective method to enhance the efficiency of a-Si:H solar cells.

The ARGO-YBJ experiment is an air shower detector for gamma ray astronomy and cosmic ray studies with an energy threshold of ∼500 GeV. Working in “single particle mode”, i.e. counting the single particles hitting the detector at fixed time intervals, ARGO-YBJ can monitor cosmic ray and gamma ray transients at energies of a few GeV. The single particle counting rate is modulated by the atmospheric pressure and temperature, and is affected by the local radioactivity from soil and air. Among the radioactive elements, radon gas is of particular importance since its concentration in air can vary significantly, according to environmental conditions. In this paper we evaluate the contribution of the radon daughter gamma ray emitters to the single particle counting rate measured by ARGO-YBJ. According to our analysis, the radon gas contribution is roughly 1–2%, producing a counting rate modulation of the same order of magnitude of the atmospheric effects.

Ulmus chenmoui (Ulmaceae) is an endangered tree found on Langya Mountain, eastern China. To better understand the population genetics of U. chenmoui and conserve the species, we developed microsatellite markers. Using a suppression-polymerase chain reaction technique, 74 compound microsatellite primer pairs were designed. Twelve microsatellite markers were polymorphic in 39 individuals, and the number of alleles per locus ranged from 3 to 9. The observed and expected heterozygosities ranged from 0.051 to 0.769 and from 0.533 to 0.768, respectively. Significant linkage disequilibrium was detected for three pairs of loci (P < 0.01), which may be due to a recent population bottleneck and the small population size. Nine of the 12 loci deviated from the Hardy-Weinberg equilibrium (P < 0.01), which could be explained by significant inbreeding rather than the presence of null alleles. These markers will provide a solid basis for future efforts in population genetic studies of U. chenmoui, which in turn will contribute to species conservation.

NaYF4:Yb(20%),Er(1%) microcrystals were synthesized using a hydrothermal method, and the effects of the reaction time and the particle size on the up conversion (UC) emission properties were systematically studied. The UC emission intensities of the samples are directly related to the particle size and phase structure. The increase in the reaction time resulted in the phase transformation from cubic nanoparticles to hexagonal microprisms, leading to the enhancement of the UC emission. Moreover, the emission intensities and the intensity ratios of the green and red emissions (Fg/r) of the microprisms, in which a normal two-photon UC process was displayed under excitation with a 980 nm laser, remarkably increased with the increase of grain sizes, resulted from the increase of Yb3+ concentrations in crystals.

β-NaYF 4 :Er 3+ (10%) microprisms, synthesized using a hydrothermal method, were applied to the back of a thin film hydrogenated amorphous silicon (a-Si:H) solar cells to investigate response to sub-band gap near-infrared irradiation. Currents of 0.3 μA and 0.01 μA were measured during single-illumination with 60 mW (80 mW/cm 2 ) 980 nm and 1560 nm diode lasers, respectively, due to frequency upconversion (UC). Under co-excitation by 60 mW 980 nm and 100 mW 1560 nm lasers, a current improvement to 0.54 μA was obtained, resulting from enhancements in red emission. The finding indicates that co-excitation with multiple wavelengths accessible to UC materials is very effective in enhancing the efficiency of solar cells.

Cu2ZnSnS4 (CZTS) films were successfully prepared using a co-electrodeposition-annealing route, in which metal precursor layers were deposited by a co-electrodeposition in aqueous ionic solution, followed by the sulfurization in elemental sulfur vapor ambient at 400 °C for 30 min using nitrogen as the protective gas. The dependence of the structural and optical properties on composition in aqueous solution is investigated. It is shown that CZTS film synthesized at Cu/(Zn + Sn) = 0.71 and Zn/Sn = 1 has a kesterite structure with an absorption coefficient in the order of 104 cm− 1, and the band-gap can be feasible modified by changing the element ratios in solution. This indicates that co-electrodeposition-annealing method is a viable process for the growth of CZTS films for the application in photovoltaic device.

The mechanical process of single-crystal aluminium thin films under uniaxial tensile strain was simulated with molecular dynamics method at different temperature. The stress–strain curve and potential energy–strain curve of thin aluminium film under uniaxial tensile deformation were obtained by molecular dynamics simulations. With the changes of sample temperatures in uniaxial extension, the variation characteristics of stress–strain curves are alike at the elastic stage and different at the plastic one below and above 370 K, respectively. From the stress–strain curves, we gained the first local maximum stress-temperature curve and the strain at the first local maximum stress-temperature curve, and found that the strange temperature dependence of first local maximum stress: when the temperature is above 370 K, the stress goes down quickly with temperature, and when below 370 K, it descends slowly. With increasing temperature, the difference between two strain values corresponding to two maximal potential energies changes slowly below and above 370K but it goes up quickly about 370K. By these dependences, we have identified the critical temperature （370K） for the transition of plastic flow mechanism.

The molecular dynamics simulations are performed with single-crystal copper thin films under uniaxial tensile and cyclic loading to investigate temperature effects on the mechanical responses. With the changes of sample temperatures in uniaxial extension, the variation characteristics of maximum stress, the Young’s modulus, the maximal potential energy, the atomic structure of the emerging dislocation, and activation volume and activation free energy at the maximum stress point make us identify and explain the critical temperature for the transition of deformation mechanism in a temperature range from 293 to 460 K. Under cyclic loading, with raising temperature, the number of cycles to failure of copper films increases under different manners in different temperature range, which can be explained by our constructing model based on the evolutionary features of dislocation. Thus, the mechanisms of the strange temperature dependence of tensile and cyclic deformation have been explained. When the temperature is above 370 K, the rate controlling mechanism is dislocation climbing during uniaxial loading, and the number of cycles to failure goes up quickly with temperature; when below 370 K, the mechanism of uniaxial tensility is mainly characterized by the overcoming of Peierls–Nabarro barrier and a few localized pinnings, the number of cycles rises slowly; and when about 370 K, the mechanism in single-axial tension is pipe diffusion, the number of cycles increases at middle speed.

We present a numerical gas phase reaction model for hydrogenated microcrystalline silicon (μc-Si:H) films from SiH4 and H2 gas mixtures with plasma enhanced chemical vapor deposition (PECVD). Under the typical μc-Si:H deposition conditions, the concentrations of the species in the plasma are calculated and the effects of silane fraction (SF=[SiH4]/[H2+SiH4]) are investigated. The results show that SiH3 is the key precursor for μc-Si:H films growth, and other neutral radicals, such as Si2H5, Si2H4 and SiH2, may play some roles in the film deposition. With the silane fraction increasing, the precursor concentration increases, but H atom concentration decreases rapidly, which results in the lower H/SiH3 ratio.

The molecular dynamics simulations are performed with single-crystal copper thin films under uniaxial tensile loading to investigate temperature effects on the mechanical responses. We found that with increasing sample temperatures, both the maximum stress and the Young’s modulus decrease, but the maximal potential energy increases. So, we identified the critical temperature for the transition of deformation mechanism. Then, the deformation was analyzed by examining the variation of the atomic structure of the emerging dislocation. Finally, activation volume and activation free energy of tensile deformation at the maximum stress point of thin Cu film have been calculated for the first time in a temperature range from 293 to 460 K. Thus, the mechanisms of the strange temperature dependence of tensile deformation have been explained. It is found that there exist three temperature regions, which correspond to different thermal activation mechanisms of dislocation motion. When the temperature is above 370 K, the rate-controlling mechanism is dislocation climbing; when below 370 K, the mechanism is mainly characterized by the overcoming of Peierls–Nabarro barrier and a few localized pinnings; and when about 370 K, the mechanism is pipe diffusion.

Microcrystalline silicon thin film is deposited under different conditions by plasma enhanced chemical vapor deposition. The light stability with different crystallinity and grain size is studied, and the growth mechanism is analyzed using the scaling behavior of roughening surface evolution. Degradation of photoconductivity mainly depends on crystallinity and grain size, but fundamentally, on the growth mechanism. Materials with high crystallinity and large grain size are more stable under light soaking. With the increasing of deposition pressure and input power, growth process transfers to zero diffusion limit growth mechanism, and films deposited present less grain size and poor light stability.

Detection of weak underwater signals is an area of general interest in marine engineering. A weak signal detection scheme was developed; it combined nonlinear dynamical reconstruction techniques, radial basis function (RBF) neural networks and an extended Kalman filter (EKF). In this method chaos theory was used to model background noise. Noise was predicted by phase space reconstruction techniques and RBF neural networks in a synergistic manner. In the absence of a signal, prediction error stayed low and became relatively large when the input contained a signal. EKF was used to improve the convergence rate of the RBF neural network. Application of the scheme to different experimental data sets showed that the algorithm can detect signals hidden in strong noise even when the signal-to-noise ratio (SNR) is less than −40d B.

High-quality hydrogenated amorphous silicon films (a-Si:H) were deposited on quartz glass substrates by radio-frequency plasma-enhanced chemical vapor deposition method. The films were then annealed at 800 °C for 3 min by rapid thermal processing (RTP). As confirmed by X-ray diffractometry and Raman spectrometry, hydrogenated microcrystalline silicon films were obtained after the annealing procedure. The mechanism of the rapid solid-phase recrystallization of a-Si:H film by RTP was theoretically mainly attributed to the interaction between short-wavelength photons and ground-state precursor radicals (silicon, SiH 2 and SiH 3 ).

Ag2O film was prepared on glass substrate by direct current reactive magnetron sputtering under a careful control of the preparation parameters. The analysis of the dielectric constants of the Ag2O film related to the optical properties was conducted by spectroscopic ellipsometry (SE) and single-oscillator model. The dielectric constants were fitted in terms of general oscillator model (a model combined with three Tauc–Lorentz oscillator models) by using the measured SE data. Refractive-index dispersion data below the interband absorption edge of the Ag2O film were analyzed using a single oscillator fit of the form n 2 − 1 = E d E 0 / ( E 0 2 − ℏ 2 ω 2 ) proposed by Wemple and DiDomenico, where ℏω is the photon energy, E0 is the single oscillator energy, and Ed is the dispersion energy. The optical energy gap of approximately 2.32 eV was fitted by single oscillator model, which was in good agreement with that in terms of Tauc relation. The fitted dispersion energy Ed of approximately 20.28 eV determined the parameter β of approximately 0.32 by a simple empirical relationship Ed=βNcZaNe, which indicated that Ag2O film falls into covalent class. Additionally, the band gap parameter Ea and plasma frequency ℏωp fitted were 1.16 and 4.85 eV, respectively.

The method of coupled mode is introduced for investigation of bi-static distant bottom reverberation of impulsive source in shallow water, which will not contradict with principle of reciprocity in all cases. And the method of multi-pole for directional source is also introduced. It shows that in case of layered medium, intensity of bi-static bottom reverberation will decease according to the cubic power of receiving time t, and the transverse spatial correlation of bottom reverberation is a little greater than longitudinal correlation for equal separation of receivers, and both vary in form with the receiving time.

The energy extracted from solar radiation is the most abundant and accessible source of renewable energy, which will become progressively more important as time goes on. Solar cells are regarded as one of the most promising candidates for generating renewable clean energy. Recently, a new class of semiconducting material called organic-inorganic halide perovskite has received great attention of academia, and the record power conversion efficiency (PCE) of perovskite solar cell (PSC) rapidly increased from 3.8% in 2009 to 22.7% in late 2017 through intensive research due to some advantages as follows. 1) Excellent optoelectronic property. Perovskite materials exhibit excellent properties, including long diffusion length, high carrier mobility, and high absorption coefficient. 2) Low cost. The ingredients of perovskite materials are cheap, and PSCs can be manufactured by a solution process. 3) Tunable bandgap. Perovskite materials have highly tunable bandgap (1.2-2.2 eV), contributing to the further improvement in PCE of single junction PSCs by realizing the ideal bandgap (1.3-1.4 eV) as demonstrated by the Shockley-Queisser detailed balanced calculation. The basic architectures of PSCs are divided mainly into mesoscopic and planar heterojunction structures. Compared with the former configuration, the later configuration combined with low-temperature processable interlayers provides a method of fabricating flexible PSCs and tandem PSCs. Furthermore, the nonuse of the mesoscopic structure simplifies the structure of PSCs and reduces the cost and time of fabrication. The key requirement to achieve an efficient and reproducible planar heterojunction PSCs is that the perovskite layer should be uniform, continuous, and pinhole free to minimize shunting pathways. So, significant research effort is being devoted to the quality management of perovskite films with the goal of achieving the controllable preparation, including the optimization of their morphology (uniformity, coverage, roughness) and microstructure (grain size/distribution, texture), and the elimination of defects (voids, pinholes, grain boundaries), which influence the PSC performance directly. Especially for the one-step solution coating method, the film quality of perovskite on different planar substrates under varied deposition conditions exhibits a large difference, due to the complex crystallization process and the heightened sensitivity to environmental conditions. In this paper, the characteristics of perovskite materials, the nucleation-growth mechanism of films in the one-step solution method, and the evolution of cell structures are described briefly. The latest quality control methods of high-quality perovskite films prepared by solution method are then discussed emphatically. Finally, to provide references for the future research, the development and existing problems of PSCs are addressed and prospected.

In the real ocean environment, the compressional and shear wave velocities in an elastic sediment layer vary with depth, leading to the coupling between compressional and shear waves. As the coupling will affect the underwater sound field, in this paper, a typical sound velocity distribution (where the compression wave velocity has an n2 linear distribution and the square of shear wave velocity has a linear distribution) is analyzed. Based on the wave equation in inhomogeneous elastic medium, coupled equations of wavenumber kernels of scalar and vector potential functions are established. Based on the perturbation method, approximate analytical solutions of integration kernels are acquired by successive differentiation. The comparison between theoretical prediction and experimental data, which are from the pressure sensor of ocean-bottom seismometer (OBS) consisting of three orthogonal hydrophones and one hydrophone, located at the bottom of the sea near Qingdao City, shows that the coupling between shear wave and compression wave has little effect on near-field sound propagation, while the prediction of long-range sound propagation needs to consider the influence of eigenvalue change caused by coupling. Theoretic analysis shows that there will be coupling between the two waves only if the gradient, σ, of the square of the shear wave velocity is nonzero. When α, the gradient of the reciprocal of the square of the compression wave velocity, becomes larger, and σ remains unchanged, the simulation results show that the change of the eigenvalue is very small when considering the coupling effect. Thus, transmission loss curves calculated by the coupled and uncoupled algorithm are almost the same. When σ becomes larger while α remains unchanged, the simulation results show that eigenvalues are changed to some extent if considering the coupling effect, and that the difference between transmission loss calculated by the coupled and uncoupled algorithms increases. That means the effect of σ value on coupling is greater than that of α value. In addition, the coupling between the compression wave and shear wave can lead the eigenfunctions and derivative eigenfunctions in the sediment to change. The horizontal displacement and vertical displacement are the Fourier-Bessel integral functions of eigenfunctions and derivative eigenfunctions. So the displacement field of particle in the sediment layer is different in the coupled case from that in the uncoupled cases. By comparing the transmission loss of sound pressure simulated by COMSOL software and that obtained from our proposed method, the correctness of the proposed method is verified. And the calculation time is much shorter than the calculation time by using COMSOL software.

Inorganic-organic metal halide perovskite solar cells (PSCs) have drawn tremendous attention as a promising next-generation solar-cell technology because of their high efficiencies and low production cost. Since the first report in 2009, the recorded power conversion efficiency (PCE) of PSCs has rapidly risen to 22.1% by using 2, 2', 7, 7'-tetrakis (N,Ndi-p-methoxyphenyl-amine) 9,9-spirobifluorene (spiro-MeoTAD) as hole transport material (HTM), with the efforts devoted to the device architecture optimization, material compositional engineer and interface engineering. Nevertheless, the synthesis and cost of the organic HTM (OHTM) become a major challenging issue and therefore alternative materials are required. In the past few years, the applications of inorganic HTMs (IHTMs) in PSCs have shown large improvement in PCE and stability. For example, PSCs with CuOx as IHTM reached a PCE of 19.0% with better stability. Even more exciting, the theoretical PCE of PSC based on Cu2O HTM reaches 24.4%. So, Cu2O is a promising IHTM for future optimized PSC and the large area uniform preparation is very important. In this paper, Cu2O films have been successfully prepared using electron beam evaporation followed by air annealing. The influences of annealing temperature and time on the composition, structure, and photoelectric characteristics of film are investigated in detail. It is found that the as-deposited film is a mixture of Cu2O and Cu. With the increase of annealing temperature, material composition is transformed from mixture to pure Cu2O phase, and then to CuO, due to the oxidation in air. In an annealing temperature between 100℃ to 150℃, pure Cu2O film can be obtained with an average transmission rate over 70%, optical band-gap of 2.5 eV, HOMO level of -5.32 eV, and a carrier mobility of 30 cm2·V-1·s-1. When the film is treated with a UV lamp, the structure and composition of the film can be changed more easily because of the enhancement of oxidation. Finally, reverted planar PSCs with the structure of Ag/PCBM/CH3NH3PbI3/HTMs/ITO are constructed and compared carefully based on HTMs of Cu2O, with poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)(PEDOT:PSS), and Cu2O/PEDOT:PSS layers, respectively. An optimum thickness of 40 nm of Cu2O HTM is achieved with high carrier extraction rate. However, the performances of all of the PSCs are inferior to those of PEDOT:PSS-based devices, due to the formation of pinholesin absorber layer resulting from the strong hydrophobicity of Cu2O film. However, the efficiency of PSC based on Cu2O/PEDOT:PSS double-HTM is deteriorated because of the chemical interaction between PEDOT:PSS and Cu2O. These findings provide some important guidelines for the design of HTMs.

Towed fishery detector in horizontality works passively to detect the location of the shoals of fish through detecting their noises. It can facilitate the detection and reduce the cost as well. It can offset the noise in the signals received by the two vector hydrophones in the tow and reduce the interference from the ship for the efficient range of target detection. It can indicate the azimuth of each target by computing relatively on sound pressure and vector velocity and with the help of non-linear optimizing technology and multi-sources distinguishing by single vector hydrophone.

In is paper, the transient behavior of silane molecules in the initial plasma ignition stage on the properties of microcrystalline silicon films is studied using tailored initial SiH4 density method, and the results are analyzed by Raman spectroscopy and spectroscopic ellipsometry. Compared with standard plasma ignition conditions, tailored initial SiH4 density conditions result higher crystallinity in the interface between substrate and bulk film. Finally, tailored and standard conditions are used in i-layer deposition processes of p-i-n and n-i-p solar cells. It is demonstrated that tailored initial SiH4 density conditions is helpful for the efficiency improvement of n-i-p solar cells and standard plasma ignition conditions for p-i-n solar cells.

Effect of 5.0% diluted NH 4 Cl aqueous solution was comparably investigated on the postdeposition surface texture of the as-deposited smooth aluminum-doped zinc oxide (AZO) films by direct current pulse reactive magnetron sputtering (DCP-sputtering) and direct current reactive magnetron sputtering (DC-sputtering). The as-deposited AZO films by DCP-sputtering showed an effective surface texture for light trapping upon the etching of 5.0% diluted NH 4 Cl solution, while the as-deposited AZO films by DC-sputtering demonstrated an obscure surface texture upon the same etching treatment. The different result might be attributable to a big difference in film strain and film compactness. The formation of interstitial Zn, interstitial Al and grain boundary is the key to realize effective surface texture for the as-deposited AZO films.

Microstructure and electrical properties of hydrogenated nanocrystalline silicon (nc-Si:H) film deposited on glass substrate at low temperature were characterized by average grain size, crystallinity, and dark electrical conductivity data obtained from the Raman and electrical conductivity spectroscopy, respectively. The average grain size, crystallinity and electrical conductivity have a similar change with substrate temperature. A threshold substrate temperature determined by silane concentration appears in their corresponding spectroscopy vs. substrate temperature. The dependence of crystallinity, average grain size and electrical conductivity on substrate temperature were accounted for by surface diffusion model and heterojunction quantum dot model, respectively.

All as-deposited AZO films by direct current magnetron reactive sputtering (DC-MS) exhibit ZnO characteristic (002) and (103) diffraction peaks. Especially, AZO films prepared at 200° C show a strongest (002) c-axis preferential orientation due to the minimum stress along the (002) orientation. The results show that larger stress easily induces a rougher surface. The film real and imaginary parts of dielectric constants show a sharp changes near the optical absorption edge due to the interband direct transition. The film blue and red shifts of the optical absorption edge can be explained in terms of the change of free-electron concentration in as-deposited AZO films.

Intrinsic microcrystalline silicon has been deposited by very high frequency plasma enhanced chemical vapor deposition technique at frequency of 75 MHz. Different gas mixtures of silane and hydrogen were utilized, and the evolution of microstructure and phase in film were studied, while keeping the substrate temperature at 200 °C and the chamber pressure at 0.5 Torr. Optimised material was inserted in p–i–n solar cells: preliminary efficiency of 5.5% was reached for 1 μm-thick solar cells with the V oc around 0.6 V.

Using diborane as doping gas, p-doped μc-Si:H layers are deposited by using the plasma enhanced chemical vapour deposition (PECVD) technology. The effects of deposition pressure and plasma power on the growth and the properties of μc-Si:H layers are investigated. The results show that the deposition rate, the electrical and the structural properties are all strongly dependent on deposition pressure and plasma power. Boron-doped μc-Si:H films with a dark conductivity as high as 1.42 Ω−1cm−1 and a crystallinity of above 50% are obtained. With this p-layer, μc-Si:H solar cells are fabricated. In addition, the mechanism for the effects of deposition pressure and plasma power on the growth and the properties of boron-doped μc-Si:H layers is discussed.

Vector transducer can simultaneously measure components of particle velocity as well as pressure at some point in sound field. In this paper, a series of equations are obtained from the correlation of particle velocity and pressure of the incident wave field, the error of each equation with white noise is studied, and Differential Evolution is used in solving the equations to distinguish multi-sources. Results of computer simulation show that Differential Evolution has more superiority than Genetic Algorithms on the rate and precision of convergence under the same condition.

β-NaYF 4 :Yb 3+ (25%),Ho 3+ (1%) microprisms with different grain sizes were synthesized by a hydrothermal method. The structure, composition and upconversion emission properties of the products were characterized by scanning electron microscopy, x-ray diffractometer, inductively coupled plasma atomic emission spectrometry and spectrophotometer. It is found that with the decrease of NaF/NH 4 HF 2 ratios in solution, the lengths of the β-NaYF 4 :Yb 3+ (25%),Ho 3+ (1%) microprisms increase from ~ 5 to ~ 15 μm. The enhancements in the UC emissions with the increase of grain sizes resulted from the raise of the Yb 3+ concentrations in crystals. Applying these materials at the back of a-Si single junction and a-Si/a-Si tandem solar cells, currents of 2.34 and 1.02 μA are obtained under 60 mW (80 mW/cm 2 ) 980 nm laser excitation, respectively.

African-Americans (AA) with congestive heart failure (CHF) are typically sicker, poorer, less educated, and have more co-morbid conditions than White older adults with CHF. Despite evidence of benefits of home tele-monitoring on mortality and hospitalizations, few care models have been designed specifically for African-Americans with CHF. This session reports on an intervention program conducted in South Carolina, where rates of hospitalization for CHF are among the highest in the country. The intervention was informed by qualitative research documenting specific needs for improving self-care and treatment compliance as identified by AA patients in a hospital-based Home Care Program. The low-cost intervention utilizes a mobile phone with a software application that: monitors CHF symptoms; improves self care by providing educational and motivational messages to reduce risks for CHF progression; and improves health care navigation by making it easy for patient to connect to health care providers.

The thin-film solar cell structure with a broadband absorption enhancement is reported. We designed spherical silver (Ag) nanoparticle arrays on or embedded partially into indium tin oxide (ITO) layer of the hydrogenated microcrystalline silicon ([Formula: see text]c-Si:H) thin-film solar cells. The geometrical parameters, such as nanoparticle radius ([Formula: see text], array period ([Formula: see text] and ITO layer thickness ([Formula: see text] are optimized by using the finite element method (FEM). The numerical results show that the key parameter that influences the integrated absorption is period/radius ratio ([Formula: see text]/[Formula: see text] for Ag nanoparticle arrays. Embedding nanoparticle arrays partially into ITO layer with the appropriate thickness can improve broadband light-trapping. The optimized structure shows 50.1% enhancement in the integrated absorption compared to the reference cell when [Formula: see text][Formula: see text]nm, [Formula: see text][Formula: see text]nm and [Formula: see text][Formula: see text]nm. Furthermore, physical mechanisms of absorption enhancement in different wavelength range are discussed according to the electrical field amplitude distributions in the solar cells.

OPTICA APPLICATA; 3/2014; ISSN 1429-7507

By using the combination of the first-nearest neighbor tight-binding model sp3s* and Green function method in the frame of the scattering theory, we studied the electronic structure of ZnTe/CdSe(100) heterojunction with cation layers interchange across ZnSe-like or CdTe-like interface, and presented the interface band structures and wavevector-resolved interface layer densities of states. By comparing with the electronic states of ideal interfaces, we analyzed the nature and origins of all interface states, and discussed the influence of atom layers interchange on interface electronic structure.

Using the scattering-theoretic method and employing the nearest-neighbor tight-binding formalism to describe the bulk electronic structure, we have studied the electronic structure of Si(337) surface. The wave-vector-resolved layer densities of states are presented. The results show that there are six surface bound states in the range from -12.0 to 2.0 eV. Some properties of these surface states are discussed.