Effect of thickness of antimony selenide film on its photoelectric properties and microstructure

Antimony selenide(Sb2Se3) films are widely used in phase change memory and solar cells due to their stable switching effect and excellent photovoltaic properties. These properties of the films are affected by the film thickness. A method combining the advantages of Levenberg–Marquardt method and spectral fitting method(LM–SFM) is presented to study the dependence of refractive index(RI), absorption coefficient, optical band gap, Wemple–Di Domenico parameters, dielectric constant and optical electronegativity of the Sb2Se3films on their thickness. The results show that the RI and absorption coefficient of the Sb2Se3films increase with the increase of film thickness, while the optical band gap decreases with the increase of film thickness. Finally, the reasons why the optical and electrical properties of the film change with its thickness are explained by x-ray diffractometer(XRD), energy dispersive x-ray spectrometer(EDS), Mott–Davis state density model and Raman microstructure analysis.

Aircraft parameter estimation using a stacked long short-term memory network and Levenberg-Marquardt method

To effectively estimate the unknown aerodynamic parameters from the aircraft’s flight data,this paper proposes a novel aerodynamic parameter estimation method incorporating a stacked Long Short-Term Memory(LSTM)network model and the Levenberg-Marquardt(LM)method.The stacked LSTM network model was designed to realize the aircraft dynamics modeling by utilizing a frame of nonlinear functional mapping based entirely on the measured input-output data of the aircraft system without requiring explicit postulation of the dynamics.The LM method combines the already-trained LSTM network model to optimize the unknown aerodynamic parameters.The proposed method is applied by using the real flight data,generated by ATTAS aircraft and a bio-inspired morphing Unmanned Aerial Vehicle(UAV).The investigation reveals that for the two different flight data,the designed stacked LSTM network structure can maintain the efficacy of the network prediction capability only by appropriately adjusting the dropout rates of its hidden layers without changing other network parameters(i.e.,the initial weights,initial biases,number of hidden cells,time-steps,learning rate,and number of training iterations).Besides,the proposed method’s effectiveness and potential are demonstrated by comparing the estimated results of the ATTAS aircraft or the bio-inspired morphing UAV with the corresponding reference values or wind-tunnel results.

Height centile curve for child and adolescents in Shaanxi province

Objective: It has been recommended that age-related centile curves of anthropometric indexes(such as height, weight) be used rountinly to evaluate the growth and development statues in children. Presented here is the age-related height centile curves for children aged 0-18 years in Shaanxi, China,1995. Methods: Data of the Shaanxi population were retrieved from The Third Nationwide Growth Survey to construct the age-related height centile curves. The LMS method was used for curve fitting; all analyses were carried out on the basis of different sexes through a special program for LMS(λ-median-coefficient) method which was devised by Cole TJ. Results: Centile curves for boys and girls, showing similar age-related features but girls'puberty coming two years earlier than boys'. The period of puberty growth increment was about 2 years longer for boys. At age 18, boys were taller than girls for about 14 cm. Compared with height standard of NCHS(national center of health statistics), Shaanxi children were taller than American children before 14 years for boys, 12 years for girls, but after 15 years for boys and 13 years for girls, Shaanxi children were shorter than American ones. At age 18, Shaanxi children was 5.6 cm for boys and 4.9 cm for girls shorter than NCHS. Shaanxi children's height increase range from 1958 to 1995 at the same age was 4.9-15.1 cm ,with the mean of 9.59 cm for boys, and 3.7-12.5 cm, with the mean of 8.38 cm for girls. Between 1958-1995, the increasing velocity every ten years were 2.57 cm for boys and 2.26 cm for girls, which indicated that the children have reached the optimum. Conclusion: By means of LMS method, we constructed age-related height centile curves for Shaanxi children aged 0-18 years, these height centile curves are the first one for the Chinese children. It can be used as a reference for assessing growth and development status of Shaanxi children aged 0-18 years.

Preparation of Fe-Mn/K/Al2O3 Fischer-Tropsch Catalyst and Its Catalytic Kinetics for the Hydrogenation of Carbon Monoxide

A K promoted iron-manganese catalyst was prepared by sol-gel method,and subsequently was tested for hydrogenation of carbon monoxide to light olefins.The kinetic experiments on a well-characterized Fe-Mn/K/Al2O3 catalyst were performed in a fixed-bed micro-reactor in a temperature range of 280-380 ℃,pressure range of 0.1-1.2 MPa,H2/CO feed molar ratio range of 1-2.1 and a space velocity range of 2000-7200 h-1.Considering the mechanism of the process and Langmuir-Hinshelwood-Hogan-Watson（LHHW） approach,unassisted CO dissociation and H-assisted CO dissociation mechanisms were defined.The best models were obtained using non-linear regression analysis and Levenberg-Marquardt algorithm.Consequently,4 models were considered as the preferred models based on the carbide mechanism.Finally,a model was proposed as a best model that assumed the following kinetically relevant steps in the iron-Fischer-Tropsch（FT） synthesis：（1） CO dissociation occurred without hydrogen interaction and was not a rate-limiting step;（2） the first hydrogen addition to surface carbon was the rate-determining steps.The activation energy and adsorption enthalpy were calculated 40.0 and -30.2 kJ.mol-1,respectively.

Modeling and prediction of children’s growth data via functional principal component analysis

We use the functional principal component analysis(FPCA) to model and predict the weight growth in children.In particular,we examine how the approach can help discern growth patterns of underweight children relative to their normal counterparts,and whether a commonly used transformation to normality plays any constructive roles in a predictive model based on the FPCA.Our work supplements the conditional growth charts developed by Wei and He(2006) by constructing a predictive growth model based on a small number of principal components scores on individual's past.