Theoretical analysis on springback of L-section extrusion in rotary stretch bending process

The theoretical analysis of springback in rotary stretch bending process of L-section extrusion was studied. The models for characterizing the springback angle after unloading were established based on the stress and strain distributions in the cross-section of the part. With the proposed model, analysis of the effect of pre-stretch force and post-stretch force on springback angle shows that springback decreases as the pre-stretch force or post-stretch force increases. Comparative study with experiments clearly demonstrates that the prediction of springback can resort to the current model without the loss of accuracy.

OBSERVER/FILTER STRUCTURE BASED ADAPTIVE FRICTION COMPENSATION FOR HIGH PRECISION TURNTABLE

Two adaptive friction compensation schemes are developed for a high precision turntable system with nonlinear dynamic friction to handle two types of parametric uncertainties in the friction. Both schemes utilize a nonlinear observer/filter structure to compensate for uncertainties in corresponding friction parameters associated with the turntable system. Moreover, in the second scheme, adjustable gains are introduced into the dual nonlin- ear filters and they can be tuned to improve the position tracking performance. In both cases, a Lyapunov-like argument is provided for the global asymptotic stability of the closed-loop system. Simulation results demonstrate the effectiveness of the proposed schemes.

Effect of sputtering conditions on growth and properties of ZnO :Al films

Al-doped zinc oxide（AZO） films were deposited on glass substrates by mid-frequency magnetron sputtering. The effects of substrate rotation speed and target-substrate distance on the electrical, optical properties and microstructure and crystal structures of the resulting films were investigated by scanning electron microscopy（SEM）, atomic force microscopy（AFM）, X-ray diffraction（XRD）, spectrophotometer and Hall-effect measurement system, respectively. XRD results show that all AZO films exhibit a strong preferred c-axis orientation. However, the crystallinity of films decreases with the increase of substrate rotation speed, accompanying with the unbalanced grains grows. For the films prepared at different target-substrate distances, the uniform microstructure and morphology are observed. The highest carrier concentration of 5.9×1020 cm-3 and Hall mobility of 13.1 cm^2/（V·s） are obtained at substrate rotation speed of 0 and target-substrate distance of 7 cm. The results indicate that the structure and performances of the AZO films are strongly affected by substrate rotation speed.

Novel approach for determining the optimal axial preload of a simulating rotary table spindle system

This paper presents a new theoretical model to determine the optimal axial preload of a spindle system, for challenging the traditional method which relies heavily on experience of engineers. The axial preloading stiffness was treated as the sum of the spindle modal stiffness and the framework elastic stiffness, based on a novel concept that magnitude of preloads can be controlled by measuring the resonant frequency of a spindle system. By employing an example of a certain type of aircraft simulating rotary table, the modal stiffness was measured on the Agilent 35670A Dynamic Signal Analyzer by experimental modal analysis. The equivalent elastic stiffness was simulated by both finite element analysis in ANSYS? and a curve fitting in MATLAB?. Results showed that the static preloading stiffness of the spindle was 7.2125×107 N/m, and that the optimal preloading force was 120.0848 N. Practical application proved the feasibility of our method.

Effect of working parameters on performance characteristics of hydrostatic turntable by using FSI-thermal model

Effects of working parameters on performance characteristics of hydrostatic turntable are researched by applying the fluid-structure-thermal coupled model.Fluid-structure interaction(FSI)technique and computational fluid dynamics(CFD)method are both employed by this new model,and thermal effects are also considered.Hydrostatic turntable systems with a series of oil supply pressures,various oil recess depth and several surface roughness parameters are studied.Performance parameters,such as turntable displacement,system flow rate,temperature rise of lubrication,stiffness and damping coefficients,are derived from different working parameters(rotational speed of turntable and exerted external load)of the hydrostatic turntable.Numerical results obtained from this FSI-thermal model are presented and discussed,and theoretical predictions are in good agreement with the experimental data.Therefore,this developed model is a very useful tool for studying hydrostatic turntables.The calculation results show that in order to obtain better performance,a rational selection of the design parameters is essential.

An iterative calibration method for nonlinear coefficients of marine triaxial accelerometers

Single-axis rotation technique is often used in the marine laser inertial navigation system so as to modulate the constant biases of non-axial gyroscopes and accelerometers to attain better navigation performance.However,two significant accelerometer nonlinear errors need to be attacked to improve the modulation effect.Firstly,the asymmetry scale factor inaccuracy enlarges the errors of frequent zero-cross oscillating specific force measured by non-axial accelerometers.Secondly,the traditional linear model of accelerometers can hardly measure the continued or intermittent acceleration accurately.These two nonlinear errors degrade the high-precision specific force measurement and the calibration of nonlinear coefficients because triaxial accelerometers is urgent for the marine navigation.Based on the digital signal sampling property,the square coefficients and cross-coupling coefficients of accelerometers are considered.Meanwhile,the asymmetry scale factors are considered in the I-F conversion unit.Thus,a nonlinear model of specific force measurement is established compared to the linear model.Based on the three-axis turntable,the triaxial gyroscopes are utilized to measure the specific force observation for triaxial accelerometers.Considering the nonlinear combination,the standard calibration parameters and asymmetry factors are separately estimated by a two-step iterative identification procedure.Besides,an efficient specific force calculation model is approximately derived to reduce the real-time computation cost.Simulation results illustrate the sufficient estimation accuracy of nonlinear coefficients.The experiments demonstrate that the nonlinear model shows much higher accuracy than the linear model in both the gravimetry and sway navigation validations.

日本的传统戏剧舞台

The article is presented an outline of two major traditional pe rforming arts genres in Japan with an introduction of theirs stages. Noh, the be st-known Japanese theatrical art is strictly formalized and dignified. In contra st with Noh theaters that was sponsored and refined by the ruling class, one of Japan’s cultural treasures Kabuki was cultivated mainly by merchant class. It i s a highly stylized performing art that combines acting, dancing and music in an extraordinary spectacle of form, color and sound. The kabuki stage is a rotatin g stage and is further equipped with several gadgets like trapdoors through whic h the actors can appear and disappear. Another speciality of the kabuki stage is a footbridge that leads through the audience.

An improved computation scheme of strapdown inertial navigation system using rotation technique

To improve the accuracy of strapdown inertial navigation system(SINS) for long term applications,the rotation technique is employed to modulate the errors of the inertial sensors into periodically varied signals,and,as a result,to suppress the divergence of SINS errors.However,the errors of rotation platform will be introduced into SINS and might affect the final navigation accuracy.Considering the disadvantages of the conventional navigation computation scheme,an improved computation scheme of the SINS using rotation technique is proposed which can reduce the effects of the rotation platform errors.And,the error characteristics of the SINS with this navigation computation scheme are analyzed.Theoretical analysis,simulations and real test results show that the proposed navigation computation scheme outperforms the conventional navigation computation scheme,meanwhile reduces the requirement to the measurement accuracy of rotation angles.

A community-based epidemiological study of elevated serum alanine aminotransferase levels in Kinmen, Taiwan

AIM: To explore any gender-related differences in prevalence of and condition-associated factors related to an elevated serum alanine aminotransferase (ALT) level amongst residents of Kinmen, Taiwan. METHODS: A total of 11 898 of a potential 20 112 regional residents aged 30 years or more completed a related questionnaire that was carried out by the Yang-Ming Crusade between 1991 and 1994 inclusively, with blood samples being collected by public nurses. The overall questionnaire response rate was 59.3% (52.4% for males and 66.0% for females). RESULTS: The prevalence of an elevated serum ALT level for this sub-population was found to be 7.2%, the prevalence revealing a statistically significant decrease with increasing population age (P<0.0001). Males exhibited a greater prevalence of elevated serum ALT level than did females (9.4% vs 5.3%, P<0.0001). Using multiple logistic regression analysis, in addition to male gender, a younger age, greater waist circumference, presence of type-2 diabetes and hyperuricemia were the significant factors associated with an elevated serum ALT level for both males and females. Gender-related differences as regards associated factors were also revealed. For males, obesity was significantly related to an elevated serum ALT level (OR = 1.28, 95%CI: 1.00-1.66) but this was not so for females (OR = 1.09, 95%CI: 0.84-1.42). Hypertriglyceridemia (OR = 1.80, 95%CI: 1.36-2.39) and hyperuricemia (OR = 1.61, 95%CI: 1.03-2.52) were significantly related to elevated serum ALT levels only for females. CONCLUSION: Several gender-related differences were noted pertaining to the prevalence of and relationship between obesity, hypertriglyceridemia and hyperuricemia and elevated serum ALT level in the present study.

Dynamic error research and application of an angular measuring system belonging to a high precision excursion test turntable

Angular measuring system is the most important component of a servo turntable in inertial test apparatus. Its function and precision determine the turntable＇ s function and precision. It attaches importance to research on inertial test equipment. This paper introduces the principle of the angular measuring system using amplitude discrimination mode. The dynamic errors axe analyzed from the aspects of inductosyn, amplitude and function error of double-phase voltage and wavefonn distortion. Through detailed calculation, theory is provided for practical application; system errors are allocated and the angular measuring system meets the accuracy requirement. As a result, the schedule of the angular measuring system can be used in practice.

Light pen whole space coordinate measuring system based on a tracking turntable

Light pen coordinate measuring system(LPCMS)is a kind of portable coordinate measuring technique based on vision metrology.In classical LPCMS,the measuring range is limited to the camera’s field of view.To overcome this defect,a new LPCMS is designed in this paper to fulfil whole space coordinate measurement.The camera is installed on a turntable instead of a tripod,so that the camera can rotate to track the movement of the light pen.The new system can be applied to large scale onsite measurement,and therefore it notably extends the application of LPCMS.To guarantee the accuracy of the new system,a method to calibrate the parameters of the tracking turntable is also proposed.Fixing the light pen at a stationary position,and changing the azimuth angles of the turntable’s two shafts,so that the camera can capture the images of the light pen from different view angles.According to the invariant spatial relationship between the camera and the pedestal of the tracking turntable,a system of nonlinear equations can be established to solve the parameters of the turntable.Experimental results show that the whole space coordinate measuring accuracy of the new system can reach 0.25 mm within 10 m.It can be concluded that the newly designed system can significantly expand the measuring range of LPCMS without losing too much accuracy.

TiO2 Nanoparticles Produced by Electric-Discharge-Nanofluid-Process as Photoelectrode of DSSC

Self-made TiO2 nanoparticles were used as photoelectrode material of dye sensitized solar cell. The TiO2 thin film coats through spreading nanoparticles evenly onto the ITO glass via self-made spin-heat platform, and then TiO2 thin film is soaked in the dye N-719 more than 12 h to prepare the photoelectrode device. The TiO2 nanoparticles produced by electric-discharge-nanofluid-process have premium anatase crystal property, and its diameter can be controlled within a range of 20-50 nm. The surface energy zeta potential of nanofluid is from -22 mV to -28.8 mV, it is a stable particle suspension in the deionized water. A trace of surfactant Triton X-100 put upon the surface of ITO glass can produce a uniform and dense TiO2 thin film and heating up the spin platform to 200 oC is able to eliminate mixed surfac-tant. Self-made TiO2 film presents excellent dye absorption performance and even doesn＇t need heat treatment procedure to enhance essential property. Results of energy analysis show the thicker film structure will increase the short-circuit current density that causes higher conversion efficiency. But, as the film structure is large and thick, both the open-circuit voltage and fill factor will decline gradually to lead bad efficiency of dye-sensitized solar cell.

Driving Mechanism of Cultivated Land Transition in Yantai Proper,Shandong Province,China

Cultivated land transition and its driving mechanism are the hotspots among studies on land use change. In this study, we constructed a framework to study the driving mechanism of cultivated land transition from the quantitative perspective. Based on the vector data of land use in 1990, 2000 and 2009 of Yantai Proper, Shandong Province China, 11 explanatory variables were chosen from two aspects: the elevation, slope, cost distance to major water area and cost distance to minor water area, which presented physical factors; cost distance to district center, cost distance to town center, cost distance to city expansion center, cost distance to major roads, cost distance to city roads, cost distance to county roads and cost distance to rural roads, which presented the socio-economic factors. Combined with spatial analysis tools and Logistic regression analysis model, we construct Logistic regression analyses with four objectives that were urban construction land, rural residential land, orchard and other lands. The results show that, cost distance to district center, cost distance to town center, cost distance to city expansion center and cost distance to city roads are the significant explanatory variables for the transition of cultivated land into urban construction land. The main explained factors on the transition of cultivated land into rural residential land are slope, cost distance to town center, cost distance to county roads and cost distance to rural roads. Slope, cost distance to minor water area, cost distance to town center, cost distance to county roads and cost distance to rural roads are the significant explanatory variables for the transition of cultivated land into orchard land. Elevation, slope, cost distance to major water area and cost distance to minor water area are the main explanatory variables on the transition of cultivated land into other land uses.

Design, Development and Geometric Error Analysis of an Aerostatic Rotary Table

Rotary tables are equipments in precision machinery applied in five-axis Machine Tools and CMM （Coordinate Measuring Machines）, offering rotational （C-axis） and tilting motion （A-axis）, allowing the obtaining of several configurations for manufacturing or inspection of parts with complex geometries. The demand for high accuracy, high efficiency and fewer errors in the positioning of the part in precision machines increases every day, thus ensuring their high confidence and the use of aerostatic bearings enable constructive innovations to the equipment. In this context, this work presents the mechanical design, the development and error analysis of a prototype of an aerostatic rotary table. This study emphasizes the analysis of a prototype that uses the air as a working principle for reducing friction between moving parts, increasing the mechanical efficiency, and its influence of motion error is also discussed based on the experimental results. For the geometrical errors analysis, experimental tests were realized in laboratory using a DBB （Double Ballbar）. The tests are performed with only one axis moving, observing the behavior of the system for different feedrate at the C-axis.

Polymorphisms of uridine-diphosphoglucuronosyltransferase 1A7 gene in Taiwan Chinese

AIM: Single nucleotide polymorphisms (SNPs) of uridinediphosphoglucuro -nosyltransferase 1A7 (UGT1A7) gene are associated with the development of orolaryngeal cancer, hepatocellular carcinoma, and colorectal cancer. We performed this research to establish the techniques for determining UGT1A7 gene and basic data of this gene for Taiwan Chinese. METHODS: We collected blood samples from 112 healthy adults and 505 subjects carrying different genotypes of UGT1A1, and determined the promoter area and the entire sequence of UGT1A7 exon 1 by polymerase chain reaction. We designed appropriate primers and restriction enzymes to detect variant UGT1A7 genotypes found in the study subjects. RESULTS: Six SNPs at nucleotides 33, 387, 391, 392, 622, and 756 within the coding region of UGT1A7 exon 1 were found. The incidence of UGT1A7*l/*2 (N129R131W208/ K129K131W208) was predominant (35.7%) while that of UGT1A7 *3/*3 (K129K131R208/K129K131R208) was the least (2.7%). The allele frequency of UGT1A7*3, which exists in a considerable proportion of Caucasians (0.361) and Japanese (0.255), was identified only to be 0.152 in our study subjects. A novel variation at nucleotide -57 in the upstream was found, which was associated with SNPs at nucleotides 33, 387, 391, 392, and 622 in one of the variant haplotypes. The nucleotide changes at positions 387, 391, 392 and 756 were in linkage in another variant haplotype. The allele frequency of UGT1A7*3 was 0.018, 0.158, 0.242, 0.433, and 0.920 in subjects carrying wild, A(TA)6TAA/A(TA)7TAA, A(TA)7TAA/A(TA)7TAA, 211G/211A, and 211A/211A variants of UGT1A1 gene, respectively. By using natural or mutagenesis primers, we successfully detected the variations at nucleotides -57, 33, 387, and 622 with the restriction enzymes HpyCH4 Ⅳ, TaqⅠ, AflⅡ, and Rsa Ⅰ, respectively. CONCLUSION: The results indicate that the allele frequencies of UGT1A7 gene in Taiwan Chinese are different from those in Caucasians and Japanese. Carriage of the nucleotide 211- variant UGT1A gene is highly associated with UGT1A7*3. The restriction-enzymedigestion method for the determination of nucleotides-57 (or 33, or 622) and 387 can rapidly identify genotypes of UGT1A7 in an individual.

Study on Influence of Gasoline Sulfur Content on Performance of Vehicle Exhaust Catalytic Converter

This paper has investigated the influence of gasoline sulfur content on durability of catalytic converter for vehicle exhaust gas. Two gasoline samples with different sulfur contents (equating to 150 μg/g and 50 μg/g of sulfur, respectively) were used to examine the durability and performance of catalytic converter on the bench test. The test results have revealed that in comparison to the influence of sulfur on ageing of catalytic converter the thermal ageing had a more remarkable impact on the performance of catalytic converter, and the performance of catalytic converter could be restored by high-temperature desulfurization process after ageing by the high-sulfur gasoline sample (containing 150 μg/g of sulfur) .

Single Platform Integration Environment for Turbine Rotor Design and Analysis

The present article covers briefly state of the art software interoperability technical solutions and the development of the first module of a new single platform D ＆ A （design ＆ analysis） tool for simulation and prediction of stress and burst behavior of turbine rotating disc a preliminary design stage. This platform singularity requires integration of multiple CAD （computer assisted design） ＆ FEA （finite element analysis） tools processing in batch mode and driven from a SPIE （single platform integration environment）. This first module is also to demonstrate, for an axial turbine disc hub axi-symmetric component, feasibility and usefulness of such a platform at preliminary design stage. Expected benefits of the D ＆ A single platform are to improve output accuracy, reduce cycle time, improve process quality and improve resource productivity.

Study on online elimination of sudden unbalance-induced vibration using active balancing technology

An active balancing technology has been applied to solve the severe vibration caused by sudden unbalance in rotating machineries during their working process. First, based on the generation principle of sudden unbalance, a simulation test stand with a sudden unbalance generation device was set up. Then, the balancing planes were optimized by using the finite element method （FEM） to determine the position for balancing device installation. Finally, the active balancing experiments were carried out on the test stand. The experimental results indicate that the vibration response caused by sudden unbalance can be decreased from 77μm to 8μm by using the active balancing device, and the vibration amplitude reduction was up to 89.6%. From this example, it can be concluded that the active balancing device, which is installed on a proper position of the rotor, can effectively control the random transient synchronous vibration, demonstrating its high value in engineering practice.

Statistical Modeling of the High Altitude Platform Dual-Polarized MIMO Propagation Channel

In order to investigate the benefit of multiple-input multiple-output(MIMO) technique applying to the high altitude platform(HAP), a 2×2 MIMO statistical model, which can accurately describe the channel between HAP and high-speed train, is presented. And dual polarization diversity is particularly considered. Based on first-order three-state Markov chain, the single-input single-output(SISO) channel, a subset of the MIMO channel is first established. The ray tracing approach applied to the digital relief model(DRM) which covers the railway between Xi'an and Zhengzhou is used to obtain the state probability vector and matrix of the state transition probability. The proposed model considers both Doppler shift and temporal correlation, and the polarization correlation and spatial correlation statistical properties of large-scale fading and smallscale fading are analyzed. Moreover, useful numerical results on the MIMO HAP channel outage capacity are provided based on which, significant capacity gains with respect to the conventional SISO case are illustrated. Such statistical channel model can be applied to the future wireless communication system between HAP and high-speed train.

Kinematics and dynamics analysis of a three-degree-of-freedom parallel manipulator

Kinematics and dynamics analyses were performed for a spatial 3-revolute joint-revolute joint-clylindric pair(3-RRC) parallel manipulator.This 3-RRC parallel manipulator is composed of a moving platform,a base platform,and three revolute joint-revolute joint-column pair chains which connect the moving platform and the base platform.Firstly,kinematics analysis for 3-RRC parallel manipulator was conducted.Next,on the basis of Lagrange formula,a simply-structured dynamic model of 3-RRC parallel manipulator was derived.Finally,through a calculation example,the variation of motorial parameters of this 3-RRC parallel manipulator,equivalent moment of inertia,driving force/torque and energy consumption was discussed.The research findings have important significance for research and engineering projects such as analyzing dynamic features,mechanism optimization design and control of 3-RRC parallel manipulator.