[en] We propose a method of rotation angle measurement with high precision in machine vision. An area scan CCD camera, imaging lens, and calibration pattern with a spot array make up the measurement device for measuring the rotation angle. The calibration pattern with a spot array is installed at the rotation part, and the CCD camera is set at a certain distance from the rotation components. The coordinates of the spots on the calibration pattern is acquired through the vision image of the calibration pattern captured by the CCD camera. At the initial position of the calibration pattern, the camera is calibrated with the spot array; the mathematical model of distortion error of the CCD camera is built. With the equation of coordinate rotation measurement, the rotation angle of the spot array is detected. In the theoretic simulation, noise of different levels is added to the coordinates of the spot array. The experiment results show that the measurement device can measure the rotation angle precisely with a noncontact method. The standard deviation of rotation angle measurement is smaller than 3 arc sec. The measurement device can measure both microangles and large angles.

[en] Scanning tunneling microscopy (STM) can detect individual molecular configuration with its high spatial resolution ability, but some intrinsical and extrinsic factors result in the complexities of STM imaging of single molecules. By combining STM experimental work and theoretical simulation with the local density approximation based on Bardeen perturbation method, we have explored the atomic-scale configuration of the following molecular systems: C₆₀ molecules adsorbed on Si(1 1 1)-(7x7); alkanethiol self-assembly monolayers on Au(1 1 1); C₆₀ molecule imaged by STM tip adsorbed with another C₆₀ molecule; O₂ molecule adsorbed on Ag(1 1 0) and CO molecule adsorbed on Cu(1 1 1) imaged by CO chemically modified STM tip. Some related problems including: molecule-substrate interactions, STM imaging mechanism, chemically modified STM tip, etc., are discussed

[en] PDCA Circulation (Plan, Do, Check, Action) is applied in quality-control management during the welding process of Titanium alloy steam generator pipe. The weld defects is controlled effectively and the ratio of certified weld rose steadily, which achieve its target (90%). Experiments and engineering application show that, if the process-control could be carried out according to the PDCA circulation, activity which affect quality could be ensured to be controlled effectively without being omitted, and finally, steadily and dependable manufacture techniques could be formed so that the quality of products can be improved perpetually. (authors)

[en] Enzymes from the 2-oxoacid: ferredoxin oxidoreductase (OFOR) family engage in both CO_2 evolution and reduction in nature, depending on their physiological roles. Two enzymes and their redox partner ferredoxins (Fds) from Hydrogenobacter thermophilus and Desulfovibrio africanus were examined to investigate the basis of the catalytic bias. The Fd1 from H. thermophilus demonstrated a potential of ∼ −485 mV at room temperature, the lowest for known single [4Fe-4S] cluster Fds. It suggests a low potential electron donor may be the key factor in overcoming the large thermodynamic barrier of CO_2 reduction. The Fd-mediated electrocatalytic experiments further demonstrated the impact of Fd’s potential on the direction of the OFOR reaction: as OFOR enzymes could essentially catalyze both CO_2 evolution and reduction in vitro, the difference in their physiological roles is associated with the reduction potential of the redox partner Fd. The electrocatalytic assay could study both CO_2 evolution and reduction in one setup and is a good tool to probe Fds’ reactivity that arise from their reduction potentials.

[en] An electron added to a solvent polarizes its surrounding medium to minimize the free energy. Such an electron with its polarization cloud, which we refer to as the solvated electron, is one of the most fundamental chemical reagents of significant experimental and theoretical interest. The structure and dynamics of solvated electrons in protic solvents have been explored ever since the discovery of intense blue coloration in solutions of alkali metals in ammonia. Because solvated electrons are the most fundamental chemical reagents as well as carriers of negative charge, substantial experimental and theoretical efforts have focused on elucidating their equilibrium structure and solvation dynamics in a variety of neat liquids. One of the most important but least explored environments for solvated electrons, namely, the two-dimensional liquid/solid and liquid/vacuum interfaces, is the subject of this review.

[en] The native defects and magnetic properties in undoped rutile TiO_2 are studied using local density approximation (LDA) and LDA adding Hubbard parameters (U) schemes. The band gap is adjusted to experimental value of 3.0 eV by combination of U_T_i_d=4.2 eV and U_O_p=4.8 eV. This LDA+U methodology overcomes the band-gap problem and renders the approach more predictive. The formation energies of oxygen vacancy (V_O), oxygen interstitial (O_i), titanium vacancy (V_T_i), titanium interstitial (Ti_i), oxygen anti-sites (O_T_i), and titanium anti-sites (Ti_O) are investigated by the LDA and LDA+U methods. In addition, some ground state configurations can be obtained by optimization of total spin. It is found that native defects can induce spin polarization and produce magnetic moment. - Highlights: • The formation and ionization energies of native defects in undoped TiO_2 are investigated. • Some ground state configurations are obtained by optimization of total spin. • Impact of native defects on magnetic moment is discussed.

[en] In this paper, a computer program, Drum Boiler Start-up Simulation Program (DBSSP), is developed for simulating the start up behavior of controlled circulation and natural circulation boilers. The mathematical model developed here is based on the first principles of mass, energy and momentum conservations. In the boiler model, heat transfer in the waterwall, the superheater, the reheater and the economizer is simulated by the distributing parameter method, while heat transfer in the drum and the downcomer is simulated by lumped parameter analysis. The program can provide detailed flow and thermodynamic characteristics of the boiler components. The development of this program is based only on design data, so it can be used for any subcritical, controlled or natural circulation boiler. The simulation results were compared with experimental measurements, and good agreements between them were found. This program is expected to be useful for predicting the characteristics and the performance of controlled circulation and natural circulation boilers during the start up process. It also can be used to optimize a start up system for minimum start up time

[en] Asymmetric self-phase modulation (SPM) of an intense laser pulse propagating in a plasma is analyzed in the case of resonance and non-resonance. The effect of wakefield modulates the refractive index asymmetrically and results in the asymmetry of pulse SPM. This asymmetry releases when the initial electron density or the pulse width is far from the resonant value. And analytical expressions for the nonlinear phase and instantaneous frequency shifts are obtained in the weakly relativistic limit

[en] Nuclear Island (NI) is safety-related structure in NPP and there're strict standards and requirements on the quality of concrete used for NI construction. This paper introduces the whole process of Haiyang NPP unit 1 NI construction, illustrates the technical requirements on the process of concrete design, test and construction, which can serve as some references for the construction of later AP1000 projects. (authors)

[en] Objective: To evaluate the effect of epidural analgesia on stress status in laboring women through measurement of the changes of plasma PRA, A II, ALD and COR levels. Methods: Sixty primiparae were divided into two groups: with epidural analgesia (n=30) and controls (without analgesia, n=30). Plasma levels of PRA, A II, ALD and COR were measured with RIA in both groups at 1. cervical os = 3 cm, 2. cervical os completely opened, 3. delivery. Results: In the group with analgesia, plasma PRA, A II and COR levels were significantly lowered (p<0.05) when cervical os was completely opened. with the controls, values were about the same in all measurements (p>0.05). Conclusion: The stress hormones levels were much decreased with epidural analgesia