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Recently, deep convolutional neural networks (CNNs) have been widely explored in single image super-resolution(SISR) and obtained remarkable performance. However, most of the existing CNN-based SISR methods tend to produce over-smoothed outputs and miss some textural details. To address these issues, we propose a wavelet-based asymmetric convolution network (WACN). Different from conventional CNN methods that directly infer HR images, our approach firstly learns to predict the LR’s corresponding series of HR’s wavelet coefficients before reconstructing HR images from them. This helps to capture more structural information in images to preserve texture information and avoid artifacts. To enhance the ability of feature extraction, we propose an asymmetric convolution block (ACB) structure to form a very deep network. In the training phase, ACB can provide different receptive fields to enrich feature information. In the inference phase, ACB’s asymmetric convolution kernel can be equivalently fused into the standard square-kernel layers, such that no extra computational burdens are introduced in the inference phase. Furthermore, we propose a variance-based channel attention (VCA) mechanism to adaptively rescale channel-wise features by considering interdependencies among channels. Extensive experimental results demonstrate the superiority of the proposed WACN in comparison with the state-of-the-art methods.

In order to further improve the reliability of high-power output of high-brightness semiconductor lasers, 808 nm semiconductor laser chips with a stripe width of 100 µm were packaged by SiC and AlN...

Under long-term uneven loading, joint surfaces between the components of heavy-duty machine tools become inclined owing to both external loads as well as the heavy weight of the machinery itself. In this study, to reconstruct the real contact parameters at certain angles of inclination, the macro contact angle was first converted into a micro contact angle based on the stress characteristics and the deformation of asperities were considered. The real contact surface area was then calculated using piecewise integration according to three stages deformation: elastic, elastoplastic, and completely plastic. A stiffness model of the joint surface was derived according to classification theory. Finally, an experimental system with inclinations between the joint surfaces was built and used to validate the model by comparing theoretical and experimental mode values. The present paper analyzes the influence of different fractal parameters, inclination values, and other important parameters on the characteristics of the joint surface using the proposed fractal model and provides a theoretical basis for improving the design and precision of heavy-duty CNC machine tools.

To investigate the characteristics of hydrate formation in oil–water systems, a high-pressure cell equipped with visual windows was used where a series of hydrate formation experiments were performed from natural gas + diesel oil + water systems at different water cuts and anti-agglomerant concentrations. According to the temperature and pressure profiles in test experiments, the processes of hydrate formation under two kinds of experimental procedures were analyzed first. Then, based on the experimental phenomena observed through the visual windows, the influences of water cut and anti-agglomerant on the places of hydrate formation and distribution, hydrate morphologies and hydrate morphological evolvements were investigated. Hydrate agglomeration, hydrate deposition and hydrate film growth on the wall were observed in experiments. Furthermore, three different mechanisms for hydrate film growth on the wall were identified. In addition, the influences of water cut and anti-agglomerant on the induction time of hydrate formation were also studied.

The dual-camera coded aperture snapshot spectral imager(DC-CASSI) includes the coded aperture snapshot spectral imager(CASSI) and panchromatic imager. CASSI can obtain the three-dimensional spectral image information of the target in a single coding within a single integral time, but it is difficult to achieve high-quality reconstruction of spectral image in a single coding. Therefore, the panchromatic image acquired by the panchromatic imager should be fused with it to obtain high-quality multispectral reconstruction images. Based on the imaging characteristics of DC-CASSI, a multispectral and panchromatic image fusion algorithm based on Non-subsampled Shearlets Transform (NSST) and improved Pulse Coupled Neural Network(PCNN) is proposed. The fusion experimental results show that compared with other traditional fusion algorithms, the proposed fusion algorithm can be well applied to DC-CASSI and maximum improving the spatial resolution of multispectral coded image while preserving spectral characteristics of the multispectral coded image.

The machine bed and the concrete foundation are connected by anchor bolts. Foundation creep is a comprehensive manifestation of foundation stability. The size and change of foundation creep affect the dynamic characteristics of the bed-foundation interface and the working state of heavy machine tools. In this paper, the contact problem between bed and foundation made of heterogeneous materials is solved, a concrete crushing hypothesis is proposed, and the basis for determining the elastic–elastoplastic–crushing critical deformation parameters of the concrete surface is formulated. Based on the Hertz contact and fractal theories, an equivalent contact model of the joint is developed, revealing the nonlinear mechanical behavior of the bolted contact surface. The cement hydration and foundation creep factors under continuous loading are taken simultaneously into consideration, and the change trend of the compressive strength and elastic modulus of the concrete at the later stage of loading is determined. By comprehensively analyzing the simulation and experimental results, the error of the theoretical model was found to be within 10%, which verifies the correctness of the proposed theoretical model. Finally, by assuming that the external load remains unchanged, a contact stiffness prediction model based on foundation creep is developed, which can provide a new basis for the contact modeling of bed-concrete foundation joint surfaces.

We design high-power AlGaInP laser diodes emitting at ~640 nm. AlN and SiC submounts are used as heat sinks for the laser chips. The laser diode with SiC submount showed a higher thermal rollover power of 3.9 W and higher maximum conversion efficiency of 39% at 25°C. In the range of 15 – 35°C, the two types of lasers have similar characteristic temperature T0. At higher temperatures beyond 40°C, the laser chip mounted on SiC revealed an improved T0, compared to that on AlN. By measuring the wavelength drift of the two types of lasers, we estimate the thermal resistance to be 9.1 K/W for the laser diode on AlN and 5.6 K/W for the laser diode on SiC.

Human umbilical cord-derived mesenchymal stem cell (hUC-MSC) transplantation is thought to be a promising strategy for treating spinal cord injury (SCI). However, the low survival rate of transplanted hUC-MSCs limits their clinical application in cell replacement therapy. Curcumin can suppress inflammation after SCI; however, it remains unknown whether curcumin can modulate the survival of transplanted hUC-MSCs. In this study, to investigate whether curcumin could strengthen the therapeutic effects of hUC-MSC transplantation on SCI, we induced hUC-MSC apoptosis with TNF-α, transplanted hUC-MSC into SCI rats, and assessed the antiapoptotic effect and mechanism of curcumin. LDH release analysis and flow cytometry demonstrated that TNF-α led to hUC-MSC apoptosis and that curcumin increased the hUC-MSC survival rate in a dose-dependent manner. In addition, we showed that the phosphorylation levels of ERK1/2, JNK, and P38 were upregulated in apoptotic hUC-MSCs, while curcumin increased the phosphorylation of ERK1/2 but did not activate JNK or P38, and these effects were reversed by the p42/44 antagonist U0126. Furthermore, we found that the motor function scores and number of surviving HNA-positive cells were significantly increased after curcumin and hUC-MSC transplantation therapy 8 weeks post-SCI, while U0126 markedly attenuated these effects. These data confirmed that curcumin suppressed hUC-MSC apoptosis through the ERK1/2 signaling pathway and that combined curcumin and hUC-MSC treatment improved motor function in rats after SCI. The current research provides a strong basis for hUC-MSC replacement therapy in conjunction with curcumin in the treatment and management of SCI in humans.

During the exploitation of subsea natural gas hydrate (NGH) deposits, the muddy silt from marine sediment is carried by the fluid inside the wellbore. Furthermore, NGH is readily formed inside the wellbore when the fluid is in a hydrate formation area. Once NGH has formed inside the wellbore, the exploitation operation will be hindered, or shut down, due to the blockage. Understanding the kinetic characteristics and morphology of NGH formation is important to prevent its occurrence. To this end, a high-pressure autoclave system was designed and constructed in this work. Experiments were conducted to determine the mechanism of sand aggregation, the effect of sand on the kinetic characteristics and the morphology of hydrate formation. Additionally, models of hydrate particle formation with sand and sand aggregation, and structure of wall-attached hydrate layer growth were proposed. The results showed that sand could promote the growth of hydrate and the wall-attached hydrate layer. Additionally, it was observed that hydrate particles were formed with and without sand, and that the wall-attached hydrate layer presented a sandwich structure. The rolling and colliding implantations of hydrate particles were also observed experimentally. Sand aggregation was caused by hydrate particle implantation and the carrying sand effect. Hydrate particle formation with sand can be divided into four stages: nucleation, surface growth, shell formation, and shell growth. The sand aggregation process can also be divided into four stages: hydrate film formation, rupture of hydrate film, particle aggregation, and hydrate layer sintering. For structure of wall-attached hydrate layer growth, the growth front of the hydrate layer was concave-upward.

An X-ray equivalent absorption technique is developed to determine the doped concentrations of the inertial confinement fusion shells. Doped atoms in the shells are used to increase the opacity for radiation, to improve the absorptive capacity of the shell wall for X-ray, and to restrain the growth of hydromechanics instability. The doped concentrations in the shells are difficult to determine for the relatively thick shell wall and the spatial resolution. A novel model is proposed to determine the doped concentrations by a theory of X-ray equivalent absorption. The advantage of this model is that optical density (D) and the exposure curve [D = Φ(I)] of film plates are not necessary to calculate the doped concentrations. The model is validated with a thickness error of 2% by the polypropylene step wedge, the aluminum step wedge, and the polystyrene sphere. The error of results for doped concentration between this method and the energy-dispersive spectroscopy method is less than 0.1 at. %. The unce...

To investigate hydrate plugging processes and hydrate plugging mechanisms, a high-pressure flow loop was newly designed and constructed where hydrate plugging experiments were performed from natural gas+diesel oil+water systems for a range of water cuts (30–100%) and initial liquid flow rates (1600–2400 kg h −1 ). Based on the experimental data of hydrate morphology and flow parameters, hydrate formation and distribution characteristics in the flow loop were analyzed and two hydrate plugging processes together with the corresponding hydrate plugging mechanisms were proposed. For gradual hydrate plugging, the plugging process can be divided into four stages. Formation and growth of a hydrate deposition layer is the governing plugging mechanism. For rapid hydrate plugging, the plugging process can also be divided into four stages. Liquid stratification and a sharp increase in viscosity is the governing plugging mechanism for rapid hydrate plugging. In addition, silt-like hydrates and flocculent-like hydrate deposition layer were observed in gradual plugging experiments, whereas slurry-like hydrates with no obvious deposition layer were observed in rapid plugging experiments.

An in situ reaction of two optoelectronically active organic ligands (anionic thenoyltrifluoroacetylacetone, tta−, and neutral triphenylphosphine oxide, tppo) with erbium(III) ion in the presence of a base yielded a new erbium complex, [Er(tta)3(tppo)]. The solid and solution structure of the complex was established by X-ray crystallography, NMR, ESI-MS, FTIR, TGA and Raman spectroscopy. They indicate that the Er(III) ion is coordinated to seven oxygen atoms of three tta ligands and one tppo ligand in a monocapped octahedral geometry. The Judd–Ofelt parameters of the complex were determined by a least squares fitting and dealt with its chemical structure. On UV excitation through ligand mediation, the complex shows the characteristic near-infrared emission of the corresponding Er(III) ion at 1534 nm. Furthermore, a near infra-red organic light emitting diode (NIR-OLED) was fabricated with structure: ITO/[N,N′-bis(naphthalen-2-yl)-N,N′-bis(phenyl)benzidine]/[Er(tta)3(tppo)]/[2,2′,2′′-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)]/LiF/Al. This device, with maximum applied voltage of 23 V, shows a total quenching of visible emission and electroluminescence in the C-band region (1534 nm) which is suitable for third communication window applications in fiber optics. Finally, an organic diode was fabricated to determine charge carrier mobility of the complex using a steady-state method.

The situation assessment and decision-making of underwater robots is very important. With evaluating situation information reasonably and making the decision correctly, the underwater robot could accomplish the task excellently. Situation assessment is the process that transforms environmental information collected by sensors into situation information, and decision-making is the process that uses situation assessment results to guide the robot's action. However, the problems of poor objectivity, low precision and low efficiency often exist in robot situation assessment and decision-making, which has attracted the interest of many researchers. This paper proposes a method of situation assessment and decision-making for underwater robots. Firstly, multi-agent situation assessment factors are selected to build a dataset and used as the input data. A BP neural network is used to train the mapping relationship from the evaluation factor data to the situation scores. A reinforcement learning method is then used to guide the robot's action according to the situation score. The experimental results of the underwater robot match show that this method is more reasonable and effective than other competitive methods.

Visual servoing is a vision-based control method with a mechanism of closed-loop, which uses feedback information extracted from the camera to control the motion of a robot. In this paper, we propose a fuzzy-based visual servoing integrated with a bagging method for the wheeled mobile robot (WMR). Previous studies have shown that the value of the mixture parameter for the image Jacobian matrix affects the performance of image-based visual servoing(IBVS). However, the mixture parameter value is constant in most visual servoing methods. To address this problem, we propose a fuzzy-based method to adjust the mixture parameter during the process of visual servoing. Meanwhile, in order to reduce the effect of image noise and the computational complexity of the pseudoinverse matrix, we propose a bagging method to calculate the inverse kinematics, instead of using the Moore-Penrose pseudoinverse method. The results of simulation and real experiments demonstrate the effectiveness of the proposed IBVS method.

Situation assessment system describes the relationship among entities, events, entities and events, and provides a complete high-level description of the current situation based on the scene object domain model acquired by data fusion system. Whereas, problems of poor objectivity, low accuracy, etc. always existing in evaluation methods of the complex systems attract interests of many researchers. This paper puts forward a situation assessment for soccer robots using deep neural network. The key situation factors are designed firstly to build the data set and the model input. A deep neural network model are proposed in this paper to train the map relationship from the input layer to the output layer. The results of experiments in the soccer robot platform demonstrate that the proposed method has better properties in efficiency than the competing methods.

Effectiveness evaluation method could give the quantitative description for an electrical system to help engineers choose the better products to use. Whereas, problems of poor objectivity, low generality, low accuracy, etc. always existing in evaluation methods of the electrical systems attract interests of many researchers. This paper puts forward a novel synthetic effectiveness evaluation method with fuzzy neural network. The fuzzy comprehensive evaluation method is utilized to obtain the weight vector of the evaluation factors. Meanwhile, in order to improve the accuracy of evaluation, the time series data of the factors is chosen instead of the transient data. Complying with the high subjectivity of many methods, the scoring method for single factor based on neural network (S-NN) is presented. The results of experiments demonstrate that the proposed method has better properties in efficiency than the competing methods.

A highly charged manned spacecraft threatens the life of an astronaut and extravehicular activity, which can be effectively reduced by controlling the spacecraft surface charging. In this article, the controlling of surface charging on Chinese Space Station (CSS) is investigated, and a method to reduce the negative potential to the CSS is the emission electron with a hollow cathode plasma contactor. The analysis is obtained that the high voltage (HV) solar array of the CSS collecting electron current can reach 4.5 A, which can be eliminated by emitting an adequate electron current on the CSS. The theoretical analysis and experimental results are addressed, when the minimum xenon flow rate of the hollow cathode is 4.0 sccm, the emission electron current can neutralize the collected electron current, which ensures that the potential of the CSS can be controlled in a range of less than 21 V, satisfied with safety voltage. The results can provide a significant reference value to define a flow rate to the potential controlling programme for CSS.

In the bolt tightening control, when the input torque is given, the complicated friction phenomenon at the bolted joint interface will lead to the non-uniqueness of the pre-tightening force. Moreover, due to the coupling effect of uncertain physical factors such as the geometric tolerance, assembly error, bolt tightening sequence, etc., an inclination angle of the bolted joint interface will appear, so the pre-tightening force becomes more complex. To this problem, firstly, a friction model with an inclination angle is established from a micro-macro perspective. Then the finite element method is used to analyze the bolt tightening behavior with different inclination angles. Finally, the correctness of this model is verified by the tightening experiment. The results show that surface topography parameters D and G and an inclination angle β have significant effects on the friction coefficient, because surface topography affects the real contact area and contact load distribution, resulting in the change of friction coefficient, thus affecting the bolt pre-tightening force.

Based on an as-prepared high-quality tin diselenide-polyvinyl alcohol (SnSe2-PVA) film, a stable passively erbium-doped (Er-doped) soliton mode-locked fiber laser at 1561.38 nm was realized. The output performances were investigated experimentally. At the pump power of 310 mW, the shortest pulse duration of 1.197 ps was obtained with a fundamental frequency of 3.45 MHz, corresponding to the peak power of 317 W, which is much higher than previous reports of SnSe2 mode-locked fiber lasers. The results show that SnSe2 can offer an exciting platform for stable high peak power and ultrashort pulse generation.

China is facing severe climate pollution, thus the CO2 emissions of thermal power plants which consume a lot of fossil energy, need to be strictly monitored. At the same time, the thermal power plants and the government will face brand new environment, where the exactly appropriate monitoring approach of CO2 emission remains ambiguous. This study aims to distinguish monitoring approaches between Continuous Emission Monitoring System (CEMS) and factor-based approach on the basis of the operation features of China’s thermal power plants, analyzing the extension of CEMS. We review the major reducing greenhouse gas initiative in China—carbon market, and different emission monitoring approaches at first. We present the prospects of extension in CEMS’s technical features by analyzing an example of two generations using coal and gas, respectively, finding that CEMS is more accurate and dynamic. This study also presents the challenges by analyzing the refinement of factor-based monitoring approach. However, In contrast to many previous studies, we consider different influence in prospect and challenge from the market itself, the application experience and equipment installation basis. We finally draw an important conclusion that the factor-based monitoring approach is more suitable for China’s thermal power plants currently, but CEMS is more promising.

Traffic noises, especially the vehicle horn sounds, affect the normal life of people and researchers have done many researches on the recognition and location of the traffic noises. This paper proposes a vehicle horn sound location method with an improved SRP-PHAT. Through analyzing the sounds, the frequency domain features for recognizing the vehicle horn sound are selected and the corresponding sound recognition method based on time-frequency transformation (VHSR-TFT) is presented. Complying with the large time cost of SRP-PHAT method for sounds location, the stochastic region contraction method is utilized to improve the real-time performance. The results of simulations and experiments demonstrate that the proposed method has better properties in accuracy and efficiency than the competing methods.

In order to improve the quality of greenhouse vegetable plug seedlings and realize rapid detection of growth information of greenhouse vegetable plug seedlings, a device for detecting the growth information was designed. The detection device contained a weighing unit, an image acquisition unit, a light source unit and a control processing unit, mainly realizing vegetable seedling morphological index of projection area, stem diameter and plant height detection and weight information collection. The light source unit was composed of high-power LEDs. The image acquisition unit was made up of two cameras, the first camera in the vertical downward orientation, was used to obtain projection area parameter of vegetable seedling, the second camera in the horizontal position, was employed to capture of vegetable seedling stem diameter and plant height parameters. The weighing unit adopted a high precision weight sensor to obtain the weight information of the vegetable seedlings. The control processing unit included a single chip microcomputer and a computer. The single chip microcomputer was introduced to control the background board opening and closing, and to control camera work. The computer was mainly used to process images and realize information fusion and the design of humancomputer interaction interface. The software system of the device was developed based on C++ language, including image processing algorithm and control programs. The detection error of the device was less than 5% for morphological indicators and weight information. The results showed that the greenhouse vegetable seedling growth information detection device had high detection accuracy.

Impurity of melon seeds variety will cause reductions of melon production and economic benefits of farmers, this research aimed to adopt spectral technology combined with chemometrics methods to identify melon seeds variety. Melon seeds whose varieties were "Yi Te Bai", "Yi Te Jin", "Jing Mi NO.7", "Jing Mi NO.11" and " Yi Li Sha Bai "were used as research samples. A simple spectral system was developed to collect reflective spectral data of melon seeds, including a light source unit, a spectral data acquisition unit and a data processing unit, the detection wavelength range of this system was 200-1100nm with spectral resolution of 0.14 ~7.7nm. The original reflective spectral data was pre-treated with de-trend (DT), multiple scattering correction (MSC), first derivative (FD), normalization (NOR) and Savitzky-Golay (SG) convolution smoothing methods. Principal Component Analysis (PCA) method was adopted to reduce the dimensions of reflective spectral data and extract principal components. K-nearest neighbour (KNN) and Fisher discriminant analysis (FDA) methods were used to develop discriminant models of melon seeds variety based on PCA. Spectral data pretreatments improved the discriminant effects of KNN and FDA, FDA generated better discriminant results than KNN, both KNN and FDA methods produced discriminant accuracies reaching to 90.0% for validation set. Research results showed that using spectral technology in combination with KNN and FDA modelling methods to identify melon seeds variety was feasible.

This paper presents a new candidate region selecting strategy for detecting clustered tomato fruits using RGB-D data, which is taken in complex greenhouse scenes. The strategy employs both color and depth information in the same Kinect sensing frame. First, one Kinect frame is processed to generate three separate images, including depth image, RGB color image, and S channel image in HSI color space. The images are processed with depth threshold, green enhancement and saturation threshold correspondingly. And a frontground mask image will be generated with the processed images through intersection and union operations. Second, depth gray image and color gray image will be filtered with the frontground mask. And candidate fruit regions can be obtained after open-close reconstruction. Experimental results show that the strategy can greatly cut down the regions of interests while keeping all the true fruit regions.

STUDY DESIGN Expansive pedicle screw (EPS) and polymethylmethacrylate-augmented pedicle screw (PMMA-PS) were inserted in sheep vertebrae in vitro and were evaluated by performing biomechanical tests, radiographic examinations and histological observations. OBJECTIVE The objective of the study was to compare the biomechanical and interfacial performances of EPS and PMMA-PS in sheep lumbar vertebrae in vitro. SUMMARY OF BACKGROUND DATA It is a great challenge for orthopedic surgeons performing transpedicular fixation in the osteoporotic spine. It was reported that either the EPS or PMMA-PS could increase the screw stability. However, there are no studies comparing the 2 kinds of screws especially in primary spinal instrumentation. METHODS A total of 60 sheep lumbar vertebrae were randomly divided into 3 groups. A pilot hole was made in advance in all samples using the same method. Thereafter, the conventional pedicle screw (CPS) was inserted directly into the pilot hole in the CPS group; the hole in PMMA-PS group was first filled with polymethylmethacrylate (PMMA; 1.0 mL) and then inserted with CPS; and the EPS was inserted directly into the vertebrae in EPS group. After a period of 24 hours, biomechanical tests were performed to evaluate screw stability, and x-ray examination, micro-computerized tomography analysis, and histologic observation were performed to evaluate the interface between screw and bone. RESULTS Compared with the stability of CPS, those of EPS and PMMA-PS were significantly enhanced. However, no significant differences were detected between the stabilities of EPS and PMMA-PS. The PMMA surrounding the screw blocked direct contact between bone and screw and formed a "screw-PMMA-bone" interface in the PMMA-PS group. There was a "screw-bone" interface in both CPS and EPS groups. Nevertheless, the expanded anterior part of EPS formed a claw-like structure pressing the surrounding bone trabeculae, which made the local bone tissue more compacted and denser than that in the CPS group. CONCLUSIONS EPS can enhance the screw stability as markedly as the traditional PMMA-PS in primary surgery, and EPS can form a better immediate interface between screw and bone compared with PMMA-PS. EPS also can effectively avoid thermal injury, leakage, and compression caused by PMMA. A great feasibility was proved in this study to perform comparisons between the 2 kinds of pedicle screws in osteoporotic sheep vertebrae in vivo in the further research. In conclusion, we propose that EPS has a great application potential in augmentation of screw stability in the clinic.

As a high-resolution imaging instrument, angular resolution is the most important index of Lyman-α ultraviolet telescope. In this paper a new allocation and budget method is introduced. An resolution error allocation of surface roughness, figure error and alignment error was developed early in the program. And the allocation was used to guide the design. Though testing the surface roughness and figure error in visible light, the variation of diffraction encircled energy can be obtained by non-sequence model and Zernike coefficients brought into optical design software. The numerical results show that the effective RMS surface roughness of primary and secondary mirrors are 0.49nm and 0.40nm in the spatial frequency from 1/D (D is the diameter of the mirror) to 1/λ (λ is an incident wavelength). And the effects of the surface roughness are both less than 0.1″. The figure error of the primary and secondary mirrors are 0.009λ and 0.007λ (Λλ=632.8nm). The resolution errors which were brought by the figure error are 0.33″ and 0.16″. Then the effect of alignment error on angular resolution was gotten by testing visual resolution. Finally the angular resolution in ultraviolet band can be calculated. The focal length of Lyman-α ultraviolet telescope is 2000mm and the pixel size of detector is 14μm. So the pixel resolution is 1.4″. Experimental results show that the angular resolution of Lyman-α ultraviolet telescope is 0.59″, which is approached to the estimate and meet the requirement.

Conflict of pulse repeat frequency (PRF) to high resolution and wide swath can be resolved by using pulse push-broom imaging mode based on slow platform. We study the system design of synthetic aperture radar (SAR) according to the characteristic of slow platform. In order to exert campaign capability to the full, we present pulse push-broom mode. This mode can be implemented by use of broad-band and wide-angle electronic scanning capability based on active phased array antenna. Simulation analysis and flight experiment of slow platform SAR system is carried out in the case of pulse push-broom imaging mode. The results indicate that swath is more than 50 kilometers for 0.3 meter resolution and swath is more than 100 kilometers for 1 meter resolution, when flight altitude is 20 kilometers and flight velocity is 10 meters per second.

Retrodirective array (RDA) is a new type of array antenna with automatically backtracking function, which has special application value in radar countermeasures. When it is used to jam the linear frequency modulation (LFM) pulse compression radar, the bandwidth of the backtracking signal is broadened by the jamming modulation, resulting in the beam pointing error. A model of repeater jamming using the phase conjugate array is established, and the influences on the beam pointing error of the bandwidth variety, the number of array element, the scanning angle and the leakage coefficient of the phase conjugate circuit are analyzed. The results show that the instantaneous frequency variety of the LFM signal has little effect on the beam pointing error, and the number of array element has a great influence on the beam pointing error. The more the number of array elements, the narrower the beam and the smaller the beam pointing error. With the scanning angle increasing, the beam pointing error is increasing. The variety of the leakage coefficient has a great influence on the sidelobe and gain of radiation pattern. Those results have important guiding significance for the use of RDA in radar countermeasures.

Derivation of the conic coefficient error of practical aspheric optic surface is quite significant to aspheric machining accuracy, optical system imaging quality analysis and decomposition analysis of optical lenses. The primary mirror of R-c telescope system was tested by Taylor Hobson Talysurf. The practical surface was fitted using Zernike polynomials based on the date measured from Talysurf. Though taking the Zernike coefficients into the optical system, the effect of the aberration which was brought by optical machining to the optical system imaging quality was obtained. The analysis shows that the spherical aberration was brought into the optical system because of the figure error of the primary mirror. And the value of the spherical aberration was same to the practical alignment result. Then the conicoid aspherical degree of the primary mirror was tested by the Talysurf. The machining deviation of the conic coefficient was gotten though comparing the conicoid aspherical degree of the practical primary mirror with that of the perfect primary mirror. The practical conic coefficient was calculated by the deviation. Taking the practical conic coefficient into the R-c telescope system, the degradation of the optical system imaging quality was known. Also the spherical aberration was brought into the optical system. Experimental results show that the value of the spherical aberration analyzed by the two methods is same and consist with the practical alignment result. That is to say that the conic coefficient changed due to machining error of the conicoid aspherical degree. Because of the change the spherical aberration was attached to primary mirror. And which caused the optical system imaging quality declined. Finally, corrector was designed to balance the spherical aberration of the primary mirror. Ensure that the optical system imaging quality meet the requirement.

The removal of one of the transmission lines will cause power flow transfer. The transferred load of for the affected lines is different. According to the degree of the power flow transfer and using the flow transfer coefficient as the weight, this paper proposes an adaptive distance backup protection scheme. Based on the real-time flow distribution measured by the wide-area measurement system (WAMS), the flow transfer coefficient can be calculated. Then, using the coefficient as a weight, the degree of the setting impedance shrinkage can be adjusted. This scheme could not only prevent maloperation, but also identify the fault and it has the ability of enduring transition resistance. The simulation results on an IEEE 39-bus testing system illustrate the validity of the scheme.

The National Medium- and Long-Term Educational Reform and Development Guideline (2010-20) (hereafter abbreviated as the Guideline) has pointed out that the core mission for the development of China’s higher education in the next decade is to improve quality. This development mission was put forward against the background of China’s higher education having experienced 10 or more years of rapid expansion, of the enrollment rate and overall enrollment having reached certain levels, and of the substantial gap in quality as compared with the developed countries remaining. The main elements of improving quality are improving the quality of talent training, raising the level of research, enhancing the ability [of higher education] to serve society, and optimizing its structure. In the process of improving the quality of higher education, China must establish first-rate universities and disciplines, and at the same time, urge local colleges and universities, tertiary vocational colleges, and private colleges to develop distinctive characteristics and improve their standards.

Aims: Some studies investigated the association between CCND1 rs9344 polymorphism and hepatocellular carcinoma (HCC) risk. However, the results were inconclusive. Thus, we did a meta-analysis to determine this relationship. Materials and Methods: Relevant studies were systematically searched using the PubMed, CNKI, and EMBASE databases. The strength of the association was calculated with the odds ratio (OR) and respective 95% confidence intervals (Cis). Results: We investigated the association between CCND1 rs9344 polymorphism and HCC risk in the dominant models. The result of this meta-analysis showed that CCND1 rs9344 polymorphism did not significantly associated with HCC risk (OR = 1.09; 95% CI 0.88–1.34). In the stratified analysis by ethnicity, we found that this polymorphism was significantly associated with HCC risk in Caucasians (OR = 1.55; 95% CI, 1.05–2.29). However, we did not find any significant association between this polymorphism and HCC risk in Asians (OR = 0.91; 95% CI, 0.71–1.18). Conclusions: This meta-analysis suggested that CCND1 rs9344 polymorphism might be associated with the risk of HCC among Caucasians.

Accountability, which is closely related to evaluation of efficiency, effectiveness, and performance, requires proving that higher education has achieved planned results and performance in an effective manner. Highlighting efficiency and effectiveness and emphasizing results and outcomes are the basic characteristics of accountability in higher education. Evaluating higher education is a major approach for implementing accountability as well as a basic means of assuring quality. Strengthening quality assurance by means of evaluations reflects a new culture of accountability in the higher education governance. The inherent complexity of the higher education process determines the difficulty of accountability and of measuring performance. In order to realize the objective of ensuring and improving quality and avoid unfavorable effects on institutional autonomy, China's higher education evaluation should absorb existing experiences, use helpful foreign experiences as reference, and initiate creative explorat...

It has been said that plant grafting technology was invented 3,000 years ago in China for fruit trees, however it was firstly applied for actual vegetable cultivation in Japan. China started investigations on vegetables grafting in 1960s. In 1980s vegetable grafting was disseminated to vegetable cultivation in order to control the soil sickness induced by continuous cropping, because vegetable production had extended with development of sunlight greenhouses. Meanwhile significant increase in cropping area of water melon in China promoted grafting technology to water melon production also for control the soil sickness. Grafting cultivation has been used in every vegetable production in China after 2000, as an important cultivation method. The Chinese Agricultural Ministry promulgated a non- pollution cultivation standard of vegetables in 2002. To realize the non-pollution cultivation, grafting technology for vegetables is also one of the promising supporting technologies. However, current production capacity cannot meet the demand of grafting seedlings from farmers, some Chinese universities has started development of automatic or semi-automatic grafting machines.

In order to ensure the power system satisfying the security and stability constraints for different fault condition, we put forward the idea that the operational risk can be applied to the coordination problem for preventive control and corrective control. Therefore, a prevention-correction coordinated control model is established. In order to solve this model quickly, the bi-level programming model is used to decompose the proposed model. A mixed method, which applies the interior-point method into particle swarm optimization algorithm, is presented to solve the optimized model. Finally, through the comparative simulation on a six nodes test system between the proposed model and the traditional model, the rationality of the proposed model is verified.

Large frames made of compound material are widely used in many areas such as industry and aerospace. To ensure the frames working properly, monitor of its deformation after expansion is of great importance. A real time measurement system based on retro-reflective technique and vision method is proposed. Several round retro-reflective marks are placed on some defined positions of the frame as mark points which can precisely describe the shape of the frame. The marks are illuminated by laser beams and the image of the marks is captured by a camera. The positions of the marks on the camera are determined by designed image process program. Experimental results show that the whole process can be finished within 0.1 second. The designed system can measure the deformation of up to 50mm and the accuracy of the measurement is better than 0.02 mm.

It is a very important task to automatically fix the number of die in the image recognition system of a fully automatic die bonder. A multiobjective image recognition algorithm based on clustering Genetic Algorithm (GA), is proposed in this paper. In the evolutionary process of GA, a clustering method is provided that utilizes information from the template and the fitness landscape of the current population. The whole population is grouped into different niches by the clustering method. Experimental results demonstrated that the number of target images could be determined by the algorithm automatically, and multiple targets could be recognized at a time. As a result, time consumed by one image recognition is shortened, the performance of the image recognition system is improved, and the atomization of the system is fulfilled.

This article examines the center–periphery concept by focusing on the impact of educational transfer from the US to China on teaching reform in China's higher education institutions from the early 1980s to the present. As the scale and scope of the Sino–US exchange expanded, the impact on China deepened. This was especially evident in the transformation of teaching ideas, curricula, teaching methods, and administrative systems. Chinese scholars returning from the US bring with them not only knowledge but also American academic models. While the American experience was one of the most important forces advancing teaching reform in China's higher education institutions, it primarily existed as a kind of external cause rather than a fundamental impetus. This article shows that peripheral countries, even gigantic peripheral ones, should only import educational experiences from the central countries selectively, and not copy those models blindly.

We report our development of a novel NLDMOS in SOI based smart power technology, integrated into Freescale's 0.13μm CMOS platform. The new NLDMOS not only achieves BVDSS up to 140V in both low side and high side operations, but more importantly, the Rdson*Area is able to shrink at least 35-40% below the current benchmark, which is the lowest reported for BVDSS ranging from 50V to 138V. For the first time, we demonstrated LDMOS devices which approach the Si limit. The devices also achieve very competitive performance in both SOA and the reliability tests under HCI stress as well as high temperature reverse bias (HTRB) stress.

In this paper, we present a high power TM Polarized GaAsP laser diode of 808nm wavelength. For high power and narrow beam divergence, an asymmetry broad waveguide structure and a tensile strained GaAsP quantum well were used and the epilayers were grown by low-pressure metalorganic chemical vapor deposition. We have obtained an optical power of 20.86W at 20A without COMD and the vertical farfield of 27°. It is expected that Al-free GaAsP quantum well laser diodes will have good reliability without any facet treatment.

The Extreme Ultraviolet Telescopes resolution tests were carried out at visible wavelength. At working wavelength, an upper limit estimate of telescope’s resolution was obtained about 0.4705 arcsec.

We have experimentally observed the reduction of light speed in a rubidium vapour medium coherently prepared by electromagnetically induced transparency. The light speed reduction was deduced by directly measuring the time delay of a probe light when it passed through the medium. The time delay varies with the intensity of the coupling laser, and the typical time delay we recorded was 1.8 μs, corresponding to a light speed of 56000 m/s.

In cases where hepatocellular carcinoma cannot be surgically removed either due to the capacity of hepatic functional reserve or the special location of the tumor, a radiofrequency ablation (RFA) is recognized to be an effective and minimally invasive treatment. However, when the tumor is adjacent to the main bile duct and blood vessels, it is feared that due to the “heat-sink effect” of the blood and the possible damage to the duct and blood vessels, complete tumor ablation is hard to achieve. We report here a case of complete RFA of hepatocellular carcinoma, adjacent to the main bile duct and blood vessels between the first and the second hepatic portal, with emphasis on the safety of the approach for complete ablation of the tumor.