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Cotton fabrics have been chemically modified with two cationic compounds. They were 3-chloro-2-hydroxypropyltrimethylammonium chloride and the copolymer of dimethyl diallyl ammonium chloride and allyl glycidyl ether, respectively. Under the conditions of no inorganic salt, two modified cotton fabrics were dyed with reactive dyes. The dyeing mechanism of two modified cotton fabrics was investigated in comparison with traditional dyeing of untreated cotton fabrics. It involved the adsorption type, adsorption thermodynamics, and adsorption kinetics between reactive dyes and modified cotton fabrics in the dyeing process. The color-fixing process of modified cotton fibers was also studied in detail. The results showed that there were obvious distinctions between the salt-free dyeing mechanism of modified cotton fabrics and traditional dyeing of untreated cotton fabrics. The adsorption isotherm model of the two modified cotton fabrics conformed to the Langmuir-model. The kinetic model of two modified cotton fabrics conformed to the pseudo-second-order kinetic model. The adsorption of modified cotton fabrics was an endothermic process. The adsorption of unmodified cotton fabrics was an exothermic process. These will serve as a theoretical basis of the industrial production of salt-free dyeing of modified cotton fiber.

This paper proposes a novel unglazed photovoltaic/thermal (PV/T) system completely covered by photovoltaic (PV) cells, the system can significantly increase the power generation, and unglazed structure helps to improve the performance of the electricity. The variable flow experiment shows that the average value of the unglazed PV/T daily electrical and thermal efficiencies can reach 18.62% and 26.86%, respectively, and the corresponding exergy and energy saving efficiencies are 20.51% and 73.76%. Compared with PV module, the electrical efficiency of the PV/T module is increased by 11.54%. As for the large heat loss of unglazed PV/T, a series or parallel system composed of PV/T modules was built to improve heat collection capacity. The results show that the electrical and thermal energy of the series or parallel system increases significantly; temperature of water can be increased by 20 °C when the water volume is more than doubled. However, the electrical efficiency of the system is lower than that of the single PV/T, and the maximum value is 17.32%. Combined with economic analysis, the unglazed PV/T system with higher exergy efficiency and the cost is lower than that of glazed PV/T.

Vacuum interrupter is widely used in the medium-voltage power system. Controlling the arc by the magnetic field is an effective method to improve the breaking capacity. The transverse magnetic field (TMF) forces the constricted arc to rotate to reduce local overheating. In this paper, three kinds of TMF contacts, which are Swastika-type contact, cup-shaped contact, and double-TMF contact that combines Swastika-type and cup-shaped contacts coaxially, are investigated in a demountable vacuum chamber with a high-speed camera. The arc voltage and current are also recorded. The experiments were conducted with circuit currents from 5 to 20 kA (root mean square) with a frequency of 50 Hz. There are four current levels in the experiment, which are 5, 10, 15, and 20 kA, and at least three tests are taken for each current level. The results showed that under low current (I = 10 kA), the arc of the three TMF contacts did not rotate. Under high current (I = 20 kA), it was observed that the arc of Swastika-type and double-TMF contacts rotated in the gap. The arc speed of double-TMF contacts is higher than that of Swastika-type contacts. The cup-shaped contacts have the highest arc voltage and noise among the three TMF contacts. The Swastika-type contacts were eroded most seriously. The simulation results show the force distribution of the arc on different locations. The resultant force makes the arc rotate counterclockwise.

Using magnetic fields to control the vacuum arc is a major way to improve the breaking capacity of vacuum interrupters. Besides the single transverse magnetic field (TMF) and single axial magnetic field (AMF), new type of TMF-AMF contact and TMF-TMF contact structures have been put forward to control the vacuum arc in recent years. In this paper, three different structural contacts are used in the experiments. The arc evolution was captured by an high-speed digital video camera, and at the same time, the arc current and arc voltage wave were recorded. The experiment was conducted under current ranging from 5 to 20 kA (root mean square) and 10 mm of gap distance. There are 12 current shots performed on one contact design. There are four current levels in the experiment which are 5, 10, 15, and 20 kA, and three tests are taken for each current level. The results showed that for TMF-AMF contacts, under low current (I = 5 or 10 kA), the arcs of the two kinds of contacts both kept diffused and rotating. Under high current (I = 20 kA), the arc of the TMF-AMF contact with six slots was constricted and rotated on the plate, and the melting was uniform and slight. As for the eight-slot contacts, the arc was constricted but did not rotate which resulted in significant melting in the local region. As for TMF-TMF contacts, the result is similar under low current, while the arc was constricted and rotated quickly on the inner plate under high current. The simulation results show that when the arc core is located on the outer plate; the total Lorentz force is near zero. When the arc core is located on the inner plate, the direction of total force is counterclockwise.

Architectural integration is a crucial issue in the development and spreading of solar collectors, especially in China, where several traditional buildings have pitch roof with tiles. In this paper, a novel roof solar collector (Type 1) providing hot water and space heating is designed to enable effective collection of solar heat as well integrating naturally. A dynamic numerical model is developed and validated with experimental data. The simulation of the Type 1 collector demonstrates its good characteristics regarding to the thermal insulation and transmission of solar radiation. A linear correlation between the instantaneous efficiency and the reduced temperature is established. Simulated results of the Type 1 collector are further compared with the other two types of roof solar collectors (i.e., Type 2 and Type 3). The comparisons indicated that the similar maximum instantaneous efficiency are achieved. However, the Type 1 collector is preferred as its heat loss coefficient is 54.4% lower compared to the Type 2 collector, and is 65.8% lower compared to the Type 3 collector. The afore-mentioned results confirm that the Type 1 collector introduced has potential to address the issue on the poor architectural quality of roof integrated solar collectors for Chinese traditional buildings.

A novel PV blind-integrated Trombe wall module (PVBTW) was first designed and constructed in the present study. A series of experiments were carried out to measure and analyze the impact of different inlet air flow rates and PV blind angles on electricity generation and heat gains of the PVBTW module. The results showed that the inlet air flow rate of 0.45 m/s and the angle of 50° were considered to be preferable for the PVBTW module. In order to determine the behavior of the designed PVBTW module, comparative experiments between the PVBTW module and the existing two types of PV-Trombe wall modules, namely PV cells fixed on the exterior glazing (PVGTW) and PV cells attached to massive wall (PVMTW) were then conducted under the real conditions. Through comparative experiments, it was found that electricity generation of the PVGTW module was highest, and those of the PVMTW and PVBTW modules were similar, whereas regarding to the heat gains, the ascending order became PVGTW, PVMTW and PVBTW. Combining heat gains and electricity generation, the PVBTW module was superior by 14.5% compared to the PVGTW and by 14.1% compared to the PVMTW with respect to the total efficiency.

It is of great significance to achieve good cooperation between the fast vacuum switch driven by the electromagnetic repulsion mechanism and the buffer system. The purpose of this paper is to study the cooperation of the 40.5kV fast vacuum switch driven by the electromagnetic repulsive mechanism and the oil damper. Firstly, the dynamic characteristics of the electromagnetic repulsion mechanism during the opening process were simulated by MAXWELL software. Then, based on the dynamic characteristics of the electromagnetic repulsive mechanism, a simplified model of the oil buffer is established by AMESim software and its cushioning characteristics are simulated. Moreover, the influence of the buffer piston area and the annular gap width on the cushioning characteristics of oil buffer is analyzed. Finally, the dynamic characteristics of the electromagnetic repulsion mechanism under the action of the oil damper are simulated and analyzed. It provides some guidance for the cooperation of the fast vacuum switch driven by the electromagnetic repulsive mechanism and the oil damper.

The high-voltage dis-connector, as a key substation equipment in the power grid structure, is vitally important to the quality of the power grid operation. Due to the geographic location of Guangdong Province of China, many strong typhoons have caused great damage to power facilities in recent years. And the loss of the dis-connector is the most serious, which severely affects the reliability of the power supply. However, the research on the wind resistance of the dis-connector is still few, so the improvement work of the device is quite difficult. The phenomenon of strong typhoon destroying the dis-connector mainly includes the fracture of post insulator and the conductive arm. In the study of the mechanical properties of post insulator and the conductive arm, almost all wind loads are treated as a concentrated force, but the surfaces of the post insulator and the conductive arm are actually subjected to a continuous wind pressure distribution. The magnitude of the wind load and the error of its application method will inevitably lead to inaccurate stress and strain data obtained in the calculation of the strength of the post insulator and the conductive arm, so that the post insulator and the conductive arm cannot be accurately designed. In this paper, the wind resistance of the dis-connector are studied by using the fluid-structural coupling analysis method. Firstly, the hydrodynamic RNG k-e turbulence model is used to simulate the wind field around the dis-connector, so as to obtain the accurate result of the wind pressure distribution on the surface of the dis-connector. Then the surface pressure of the dis-connector calculated by hydrodynamics simulation is introduced into the structural module of Ansys software as the applied load. The finite element method is used to simulate and calculate the stress and strain of the dis-connector, so as to obtain the mechanical characteristics of the dis-connector under strong wind. In addition, this paper analyzes the effects of different wind speeds and different wind directions on the wind load applied to the surface of dis-connector, and provide a basis for wind resistance design of dis-connector.

Circuit breakers are important control and protection devices in power systems and are essential for ensuring safe and reliable operation of power systems. In recent years, the application of fast electromagnetic repulsive mechanism based on the principle of eddy current in vacuum circuit breaker has gradually become a hot research topic. However, due to the large mass of the moving mechanism and the large opening distance in the high voltage vacuum circuit breaker, it is difficult for the ordinary mechanism to break quickly. Therefore, a double-layer coil type fast electromagnetic repulsive mechanism is proposed, which can generate a larger electromagnetic repulsive force to achieve fast driving of the mechanism. Taking the 40.5kV/50kA vacuum circuit breaker as an example, the 2D finite element model was built by MAXWELL software, and its motion characteristics were simulated. In addition, the effect of the metal plate thickness, coil inner radius, number of coil turns and initial gap on the motion characteristics of the fast electromagnetic repulsive mechanism is investigated. The results show that the rise time of the electromagnetic repilsive force is very short. In contrast, the electromagnetic repilsive force has a long time to fall, and the peak value of the electromagnetic repilsive force is large. Thickening the metal plate, increasing the inner radius of the coil plate, increasing the number of coil turns and reducing the initial gap can increase the speed of the rapid electromagnetic repulsive mechanism. The simulation analysis provides a basis for further design of the electromagnetic repilsive mechanism.

In this paper, a molecularly directed evolution-based approach was applied to modify the nitrilase from Rhodococcus rhodochrous tg1-A6 for improving properties in catalyzing nitriles. In the process of error-prone polymerase chain reaction (PCR) with the wild-type nitrilase gene acting as the template, a library of the randomly mutated nitrilase gene was constructed. Since the pH value of catalyzing solution decreased when glycolonitrile was used as the substrate of nitrilase, a high-throughput strategy based on the color change of a pH-sensitive indicator was established for rapid screening of the mutated nitrilase. After three rounds of random mutation and screening about 5000 clones, a variant (Mut3) with 5.3-fold activity of the wild-type counterpart was obtained. Five amino acid substitutions (D27E, N97K, L246F, D108E, and S111R) were found in the variant Mut3. The properties of three mutated enzymes obtained in the three-round mutation were investigated. In the conversion of glycolonitrile, the variant (Mut2) accumulated the highest concentration of glycolic acid at 10.6 g l(-1), a much higher value than the wild type (3.2 g l(-1)).

Electrocardiogram (ECG)signals are important sign signal of human heart health. Arrhythmia is one of the main features of heart disease. Therefore, ECG signal recognition and classification have important clinical significance. In this paper, the ECG signals in the MIT - BIH standard library were used as sample data, which were identified and classified based on the algorithm of convolutional recurrent neural network (CRNN)in order to realize the intelligent identification and classification of ECG signals. The R-wave peak location and heartbeat segmentation of the ECG signals were performed on the sample data using the differential threshold method, and a convolutional recurrent neural network was constructed to identify and classify the signals. The classification results show that the overall recognition rate of ECG signals in the MIT - BIH database sample is 98.81 %, the recognition rate of normal ECG signals is up to 99.67%. The results show that the CRNN has strong generalization ability, fast convergence rate and a good recognition classification rate for ECG signals.

Research on PV/T (photovoltaic/thermal) solar collectors has been conducted for years because the collector can provide electric power and thermal energy simultaneously. A tri-functional PV/T collector is presented and studied in this paper. The collector can work in PV/water-heating mode or PV/air-heating mode for different energy demands. For two working modes, steady-state model and dynamic model of the collector are developed and validated with experimental results. Based on the validated models, the performance of collector is investigated under different flow rates, wind speeds, inlet air temperatures, and initial water temperatures. For PV/air-heating mode, the effects of wind speed and flow rate are investigated. A flow rate of 0.02 kg/(m2·s) is recommenced to balance the temperature increase and thermal efficiency. For PV/water-heating mode, the decrease of thermal efficiency with wind speed increase is observed but it slows down when wind speed is over 5 m/s. The curve of daily thermal efficiency is plotted with different initial water temperature in tank. With annual analysis under different climates, the tri-functional PV/T collector is proved to have better annual performance than separated PV/T water collector and PV/T air collector which could be left unused in some seasons.

Applied with remote sensing, GIS, and mathematical statistics, the spatial-temporal evolution characteristics of urbanization expansion of Yantai city from 1974 to 2009 was studied. Based on landscape pattern metrics and ecological risk index, the landscape ecological risk from the landscape pattern dynamics was evaluated. The results showed that the area of urban land increased by 189.77 km2with average expansion area of 5.42 km2 y−1from 1974 to 2009. The urbanization intensity index during 2004–2009 was 3.92 times of that during 1974–1990. The land use types of urban land and farmland changed greatly. The changes of landscape pattern metrics for land use patterns indicated that the intensity of human activities had strengthened gradually in study period. The landscape ecological risk pattern of Yantai city shaped half-round rings along the coastline. The ecological risk index decreased with increase of the distance to the coastline. The ratio of high ecological risk to subhigh ecological risk zones in 2009 was 2.23 times of that in 1990. The significant linear relationship of urbanization intensity index and regional ecological risk indicated that the anthropological economic activities were decisive factors for sustainable development of costal ecological environment.

The effects of the initial preheating perturbation on the dynamical behaviors of FGC wave propagation instability for low-velocity FGC in packed bed are studied numerically. The behaviors of the flame front inclination, break, and shrinking instabilities are always observed in experiments. Based on the experimental phenomena, an initial thermal perturbation model is numerically proposed as to predict the deformation behaviors of the flame front instabilities. The typical flame shapes are obtained depending on filtration velocity, equivalence ratio, and initial preheating temperature difference. It is demonstrated that the development of flame front inclination instability is proportional to the magnitude of initial preheating perturbation. At a lower equivalence ratio, the initial thermal perturbation of 300 K leads to the evolution of flame front break. Increasing filtration velocity leads to the appearance of flame front break, due to the intensification of the hydrodynamic instability. In addition, a perculiar instability of flame front shifting is also confirmed with the initial thermal perturbation of 400 K, which results in a fuel leakage of incomplete combustion.

Based on the operation of a Ground Source Heat Pump (GSHP) in Hefei, the heat exchange of the 100m depth vertical u-shaped pipe buried in the ground was analyzed, and the heat transfer performance, efficiency of the system and temperature variation of the ground were studied experimentally under the typical climate in Hefei. Temperature changes of the field near the heat exchanger after 8h and 24h were analyzed by numerical simulation. Results show that the system has a good performance in winter.

A fuzzy-Hammerstein model predictive control method is proposed for a continuous stirred-tank reactor (CSTR). In this paper T-S fuzzy model is used to approximate the static nonlinear characteristics of Hammerstein model, and a linear autoregressive model is used to solve the results of optimal control. The designed nonlinear predictive controller using Hammerstein model make good use of the ability of universal approach nonlinear of T-S model, and divide the question of nonlinear predictive control into the nonlinear model recongnization and the question of linear predictive control. The application results of CSTR process show the proposed control method has good control performance compared to PID controller.

A design of solar collector that is able to provide both hot water and hot air has been proposed to increase annual thermal conversion ratio of solar energy. By modifying the conventional flat-plate solar water heater, the collector with L-shape fins can also function as a double-flow solar air heater. Experiments have been conducted to investigate the dual functions of the collector. It is shown that the thermal efficiency of the collector reached 50% in water heating, and varied from 41% to 55% in air heating depending on the ambient condition and flow rate. Mathematical model has been presented for the collector working in air heating mode. The theoretical results are in good agreement with the experiment results. Theoretical results show that the air flow rate is a dominant factor to determine the efficiency. The enhancement of the L-shape fins on the performance of the collector in air heating is also proved from the theoretic results.

An improved two-dimensional axisymmetric swirl model based on former work has been developed to describe the detailed physical process in the formation and development of vacuum arc cathode spot. In the current model, the influence of plasma cloud, evaporation, backing ion, thermo-field (T-F) emission, back-diffused electron, self-generated magnetic field and Lorentz force are all considered. External parameters include electron temperature, near cathode voltage drop, average charge number, ion number density, space function and time function. The compositions of current density, energy flux density and external pressure are discussed and the influence of external parameters are studied. Simulation results show that electron current density from T-F emission is the most important component for current density; as for energy flux density and pressure, ion flux from plasma cloud is dominant. Ablation on a refractory metal is much less than that on a fusible metal under the same external conditions. The simulation results are in good agreement with other researchers' results.

In this paper, the arc characteristics of cup-shaped AMF contacts in vacuum arc experiments under different materials was studied. The experiment was conducted in a detachable vacuum chamber with a gas pressure of 10-4Pa. The arc voltage and current were measured at the same time by high-voltage probe and Rogowski coil, and the arc pictures were photographed with a high-speed camera. The cup and the rod of the contact are made of pure copper material, and the contact pieces are selected ten common contact materials for comparison (CuCr10, CuCr 20, CuCr 30, CuCr 40, CuCr 50, WCu10, WCu20, WCu30, CuW-WC). Fixed-distance trigger experiments were conducted with currents of 5kA (rms), 10kA (rms), and 15kA (rms) for each contact. The arc appearance, cathode surface morphology, and anode status morphology were observed. The shape of the arc was analyzed in conjunction with the voltage and current after the experiment. The morphology of cathode and anode surface was analyzed by combining the erosion after the experiment. The effect of various material properties was discussed under the AMF. It’s found that the center of the anode erosion area is approximately hexagonal, and the slot is burned more outward than the plane. WCu contact has better erosion resistance than CuCr contact. For CuCr, the erosion of CuCr30 is the slightest with low depth and small area.In this paper, the arc characteristics of cup-shaped AMF contacts in vacuum arc experiments under different materials was studied. The experiment was conducted in a detachable vacuum chamber with a gas pressure of 10-4Pa. The arc voltage and current were measured at the same time by high-voltage probe and Rogowski coil, and the arc pictures were photographed with a high-speed camera. The cup and the rod of the contact are made of pure copper material, and the contact pieces are selected ten common contact materials for comparison (CuCr10, CuCr 20, CuCr 30, CuCr 40, CuCr 50, WCu10, WCu20, WCu30, CuW-WC). Fixed-distance trigger experiments were conducted with currents of 5kA (rms), 10kA (rms), and 15kA (rms) for each contact. The arc appearance, cathode surface morphology, and anode status morphology were observed. The shape of the arc was analyzed in conjunction with the voltage and current after the experiment. The morphology of cathode and anode surface was analyzed by combining the erosion after the exp...

A DNA fragment containing the entire coding sequence of nitrilase gene was amplified from Rhodococcus rhodochrous tg1-A6 with high nitrilase activity using PCR and sequenced. The open reading frame of the nitrilase gene contains 1,101 base pairs, which encodes a putative polypeptide of 366 amino acid residues. The nitrilase gene was cloned into an expression vector pET-28a and expressed in an Escherichia coli strain BL21(DE3). The enzymatic activity of nitrilase, which converts various nitriles to the corresponding carboxylic acids, was detected to reach 24.5 U/ml at 9 h in the recombinant bacteria.

Background: GLP-1 and its analogs have a variety of anti-diabetic effects. However, short half-life and rapid degraded by DPP-IV limits the therapeutic potential of the native GLP-1. So, many DPP-IV-resistant and long-acting GLP-1 analogs were developed. In this study, an antibody-like extendin-4-IgG4 fusion protein was developed. Methods: The γ4 constant region contains two amino acid substitutions relative to native γ4 (S228P and L235E) lead to affinity for FcγRI to be low and stability of the IgG4 molecular. The fusion protein was expressed in CHO cells and assembled into an immunoglobulin-like structure with molecular weight of approximately 130 kDa. Results: The Exendin-4-IgG4 fusion protein was found to affinity bind GLP-1R in vitro. In vivo when compared the potency and duration of glucose-lowering effects in diabetic (db/db) mice at the same dose, exendin-4 resulted in a glucose-lowering effect that persisted only for 6 hours, but the extendin-4-IgG4 fusion protein for more than 168 hours. Injecting subcutaneously with a high dose of the fusion protein led normal BALB/c mice to the lower blood glucose level but did not cause serious hypoglycemia. Especially, the half-life time of the fusion protein in cynomolgus monkeys was about 180 hours, almost the longest half-life time among the developed GPL-1 analogues, which suggested a longer half-life time in human. Conclusions: The intact antibody-like fusion protein has more advantages than the Fc fusion protein including the intent of prolonging the half-life. These results also suggested the fusion protein was a safe and long-acting potential anti-diabetic agent.

The water catchment water quality of northwest China is evaluated and managed through the principal component analysis. The results show that the water quality is characterized by high organic load and turbidity, and the felted roof and tiled roof achieve the requirements of category. The evaluation results conform to actual situation of the rainwater-collecting drinking water source area objectively and practically. Through this article, more objective reference for the region water resources planning, utilization, development and environmental system optimization is provided.

TOSA method is a new technique for faster time to improved SA. TOSA method traces optimal elements for reduce ineffective select in the simulated Annealing process. But TOSA take the uneven results in quality. In this paper, we propose a new technique that traces optimal solution in the SA process for high quality. We applied the method to the simple global placement problems, and found that it achieved more than 17 % better solution as the best case than TOSA.