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Permanent junctional reciprocating tachycardia (PJRT) occurs primarily in young patients and causes nearly incessant tachycardia that is frequently refractory to pharmacologic treatment. Previous nonpharmacologic therapy has included surgical or direct-current catheter ablation of either the His bundle or the accessory pathway. The accessory pathway in PJRT has been described as having retrograde and anterograde decremental conduction properties, and is typically identified in the posterosoptal location. This report describes radiofrequency catheter ablation of accessory pathways in 8 patients with PJRT. All ablations were successful and without adverse effects. Accessory pathway potentials were detected just before atrial activation in 6 of 8 patients. A new finding was that 5 of the 8 pathway locations, as identified by the site of successful ablation, were not in the typical posteroseptal region. In 1 patient it was located in the right posteroseptal region, 2 were in the right atrial freewall, 1 was in the right anterior seprum and 1 was in the left posterior region just outside of the septal region. In conclusion, radiofrequency catheter ablation can be a highly effective and safe method for treatment of young patients with PJRT. Because the accessory pathways can be located outside of the postero-septal region, careful mapping of beth the right and left atrioventricular groove may be necessary for successful ablation. (Am J Cardiol 1992;70:1559-1564)

A study uses questionnaire responses to explore the association between knowledge acquisition, knowledge absorptive capacity, and innovation performance in small and medium enterprises (SMEs). Results indicate that the technical and industrial experiences of an SMEEs owner influences its knowledge absorptive capacity, which along with the SMEEs knowledge acquisition activities affect its innovation performance.

One important kinematic propertie of breaking waves is the wave celerity. Constant wave celerity has been used for the wave breaking criterion by many researchers. However, this approach does not consider the variation of wave celerity at different phases before breaking. Hence, this article examines the aspects of the wave breaking criterion and dynamics of wave celerity before wave breaking. Breaking waves were generated using the JONSWAP focused spectrum and a semi-empirical formula for the wave celerity estimation was established.

Chemical looping of iron oxides has emerged as a promising approach to produce hydrogen with inherent gas separation. In this work, we use sol–gel‐prepared Fe2O3/MgAl2O4as an oxygen carrier to produce hydrogen from biomass pyrolysis oil. The results showed that 950 °C was the optimum gasification temperature to achieve a high carbon conversion and gas yield. At this temperature, we produced hydrogen by chemical looping. However, the produced hydrogen was polluted severely by CO and CO2because of coke formation during reduction. To solve this problem, we adjusted the reduction atmosphere by adding steam, which was an effective method to enhance the hydrogen purity. At a steam‐to‐oil ratio of 1.5, the purity of hydrogen reached 96 % in contrast to 84 % without steam. In the presence of steam, we also found a more stable porosity, which led to improved cyclic performance. Our current results demonstrate an approach to enhance hydrogen purity and material recyclability. This can be extended to improve other thermochemical hydrogen‐production processes. High‐quality hydrogen: Hydrogen derived from renewable energy has received growing attention. We describe an approach to produce high‐purity hydrogen from biomass pyrolysis oil. We use chemical looping as a fuel‐processing platform to convert the oil into hydrogen. To enhance the hydrogen purity, we improve the looping process by adjusting the redox atmosphere. We demonstrate a new method to produce high‐quality hydrogen from oil and other liquid fuels.

The effect of Hf on the grain refinement of as-cast aluminum was investigated using optical microscopy, electron microscopy and X-ray diffraction. The result shows that the grain size of studied alloy decreases effectively with the addition of Hf, Hf can react with Al to form Al3Hf particles during the solidification, the primary Al3Hf particles are highly potent nucleants for Al and the nanoscale coherent Al3Hf particles can inhibit the grain growth by pinning effect. The grain refinement mechanism of studied alloys was verified by the solute theory and the crystallography study, and it can be divided into two distinct types: At low Hf contents, there are no primary Al3Hf phases to form, the acquired grain refinement is primarily attributed to the constitutional undercooling induced by the Hf solute. At medium and high Hf contents, both Hf solute and Al3Hf particles contribute to the refinement.

The microstructure evolution and properties of an Al–Zn–Mg–Cu alloy were investigated under different non-linear cooling processes from the solution temperature, combined with in-situ electrical resistivity measurements, selected area diffraction patterns (SADPs), transmission electron microscopy (TEM), and tensile tests. The relative resistivity was calculated to characterize the phase transformation of the experimental alloy during different cooling processes. The results show that at high temperatures, the microstructure evolutions change from the directional diffusion of Zn and Mg atoms to the precipitation of Sphase, depending on the cooling rate. At medium temperatures, η phase nucleates on Al3Zr dispersoids and grain boundaries under fast cooling conditions, while Sphase precipitates under the slow cooling conditions. The strength and ductility of the aged alloy suffer a significant deterioration due to the heterogeneous precipitation in medium temperature range. At low temperatures, homogeneously nucleated GP zone, η' and ηphases precipitate.

Oryzaeins A–D (1-4), four new isocoumarin derivatives, along with five known ones (5-9) were isolated from solid cultures of an endophytic fungus Aspergillus oryzae. Their structures were elucidated by detailed spectroscopic analysis and by comparison with reported data of related derivatives. Among them, compounds 1 and 2 represent the first examples of isocoumarins possessing an unusual 2-oxopropyl group and a rare 3-hydroxypropyl group. Compounds 1 and 2 displayedmoderate anti-tobacco mosaic virus activities with inhibition rates of 28.4% and 30.6%, respectively, at the concentration of 20 μM. The new compounds showed moderate inhibitory activities against several human tumor cell lines with IC50 values in the range of 2.8-8.8 μM. [ABSTRACT FROM AUTHOR]

The effects of the solid solution conditions on the microstructure and tensile properties of Al–Zn–Mg–Cu aluminum alloy were investigated by in-situ resistivity measurement, optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and tensile test. A radial basis function artificial neural network (RBF-ANN) model was developed for the analysis and prediction of the electrical resistivity of the tested alloy during the solid solution process. The results show that the model is capable of predicting the electrical resistivity with remarkable success. The correlation coefficient between the predicted results and experimental data is 0.9958 and the relative error is 0.33%. The predicted data were adopted to construct a novel physical picture which was defined as “solution resistivity map”. As revealed by the map, the optimum domain for the solid solution of the tested alloy is in the temperature range of 465–475 °C and solution time range of 50–60 min. In this domain, the solution of second particles and the recrystallization phenomenon will reach equilibrium.

Large-scale electronic circuits need to collect shorted signal to meet the control requirements of closing phase angle in high voltage circuit breaker testing process. . In this paper, by using photovoltaic technology and the design of a new synchronous voltage signal acquisition device, a stable, accurate voltage signal is got. This paper mainly introduces the principle, structure, advantages and applications of signal transmission interference problems of the new synchronous voltage signal acquisition device. The practical application showed that the functions of synchronization acquisition device have reached the designed requirements, which highly improves the stability of the short-circuit signal acquisition.

A survey was conducted in Hangjiahu Plain Wetlands to study the baseline information, types, vegetation, characteristics, ecological values, construction and management. The results showed that: the total area of Hangjiahu plain wetlands coverage ​​181,800 hectares, involving 5 types. The natural resources were very rich in wetlands.There are 8 birds species under national protection and 4 wild plants under national protection. There are 10 wetland places under state protection by government. This is the Nature Protection Zone of Hangzhou Xixi National Wetland Park, a name on the List of international wetlands.Taihu Wetland Park is National wetland park. Proposals on protection and management of the wetland were made by considering practical.

By using milk production data of Guangxi statistical yearbook from 2001 to 2010, based on the Grey theory and Grey prediction models, which are GM(1,1), have been adopted to predict the milk throughput of Guangxi in this paper. So we establish the GM(1,1) prediction model and predict the milk production of Guangxi from 2011 to 2020. The results show that the Grey theory and Grey prediction models have good simulation and feasibility. At the same time, with the combination of livestock products market demand, we provide livestock enterprises and farmers with some appropriate recommendations.

By using rice output data of Baise statistical yearbook from 1989 to 2010, based on the Grey theory and Grey forecast models, which are GM(1,1), have been adopted to predict the rice output of Baise city in this paper. So we get the GM(1,1) prediction model and predict the rice production of Baise city from 2011 to 2020. The results show that the Grey theory model in predicting rice output is feasibility and reasonable.

This paper mainly introduces the design scheme of the automatic door control based on the Micro-controller. The whole system adopts the modular design theory, uses high polymer piezoelectric materials as transducer and takes MC68HIIK4 as cybernetics core. Also, according to automatic door control requirement, it proposes corresponding improvement program on the basis of the common small-sized translational induction type automatic door. The system has the following advantages:simple operation,functional maturation, high sensitivity, low R&D cost.

Abstract：In this paper,HCI solution in the chemical corrosion tests carried out in room temperature,measured mass loss of CFRP tendons. After extraction and analysis, preliminary search the FRP reinforcement corrosion mechanism under acid erosion. The tensile test is done at 60d and 120d,respectively. Determination of the tensile strength of CFRP tendons. The experimental analysis of the data collected, identify the law of CFRP reinforcement corrosion. Fiber reinforced composite material (Fiber Reinforced Polymer, of FRP ) is a continuous non-metallic fibers and fabric reinforced thermosetting or thermoplastic resin matrix composite made of a new material . Fibers and resin matrix composed of FRP bars under normal circumstances is not easy to rust, but in recent years, the study found that acid salt , moisture , UV , temperature and other environmental conditions on the long-term performance of FRP bars have a certain impact[3-5]. By CFRP tendons under acidic corrosion durability test study reveals CFRP tendons under the corrosive effect of the variation of the quality and strength . Can provide a theoretical basis for CFRP tendons durability design , to provide theoretical guidance to improve the efficiency of the FRP bars in harsh conditions .

It is crucial to control the engagement of the in-coming clutch and the disengagement of the off-going clutch for the gear-shift process in order to improve the shift quality of dual clutch transmission (DCT). Aiming at the development of a 6 speed wet-type DCT, three evaluation indices of shift quality including shift time, shift jerk and friction work per unit area, were analyzed in detail. And the torque and the engine speed control strategies for the upshift and the downshift processes were discussed respectively through dividing the gear-shift process into 5 stages. The proposed strategies have been evaluated via simulation experiments of the upshift from gear position 1 to gear position 2 and downshift from gear position 2 to gear position 1, under wide-open throttle respectively. The results show that the proposed strategies can get short shift time and acceptable ride comfort, meanwhile prolong the service life of the friction elements of dual clutches.

Bootstrap method is a statistical method proposed by the American Stanford University professor of Statistics Efron, which belongs to the parameters of statistical methods. According to a given sub-sample, we do not need its distributional assumptions or increase the sample information which can be described the overall distribution characteristics of statistical inference. The basic idea of the Bootstrap statistics is unknown and can not repeat the sampling distribution function instead of using a repeat sampling of the distribution function estimates. The independent identically distributed random variable series ,have the common probability density function, with .In the paper, combining with multidimensional density function, we discuss the convergence rate with Bootstrap method for the kernel estimation of the density functional .

The principle of the Markov chain model is described in this paper, based on the combination forecasting thought and Markov chain thinking, we combine joint forecasting model with the state of the Markov chain transfer model , which is better reflected the law of development of the system of things. We get with parameters in the joint model, and use the joint model to predict the Guangxi food production. Based on historical grain yields data from 1964 to 2011 and the nature of the growth curve regression equation, we establish parameter joint prediction model of Markov and the quadratic function growth curve, which can predict the future grain production of Guangxi province, and we could proof its feasibility. The accuracy of parameter joint model prediction is high, which can be validated by historical grain yields data.

Through the axial compression experiment of 9 GFRP tubes reinforced concrete columns, this paper analyzes the failure mode and loading-strain curves under different pipe diameter, and compares bearing capacity between the experimental data with FRP reinforced concrete and the calculated value without GFRP tubes reinforced concrete. he results show that the bearing capacity and ductility of GFRP tubes reinforced concrete column have improved, because of the restriction effect of FRP tubes. The confining ability of FRP tubes on concrete reduced for a certain thickness GFRP tubes constraint concrete short column, while the pipe diameter is increasing.

Silver doped LiFePO4 powder was synthesized using the hydrothermal method, and was used as a sensing material. An Optical WaveGuide (OWG) sensor which reacted to Volatile Organic Compound (VOC) was developed by spin-coating a thin film of LiFe0.99Ag0.01PO4 onto a Tin-diffused glass optical waveguide. This OWG sensor was used to detect formaldehyde gas as a typical example of VOCs. The experimental result showed that the sensor easily and repeatedly detected 100ppt of formaldehyde, with a short response time (less than 2 s). At the low concentration (below 10ppm), the volatile organic compounds caused no interference with the detection of formaldehyde vapor. The sensor also had the characteristics of high sensitivity, a simple structure, and easy fabrication.

Through the axial compression experiment of 11 FRP reinforced concrete columns, this paper analyzes the failure mode and loading-strain curves.Comparison between the experimental data with FRP reinforced concrete and the calculated value without FRP reinforced concrete is done. The results show that the reinforcement for the component will increase ductility and ultimate bearing capacity of the composite column, but the increase of reinforcement ratio will also reduce confining ability of FRP tubes.

A series of novel Schiff bases bearing triazole structure were synthesized and characterized by IR and NMR. Mn(OAc)2/Schiff base efficiently catalyzed Henry reaction of nitroalkanes with aldehydes to produce the corresponding products of β-nitroalcohols, under mild conditions with high yields (up to 99%). A reaction mechanism is proposed based on the experimental results.

The pure electric vehicles (PEV) research is mainly focus on regenerative braking. How to improve the efficiency of battery power utilization and increase vehicles’ driving range is a crucial problem. Based on the analysis of braking feeling, super capacitor characteristics and the efficiency of regenerative braking energy recovery, the control strategy of regenerative braking system is firstly established, which has two objective functions. One is to control the regenerative braking force. The other is to improve the recovery efficiency of regenerative braking energy. Then, the main operating mode of regenerative braking system is presented. On this basis, regenerative braking controller that is based on DC-DC controller is designed and implemented in simulink software. The results show that the regenerative braking control strategy can effectively control the regenerative braking force during braking and increase driving range of electric vehicles

Schiff base–Cu(II) complex is found to be an effective catalyst for the condensation reaction of indole with aldehydes using ethanol as the solvent. The characterization of the catalysts was carried out using XRD and FT-IR.

A novel asymmetric alkylaminoborazine monomer, 2-propylamino-4,6-bis(methylamino)borazine, was synthesized for the first time, and directly polymerized to give a melt-spinnable polyborazine (PBN). This asymmetric alkylaminoborazine was synthesized by an aminolysis reaction of 2,4,6-trichloroborazine (TCB) with different amines under mild conditions. This route turns out to be much cheaper and simpler than the conventional routes. The chemical composition, structure, molecular weights and ceramic yield were investigated by EA, FTIR, NMR, GPC and TG analysis. The PBN exhibits suitable rheological property for melt-spinning, which suggests that it is a potential precursor for BN fibers.

2,4,6-Trichloroborazine has been recognized as a desirable monomer for the preparation of high-performance boron nitride fibers through polymer derived ceramics route. So a high yield and facile synthesis of 2,4,6-trichloroborazine is essential in practice. Using boron trichloride–dimethylsulfide complex ((CH3)2S·BCl3) and ammonium chloride (NH4Cl) as starting materials and toluene (C6H5CH3) as solvent, the synthesis of 2,4,6-trichloroborazine to give high yield is reported.

The properties of the white layer in the surface grinding are described. The influences of heat treatment, carbon content and grinding conditions on the white layer formation are discussed. It is found that the white layer in the hardened steel is thicker and harder than that in the annealed steel, and there is not a softer transition zone in the annealed steel. Higher carbon content tends to increase white layer thickness at the larger cutting depth, while no difference is observed at the smaller cutting depth. Increased carbon content tends to increase white layer hardness. The white layer thickness increases as the cutting depth increases. The white layer thickness increases with the rise of the table speed until a certain critical speed value is reached, beyond which the white layer thickness decreases with the increase of the table speed. The white layer in the central zone of the workpiece is thicker than that in the entrance zone, but it is thinner than that in the exit zone.

In order to understand the grinding mechanism and analyze the grinding operation, it is necessary to study the contact phenomena between wheel and workpiece during grinding operation. The contact length, the grinding temperature distribution within the contact zone, and the grinding forces are measured in-process by using Critical Contact State mode, thermocouple method, and 3-axis piezoelectric dynamometer, respectively. It is found that the grinding conditions and the properties of work material have effects on the contact length, moreover, the mechanism of which is discussed in this paper. The results show that the contact length significantly interacts with grinding force and grinding temperature in the grinding zone.

A fiberless seed mutant (fl) was identified in a commercial cotton (Gossypium hirsutumL.) variety Xu-Zhou 142 (FL). This phenotype is associated with lack of fiber cell initiation in the outer integument of the ovule, as was characterized by analysis of genes related to fiber differentiation and development. Two genes, fl-E6 and FL-E6, were cloned from fl-integument cells and FL-fiber or integument cells, respectively. Compared with FL-E6, fl-E6 showed a dramatic change in nucleotide sequence: (1) FL-E6 contained a tandem repetitive sequence in which GGCTCA (Gly-Ser) is repeated five times between the 82nd and the 93rd codon from the first ATG codon, while in fl-E6 the same sequence is repeated four times; (2) The fl-E6 gene encodes a polypeptide of 241 amino acids but lacks two codons between the 90th and 93rd codon and three between the 171st and 174th relative to FL-E6; (3) There are also 12 nucleotide substitutions which would result in 7 amino acid differences between fl-E6 and FL-E6. Analysis of RT-PCR and Northerm Blot showed that expression of the fl-E6 gene is suppressed in the fl-integument cells, but highly expressed in FL-fiber cells. The difference between fl-E6 and FL-E6 may be associated with lower expression of fl-E6 in the fl-integument cells. Searches of protein databases with the FL-E6 gene sequence showed similarity to the protein backbones of two arabinogalactan-proteins (AGPs), one from the filtrate of suspension-cultured cells ofPyrus cornmunis(AGPPc2) and the other fromNicotiana alata(AGPNa2). Although the function of the FL-E6 protein in differentiation and development of cotton fiber cells is not known, the data indicate that the mutation of fl-E6 gene from FL-E6 gene may inhibit the fiber cell initiation from epidermal cells of the outer integument of the ovule.

AbstractThiosemicarbazones (3) are effectively synthesized in a few minutes by the condensation reaction of aldehydes with thiosemicarbazide under microwave irradiation.

Abstract: The experimental results showed that: 1) The embryonic development of bay scallop is inhibited at a dissolved oxygen range of 1.38–3.64×10−3 at 23°C, and completely blocked below the lower limit. 2) The tolerance of larvae to anoxia increased with larval sizes and was related to their oxygen debt. 3) The scallop larvae exhibited specific behavioral responses to oxygen deficiency, which finally led to velum disintegration and larval death. The possible relationship between environmental oxygen deficiency and the disease of disintegration of the larval velum is also discussed. In this study, considerable oxygen debt was found in bay scallop larvae, which was greater in small animals. Based on the works of previous authors, a new concept is proposed for the estimation of oxygen debt, namely, the compensatory rate of oxygen debt (CROD). This can be used in intra—or interspecific comparison of oxygen debt. The results can be helpful in the management of water quality and for the prevention of larval diseases encountered in scallop culture.

Abstract: In this paper, a throughflow with swirling inflow in an annular diffuser is calculated. Under the assumption of small cross-flow, the flow near inner and outer wall surfaces is calculated based on the three-dimensional momentum integral equation of the boundary layer. The potential flow outside the boundary layer is computed by means of the iteration method based on the velocity gradient equation along the quasi-orthogonal direction of the meridional projection of the stream-line on the meridional surface and the constancy of flux equation[1]. The numerical results agree with the experiments quite well. This method is useful for analyzing the throughflow with pre-swirl in the annular diffuser.

Objectives. This study retrospectively assesses the technical aspects of the catheter techniques used to ablate 83 accessory atrioventricular (AV) pathways during 88 procedures in 71 pediatric and adult patients (median age 14 years, range 1 month to 55 years). A number of catheter approaches and techniques evolved that may have improved success and shortened procedure times.

The characteristics of damage by Ostrinia fumacalis (Guenee) to mungbean, Vigna radiate (L.) Wilczek, were investigated in a series of field and greenhouse experiments. The insect preferred to lay eggs on the lower leaf surface, mostly in the upper one-third of the plant. Most of the larval feeding is confined inside stems, but some larvae are also found in the root and pods. The bigger the stem diameter and longer the internodes, the greater was the O. fumacalis damage. In field trials where corn, Zea mays L., and mungbean were planted side by side, O. fumacalis damage to corn was much greater than to mungbean. Insects raised on corn were heavier and larger than those raised on mungbean. In a field test, the farther the mungbean was planted from O. fumacalis-infested corn, the less was the insect damage in mungbean.