Prediction of Hot Deformation Behavior of 7Mo Super Austenitic Stainless Steel Based on Back Propagation Neural Network

The hot compression tests of 7Mo super austenitic stainless(SASS)were conducted to obtain flow curves at the temperature of 1000-1200℃and strain rate of 0.001 s^(-1)to 1 s^(-1).To predict the non-linear hot deformation behaviors of the steel,back propagation-artificial neural network(BP-ANN)with 16×8×8 hidden layer neurons was proposed.The predictability of the ANN model is evaluated according to the distribution of mean absolute error(MAE)and relative error.The relative error of 85%data for the BP-ANN model is among±5%while only 42.5%data predicted by the Arrhenius constitutive equation is in this range.Especially,at high strain rate and low temperature,the MAE of the ANN model is 2.49%,which has decreases for 18.78%,compared with conventional Arrhenius constitutive equation.

A review: Enhanced recovery of natural gas hydrate reservoirs

Natural gas hydrate(NGH)is a highly efficient and clean energy,with huge reserves and widespread distribution in permafrost and marine areas.Researches all over the world are committed to developing an effective exploring technology for NGH reservoirs.In this paper,four conventional in-situ hydrate production methods,such as depressurization,thermal stimulation,inhibitor injection and CO2 replacement,are briefly introduced.Due to the limitations of each method,there has been no significantly breakthrough in hydrate exploring technology.Inspired by the development of unconventional oil and gas fields,researchers have put forward some new hydrate production methods.We summarize the enhanced hydrate exploiting methods,such as CO2/N2–CH4 replacement,CO2/H2–CH4 replacement,hydraulic fracturing treatment,and solid exploration;and potential hydrate mining techniques,such as self-generating heat fluid injection,geothermal stimulation,the well pattern optimization of hydrate exploring.The importance of reservoir stimulation technology for hydrate exploitation is emphasized,and it is believed that hydrate reservoir modification technology is a key to open hydrate resources exploitation,and the major challenges in the process of hydrate exploitation are pointed out.The combination of multiple hydrate exploring technologies and their complementary advantages will be the development trend in the future so as to promote the process of hydrate industrialization.

Thermogravimetric-Mass Spectrometric Study of the Pyrolysis Behavior of PVC

The pyrolysis characteristics of PVC were systematically investigated using a Netzschne TG thermo-balance coupled to a quadrupole mass spectrometer. The pyrolysis conditions were 0.1 MPa of Ar, a heating rate of 10 ℃/min and a final temperature of 1000℃. Both the thermogravimetric properties and the simultaneous evolution of gaseous products during pyrolysis were studied. The TG/DTG results showed that as the pyrolysis temperature increases the weight loss and weight loss rate of PVC increases. Near 412℃ the weight loss rate attained its peak value. At higher temperatures the rate of loss gradually decreases. The gases evolved during thermogravimetric analysis were analyzed by a mass spectrometer, monitoring the relative intensity of HC1, C6H6, light hydrocarbon and chlorine-containing gases The evolution curves showed that HC1, C6H6, light hydrocarbon and chlorine-containing gases all peak at about 416℃. This is consistent with the fact that the weight loss curves also peak at about 412℃. The extensive HCl evolution is consistent with the high chlorine content of PVC. The formation of these gases can be explained by considering these reactions： dehydrochlorination, intramolecular cyclization and the addition of HCl to unsaturated hydrocarbons.

Effect of temperature on microstructure and texture evolution of Mg-Zn-Er alloy during hot compression

The microstructure and texture evolutions in Mg-Zn-Er alloy during hot compression were investigated by using opticalmicroscope （OM）, field emission scanning electron microscope （EBSD） and transmission electron microscope （TEM）. The resultsindicate that the temperature plays an important role in dynamic recrystallization （DRX） mechanism. The twin dynamicrecrystallization （TDRX） is induced at a strain of 0.6 because of the activation of non-basal slip （a＋c ） dislocations at 200 ℃.Meanwhile, the continuous DRX （CDRX） occurs at 350℃, which is identified by the typical necklace-like structure around theresidual initial grains. The DRX contributes to the modification of texture significantly. The tension twins are responsible for theweak texture at 200 ℃. Meanwhile, the decrease in the basal texture is ascribed to the DRX sites which transfer from twinboundaries to initial grain boundaries as the temperature is increased from 200 to 350 ℃.

Synthesis,Crystal Structure,DFT Studies and Antifungal Activity of 5-(4-Cyclopropyl-5-((3-fluorobenzyl)sulfonyl)-4H-1,2,4-triazol-3-yl)-4-methyl-1,2,3-thiadiazole

5-（4-Cyclopropyl-5-（（3-fluorobenzyl）sulfonyl）-4H-1,2,4-triazol-3-yl）-4-methyl-1,2,3-thiadiazole was synthesized and recrystallized from Et OH. The compound was characterized by ^1H NMR,MS,elemental analysis and X-ray diffraction. The structure-active relationship and the antifungal activity based on density functional theory calculation（DFT） and antifungal activities were investigated. The compound crystallizes in the monoclinic space group P121/n1 with a = 8.929（3）,b=12.715（4）,c=15.161（5） A°,β = 106.142（3）o,V = 1653.3（9） A°3,Z = 4 and R = 0.0393 for 3930 observed reflections with I 〉 2σ（I）. Theoretical calculation of the title compound was carried out with B3LYP/6-31G（d,p）. The full geometry optimization was carried out using the 6-31G（d,p） basis set.The frontier orbital energy and atomic net charges were discussed. The observed results of the compound have been compared with theoretical results and the experimental data show good agreement with the calculated values. The compound exhibits good antifungal activity.

Efficient hydrolysis of cellulose to glucose catalyzed by lignin-derived mesoporous carbon solid acid in water

Two kinds of mesoporous carbon solid acids(LDMCE-SO3H and LDMCS-SO3H)were successfully prepared using masson pine alkali lignin as carbon source by evaporation-induced self-assembly(EISA)and salt-induced selfassembly(SISA)followed by sulfonation,respectively.In terms of preparation process,SISA(self-assembly in water and preparation time of 2 days)is greener and simpler than EISA(self-assembly in ethanol and preparation time of 7 days).The prepared LDMCE-SO3H and LDMCS-SO3H exhibit obvious differences in structural characteristics such as pore channel structure,specific surface area,mesopore volume and the density of-SO3H groups.Furthermore,the catalytic performances of LDMCE-SO3H and LDMCS-SO3H were investigated in the hydrolysis of microcrystalline cellulose in water,and the glucose yields of 48.99%and 54.42%were obtained under the corresponding optimal reaction conditions.More importantly,the glucose yields still reached 28.85%and 30.35%after five runs,and restored to 39.02%and 45.98%through catalysts regeneration,respectively,demonstrating that LDMCE-SO3H and LDMCS-SO3H have excellent recyclability and regenerability.

Current situation and trend of marine data buoy and monitoring network technology of China

Marine data buoy can provide a long-term, continuous, real-time, reliable data of ocean observation in a variety of complex marine environment. It is one of the most reliable, most effective and important means of ocean monitoring technology. In this paper, the classification, main theory and technology system of marine data buoy are summarized. The typical technological breakthrough of the development of marine data buoy in recent years is summarized. The composition and application of marine monitoring network in China was introduced, and the gap between the technology of China＇s marine data buoy and the international advanced countries is compared.Combined on the situation and demand of China＇s current situation and needs, the development trend of marine data buoy and buoy monitoring network are expected.

Effects of punch velocity on microstructure and tensile properties of thixoforged Mg2Sip/AM60B composite

The effects of punch velocity on the microstructures and tensile properties of Mg2 Sip/AM60 B composite were investigated.In comparison,the tensile properties of the permanent mold casting of this composite were also analyzed.The results indicate that the punch velocity obviously influences the microstructure through changing the secondary solidification behaviors and semisolid deformation mechanisms.The variations of the microstructures and deformation mechanisms are responsible for the changes in tensile properties and fracture modes of the composites.The best comprehensive tensile properties of this composite are obtained under the punch velocity of 60 mm/s.The resulting ultimate tensile strength and elongation of the composite are found to be 198 MPa and 10.2%,respectively.The excellent tensile properties of the thixoforged composite are ascribed to the elimination of porosities and the work hardening.

Development of an analytical method for multi-residue quantification of 18 anthelmintics in various animal-based food products using liquid chromatography-tandem mass spectrometry

In this study,we developed a simple screening procedure for the determination of 18 anthelmintics(including benzimidazoles,macrocyclic lactones,salicylanilides,substituted phenols,tetrahydropyrimidines,and imidazothiazoles)in five animal-derived food matrices(chicken muscle,pork,beef,milk,and egg)using liquid chromatography-tandem mass spectrometry.Analytes were extracted using acetonitrile/1% acetic acid(milk and egg)and acetonitrile/1% acetic acid with 0.5 mL of distilled water(chicken muscle,pork,and beef),and purified using saturated n-hexane/acetonitrile.A reversed-phase analytical column and a mobile phase consisting of(A)10 mM ammonium formate in distilled water and(B)methanol were used to achieve optimal chromatographic separation.Matrix-matched standard calibration curves(R^(2)≥0.9752)were obtained for concentration equivalent to ×1/2,×1,×2,×3,×4,and×5 fold the maximum residue limit(MRL)stipulated by the Korean Ministry of Food and Drug Safety.Recoveries of 61.2e118.4%,with relative standard deviations(RSDs)of ≤19.9%(intraday and interday),were obtained for each sample at three spiking concentrations(×1/2,×1,and ×2 the MRL values).Limits of detection,limits of quantification,and matrix effects were 0.02e5.5 mg/kg,0.06e10 mg/kg,and -98.8 to 13.9%(at 20 μg/kg),respectively.In five samples of each food matrix(chicken muscle,pork,beef,milk,and egg)purchased from large retailers in Seoul that were tested,none of the target analytes were detected.It has therefore been shown that this protocol is adaptable,accurate,and precise for the quantification of anthelmintic residues in foods of animal origin.

Optimal control of oscillation wave energy system using velocity premonition

Recently ocean wave energy draw much more attention for its widespread,abundant and highly energy flux density properties.Extracting energy from incident wave however,is limited for the random and unstable power input.Motion control for WEC is a promising method to improve the energy absorption and some practical applications are also verified such as latching control.In this paper,an active control strategy is proposed to achieve maximum energy capture.The mathematical description shows that the active control has the characteristic of anti-causal and the wave premonition is necessary for controller design.But the fact of premonition time horizon is still unclear.In this paper,the premonition nature is described mathematically based on hydrodynamic theory.Furthermore,a simulation is also performed to study the impacting of premonition time horizon on WEC's properties and give a more insightful understanding of WEC active control.

A Study on the Integration of Traditional Chinese Culture into College English Education Under the Context of Course-Based Ideological and Political Education

The construction of course-based ideological and political education is currently in its full swing.With both instrumentality and humanity,college English is the ideal carrier of ideological and political education.College English education should keep pace with the era,integrate with ideological and political education based on traditional Chinese culture,and construct a teaching system with Chinese characteristics.It is necessary to strengthen ideological and political orientation,reasonably integrate the teaching content,comprehensively enhance the quality of teachers,and actively innovate the teaching method,so as to further improve the effect of course-based ideological and political practice as well as realize the fundamental task of cultivating students through moral cultivation in higher education.

Effect of degree correlation on edge controllability of real networks

We use the controllability limit theory to study impact of correlation between in- and out-degrees (degree correlation) on edge controllability of real networks. Simulation results and analytic calculations show that the degree correlation plays an important role in the edge controllability of real networks, especially dense real networks. The upper and lower controllability limits hold for all kinds of real networks. Any edge controllability in between the limits is achievable by properly adjusting the degree correlation. In addition, we find that the edge dynamics in some real networks with positive degree correlation may be difficult to control, and explain the rationality of this anomaly based on the controllability limit theory.

A Two-step Biotechnological Process for Improving Nutrition Value of Feather Meal by Bacillus licheniformis S6

A two-step biotechnological process was developed using Bacillus licheniformis S6 to provide a simple and economical procedure which significantly improved feather meal nutrition value. Compared with IFM （initial feather meal） and CFM （commercial feather meal）, SFEFM （feather meal gained by solid fermentation and enzymolysis with continuous agitation） had a significant improvement （P〈0.05） in vitro digestibility, contents of oligopeptides and soluble protein released in digestive juice by pepsin- pancreatin digestion procedure, furthermore, some deficient essential amino acids in feather protein （histidine, methionine, lysine） were enhanced. Comapared with CFM, the oligopeptides released into digestive juice of ISFM （feather meal obtained by the biotechnological process described in the paper with intermittent shaking） was significantly enhanced （P〈O.05）, and its in vitro digestibility was statistically （P〉0.05） equivalent to CFM. The summary of the finding to IFM treatment and possible means of further improvements were also listed.

Dynamic Characteristics of Single-frequency Signal after Modulated by Feedback Control System

In order to study the dynamic characteristics of the single-frequency signal through the nonlinear control system,the system control mode,the outer excitation patterns of the model and the amplitude are investigated by using the methods of the nonlinear dynamical analysis. The time-domain diagram,power spectrum,phase diagram and the largest Lyapunov exponent obtained from the process of the signal propagate through different control module are given. The researches on different control systems demonstrate that: after single-frequency signal goes through the nonlinear controller,it is still non-chaotic although the output contains more frequency components; but with the feedback and the external perturbation,the output is a continuous broadband spectrum and the result shows that there is chaos. The energy of the input signal reduces with some appropriate parameters. Therefore,the control system of the nonlinear feedback is a good way to broaden the spectrum of output with inputting a single-frequency signal.

Conversion of Bioethanol to Olefins over ZrO_(2) Catalyst

Ethylene and 1,3-butadiene are important organic chemical raw materials.Petroleum hydrocarbon cracking is the most widely used method for ethylene fabrication worldwide.In this study,the use of a ZrO_(2) catalyst,which can be easily synthesized,for the efficient conversion of bioethanol to ethylene and 1,3-butadiene was analyzed.X-ray diffraction,transmission electron microscopy,temperature-programmed desorption,and Fouriertransform infrared spectroscopy analyses were used to evaluate the surface properties of ZrO_(2).The selectivity of ZrO_(2) toward ethylene and 1,3-butadiene was as high as 98.2%.Catalyst selectivity toward dehydration or dehydrogenation products depends on the nature of the weak acid-base catalytic sites,whereas high-strength base and intermediate-strength acid catalytic sites selectively yield ethylene.

Static recrystallization behaviors and mechanisms of 7Mo super-austenitic stainless steel with undissolved sigma precipitates during double-stage hot deformation

Static recrystallization(SRX)behaviors and corresponding recrystallization mechanisms of 7Mo super-austenitic stainless steel were studied under different deformation conditions.The order of influence of deformation parameters on static recrystallization behaviors,from high to low,is followed by temperature,first-stage strain and strain rate.Meanwhile,the effect of holding time on static recrystallization behaviors is significantly controlled by temperature.In addition,with the increase in temperature from 1000 to 1200°C,the static recrystallization mechanism evolves from discontinuous static recrystallization and continuous static recrystallization(cSRX)to metadynamic recrystallization and cSRX,and finally to cSRX.The cSRX exists at all temperatures.This is because high stacking fault energy(56 mJ m−2)promotes the movement of dislocations,making the deformation mechanism of this steel is dominated by planar slip of dislocation.Large undissolved sigma precipitates promote static recrystallization through particle-stimulated nucleation.However,small strain-induced precipitates at grain boundaries hinder the nucleation of conventional SRX and the growth of recrystallized grains,while the hindering effect decreases with the increase in temperature.

Hybrid intelligent PID control design for PEMFC anode system

Control design is important for proton exchange membrane fuel cell (PEMFC) generator. This work researched the anode system of a 60-kW PEMFC generator. Both anode pressure and humidity must be maintained at ideal levels during steady operation. In view of characteristics and requirements of the system, a hybrid intelligent PID controller is designed specifically based on dynamic simulation. A single neuron PI controller is used for anode humidity by adjusting the water injection to the hydrogen cell. Another incremental PID controller, based on the diagonal recurrent neural network (DRNN) dynamic identification, is used to control anode pressure to be more stable and exact by adjusting the hydrogen flow rate. This control strategy can avoid the coupling problem of the PEMFC and achieve a more adaptive ability. Simulation results showed that the control strategy can maintain both anode humidity and pressure at ideal levels regardless of variable load, nonlinear dynamic and coupling characteristics of the system. This work will give some guides for further control design and applications of the total PEMFC generator.

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.

GPU Accelerated Marine Data Visualization Method

The study of marine data visualization is of great value. Marine data, due to its large scale, random variation and multiresolution in nature, are hard to be visualized and analyzed. Nowadays, constructing an ocean model and visualizing model results have become some of the most important research topics of ‘Digital Ocean'. In this paper, a spherical ray casting method is developed to improve the traditional ray-casting algorithm and to make efficient use of GPUs. Aiming at the ocean current data, a 3D view-dependent line integral convolution method is used, in which the spatial frequency is adapted according to the distance from a camera. The study is based on a 3D virtual reality and visualization engine, namely the VV-Ocean. Some interactive operations are also provided to highlight the interesting structures and the characteristics of volumetric data. Finally, the marine data gathered in the East China Sea are displayed and analyzed. The results show that the method meets the requirements of real-time and interactive rendering.

Interrogating a Fiber Bragg Grating Vibration Sensor by Narrow Line Width Light

A method to interrogate fiber Bragg grating vibration sensor by narrow line width light is demonstrated. The interrogation scheme takes advantage of the intensity modulation of narrow spectral bandwidth light, such as distributed feedback laser, when a reflection or transmission spectrum curve of an fiber Bragg grating （FBG） moves due to the strain which is applied on the sensor. The sensor＇s response to accelerating frequency and amplitude is measured by experiment. The factors which have impacts on the sensitivity of the interrogation system are also discussed.