混合模板剂合成TS-1的非成键互作用能学分析

本文通过对四甲基铵、四乙基铵、四丙基铵、四丁基被四种模板剂与ＭＦＩ分子筛骨架的互作用能量计算以及两两混合的模板剂与ＭＦＩ分子筛的互作用能计算，对一些有关ＴＳ－１合成实验结果进行解释。

SAPO-11分子筛模板剂理论筛选及改进合成

本文通过能学计算,表明二乙胺比二丙胺更有利于合成出高Si含量的SAPO-11分子筛。以二乙胺作模板剂、较高温度水热条件下合成出不同Si/Al比的SAPO-11样品。Si/Al比升高,结晶度下降,晶粒变小。29SiNMR谱表明Si/Al比为0.33的SAPO-11的SAPO区明显扩大。

Iron reduction in aluminum by electroslag refining

The effect of electroslag refining on iron reduction from commercial aluminum was investigated.Cast electrodes of commercial aluminum were electroslag refined using KCl-NaCl-Na3AlF6 slag containing Na2B4O7.Experimental results indicate that the iron content decreases with increasing Na2B4O7 addition and remelting time,and the iron content decreases from 0.400% to 0.184% under 9% Na2B4O7 addition for 30 min remelting.The elastic modulus,yield strength and ultimate tensile strength commercial aluminum are improved,and the tensile elongation is increased by 43% after electroslag refining.The chemical reaction between melt and slag to form Fe2B is the main reason for iron reduction and the thermodynamic calculation of the chemical reaction theoretically accounts for the formation of Fe2B.

Calculation model of edge carbon atoms in graphite particles for anode of lithium-ion batteries

Based on the hexagonal crystallite model of graphite,the electrochemical characteristics of carbon atoms on the edge and basal plane were proposed by analyzing graphite crystal structure and bonds of carbon atoms in different sites.A spherical close-packed model for graphite particle was developed.The fractions of surface carbon atoms（SCA） and edge carbon atoms（ECA） were derived in the expression of crystallographic parameters and particle size,and the effects of ECA on the initial irreversible capacity and the mechanisms of action were analyzed and verified.The results show that the atoms on the edge are more active for electrochemical reactions,such as electrolyte decomposition and tendency to form stable bond with other atoms and groups.For the practical graphite particle,corresponding modifying factors were introduced to revise the difference in calculating results.The revised expression is suitable for the calculation of the fractions of SCA and ECA for carbon materials such as graphite,disordered carbon and modified graphite.

Recent advances in micro-alloyed wrought magnesium alloys:Theory and design

Micro-alloying design of wrought magnesium(Mg) alloys is an important strategy to achieve high mechanical properties at a low cost. In the last two decades, significant progress has been made from both theory and experiment. In the present review, we try to summarize recent advances in micro-alloying design of wrought Mg alloys from both theoretical and pragmatic perspectives, and provide fundamental data required for establishing the relationship between chemical composition and mechanical properties of Mg alloys. We start with theoretical attempts for understanding the mechanical properties of Mg alloys at different scales, by involving first principle calculations,molecular dynamics, cellular automata, and crystal plasticity. Then, the role of alloying elements is discussed for a series of promising Mg alloys such as Mg-Al, Mg-Zn, Mg-RE(rare-earth element), Mg-Sn, and Mg-Ca families.Potential challenges in the micro-alloying design of Mg alloys are highlighted at the end. The review is expected to provide helpful guidance for the intelligent design of novel wrought Mg alloys and inspire more innovative ideas in this field.

Experimental and Theoretical Study of Deprotonation of DNA Adenine Cation Radical

Among all the DNA components, extremely redox-active guanine （G） and adenine （A） bases are subject to facile loss of an electron and form cation radicals （G＋＂ and A＋＇） when exposed to irradiation or radical oxidants. The subsequent deprotonation of G＋＇ and A＋＇ can invoke DNA damage or interrupt hole transfer in DNA. However, compared with intensive reports for G＋, studies on the deprotonation of A＋ are still limited at present. Herein, we investigate the deprotonation behavior of A＋. by time-resolved laser flash photolysis. The deprotonation product of A（N6-H）＇ is observed and the deprotonation rate constant, （2.0±0.1）×10 7 s-1, is obtained at room temperature. Further, the deprotonation rate con- stants of A＋. are measured at temperatures varying from 280 K to 300 K, from which the activation energy for the N6-H deprotonation is determined to be （17.1±1.0） kJ/mol by Arrhenius equation. In addition, by incorporating the aqueous solvent effect, we perform density functional theory calculations for A＋ deprotonation in free base and in duplex DNA. Together with experimental results, the deprotonation mechanisms of A＋ in free base and in duplex DNA are revealed, which are of fundamental importance for understanding the oxidative DNA damage and designing DNA-based electrochemical devices.

Time-domain CFD computation and analysis of acoustic attenuation performance of water-filled silencers

The multi-dimensional time-domain computational fluid dynamics(CFD) approach is extended to calculate the acoustic attenuation performance of water-filled piping silencers. Transmission loss predictions from the time-domain CFD approach and the frequency-domain finite element method(FEM) agree well with each other for the dual expansion chamber silencer, straight-through and cross-flow perforated tube silencers without flow. Then, the time-domain CFD approach is used to investigate the effect of flow on the acoustic attenuation characteristics of perforated tube silencers. The numerical predictions demonstrate that the mean flow increases the transmission loss, especially at higher frequencies, and shifts the transmission loss curve to lower frequencies.

Investigation of Eddy Current Nondestructive Testing for Carbon Fiber-Reinforced Plastic （CFRP） Based on Electromagnetic Field Analysis

CFRP （carbon fiber reinforced plastic） is used extensively in aircraft and spacecraft structures, because of its excellent mechanical properties. Ultrasonic testing, which is used as a non-destructive testing technique for CFRP, requires a contact medium. In contrast, eddy current testing does not require a contact medium, and when used for CFRP testing it has advantages not available with other techniques. CFRP is a laminate, with each layer being anisotropically conductive, and the distribution of the induced eddy current is yet to be determined. Here, to determine the eddy current distribution in the detection of flaws in cross-ply CFRP （0°/90°） by using a cross-point probe, we performed an FEM （finite element method） analysis of electromagnetic fields. We investigated the nature of the flaw signals and the differences in eddy current distributions between materials with and without flaws.

Inhibiting effect of[HOEmim][BF_4]and[Amim]Cl ionic liquids on the cross-linking reaction of bituminous coal

In order to reduce the hazard of coal spontaneous combustion,the cross-linking reaction between O-containing functional groups of coal should be inhibited.So the inhibitory effect of an ionic liquid(IL) on the cross-linking reaction was studied.The O-containing functional groups change the weight loss and H_2O,CO_2,CO yields of bituminous coal before and after[H0Emim][BF_4]and[Amim]Cl pre-treatment and were detected by Fourier Transform Infrared spectroscopy(FT1R) and Thermo Gravimetric(TC) analysis.The results show that | AmimjCI has a weaker ability to inhibit the cross-linking reaction of bituminous coal compared to[HOEmim][BF_4].Besides,based on Quantum Chemistry calculation,it was found that the different inhibiting effects of |H0Emim][BF_4]and[Amim]Cl are greatly related to their anions and the H linked with C2 atom on the imidazole ring.The H-donor ability of coal will be enhanced by[HOEmim][BF_4]leading to a weaker cross-linking reaction of coal.

Study on How to Design Knitted Fabric Pattern with Mathematical Theory

To improve design capabilities for the knitted fabric pattern,a preliminary study is carried out for the design method.Based on mathematical theory,pattern could be created automatically by computer with inputting different parameters for mathematical functions.The knitted fabric simulation is realized by M1 CAD pattern preparation system of STOLL Company.In the pattern,different color unit is replaced by obverse stitch with different color,or by obverse stitch and reverse stitch with the same color separately,after that the effects of knitted fabrics could be simulated.Designing with this method,it would not only help to acquire a great of diversity patterns,but also improve design efficiency and save cost.

Semi-empirical modeling of volumetric efficiency in engines equipped with variable valve timing system

Volumetric efficiency and air charge estimation is one of the most demanding tasks in control of today's internal combustion engines.Specifically,using three-way catalytic converter involves strict control of the air/fuel ratio around the stoichiometric point and hence requires an accurate model for air charge estimation.However,high degrees of complexity and nonlinearity of the gas flow in the internal combustion engine make air charge estimation a challenging task.This is more obvious in engines with variable valve timing systems in which gas flow is more complex and depends on more functional variables.This results in models that are either quite empirical(such as look-up tables),not having interpretability and extrapolation capability,or physically based models which are not appropriate for onboard applications.Solving these problems,a novel semi-empirical model was proposed in this work which only needed engine speed,load,and valves timings for volumetric efficiency prediction.The accuracy and generalizability of the model is shown by its test on numerical and experimental data from three distinct engines.Normalized test errors are 0.0316,0.0152 and 0.24 for the three engines,respectively.Also the performance and complexity of the model were compared with neural networks as typical black box models.While the complexity of the model is less than half of the complexity of neural networks,and its computational cost is approximately 0.12 of that of neural networks and its prediction capability in the considered case studies is usually more.These results show the superiority of the proposed model over conventional black box models such as neural networks in terms of accuracy,generalizability and computational cost.

Model of Land Suitability Evaluation Based on Computational Intelligence

A novel model of land suitability evaluation is built based on computational intelligence (CI). A fuzzy neural network (FNN) is constructed by the integration of fuzzy logic and artificial neural network (ANN). The structure and process of this network is clear. Fuzzy rules (knowledge) are expressed in the model explicitly, and can be self-adjusted by learning from samples. Genetic algorithm (GA) is employed as the learning algorithm to train the network, and makes the training of the model efficient. This model is a self-learning and self-adaptive system with a rule set revised by training.

Hydrodynamic Performance of Flapping-foil Propulsion in the Influence of Vortices

Fish are able to make good use of vortices.In a complex flow field,many fish continue to maintain both efficient cruising and maneuverability.Traditional man-made propulsion systems perform poorly in complex flow fields.With fish-like propulsion systems,it is important to pay more attention to complex flow fields.In this paper,the influence of vortices on the hydrodynamic performance of 2-D flapping-foils was investigated.The flapping-foil heaved and pitched under the influence of inflow vortices generated by an oscillating D-section cylinder.A numerical simulation was run based the finite volume method,using the computational fluid dynamics(CFD) software FLUENT with Reynolds-averaged Navier-Stokes(RANS) equations applied.In addition,dynamic mesh technology and post processing systems were also fully used.The calculations showed four modes of interaction.The hydrodynamic performance of flapping-foils was analyzed and the results compared with experimental data.This validated the numerical simulation,confirming that flapping-foils can increase efficiency by absorbing energy from inflow vortices.

Structural and Bonding Properties of Al_(n)C_(4)^(−/0)(n=2−4)Clusters:Anion Photoelectron Spectroscopy and Theoretical Calculations

We measured the photoelectron spectra of Al_(n)C_(4)^(−)(n=2−4)clusters by using size-selected anion photoelectron spectroscopy.The structures of Al_(n)C_(4)^(−/0)(n=2−4)clusters were explored with quantum chemistry calculations and were determined by comparing the theoretical results with the experimental spectra.It is found that the most stable structure of Al_(2)C_(4)^(−) anion is a C_(2v)symmetry planar structure with two Al atoms interacting with two C_(2)units.In addition,Al_(2)C_(4)^(−) anion also has a D∞h symmetry linear structure with two Al atoms located at the two ends of a C_(4)chain,which is slightly higher in energy than the planar structure.The most stable structure of neutral Al_(2)C_(4)has a D∞h symmetry linear structure.The most stable structure of Al_(3)C_(4)^(−) anion is a planar structure with three Al atoms interacting with two C_(2)units.Whereas neutral Al_(3)C_(4)cluster has a C_(2v)symmetric V-shaped bent structure.The global minima structures of both Al_(4)C_(4)^(−) and neutral Al_(4)C_(4)are C_(2)h symmetry planar structures with four Al atoms interacting with the ends of two C_(2)units.Adaptive natural density partitioning analyses of Al_(n)C_(4)^(−)(n=2−4)clusters show that the interactions between the Al atoms and C_(2)units have bothσandπcharacters.

A Comparative Study of the Performance of Symmetric and Asymmetric Mixed-conducting Membranes

According to the configuration,mixed-conducting membranes are classified as symmetric membranes and asymmetric membranes consisting of a thin dense layer and a porous support.In this study,these two kinds of SrCo0.4Fe0.5Zr0.1O3-δ oxide-based membranes were systematically compared in terms of oxygen permeability and chemical stability,and their differences were elucidated by means of the theoretical calculation.For the oxygen permeability,the asymmetric membrane was greater than the symmetric membrane due to the significant decrease of bulk diffusion resistance in the thin dense layer of the asymmetric membrane.In regard to the chemical stability,the increase of oxygen partial pressure on the asymmetric membrane surface at CH4 side produced the stable time of over 1032h in partial oxidation of methane at 1123K,while the symmetric membrane was only of 528h.This study demonstrated that the asymmetric membrane was a promising geometrical configuration for the practical application.

Using Internet to Promote Students＇ English Learning Autonomy

In view of the current situation of College English Teaching in many universities in China, that is, due to limited or lack of language laboratory, many universities take the form of large-size class in organizing English teaching, the result is that teachers dominate the English classroom, and students are in a passive input state, without much or enough learning autonomy. The writer of this paper suggests a teaching model by using Internet in after-class activities, which is supposed to be helpful in promoting students＇ participation in class activities and enhancing their learning autonomy.

The Pre-processing Parallel Algorithm of A Sparse Linear Equation Group

The solution of linear equation group can be applied to the oil exploration, the structure vibration analysis, the computational fluid dynamics, and other fields. When we make the in-depth analysis of some large or very large complicated structures, we must use the parallel algorithm with the aid of high-performance computers to solve complex problems. This paper introduces the implementation process having the parallel with sparse linear equations from the perspective of sparse linear equation group.

A new approach to quantifying vehicle induced turbulence for complex traffic scenarios

Traffic-related pollutants adversely affect air quality, especially in regions near major roadways. The vehicleinduced turbulence(VIT) is a significant factor that controls the initial dilution, dispersion, and ultimately the chemical and physical fate of pollutants by altering the conditions in the microenvironment. This study used a computational fluid dynamics(CFD) software FLUENT to model the vehicle-induced turbulence(VIT) generated on roadways, with a focus on impact of vehicle-vehicle interactions, traffic density and vehicle composition on turbulent kinetic energy(TKE). We show, for the first time, that the overall TKE from multiple vehicles traveling in series can be estimated by superimposing the TKE of each vehicle, without considering the distance between them while the distance is greater than one vehicle length. This finding is particularly significant since it enables a new approach to VIT simulations where the overall TKE is calculated as a function of number of vehicles. We found that the interactions between vehicles traveling next to each other in adjacent lanes are insignificant,regardless the directions of the traffic flow. Consequently, simulations of different traffic scenarios can be substantially simplified by treating two-way traffic as one-way traffic, with less than 5% difference in the overall volume-averaged TKE. We also developed equations that allow the estimation of the overall volume-averaged TKE as a function of the number and the type of vehicles.

Combustion and energy balance of aluminum holding furnace with bottom porous brick purging system

For acquiring the details in aluminum holding furnace with bottom porous brick purging system,efforts were performed to try to find out the potential optimal operation schemes.By adopting transient analysis scheme and constant boundary temperature,combustion in the furnace was investigated numerically using computational fluid dynamics(CFD).The predicted gas temperature shows good agreement with the measured results,and the predicted energy distribution of the furnace is consistent with that obtained from energy balance experiment,which confirms the reliability of the numerical solution.The results show that as the fuel-air mixture temperature rises up from 300 K to 500 K,the energy utilization of the furnace could increase from 34.55% to 37.14%.However,as the excess air coefficient increases from 1.0 to 1.4,energy utilization drops from 34.55% to 29.56%.Increasing the combustion temperature is the most effective way to improve the energy efficiency of the furnace.High reactant temperature and medium excess air coefficient are recommended for high operation performance,and keeping the furnace jamb sealed well for avoiding leakage has to be emphasized.

Online Adaptation of Game AI with Evolutionary Learning

Since the beginning of computer games era, artificial intelligence (AI) has been a standard feature of games. The current emphasis in computer game AI is improving the quality of opponent AI. Our research question reads: How can unsupervised online learning be incorporated in Computer Role Playing Game(CRPG) to improve the strategy of the opponent AI? Our goal is to use online evolutionary learning to design strategies that can defeat the opponent. So we apply a novel technique called dynamic scripting that realizes online adaptation of scripted opponent AI and report on experiments performed in a simulated CRPG to assess the adaptive performance obtained with the technique.