Silylated and acetylated β-cyclodextrins for gas chromatographic stationary phases

Ｓｅｐａｒａｔｉｏｎｏｆｅｎａｎｔｉｏｍｅｒｓｏｆｃｈｉｒａｌｃｏｍ ｐｏｕｎｄｓｆｏｒｂｏｔｈａｎａｌｙｔｉｃａｌａｎｄｐｒｅｐａｒａｔｉｖｅｐｕｒｐｏｓｅｓｉｓａｎａｔｔｒａｃｔｉｖｅｔｏｐｉｃ ,ｅｓｐｅｃｉａｌｌｙｉｎｔｈｅｆｉｅｌｄｓｏｆｏｒ ｇａｎｉｃａｎｄｐｈａｒｍａｃｅｕｔｉｃａｌｃｈｅｍｉｓｔｒｙ .Ｄｉｒｅｃｔｇａｓｃｈｒｏｍａｔｏｇｒａｐｈｉｃｅｎａｎｔｉｏｍｅｒｓｅｐａｒａｔｉｏｎｕｓｉｎｇｃｈｉｒａｌｓｔａｔｉｏｎａｒｙｐｈａｓｅｓ (ＣＳＰｓ)ｉｓａｓｉｍｐｌｅａｎｄｅｆｆｅ…     

Alkylated and silylated β-cyclodextrin for gas chromatographic chiral stationary phases

1　ＩＮＴＲＯＤＵＣＴＩＯＮＷｉｔｈｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆｌｉｆｅｓｃｉｅｎｃｅ ,ｓｅｐａｒａ ｔｉｏｎｏｆｅｎａｎｔｉｏｍｅｒｓｆｏｒｂｏｔｈａｎａｌｙｔｉｃａｌａｎｄｐｒｅｐａｒａ ｔｉｖｅｐｕｒｐｏｓｅｓｉｓａｎａｔｔｒａｃｔｉｖｅｔｏｐｉｃ     

Alkylated and silylated β-cyclodextrin for gas chromatographic chiral stationary phases

Three new ehiral stationary phases, 2, 6-di-O-heptyl-3-O-trimethylsilyl-β-cyclodextrin( DHTBCD), 2,6-di-O-pentyl-3-O-trimethylsilyl-β-cyclodextrin (DPTBCD) and 2,6-di-O-butyl-3-O-trimethylsilyl-β-cyclodextrin (DBTBCD), were synthesized. Chromatographie properties sueh as eolumn efficieney, thermal stability and eolumn life span, were studied. The separations of enantiomers, sueh as ketone, esters, alcohols and olefines, were investigated on the alkylated and silylated β-eyelodextrin stationary phases. The influenee of diluent on ehiral separation was studied. The experimental results indieate that the stationary phases show good ehromatographie properties in separating enantiomers. It is observed that inelusion eomplexafion and hydrogen bonding interaction hardly play a role in separating enantiomers.     

Study on “fracturing-sealing” integration technology based on high-energy gas fracturing in single seam with high gas and low air permeability

To improve the gas extraction efficiency of single seam with high gas and low air permeability, we developed the “fracturing-sealing” integration technology, and carried out the engineering experiment in the 3305 Tunliu mine. In the experiment, coal seams can achieve the aim of antireflection effect through the following process: First, project main cracks with the high energy pulse jet. Second, break the coal body by delaying the propellant blasting. Next, destroy the dense structure of the hard coal body, and form loose slit rings around the holes. Finally, seal the boreholes with the “strong–weak–strong” pressurized sealing technology. The results are as follows: The average concentration of gas extraction increases from 8.3% to 39.5%. The average discharge of gas extraction increases from 0.02 to 0.10 m³/min. The tunneling speeds up from 49.5 to 130 m/month. And the permeability of coal seams improves nearly tenfold. Under the same conditions, the technology is much more efficient in depressurization and antireflection than common methods. In other words, it will provide a more effective way for the gas extraction of single seam with high gas and low air permeability.     

Preparation of insoluble β-CD polymer and its application to enantiomers and isomers separation

β ｃｙｃｌｏｄｅｘｔｒｉｎ ( β ＣＤ)ｈａｓｍａｎｙｃｈｉｒａｌｃａｒ ｂｏｎａｔｏｍｓａｎｄｓｐｅｃｉａｌｃａｖｉｔｙｓｔｒｕｃｔｕｒｅ ,ｉｔｃａｎｎｏｔｏｎｌｙｂｅｕｓｅｄｔｏｓｅｐａｒａｔｅａｒｏｍａｔｉｃｃｏｍｐｏｕｎｄｓ,ｂｕｔａｌｓｏｅｎａｎｔｉｏｍｅｒｓ.Ｔｈｅｔｒｅｍｅｎｄｏｕｓｐｏｔｅｎｔｉａｌｏｆｃｙ ｃｌｏｄｅｘｔｒｉｎｓ,ｏｒｔｈｅｉｒｄｅｒｉｖａｔｉｖｅｓｆｏｒｅｎａｎｔｉｏｍｅｒｓｓｅｐａｒａｔｉｏｎｗａｓｄｅｓｃｒｉｂｅｄ[1,2 ] .Ｂｅｃａｕｓｅｏｆｈｉｇｈｍｅｌｔｉｎｇ…     

Effect of electromagnetic force and anode gas on electrolyte flow in aluminum electrolysis cell

1 INTRODUCTIONThe movement of electrolyte has a veryi mpor-tant influence on the process of aluminumelectrol-ysis[1]. On one hand,the movement of electrolytecan help anode gas release ,accelerate the dissolu-tion and diffusion of alumina and eli minate temper-ature gradient of electrolyte ,and enhances the heattransfer between electrolyte and the freeze . Ontheother hand,the movement of electrolyte can makealuminumfluid fluctuate , causing aluminum cellsto unstably operate and re-oxidation…     

Decomposition and reconstitution principle for complex surfaces and its applications

Though there are already a variety of models for complex surfaces, they are not so convenient as needed in practice. A hierarchical model and the principle of decomposition and reconstitution for complex surfaces have been proposed, which have the potential to enhance the support of automated design systems on creative work intelligently Then the progress made is discussed involving the applications of the new principle in the following three areas:conjugation surface calculation, tool path generation in numerically controlled machining, and machining process innovation by re-recognition     

Selectivity of New β-Cyclodextrin Derivatives as CGC Stationary Phases and Application for the Analysis of Volatile Compounds in Traditional Chinese Medicines

New cyclodextrin derivatives(CDs),heptakis(2,6-di-O-methyl-3-O-methoxymethyl)-β-CD(Ⅰ)and heptakis(2,3,6-tri-O-methoxymethyl)-β-CD(Ⅱ),were investigated for their chromatographic performance as stationary phases for capillary gas chromatography(CGC).Both of the CDs exhibited good selectivity and satisfactory separation for test mixtures and aromatic positional isomers,and volatile compounds from Ligusticum chuanxiong Hort.Additionally,the selectivity and elution orders of major compounds were compared with a ...     

Laser shock-processing for fatigue and fracture resistance

The generation mechanism of stress wave induced by laser-shocking is described and the stress wave is measured with a PVDF transducer. The visual inspections and control methods of the effectiveness of laser shock-processing (LSP) are built up. A small-sized, Q switched Nd: glass laser with high-power is used for LSP The fa tigue lives of aluminum alloy are increased greatly after LSP. With 95% confidence, the mean fatigue life of 2024T62 aluminum alloy after the LSP is 4. 5-9. 8 times that of the un-shocked ones The hardness, microstructure and fracture section of materials are analysed before and after LSP. The anti-fatigue and anti-fracture mechanism is analysed and the prospects of wide applications of LSP technology are described     

Effect of HCO3^- concentration on CO2 corrosion in oil and gas fields

The effect of HCO3^- concentration on CO2 corrosion was investigated by polarization measurement of potentiodynamic scans and weight-loss method, Under the conditions of high pressure and high temperature, the corrosion rate of steel X65 decreased with the increase of HCO3^- concentration, while pH of solution increased. SEM, EDS, and XRD results of the corrosion scales indir cated that the typical FeCO3 crystallite was found at low HCO3^- concentration but Ca（Fe,Mg）（CO3）2 was found at high HCO3^- con- centration. Ca^2＋ and Mg^2＋ are precipitated preferential to Fe^2＋ at high pH value. Potentiodynamic polarization curves showed that the cathodic current density decreases with the increase of HCO3^- concentration at low HCO3^- concentration. When the HCO3^- concentration reaches 0.126 mol/L, increasing HCO3^- concentration promotes cathodic reactions. Anodic behavior is an active process at low HCO3^- concentration and the anodic current density decreases with the increase of HCO3^- concentration. An evident active-passive behavior is exhibited in anodic process at 0.126 mol/L HCO3^-.     

Microscopic phase-field simulation of L12 and D022 phases during the early precipitation process of Ni-Cr-Al alloys

1. Introduction The microscopic phase-field kinetics model was developed as a novel method of material simulation in 1990s. It is a deterministic phase-field method based on Onsager and Ginzburg-Landau theory. Ginzburg- Landau method was aimed at investig…     

Chemieal Strueturcs and Adsorptive Behaviors of Superplastieizers on β-C2S

The chemical structures of four types of superplasticizers （SPs） and their adsorptive behaviors on β-C2S were investigated. The adsorption properties of SPs on β-C2S were measured and the relationship between the adsorption quantity and the specific surface of β-C2S was analyzed. The experimental results show that the adsorption quantity increases with the surface area increase of β-C2S, but the adsorption quantity per surface area is similar, which means that the main adsorbent is β-C2S itself. Polycarboxylic ester （PCE） showed the highest adsorption amount on β-C2S, followed by β-naphthalene sulfonates （NSF） and formaldehyde-acetone condensates sulfonates （FAS）, amino sulphonate （AS） showed the least adsorption amount on β-C2S. PCE affected the surface potential of β-C2S particles in water differently in comparison with other types of SPs. The adsorption capacity of SPs on β-C2S is determined by factors such as molecular structure, functional groups and molecular weight of SPs.     

Coal and gas outburst mechanism of the “Three Soft” coal seam in western Henan

Based on the particularities of gas outbursts,i.e.,low gas bearing capacity and low gas pressure in the "Three Soft" coal seam in western Henan,we applied the theories of plate tectonics and regional structural evolution to investigate the mechanism of this seam and its impact on the coal seam gas formation.Our investigation revealed that coal and gas outbursts are distributed in a strip in a NW direction,with a number of high-penetration mines scattered towards the south side and low-gas mines largely located on the north side.We analyzed the statistics of 38 gas explosions and the rock-coal sturdiness number coefficient f of 167 sampling sites in the region and found the gas outburst mechanism that features a "low indicator outburst phenomenon".The mechanism is characterized by structural coal as its core,a low gas bearing capacity,low gas pressure and sturdiness coefficient f mostly less than 0.3.Our research results provide a theoretical foundation for effective control of gas disasters.     

Agent Architecture and Collaboration for Supply Chain Management

Recently multi-agent system(MAS)is regarded as a powerful paradigm to develop and simulate complex system. Because supply chain(SC)is a complex network,it is hard to improve supply chain management(SCM)efficiency and automate SC operating process.Researchers have applied MAS in SCM viewing enterprises in SC as different functional agents collaborating to achieve common goal.In this paper a MAS-based supply chain management framework(MSF)is developed on which agents can collaborate to conduct business activities of enterprises and customers.Six kinds of functional agents are designed,namely, management agent,order receiving agent,order decomposing agent,resource agent,manufacturing-controlling agent and trans- portation agent.Through the agents' collaboration the MSF can support SC dynamic forming and operating process.For partner selection the method to transmit customers' order into demand matrix,and transmit enterprise's resource capacity into resource matrix is described in detail.The MSF users decide which algorithm to be applied in matching the two matrixes,and algorithms are stored in model base.Finally the generic agent architecture is put formard.     

Inference and contradictory analysis for binary neural networks

A weak-inference theory and a contradictory analysis for binary neural networks (BNNs).are presented.The analysis indicates that the essential reason why a neural network is changing its slates is the existence of superior contradiction inside the network,and that the process by which a neural network seeks a solution corresponds to eliminating the superior contradiction.Different from general constraint satisfaction networks,the solutions found by BNNs may contain inferior contradiction but not superior contradiction.     

Preparation and Properties of Sialon-SiC Suspension for Gelcasting

1IntroductionGelcasting is a novel forming method for makingcomplex-shaped ceramic bodies[1,2].In this process,preparation of suspension with a high solid loading and alowviscosity is necessary.After casting,the monomerpolymerizesin situthrough the influe…     

Advances and Future Issues for STEP-compliant NC Manufacture

1 Introduction Challenges in a competitive global manufacturing market force manufacturerstolookcritically at their entirenetwork of business activities that comprise of a series of individual tasks that need to be completedin differentsystems[1].In order to streamline the design and manufacturing process ,it is necessary to maintain a homoge-nous informationflowalong the manufacturing chain.Since mid-1980s ,the international community has beenpursuing a standard, well known as STEP (ISO103…     

Fouling Characteristics and Prevention Techniques for Membrane Bioreactor

Membrane fouling is the main problem of membrane bioreactors (MBR), which seriously influences its wastewater treatment effect and running. The characteristics of microbiology and hydrodynamics concerning membrane fouling were investigated and the measure was put forward for optimum operation of MBR. The measure is that 1) the parameters of activated sludge concentration (X) and membrane flux should be lower than the critical values of X and membrane flux respectively, and 2) the activated sludge should be discharged periodically. The experimental results show that the combination backwashing of gas and permeated effluent is better than single gas backwashing or single permeated effluent backwashing. This technique can remove the cake layer deposited on the membrane surface, decrease the membrane fouling, and recover the membrane flux effectively. So it is effective for prevention of membrane fouling.     

Equalization Charging and Protection System for Electric Vehicle

A system is developed to improve the series battery packs uniformities and charging protection and the implementation of battery equalization charging and protection system is also introduced. The functions of equalization charging and overcharging protection are analyzed and the control model of series battery packs equalization charging is setup. The diverting-current and feedback bus voltage are measured during the series Li-ion battery packs equalization charging experiment. The field operation on Electric luxury transit bus BFC6100EV shows that the system betters the battery series charging uniformities and overcharging protection, improves the battery performance and extends the battery life.     

A Spatialization-based Method for Checking and Updating Metadata

1 IntroductionWith the wide application of geographical in-formation, spatial data sharing becomes more andmore prevalent. The complexity of management andaccess of huge dataset is recognized to be a criticalproblem faced by data producers and users. Dataproducers need efficient method of geographical spa-tial data management and maintenance, and usersneed find, access, acquire and use changing spatialdata more quickly and completely. Therefore, it iscrucial for people to master in time the co…