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We have read the comment on our paper “Selective ad-sorption of tannins onto hide collagen fibres, Science in China,Series B, 2003, 46(5): 495—504”. In our paper, the pseudo-second order model was used to describe the adsorption kineticsof tannins to c…     

Preface for the Special Column of the INRET 2006

I would like to take this opportunity to thank the editorial board of Journal of Natural Gas Chemistry for allowing me to write a preface for this special column. The articles appearing in this section are specially selected from the First International Conference on Natural Resources Engineering and Technology 2006 （INRET 2006）. In line with the theme of JNGC, the selected articles are focused on natural gas or low hydrocarbon conversions to important chemicals, fuels and materials. The conference was held on July 24-25, 2006 in Marriott Putrajaya, Malaysia. It was organized by the Chemical and Biotechnology （ChemBio） Focus Group, under the Research Management Centre, Universiti Teknologi Malaysia.     

A new methodology for the development of numerical methods for the numerical solution of the Schr?dinger equation

In the present paper we introduce a new methodology for the construction of numerical methods for the approximate solution of the one-dimensional Schr?dinger equation. The new methodology is based on the requirement of vanishing the phase-lag and its derivatives. The efficiency of the new methodology is proved via error analysis and numerical applications.     

Where is the road to bio-water-saving for the globe?

The First International Conference on the Theory and Practices in Bio-water-saving (ICTPB) was held from May 21 to 25, 2006 in Beijing, China. This indicated that the work related to this hot topic on the globe has been paid more attention to. Most progress in this field has been presented from near 300 participating people worldwide, who were meeting together to discuss about the theory and practices of water-saving biology and how to serve global agricultural and ecological sustainable development. The work related to bio-water-saving has been involved in different scales and soil–plant root biointerfaces. On the basis of this background and in combination with the work from our laboratory and the center, we provided some ideas for global bio-water-saving in this paper, sharing the achievement in this field and advocating true bio-water-saving for the world and promoting the pace of global bio-water-saving.     

Computational Evidence for the Smallest Boron Nanotube

One-dimensional boron nanostructures have being actively studied experimentally1 and theoretically2 in the recent years, due to their promising applications in field emission devices and high-temperature electronics. Amorphous3 and crystalline1 nanowires,…     

State of the Art for the Biosorption Process—a Review

In recent years, biosorption process has become an economic and eco-friendly alternative treatment technology in the water and wastewater industry. In this light, a number of biosorbents were developed and are successfully employed for treating various pollutants including metals, dyes, phenols, fluoride, and pharmaceuticals in solutions (aqueous/oil). However, still there are few technical barriers in the biosorption process that impede its commercialization and thus to overcome these problems there has been a steadily growing interest in this research field. This resulted in large numbers of publications and patents each year. This review reports the state of the art in biosorption research. In this review, we provide a compendium of know-how in laboratory methodology, mathematical modeling of equilibrium and kinetics, identification of the biosorption mechanism. Various mathematical models of biosorption were discussed: the process in packed-bed column arrangement, as well as by suspended biomass. Particular attention was paid to patents in biosorption and pilot-scale systems. In addition, we provided future aspects in biosorption research.     

Systematic study for the stereochemistry of the Atherton–Todd reaction

Under the Atherton–Todd reaction conditions, the stereochemistry on the reaction of H-phosphinates with different nucleophiles (e.g., amines, alcohols, phenols) was investigated. All reactions took place stereospecifically with inversion of configurations at the phosphorus centers. The reaction might proceed via a phosphoryl chloride intermediate with retention of configuration at phosphorus, followed by the attack of nucleophiles from the backside of Cl to give the substitution products with inversion of configuration at the phosphorus center. A plausible mechanism was proposed for these reactions.     

On the Scaling Study for the A_f-A_g Type Free Radical Polymerization

根据Ａｆ－Ａｇ自由基加聚反应的数量分布函数，导出凝胶点附近的渐进分布函数和高分子矩的表示式．进一步应用标度变换，得到了描述溶胶－凝胶相变的广义标度律，从而揭示了Ａｆ－Ａｇ自由基加聚的固化反应是一个相变过程．     

Study on the Model for Regulation of the Allosteric Enzyme Activity

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Analysis of the Volmer–Krishtalic mechanism for the chlorine electrode reaction

The dependencies of the current density and surface coverage of the adsorbed intermediates on overpotential were established without kinetic approximations for the chlorine electrode reaction under the Volmer–Krishtalic mechanism. Tafelian regions were obtained which slope values cannot be derived from the use of the rate determining step criteria, such as 2.3026(2RT/3F) and 2.3026(RT/F), as well as two or three Tafel regions with different slopes in the same anodic or cathodic curve. The existence of limiting kinetic current densities was also demonstrated. Finally, the results obtained were analysed and discussed, comparing them with those obtained by the usual methods.     

Studies on the Performance and Structure of Supported Catalysts for the Partial

The catalytic properties of several supported metal catalysts on different carriers were studied in the partial oxidation of methane (POM) to syngas. In our experiment, supported noble metal catalysts exhibited better performance than the other supported transition metal catalysts. The catalyst performances were significantly influenced by the d-electron configuration of the active metal components and the dispersion of active metal components on the support. A catalyst with a moderate number of unpaired electrons in the d-orbital of the active metal support without obvious acidity or redox activity (e.g. MgO) was suitable for POM performance. The Rh/SiO2 catalyst was the best in the POM reaction, among those investigated. Reaction conditions apparently also affected the POM performance of the catalyst. The conversion of methane and the selectivity for CO increased with the reaction temperature, and a high CH4/O2 ratio was not beneficial for POM performance.     

Study on the New Fluorescence Immunoassays for the 2,4,6‐Trichlorophenol in the Environmental Water

Abstract

This study reported that the hapten of 2,4,6‐trichlorophenol (2,4,6‐TCP) was synthesized by using 2,4,6‐TCP reacted with chloroactic acid in alkaline solution. The hapten was conjugated to bovine serum albumin (BSA) with the modified active ester method to form artificial immune antigen. The anti‐TCP polyclonal antibodies were obtained by using the artificial immuneantigen (TCP‐BSA) to immunize the rabbits. Using the purified antiserum of highest specificity, an antibody‐coated fluoroimmunoassay was developed that shows an IC₅₀ of 4.8 µg/L with a limit of detection of 0.25 µg/L. The antibody showed negligible cross‐reactivity with other phenols, which makes their assays suitable for the selective detection of 2,4,6‐TCP. It shows a good accuracy and suitability to analyze, 2,4,6‐TCP in environmental water.     

Suitability of different containers for the sampling and storage of biogas and biomethane for the determination of the trace-level impurities – A review

The traceable and accurate measurement of biogas impurities is essential in order to robustly assess compliance with the specifications for biomethane being developed by CEN/TC408. An essential part of any procedure aiming to determinate the content of impurities is the sampling and the transfer of the sample to the laboratory. Key issues are the suitability of the sample container and minimising the losses of impurities during the sampling and analysis process. In this paper, we review the state-of-the-art in biogas sampling with the focus on trace impurities. Most of the vessel suitability studies reviewed focused on raw biogas. Many parameters need to be studied when assessing the suitability of vessels for sampling and storage, among them, permeation through the walls, leaks through the valves or physical leaks, sorption losses and adsorption effects to the vessel walls, chemical reactions and the expected initial concentration level. The majority of these studies looked at siloxanes, for which sampling bags, canisters, impingers and sorbents have been reported to be fit-for-purpose in most cases, albeit with some limitations. We conclude that the optimum method requires a combination of different vessels to cover the wide range of impurities commonly found in biogas, which have a wide range of boiling points, polarities, water solubilities, and reactivities. The effects from all the parts of the sampling line must be considered and precautions must be undertaken to minimize these effects. More practical suitability tests, preferably using traceable reference gas mixtures, are needed to understand the influence of the containers and the sampling line on sample properties and to reduce the uncertainty of the measurement.     

Raising the Speed Limit for β-Hairpin Formation

Understanding the folding of the β-hairpin is a crucial step in studying how β-rich proteins fold. We have studied CLN025, an optimized ten residue synthetic peptide, which adopts a compact, well-structured β-hairpin conformation. Formation of the component β-sheet and β-turn structures of CLN025 was probed independently using a combination of equilibrium Fourier transform infrared spectroscopy and laser-induced temperature jump coupled with time-resolved infrared and fluorescence spectroscopies. We find that CLN025 is an ultrafast folder due to its small free energy barrier to folding and that it exceeds the predicted speed limit for β-hairpin formation by an order of magnitude. We also find that the folding mechanism cannot be described by a simple two-state model, but rather is a heterogeneous process involving two independent parallel processes. Formation of stabilizing cross-strand hydrophobic interactions and turn alignment occur competitively, with relaxation lifetimes of 82 ± 10 and 124 ± 10 ns, respectively, at the highest probed temperature. The ultrafast and heterogeneous folding kinetics observed for CLN025 provide evidence for folding on a nearly barrierless free energy landscape, and recalibrate the speed limit for the formation of a β-hairpin.     

New method for the synthesis of α-chlorocinnamonitriles

A novel method for the preparation of nitriles of -chlorocinnamic acid from aldehydes and ketones was proposed. Transformation of carbonyl compounds into hydrazones followed by treatment of the reaction mixture with CCl₃CN in the presence of copper chloride(i) yields -chlorocinnamonitriles.     

Non-linear Constitutive Model for the Oligocarbonate Polyurethane Material

The polyurethane, which was the subject of the constitutive research presented in the paper, was based on oligocarbonate diols Desmophen C2100 produced by Bayer？. The constitutive modelling was performed with a view to applying the material as the inlay of intervertebral disc prostheses. The polyurethane was assumed to be non-linearly viscohyperelastic, isotropic and incompressible. The constitutive equation was derived from the postulated strain energy function. The elastic and rheological constants were identified on the basis of experimental tests, i.e. relaxation tests and monotonic uniaxial tests at two different strain rates, i.e. λ= 0.1 min-1 and λ= 1.0 min-1. The stiffness tensor was derived and introduced to Abaqus？finite element（FE） software in order to numerically validate the constitutive model. The results of the constants identification and numerical implementation show that the derived constitutive equation is fully adequate to model stress-strain behavior of the polyurethane material.     

Microreactor for the Catalytic Partial Oxidation of Methane

Fixed-bed reactors for the partial oxidation of methane to produce synthetic gas still pose hot-spot problems. An alternative reactor, which is known as the shell-and-tube-typed microreactor, has been developed to resolve these problems. The microreactor consists of a 1 cm outside-diameter, 0.8 cm inside-diameter and 11 cm length tube, and a 1.8 cm inside-diameter shell. The tube is made of dense alumina and the shell is made of quartz. Two different methods dip and spray coating were performed to line the tube side with the LaNixOy catalyst. Combustion and reforming reactions take place simultaneously in this reactor. Methane is oxidized in the tube side to produce flue gases (CO2 and H2O) which flow counter-currently and react with the remaining methane in the shell side to yield synthesis gas. The methane conversion using the higher-loading catalyst spray-coated tube reaches 97% at 700℃, whereas that using the lower-loading catalyst dip-coated tube reaches only 7.78% because of poor adhesion between the catalyst film and the alumina support. The turnover frequencies (TOFs) using the catalyst spray-and dip-coated tubes are 5.75×10-5 and 2.24×10-5 mol/gcat·s, respectively. The catalyst spray-coated at 900℃provides better performance than that at 1250℃because sintering reduces the surface-area. The hydrogen to carbon monoxide ratio produced by the spray-coated catalyst is greater than the stoichiometric ratio, which is caused by carbon deposition through methane cracking or the Boudouard reaction.     

On the Criteria of Instability for Electrochemical Systems

Both cyclic-voltammetry-based and impedance-based experimental criteria that have been developed recently for the oscillatory electrochemical systems are critically appraised with two typical categories of oscillators.Consistent conclusions can be drawn by the two criteria for the category of oscillators that involve the coupling of charge transfer mainly with surface steps(e.g.ad-and desorption)such as in the electrooxidation of C1 organic molecules.Whereas,impedance-based criterion is not applicable to the category of oscillators that involve the coupling of charge transfer mainly with mass transfer(e.g.diffusion and convection) such as in the Fe(CN)6^3- reduction accompanying periodic hydrogen evolution.The reason is that the negative impedance cannot include the feedback information of convection mass transfer induced by the hydrogen evolution.However,both positive and negative nonlinear feedbacks,i.e., the diffusion-limited depletion and convection-enhanced replenishment of the Fe(CN)6^3- surface concentration,that coexist between the bistability,i.e.,Fe(CN)6^3- reduction with and without hydrogen evolution at lower and higher potential sides respectively,are all reflected in the crossed cyclic voltammogram(CCV).It can be concluded that the voltammetry-based criterion(in time domain)is more intuitive,less time-consuming and has a wider range of applications than the impedancebased one (in frequency domain).