Experimental Setup for Assessing the Energetic Materials Deflagration Propagation under High Temperature and High Pressure Conditions

The technology of "explosion in fractures" is one of new synthetic engineering methods used in low permeability reservoirs. The most important problem arose from the technology is to assess the deflagration propagation capability of milky explosives in rock fractures. In order to investigate detailed this problem in the laboratory, an experimental setup was designed and developed in which different conditions can be simulated. The experimental setup mainly includes two parts. One is the experimental part and the other is the measurement part. In the experimental setup, the narrow slots with different width can be simulated; meanwhile, different initial pressures and initial temperatures can be loaded on the explosives inside the narrow slots. The initial pressure range is from 0-60 MPa, and the initial temperatures range is from room temperature to 100 V. The temperature and the velocity of deflagration wave can be measured; meanwhile the corresponding pressure in the narrow slot is also measured. In the end, some typical measurement results are briefly presented and discussed.

Study on peak overpressure and flame propagation speed of gas deflagration in the tube with obstacles

The on-way peak overpressure and flame propagation speed of gas deflagration in the tube with obstacles are important data for process safety. Based on carbon monoxide deflagration experiments, the paper presents a multi-zone integration model for calculation of on-way peak overpressure, in which the tube with obstacles is considered as a series of venting explosion enclosures which link each others. The analysis of experimental data indicates that the on-way peak overpressure of gas deflagration can be correlated as an empirical formula with equivalence ratio of carbon monoxide oxidation, expansion ratio, flame path length, etc., and that the on-way peak overpressure exhibits a linear relationship with turbulence factor and flame propagation speed. An empirical formula of flame propagation speed is given.

An efficient in vitro method for mass propagation of Potentilla potaninii wolf

This study reports a method for high-frequency shoot organogenesis and plant establishment of Potentilla potaninii Wolf. Hypocotyl and cotyledon explants of P. potaninii were cultured on Murashige and Skoog (MS) medium supplemented with various concentrations of benzyladenine (BA) and alpha-naphthaleneacetic acid (NAA) to induce adventitious shoot formation for micropropagation. The highest frequency of adventitious shoot regeneration was achieved from hypocotyl and cotyledon explants grown on MS medium supplemented with 5.0 mg l(-1) BA and 1.0 mg l(-1) NAA. The regenerated shoots rooted most efficiently on half-strength MS medium supplemented with 1.0 mg l(-1) NAA and 0.5 mg l(-1) indole-3-acetic acid or indole-3-butyric acid. The acclimatized plants with normal morphology and growth characters flowered and set seeds in the following year.

基于克隆选择算法的非线性优化迭代学习控制；Clonal selection algorithm based nonlinear optimal iterative learning control

为实现对模型不确定的有约束非线性系统在特定时间域上输出轨迹的有效跟踪,将改进的克隆选择算法用于求解迭代学习控制中的优化问题。提出基于克隆选择算法的非线性优化迭代学习控制。在每次迭代运算后,一个克隆选择算法用于求解下次迭代运算中的最优输入,另一个克隆选择算法用于修正系统参考模型。仿真结果表明,该方法比GA-ILC具有更快的收敛速度,能够有效处理输入上的约束以及模型不确定问题,通过少数几次迭代学习就能取得满意的跟踪效果。

On the propagation rate of the chemical waves observed during the course of CO oxidation on a Ag/Pt(110) composite surface

We have analyzed the propagation rate of the chemical waves observed during the course of CO oxidation on a Ag/Pt(I 10) composite surface that were reported in our previous papers [Surf Interface Anal. 2001, 32, 179; J. Phys. Chem. B 2002, 106, 5645]. In all cases, the propagation rate v can be adequately fitted as v = v(0) + D-0/d, in which v(0) and D-0 are constants, and d is the distance between the reaction front of the chemical wave and the boundary from which the chemical wave originates. We propose that the surface species responsible for the formation of the chemical wave comes from two paths: the adsorption of molecules in the gas phase on the surface and the migration from the adjacent surface with different catalytic activity. v(0) corresponds to the contribution from the surface species due to the adsorption, and D-0/d to that of the surface species that migrates from the adjacent surface. The rate equation clearly suggests that the observed chemical wave results from the coupling between adjacent surfaces with different catalytic activities during the course of heterogeneous catalysis. These results, together with our previous reports, provide a good fundamental understanding of spillover, an important phenomenon in heterogeneous catalysis.

Retention modeling and optimization of pH value and solvent composition in HPLC using back-propagation neural networks and uniform design

A novel method for the optimization of pH value and composition of mobile phase in HPLC using artificial neural networks and uniform design is proposed. As the first step. seven initial experiments were arranged and run according to uniform design. Then the retention behavior of the solutes is modeled using back-propagation neural networks. A trial method is used to ensure the predicting capability of neural networks. Finally, the optimal separation conditions can be found according to a global resolution function. The effectiveness of this method is validated by optimization of separation conditions for both basic and acidic samples.

Chain propagation kinetics on melt grafting reaction

Graft copolymerization in the molten state is of fundamental importance as a probe of chemical modification and reactive compatibilization. However, few grafting kinetic studies on reactive extrusion have been carried out because of the inherent difficulties, as expected. In this work, we have studied chain propagation kinetics on melt grafting using pre-irradiated linear low density polyethylene (LLDPE) and three monomers, acrylic acid (AA), methacrylic acid (MAA), and methyl methacrylate (MMA), as the model system. We measured the apparent chain propagation rate coefficients of grafting (k(p,g)) and homopolymerization (k(p,h)) at an initial stage for the melt grafting by FT-IR spectroscopy and electron spin resonance spectroscopy. It was observed that the convective mixing affected the rate coefficients. The magnitude of k(p,h) and k(p,g) were in the same order, but k(p,h) was slightly larger than k(p,g) The k(p,g) of the three grafting systems increased in the order: LLDPE/MMA < LLDPE/MAA < LLDPE/AA. These results are explained in terms of phase separation, solubility, and inherent reactivity of the monomer.

Graft chain propagation rate coefficients of acrylic acid in melt graft copolymerization with linear low density polyethylene

Graft chain propagation rate coefficients (k(p.g)) for grafting AA onto linear low density polyethylene (LLDPE) in the melt in ESR tubes have been measured via Fourier transform infrared (FTIR) spectroscopy and electron spin resonance (ESR) spectroscopy in the temperature range from 130 to 170 degrees C. To exclude the effect of homopolymerization on the grafting. the LLDPE was pre-irradiated in the air by electron beam to generate the peroxides and then treated with iodide solution to eliminating one kind of peroxides, hydroperoxide. The monomer conversion is determined by FTIR and the chain propagation free-radical concentration is deduced from the double integration of the well-resolved ESR spectra, consisting nine lines in the melt. The temperature dependence of k(p.g) is expressed:The magnitude of k(p.g) from FTIR and ESR analysis is in good agreement with the theoretical data deduced from ethylene-AA copolymerization, suggesting this method could reliably and directly provide the propagation rate coefficient. The comparison of k(p.g) with the data extrapolated from solution polymerization at modest temperature indicates that the extrapolated data might not be entirely fitting to discuss the kinetics behavior in the melt.

Double propagation based on diepoxide, a facile route to high molecular weight poly(propylene carbonate)

Poly(propylene carbonate) (PPC) with number average molecular weight (M-n) higher than 200 kg/mol was prepared via the terpolymerization of carbon dioxide, propylene oxide and diepoxide using Y(CCl3OO)(3)-ZnEt2-glycerine coordination catalyst. When equimolar ZnEt2 and diepoxide were used, double propagation active species were generated in situ by nucleophilic attack of metal alkoxide on diepoxide, leading to PPC of doubled M-n value. The molecular weight of PPC has dramatic influence on its thermal and mechanical performances. PPC with M of 227 kg/mol showed modulus of 6900 MPa, while the modulus of PPC with M-n of 109 kg/mol was only 4300 MPa. Moreover, when M-n increased from 109 to 227 kg/mol, a 37 degrees C increase of the onset degradation temperature was observed.

Rapid electron propagation through molecular wire monolayers sandwiched between two gold electrodes

Conjugated bisthioester 1 was synthesized applying Sonogashira coupling reactions. Using self-assembly in combination with nanoparticles deposition techniques, we developed a novel method to fabricate a "gold electrode-molecular wire monolayers-gold nanoparticles" sandwich-like structure. Rapid electron propagation through this sandwich-like structure was observed by cyclic voltammetry and ac impedance measurements.

Comparison of photobioreactors and optimal light regime for rapid vegetative propagation of transgenic Undaria pinnatifida gametophytes

BACKGROUND: Previously, tachyplesin gene (tac) has been successfully transferred into Undaria pinnatifida gametophytes using the method of microprojectile bombardment transformation. The objectives of this study were to compare and evaluate the performance of bubble-column and airlift bioreactors to determine a preferred configuration of bioreactor for vegetative propagation of transgenic U. pinnatifida gametophytes, and to then investigate the influence of light on vegetative propagation of these gametophytes, including incident light intensity, photoperiod and light quality to resolve the problems of rapid vegetative propagation within the selected bioreactor. RESULTS: Experimental results showed that final dry cell density in the airlift bioreactor was 12.7% higher than that in the bubble-column bioreactor under the optimal aeration rate of 1.2 L air min(-1) L-1 culture. And a maximum final dry cell density of 2830 mg L-1 was obtained within the airlift bioreactor using blue light at 40 mu mol m(-2) s(-1) with a light/dark cycle of 14/10 (h). Polymerase chain reaction (PCR) analysis indicated that genes (bar and tac) were not lost during rapid vegetative propagation within the airlift bioreactor. CONCLUSION: The airlift bioreactor was shown to be much more suitable for rapid vegetative propagation of transgenic U. pinnatifida gametophytes than the bubble-column bioreactor in the laboratory. The use of blue light allows improvement of vegetative propagation of transgenic U. pinnatifida gametophytes. (C) 2009 Society of Chemical Industry

Microprojectile bombardment of Laminaria japonica gametophytes and rapid propagation of transgenic lines within a bubble-column bioreactor

A human acidic fibroblast growth factor gene, hafgf, was successfully transferred into Laminaria japonica (kelp) gametophytes via microprojectile bombardment using the biolistic PDS-1000/He gene gun. Following phosphinothricin screening, PCR detection and Southern blot analysis, transgenic L. japonica gametophytes were cultivated in an illuminated bubble-column bioreactor to optimize growth conditions. A maximal final dry cell density of 1,695 mg l(-1) was obtained in a batch culture having an initial dry cell density of 129.75 mg l(-1). This was achieved using an aeration rate of 1.08 l air min(-1) l(-1) culture in a medium containing 1.5 mM inorganic nitrate and 0.15 mM phosphate. In addition, the relationship between different nitrogen sources and growth of transgenic gametophytes indicated that both urea and sodium nitrate were effective nitrogen sources for cell growth, while ammonium ions inhibited growth of these gametophytes.

Effects of Irradiance and Temperature on the Photosynthesis and Vegetative Propagation of Caulerpa serrulata

The photosynthetic oxygen evolution of Caulerpa serrulata was determined with oxygen electrodes. The effects of light and temperature on the growth and regeneration of fragmented C. serrulata thalli were analyzed. The regenerating rate and establishment of different sizes and portions of C. serrulata were studied. The results showed that the light saturation point of C. serrulata was 200 mu mol photons/m(2) per s and the optimum growth temperature was 25-30 degrees C. Under these conditions, the maximum photosynthetic oxygen evolution rate was 15.1 +/- 0.29 mg O-2/mg Chl a/h, the growth rate and elongation rate reached the highest values, 4.67 +/- 0.09 mg FW/d and 0.78 +/- 0.01 mm/d, respectively. The fragmented C. serrulata thalli was regenerated at 20-35 degrees C and survived at 15 degrees C and 200 mu mol photons/m(2) per s. A different survival rate was detected according to fragment size. All of these results indicated that C. serrulata was a candidate to become an invasive species if introduced into a new place. Therefore, we should pay more attention to C. serrulata for its potential threat to marine ecosystem when it is sold for aquarium use.

Three Cuts for Accelerated Interval Propagation

This paper addresses the problem of nonlinear multivariate root finding. In an earlier paper we described a system called Newton which finds roots of systems of nonlinear equations using refinements of interval methods. The refinements are inspired by AI constraint propagation techniques. Newton is competative with continuation methods on most benchmarks and can handle a variety of cases that are infeasible for continuation methods. This paper presents three "cuts" which we believe capture the essential theoretical ideas behind the success of Newton. This paper describes the cuts in a concise and abstract manner which, we believe, makes the theoretical content of our work more apparent. Any implementation will need to adopt some heuristic control mechanism. Heuristic control of the cuts is only briefly discussed here.