超前倒向随机微分方程的反射解及相应的最优停止问题

证明了超前倒向随机微分方程的反射解的存在惟一性,进而解决了一类最优停止问题。

Boussinesq类方程描述有限沙坝地形Bragg反射的性能比较

利用Boussinesq方程,采用线性摄动展开法,求解波浪正向通过有限沙坝地形的一阶反射波解,研究比较Boussinesq类方程描述沙坝地形对波浪的反射作用的性能。通过研究反射系数并与势流理论结果及实验结果对比,发现:邹志利的高阶方程、张永刚及Madsen的方程适用的水深范围较广,而Nwogu和Peregrine的方程仅在共振点附近有效;当入射波的波长为沙坝波长两倍时,反射波产生共振效应(即Bragg反射),反射系数与沙坝振幅和水深的比值以及地形中沙坝的条数成正比;相对势流理论的共振时的反射系数,以张永刚为代表的一系列Boussinesq方程色散精度越高,适用水深范围越广,而高阶方程适用的水深很浅。

The MKdV Equation with Nonuniformity Terms

In this paper, the MKdV equation with nonuniformity terms is discussed. It relates to the eigenvalue problem The evolution laws of scattering data for (1. 3) are derived and the inverse scattering solutions-soliton solutions of eq(1. 1) are obtained. In the end of the paper, the single soliton solution and Double soliton solution are discussed. The result extends the situation in [1].

Numerical simulation of fluid dynamics in rare earth chloride solution in jet-flow pyrolysis reactor

Rare earth oxide was prepared via direct pyrolysis of rare earth chloride solution. Based on this technique, a new-type jet-flow pyrolysis reactor was designed, and then the fluid dynamics (pressure and velocity) inside the reactor was numerically simulated using a computational fluid dynamics method. The self-produced pressure (p) and the fuel inlet velocity (v) satisfied a quadratic function,p=0.06v2+0.23v?4.49. To fully utilize the combustion-generated heat in pyrolysis of rare earth chloride, an appropriate external pressure p=v2+3v?4.27 should be imposed at the feed inlet. The 1.25- and 1.5-fold increase of feed inlet diameter resulted in decline of adsorption dynamic pressure, but the intake of rare earth chloride increased by more than 30% and 60%, respectively. The fluid flow in the reactor was affected by the feeding rate; the fluid flow peaked near the throat of venturi and gradually smoothed down at the jet-flow reactor’s terminal along with the sharp decline of feeding rate.

Product Identification and Mass Spectrometric Analysis of n-Butane and i-Butane Pyrolysis at Low Pressure

The pyrolysis of n-butane and i-butane at low pressure was investigated from 823-1823 K in an electrically heated flow reactor using synchrotron vacuum ultraviolet photoionization mass spectrometry. More than 20 species, especially several radicals and isomers, were detected and identified from the measurements of photoionization efficiency （PIE） spectra. Based on the mass spectrometric analysis, the characteristics of n-butane and i-butane pyrolysis were discussed, which provided experimental evidences for the discussion of decomposition pathways of butane isomers. It is concluded that the isomeric structures of n-butane and i-butane have strong influence on their main decomposition pathways, and lead to dramatic differences in their mass spectra and PIE spectra such as the different dominant products and isomeric structures of butene products. Furthermore, compared with n-butane,i-butane can produce strong signals of benzene at low temperature in its pyrolysis due to the enhanced formation of benzene precursors like propargyl and C4 species, which provides experimental clues to explain the higher sooting tendencies of iso-alkanes than n-alkanes.

Improvement of clinical parameters in patients with gastroesophageal reflux disease after radiofrequency energy delivery

AIM:To evaluate the efficacy of Stretta procedure with gastroesophageal reflux disease(GERD)based on symptom control,medication changes and oesophagitis grade.METHODS:Ninety patients with a history of GERD underwent Stretta procedure from June 2007 to March 2010.All patients with GERD diagnosed by the pres-ence of endoscopically evidenced oesophagitis or abnormal esophageal pH testing.We evaluated GERD-health-related quality of life,satisfaction,medication use and endoscopy at baseline,6,12 mo after treatment.Complications of the procedure were analyzed.RESULTS:We found that patients experienced significant changes in symptoms of GERD after Stretta proce-dure.The onset of GERD symptom relief was less than 2 mo(70.0%)or 2 to 6 mo(16.7%).The mean GERD-HRQL score was 25.6(baseline),7.3(6 mo,P<0.01),and 8.1(12 mo,P<0.01).The mean heartburn scorewas 3.3(baseline),and 1.2(12 mo,P<0.05).The percentage of patients with satisfactory GERD control improved from 31.1%at baseline to 86.7%after treat-ment,and patient satisfaction improved from 1.4 at baseline to 4.0 at 12 mo(P<0.01).Medication usage decreased significantly from 100%of patients on pro-ton pump inhibitors therapy at baseline to 76.7%of patients showing elimination of medications or only as needed use of antacids/H2-RA at 12 mo.An improvement in endoscopic grade of oesophagitis was seen in 33 of the 41 patients.All patients had either no erosions or only mild erosive disease(grade A)at 6 mo.CONCLUSION:The experience with Stretta procedure confirms that it is well tolerated,safe,effective and durable in the treatment of GERD.The Stretta procedure provides the drug-refractory patients with a new mini-mally invasive method.

Common reflection surface stack using dip decomposition for rugged surface topography

We present an extension of the Common Reflection Surface （CRS） stack that provides support for an arbitrary top surface topography. CRS stacking can be applied to the original prestack data without the need for any elevation statics. The CRS-stacked zero- offset section can be corrected （redatumed） to a given planar level by kinematic wave field attributes. The seismic processing results indicate that the CRS stacked section for rugged surface topography is better than the conventional stacked section for S/N ratio and better continuity of reflection events. Considering the multiple paths of zero-offset rays, the method deals with reflection information coming from different dips and performs the stack using the method of dip decomposition, which improves the kinematic and dynamic character of CRS stacked sections.

Effect of microwave irradiation on secondary structure of α-amylase by circular dichroism

Based on the starch hydrolysis reaction accelerated by microwave irradiation with α-amylase, the circular dichroism （CD） and secondary structure changes of α-amylase under the condition of microwave irradiation and water bath were studied by circular dichroism spectra. The results showed that, both the peak heights （at 2=193 nm） of the CD spectra of the samples treated by microwave irradiation and water bath reduced. The reduced rate by microwave irradiation ranged from 140% to 220%, while the reduced rate by water bath ranged from 60% to 140%. The peak of the sample treated by microwave irradiation for 60 min disappeared at λ=193 nm, while the sample showed a wake peak by water bath. The peak position by microwave irradiation emerged a blue shift in the range of 5-8 nm at λ=204 nm and λ=220 nm, while it emerged in the range of 3-5 nm by water bath. With time going on, the microwave irradiation and water bath have prompted the secondary structure of α-helix, β-sheet, β-turn and the mutual transformations of random coil, but the trends were different.

Complete Solution of Sun Tracking for Heliostat

A general solution of sun tracking for an arbitrarily oriented heliostat towards an arbitrarily located target on the earth is published. With the most general form of solar tracking formulae, it is seen that the used azimuthelevation, spinning-elevation tracking formulae etc. are the special cases of it. The possibilities of utilizing the general solution and its significance in solar energy engineering are discussed.

DECOMPOSITION OF BLACK LIQUOR BY ULTRASOUND PROCESS

Ultrasound (US)-induced cavitation is an effective way in oxidizing organic contaminants in wastewater either as the independent operation unit or in combination with other oxidation methods. In this paper, black liquor and filtrate after acidifying and settling were sonicated. The effect of working parameters on ultrasonic degradation of black liquor, such as different combination methods, frequency, power supply, initial concentration, pH, duration time, ionic strength and catalyst were studied. The results were as follows: (1) At the conditions of 40kHz, 100W, 4h, pH at 6 and temperature 30?℃, utilizing US/US-H2O2/US-Fenton, weak-orange filtrate turned to colloid with the increase of time and little sediment produced after settling. Especially filtrate came to be milk white collides and upper water approached to nearly achromatic by US-Fenton. Compared with the US, US-H2O2/US-Fenton COD (Chemical oxidation demand) removal ratio can increase 15%, 30% respectively. Because of more hydroxyl radicals produced in the reaction process; (2) At the condition of 100W and 4h, the degradation efficiency of black liquor was better at 40kHz over at 20kHz. Moreover black liquor can be biodegraded easily. Those based on that the big molecule of contaminants in aqueous solution can be changed into the little molecule with ultrasound (3) At the condition of 40kHz and 4h, the COD removal ratio of black liquor was more higher at 60W than at 80W, while the removal ratio of COD at 60W was nearly close to the ratio at 100W; (4) The initial concentration of black liquor influenced the effect of sonochemical degradation; (5) The variation of pH had no effect on degradation; (6) The longer the duration time, the greater the removal ratio of COD. But this ratio increased slowly after 4h; (7) Adding 0.2g/L NaCl to change the ionic strength of the black liquor, the COD removal ratio can increase 10%; (8) The degradation rates increased by the coexistent catalysts of TiO2, Co2+ and Ag+.

General Solutions of Reflection Equations for Bariev Model

The integrable general open-boundary conditions for the one-dimensional Bariev chain are considered. All kinds of solutions to the reflection equation （RE） and its dual are obtained.

Investigation of Vacuum Ultraviolet Photoionization of Methylcyclohexane in Energy Region of 9-15.5 eV

Vacuum ultraviolet(VUV)photoionization and photodissociation of methylcyclohexane have been studied utilizing a reflectron time-of-flight mass spectrometer(RTOF-MS)with synchrotron radiation source.Photoionization efficiency curves(PIEs)of molecule ion C7H14^+ and fragment ions C7H13^+,C6H11^+,C6H10+,C5H10^+,C5H9^+,C4H8^+,C4H7^+,and C3H5^+ were observed.The ionization energy of methylcyclohexane was measured to be(9.80±0.03)eV,and appearance energies of fragment ions were determined from the PIEs.Optimized structures of transitional states,intermediates and product ions were characterized at the B3LYP/6-31G(d)level and the energies were calculated using G3B3 method.Formation channels of dominating fragment ions were proposed.Intramolecular hydrogen migrations and carbon ring-opening were the foremost processes in fragmentation pathways of methylcyclohexane.

Concrete Erosion in Weak Sulfate Environment

The erosion failure mechanism of concrete is studied systematically based on field investigation and laboratory experiments of concrete samples from more than 30 km concrete lining and 10 hydraulic structures of Shandong Jiaodong water diversion project, in which the concrete failed only 3-6 months after conslruction was completed. With electron microscopy scanning, energy dispersive analysis, XKD （X-ray diffraction） analysis and Raman spectrum analysis of the mineral composition of the failure concrete and precipitates, chemical and physical reactions that occurred in the concrete under engineering environment were investigated. The analysis indicated that the rapid corrosion and dissolution reaction of the concrete in weak sulfate environment is due to sulfate and carbonate corrosion with the catalytic magnesium salt at low temperature. Also, corrosion damage facilitates the sulfate ions and carbonate ions into the concrete, and the expansion of ettringite and TSA （thaumasite sulfate attack） reaction also accelerates the corrosion damage of the concrete.

基于高精度差分定位法的水文测量自动化报警系统设计

为实现异常水文位置测量信息的自动化准确报警,设计基于高精度差分定位法的水文测量自动化报警系统。采集水位、温度、湿度、流量信号,提取四种水文信息的信号功率数据,基于反射解算的水位信息测量方法解算各历元水文测量信号功率,提取水位变化数据,使用模糊自适应卡尔曼滤波的水位差分定位方法,将解算的水位数据设成模糊卡尔曼滤波初始值,由模糊推理模型,修正水文信息量测噪声,实现高精度水文信息定位测量,若水位异常,便由声光报警器报警。经测试,此系统对海面异常波动的水位定位偏差小于0.03 m,自动化报警时延小于0.5 s,具备高精度异常水文位置自动化报警能力。

Investigation of interfacial processes in graphite thin film anodes of lithium-ion batteries by both in situ and ex situ infrared spectroscopy

Graphite thin film anodes with a high IR reflectivity have been prepared by a spin coating method. Both ex situ and in situ mi- croscope FTIR spectroscopy （MFFIRS） in a reflection configuration were employed to investigate interfacial processes of the graphite thin film anodes in lithium-ion batteries. A solid electrolyte interphase layer （SEI layer） was formed on the cycled graphite thin film anode. Ex situ MFTIRS revealed that the main components of the SEI layer on cycled graphite film anodes in 1 tool L 1 LiPF6/ethylene carbonate ＋ dimethyl carbonate （1：1） are alkyl lithium carbonates （ROCOzLi）. The desolvation process on graphite anodes during the initial intercalation of lithium ion with graphite was also observed and analyzed by in situ MFTIRS.

Exact solution of three-dimensional acoustic field in a wedge with perfectly reflecting boundaries

An exact approach is presented to compute the three-dimensional(3D) acoustic field in a homogeneous wedge-shaped ocean with perfectly reflecting boundaries. This approach applies the Fourier synthesis technique, which reduces a 3D point-source ideal wedge problem into a sequence of two-dimensional(2D) line-source ideal wedge problems, whose analytical solution is well established. A comparison of numerical efficiency is provided between this solution and the solution proposed by Buckingham,which is obtained by a sequence of integral transforms. The details of numerical implementation of these two solutions are also given. To validate the present approach and at the same time compare numerical efficiency between this approach and Buckingham's analytical solution, two numerical examples are considered. One is the Acoustical Society of America(ASA) benchmark wedge problem and the other is a wide-angle wedge problem. Numerical results indicate that the present approach is efficient and capable of providing accurate 3D acoustic field results for arbitrary receiver locations, and hence can serve as a benchmark model for sound propagation in a homogeneous wedge-shaped ocean.

Construction of AFLT States by Reflection Method and Recursion Formula

The AFLT states|PY1,Y2has reflection symmetry,Sn|PY1,Y2=|PY2,Y2,nb=2P,where S is the screening charge.AFLT state can be constructed using this reflect symmetry.We propose a recursion formula for this construction.The recursion formula is factorized completely.

In-depth study on aminolysis of poly(ε-caprolactone): Back to the fundamentals

The aminolysis can effectively introduce primary amine （- quent surface fiiofunctionalization reactions. However, less NH2） groups onto polyester materials, enabling a variety of subse- attention has been paid to the basic knowledge of aminolysis reac- tion in terms of reaction kinetics and its influences on materials properties. In this study, taking the widely used poly（e-caprolactone） （PCL） as a typical example, the influences of diamines and solvent property on the surface -NH2 density are firstly assessed by using X-ray photoelectron spectroscopy （XPS） and colorimetric analysis. Results show that smaller dia- mine molecules and nonpolar alcohols could accelerate the reaction. The reaction kinetics with 1,6-hexanediamine is further investigated as a function of temperature, reaction time, and diamine concentration. During the initial stage, the reaction shows a 1^st order kinetics with the diamine concentration and has an activation energy of 54.5 kJ/mol. Ionization state of the -NH2 groups on the PCL surface is determined, revealing that the pKa of -NH3^＋ （〈5） is much lower than that of the corresponding diamine molecules in solution. After aminolysis, surface hydrophilicity of PCL membrane is significantly enhanced, while surface elastic modulus and average molecular weight are decreased to some extent, and others such as weight, surface mor- phology and bulk mechanical strength are not apparently changed. The introduced -NH2 groups are found to be largely lost at 37 ℃, but can be mostly maintained at low temperature.

Cu2O-Au Nanocomposites with Novel Structures and Remarkable Chemisorption Capacity and Photocatalytic Activity

The decomposition of Cull nanoparticles in aqueous solution has been successfully developed as a novel method for the preparation of Cu2O nanoparticles. In particular, we found that the decomposition of Cull nanoparticles in aqueous solution could be catalyzed by Au colloids, forming CU2O-Au nanocomposites. The composition and structure of the resulting Cu2O-Au nanocomposites have been characterized in detail by inductively coupled plasma atomic emission spectroscopy, powder X-ray diffraction, N2 adsorption-desorption isotherms, infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. Their visible-light-driven photocatalytic activity toward various dye molecules has also been investigated. Depending on the Au：Cu ratio, Cu20-Au nanocomposites exhibit different novel nanostructures including a beautiful flower-like nanostructure that consists of polycrystalline Cu2O, amorphous Cu2O and Au colloids. We propose that the rapidly-generated bubbles of H2 during the course of the catalytic decomposition reaction drive the simultaneously-formed Cu2O to form amorphous curved thin foils and might also act as a template to assemble curved thin foils of amorphous Cu2O, polycrystalline Cu2O and Au colloids into uniform nanostructures. A Cu2O-Au nanocomposite with a Cu：Au ratio of 40 exhibits remarkable chemisorption capacity and visible-light-driven photocatalytic activity towards methyl orange and acid orange 7 and is a promising chemisorption-photocatalysis integrated catalyst. The catalytic decomposition of the metal hydride might open up a new approach for the fabrication of other metal/metal oxide nanocomposites with novel nanostructures and properties.