在用柴油机油基础油及其中的清净分散剂耗解研究

应用理化检测及元素分析、红外光谱、气相色谱和质谱等分析技术对在用柴油机油基础油及其中的金属清净剂的耗解进行了跟踪分析。结果表明,在用柴油机油基础油在使用过程中,黏度、密度等理化指标发生显著的变化,其中金属清净剂的耗解水平可以通过油品碱值或添加剂的特征红外光谱来表征。

带最大密度限制的Navier-Stokes方程的耗散测度值解

本文研究具有最大密度限制的可压Navier-Stokes方程,其中,最大密度限制是由一个奇性的压强项给定的。利用带有参数K的Brenner模型,我们构造了Navier-Stokes方程的逼近解。为了处理压强的奇性,引入一个逼近压强pθ,δ,其中θ,δ为逼近参数。当这些参数K,θ,δ→0时,我们证明逼近解收敛到Navier- Stokes方程的耗散测度值解。

对数非线性Nelson-de La Pena方程的耗散结构解

Einstein过程的对数非线性Nelson—de la Pena方程.(?)2mD((?)φ±/(?)t)=[2mD^2(?)~2+G+bln(φ+φ-]φ_± (1)亦可用作讨论耗散结构解的基本方程;式中,φ+φ-=ρ为密度,G为位形r的任意函数,m为粒子的质量,D和b皆为大于零的常数,对数非线性Nelson-de la Pena方程的一个显著特点是满足迭加原理,这同量子力学波导理论中的非线性BB—M方程是类似的.设φ±=R(r·t)exp[±S(r·t](2)则有(?)φ±/(?)t=(1/R(?)R/(?)t±(?)S/(?)t)φ_± (3)(?)~2φ_±=[(?)~2R/R+((?)S)±(?)~2S±2/R(?)R·(?)S]φ_± (4)将(2)、(3)、(4)代人(1)式,分开其“双号”部份和“单号”部份。

一类变系数抛物系统在图像恢复中的应用

研究一类变系数非线性耦合抛物系统,证明系统解的存在性和唯一性,实验证明了改变系数和进行边界变量分离显著提高了去噪效果,同时保持了奇异性。结合Perona-Malik边界保持和Catte偏微分方程平滑处理,研究抛物系统中边界变量的自适应选择的平衡参数。最后给出试验验证该模型的效能,结果表明,在真实图像和标准数字图像中,人为加上重度噪声后,变系数抛物系统去噪效果优于一般的耦合抛物法,能去除大量斑点,同时,可以显著提高在真实图像和标准数字图像中的信噪比,表明本系统的去噪效果较之前的方法更好。

Heterojunction between anodic TiO_2/g-C_3N_4 and cathodic WO_3/W nano-catalysts for coupled pollutant removal in a self-biased system

An anodic TiO2/g-C3N4 hetero-junction and cathodic WO3/W were used to build a self-sustained catalytic fuel cell system for oxidizing rhodamine B or triclosan and reducing NO3^--N to N2 simultaneously.The WO3 nano-catalyst was formed in situ by heating and oxidizing a tungsten wire in air.Cyclic voltammetry and current-time curves were used to characterize the electrochemical properties of the electrodes and system.Aeration and activation of molecular oxygen by self-biased TiO2/g-C3N4 led to the formation of reactive oxidizing species in the fuel cell.The mechanism of simultaneous anodic oxidation of pollutants and cathodic reduction of nitrate was proposed.The spontaneously formed circuit and tiny current were used simultaneously in treating two kinds of wastewater in the reactor chambers,even without light illumination or an external applied voltage.This new catalytic pollution control route can lower energy consumption and degrade many other kinds of pollutants.

The Global Solution for a Class of Dissipative Hasegawa-Mima Equation

Applying the integral a priori estimates method, the existence and uniqueness ofthe global solution for the dissipative Hasegawa-Mima equation with initial periodic bound-ary condition was proved.

Technological Progress,Structural Change and China's Energy Efficiency

China has witnessed rapid economic development since 1978, and during the time, energy production and consumption developed at a tremendous speed as well. Energy efficiency which can be measured by energy consumption per unit of GDP, however, experienced continuous decrease. Theoretically, the change of energy efficiency can be attributed to industry structural change and technological change. In order to explain the transformation of Chinese energy efficiency, we adopt logarithmic mean Divisia index techniques to decompose changes in energy intensity in the period of 1994-2005. We find that technological change is the dominant contributor in the decline of energy intensity, but the contribution has declined since 2001. The change in industry structure has decreased the energy intensity before 1998, but raised the intensity after 1998. Decomposed technological effects for all sectors indicate that technological progresses in high energy consuming industries such as raw chemical materials and chemical products, smelting and pressing of ferrous metals, manufacture of non-metallic mineral products and household contribute are the principal drivers of China's declining energy intensity.

Moment Analysis of a Rice-Pile Model

Large scale simulations of a rice-pile model are performed. We use moment analysis techniques to evaluate critical exponents and data collapse method to verify the obtained results. The moment analysis yields well-defined avalanche exponents, which show that the rice-pile model can be coherently described within a finite size scaling framework. The general picture resulting from our analysis allows us to characterize the large scale behavior of the present model with great accuracy.

具有强迫项Dullin-Gottwald-Holm方程整体耗散解的存在性

本文借鉴Bressan和Constantin于2007年提出的新特征线法,利用具有强迫项的Dullin-Gottwald-Holm方程的平衡律和一些新的估计,证明了该方程在H^1(R)中整体耗散解的存在性.

Unified Form of Photorefractive Coupling－wave Equation in the Undepleted Pump Approximate and the Lossless Solution

The coupling-wave equations of photorefractive wave mixing processes including two-and four-wave mixing are expressed as an unified matrix equation in the undepleted pump approximation.The lossless general solution of the matrix equation is obtained.The previous formulas of five wave-mixing processes in the undepleted pump are derived from the solution when their boundary conditions are used.

Oblique Wave Motion over Multiple Submerged Porous Bars near a Vertical Wall

This study examines oblique wave motion over multiple submerged porous bars in front of a vertical wall. Based on linear potential theory, an analytical solution for the present problem is developed using matched eigenfunction expansions. A complex dispersion relation is adopted to describe the wave elevation and energy dissipation over submerged porous bars. In the analytical solution, no limitations on the bar number, bar size, and spacing between adjacent bars are set. The convergence of the analytical solution is satisfactory, and the correctness of the analytical solution is confirmed by an independently developed multi-domain BEM （boundary element method） solution. Numerical examples are presented to examine the reflection and transmission coefficients of porous bars, CR and Cv, respectively, for engineering applications. The calculation results show that when the sum of widths for all the porous bars is fixed, increasing the bar number can significantly improve the sheltering function of the bars. Increasing the bar height can cause more wave energy dissipation and lower CR and Cr. The spacing between adjacent bars and the spacing between the last bar and the vertical wall are the key parameters affecting CR and Ct. The proposed analytical method may be used to analyze the hydrodynamic performance of submerged porous bars in preliminary engineering designs.

Dissipative Travelling Wave Solution for El Nio Tropic Sea-air Coupled Oscillator

El Nifio and Southern Oscillation （ENSO） is an interannual phenomenon involved in the tropical Pacific sea-air interactions. An asymptotic method of solving equations for the ENSO model is proposed. Based on a class of oscillator of ENSO model and by employing a simple and valid method of the variational iteration, the coupled system for a sea-air oscillator model of interdecadal climate fluctuations is studied. Firstly, by introducing a set of functionals and computing the variationals, the Lagrange multipliers are obtained. And then, the generalized variational iteration expressions are constructed. Finally, by selecting appropriate initial iteration, and from the iterations expressions, the approximations of solution for the sea-air oscillator ENSO model are solved successively. The approximate dissipative travelling wave solution of equations for corresponding ENSO model is studied. It is proved from the results that the method of the variational iteration can be used for analyzing the sea surface temperature anomaly in the equatorial Pacific of the sea-air oscillator for ENSO model.

Quasilinear Hyperbolic Conservation Laws with Relaxation

In this paper, we investigate the relaxation phenomenon for quasilinear hyperbolic conservation laws, and obtain global smooth solutions and the life span of classical solutions to its Cauchy problem. These results shows that the relaxation admits the effects of dissipation.

Fuel consumption study on introducing pyrolyzed DME or ethanol into diesel engine

The present work studied fuel consumption through experiments on a diesel engine. In order to obtain lower BSFC （brake specific fuel consumption）, DME （dimethyl ether） is heated and introduced into air intake, together with fueling emulsified fuel to diesel engine. Results show that BSFC can decrease about 10% and diesel fuel consumption alone can decrease 18%. High saving rate of BSFC up to 10% is also acquired using ethanol instead of DME. To achieve high saving rate of BSFC, the heating temperature of about 1000 K is needed for DME operation, while the diesel engine exhaust temperature of about 750 K is suitable for ethanol. Hydrogen produced in DME or ethanol pyrolysis and the combustion characters of emulsified fuel are considered as main reasons for the excellent fuel saving. Besides, the technique adopted in the present work is extremely easy to be utilized, and may be firstly adopted on diesel engines for power plants, trains, and ships etc.

Construction of the Comprehensive Energy Consumption Assessment Model for Star-rated Hotels and the Difference Analysis

Recent years have witnessed a rapid development of star-rated hotels in China, especially high- end star-rated hotels. Consequently, there are now approximately12 000 hotels in China. One bottleneck within the industry is its huge energy consumption and carbon emissions, but the development of a comprehensive energy consumption assessment has lagged. Here, a comprehensive energy consumption and carbon emission model suitable for hospitality is established, using comprehensive data collected for hotels over six years and with reference to general international methods, decomposition analysis methods as recommended by the IPCC, and related standards in China. Our study shows that the maximum comparable unit energy consumption per building area among four- and five-star hotels is 73.26 kg ce m-2 y-l. Through energy-saving reconstruction, the comprehensive energy consumption of five-star hotels has declined by 4.1% in six years and is smaller than the advanced comparable value of 55 kg ce m2 y4. The comparable unit energy consumption per area building of most two- and three-star hotels （53 kg ce m2 y-l） is higher than the reasonable value. There are large numbers of hotels of this type in China and the potential energy savings are huge. Analyzing factors of energy consumption, we found that indirect carbon emissions from electricity usage are the most significant. From an energy consumption structural perspective, Heating, Ventilation and Air Conditioning （HVAC） System accounts for most energy consumption. This research provides a foundation for further examination of energy-savings, emission reduction plans and Monitoring Reporting Verification （MRV） in the hospitality sector.

Decomposition Analysis of Changes in Metropolitan Energy Consumption in China Based on the Logarithmic Mean Divisia Index

The energy consumption of China＇s metropolitan areas has expanded from production areas to other areas such as the service area,and characteristics differ across small and medium-sized cities.Using the Logarithmic Mean Divisia Index（LMDI） decomposition method,we conducted a factor decomposition analysis on changes in energy consumption for 32 Chinese metropolises from 1995–2012 that had a resident population of at least 1 million people in 1995.On the basis of a comprehensive consideration of urban economic growth,population expansion and spatial expansion,energy consumption factors can be decomposed into five indicators： economic scale,energy consumption per unit of output value,energy consumption per capita,population density and energy space support coefficient.We valued the contribution of each factor to metropolises＇ energy consumption to determine generality and regional differences.

Global Classical Solutions to Partially Dissipative Quasilinear Hyperbolic Systems with One Weakly Linearly Degenerate Characteristic

For a kind of partially dissipative quasilinear hyperbolic systems without Shizuta-Kawashima condition,in which all the characteristics,except a weakly linearly degenerate one,are involved in the dissipation,the global existence of H 2 classical solution to the Cauchy problem with small initial data is obtained.

Global Classical Solutions to Partially Dissipative Quasilinear Hyperbolic Systems

The author considers the Cauchy problem for quasilinear inhomogeneous hyperbolic systems.Under the assumption that the system is weakly dissipative,Hanouzet and Natalini established the global existence of smooth solutions for small initial data (in Arch.Rational Mech.Anal.,Vol.169,2003,pp.89-117).The aim of this paper is to give a completely different proof of this result with slightly different assumptions.

SPECTRAL GAP SOLUTIONS OF THE DISSIPATIVE KIRCHHOFF EQUATION

The author proves that for initial data in a set S ? (H2(?) ∩ H0(?)) × H0(?), 1 1 unbounded in H0(?) × L2(?), the solutions of the Cauchy-Dirichlet problem for the 1 dissipative Kirchho? equation Z ?t u ? ν + L 2 | x u|2dx xu + δ?tu = 0 (x ∈ ?, t > 0), ? are global in [0,+∞) and decay exponentially. The functions in S do not satisfy any additional regularity assumption, instead they must satisfy a condition relating their energy with the largest lacuna in their Fourier expansion. The larger is the lacuna the larger is the energy allowed.

Field observation of total dissolved gas supersaturation of high-dams

One of the possible negative environmental effects of hydropower stations is the supersaturation of total dissolved gas (TDG) downstream of high-dams,which can lead to gas bubble disease or even death of fish. By taking the TDG as the main study object,the paper launched the TDG field observations on Zipingpu,Three Gorges,Ertan,Manwan,Dachaoshan,Gongzui and Ertan dams in China. The factors affecting TDG generation and dissipation were explored. Energy dissipation structures,spill rates and operation patterns were the main factors causing TDG supersaturation. TDG saturations are essentially the same in the hydro-electric tail water and in the upper reaches,so hydro-electric tail water can be less TDG supersaturated through mixing downstream. The main factors affecting the dissipation process of the supersaturated TDG were tributary convergence,water depth and turbulence. TDG supersaturation was unevenly distributed in both the vertical and transverse directions. This study is important because it adds to the accumulating experience of TDG field observations of dam projects in China,and because it objectively and impartially evaluates the impacts of supersaturated TDG. The study also provides field data and references for future studies of TDG supersaturation caused by high-dams.