With the development of the technologies on modern photoelectron and computer technologies and the improvement on theory of digital image processing, Digital Speckle Correlation Method (DSCM) is rapidly emerging as a powerful research tool for experimental mechanics techniques. In this paper, the essential principle of DSCM is introduced and the applications of DSCM to wood science and technology, including the latest results of the test on general mechanical properties, fracture properties, micro-structural mechanical properties and the mechanical properties of wood and wood composite materials, are reviewed. Considering the characteristics of wood materials, some suggestions are proposed on the application of DSCM to wood science and technology.
Qian Xuesen made initiative theoretic contributions to architectural science in 5 aspects： the theory for positioning architectural science; the theory for positioning architectural philosophy; the theory on the establishment of Chinese landscape architecture; the theory on the establishment of urbanology; the theory for building “shan-shui city” .Studying deepening and perfecting Qian´s these theories are of momentous importance for the development of China´s architectural science
The substance of eco-province, eco-city and eco-county construction is raising the ability of a area^ sustainable development, mainly including three aspects： eco-economy, eco-environment and eco-society. The standards prescribed in this article basically reflect the constructing status and development potential in these respects. The standard of eco province is composed of 5 basic conditions and 22 examination indexes in 2 grades; Standard of eco-city is composed of 5 basic conditions and 30 examination indexes in 2 grades; Standard of eco-county is composed of 5 basic conditions and 38 examination indexes in 2 grades. They are applicable to the examination standards for eco-province, -cty and -county constructions on different scales and in different regions and can also be used as the guide and target in the construction of eco-provinces, -citise and-counties.
The history and the actualities of developing earth-penetrating weapon are described. The fighting assemblies with penetrator have been applied in accurate guided weapons widely. The technical difficulties for developing low-yield earth-penetrating nuclear weapons have not been primary obstacle. The experimental technique of gas gun and its applications in earth-penetrating weapon tests are introduced. The experimental results indicate that there is a favorable analogical relation among earth-penetrating events, but there are many essential differences between penetrating phenomena of concrete and of granite. A method for calculating profiles on acceleration, velocity and displacement of penetrating projectile upon penetrating depth data is introduced.
Yanshan Petrochemical Company after having expanded its 300 kt/a steam cracking unit to 450kt/k in 1994 is still experiencing such problems as low feedstock flexibility, high energy consumption and smaller scale as compared to other ethylene units constructed in the same time. In order to fully improve technical capability of steam crackers, reduce energy consumption, improve feedstock flexibility and increase production capacity, a lot of technical revamp cases on steam cracking were studied and compared with attention focused on the feasibility, safety, operability of the related revamp cases, as well as the advanced nature and economical features of the cases studied. As regards the pyrolysis-quench-compression system, the steam crackers will be retrofitted on the site with the pyrolysis gasoline fractionation tower, quench water tower, pyrolysis gas compressor and steam turbine replaced by new ones, respectively. The separation system will adopt a low-pressure methane removal technology with the demathanizer tower replaced, coupled with the C3 catalytic rectification/hydrogenation technology, while the high-pressure depentanizer will be replaced with the addition of a propylene rectification tower. The fractionation flow sheet and equipment will be adjusted with the addition of a propylene compressor and compressor for binary mixture of methane-ethylene cooling agents. This revamp has expanded the ethylene capacity to the target of 660 kt/a with the actual capacity reaching 710 kt/a. This revamp project has remarkably reduced the energy consumption, which is capable of using naphtha, light diesel fuel, heavy diesel fuel and the hydrocracked tail oil as the steam cracking feedstock. This project is the first to apply refrigeration by means of a mixed ccx)ling agent and has succeeded in using C3 catalytic rectification/ hydrogenation technology, which has given an impetus to the progress of steam cracking industry in the world.
The evolution of coherent structures in the wall region of a turbulent boundary layer under adverse pressure gradients was studied by using DNS method. The motions of the second and the fourth quadrant were analyzed. The results show that to the shear stress, the contribution of sweep motions is stronger than that of ejections under adverse pressure gradient. And the sweeps contribute to the transport of shear-stress and kinetic energy of turbulence more strongly than the ejections under adverse pressure gradient.
With the architectonic development, steel structure is used in more and more architectures. Because of the bad fire performance of steel structure, collapse may occur. In the American 911 accidents, the fire caused by airplane crash led to collapse of WTC, mass and personnel loss is huge. Therefore researches of building collapse caused by fire are very necessary. The absence of knowledge regarding fire dynamics linked to the fact that fire can be considered a random phenomenon has led to general use of prescriptive fire regulations all over the world. This paper mainly introduces the research on collapse probability of building.
According to statistical theory and characteristics of building fire, the probability distribution functions of fire load and the fire duration time of office buildings are presented. The influencing factors to the building collapse under the condition of fire are studied. Based on the fire statistic results, fire dynamical theory and characteristics of building fire, an evaluation method of the collapse probability of building caused by fire is developed in this paper.
The path-planning algorithm of AUV in 3D seabed environment is studied. For 3D environment, the optimal paths are classified into three different types. The optimal paths of each type are obtained flexibly by using genetic algorithm, especially the incorporating of problem-specific knowledge and penalty function. Simulation results show the feasibility and reliability of the path-planning algorithm, which has considerable value on the safe navigation of AUV in seabed environment.
Let G be a simple graph, δ and a be minimum degree and independence number of G, respectively, Faudree et al showed, in 1991, the Hamiltonian result with condition | N(x)∪ N(y) | ≥n-8. In 1993, Chen further considered the Hamiltonian with condition max |d{x) , d(y)| n/2 for each pair of non-adjacent vertices x , y with 1≤|N(x)∩NV(y)|≤a-l. In this paper a sufficient condition for a graph to be Hamiltonian graph is shown and the following result is obtained ： let G be a 2-connected graph of order n , if| N(x) U N(y) |≥ n-δ-1 for each pair of non-adjacent vertices x, y with 1≤ | N(x)∩ N(y) |α-1, then G is Hamiltonian or G∈{K(n-1)/2, (n + 1)/2, K2* V3K(n-2)/3}，This result generalizes some results in Hamiltonian graphs .
Xiluodu hydroelectric plant is the biggest plant to be built on Jinsha River, and also, Xiluodu project is the biggest hydraulic engineering in China except Three George Project. To intuitively and accurately describe the complex and dynamic spatial relationship among all sides interfered in construction layout design of Xi Luodu project, the construction layout system is divided into 6 subsystems： dam construction, diversion and enclosure construction, dynamic water flow, underground structure construction, quarry stacking and redigging, and road and traffic inside construction site, and the research on 3D dynamic visual graphic simulation for construction layout of the designed whole construction process is developed. Flow of the 3D dynamic graphic simulation data is designed. Dynamic graphic simulation data can be divided into graphic data and attribute data, which organized based on GIS, then, 3D dynamic visual digital model for construction layout is built, which itself is an important part of digital hydraulic engineering. 3D dynamic visual graphic simulation demonstration and visual inquiry of dynamic graphic simulation data are realized with this digital model. Practical engineering application shows that a scientific and intuitive visualization analysis way is provided. for construction layout design and decision-making by this research, moreover, hydroelectric design work will be promoted to develop in an intellective and modern way, and the research is worth to be spread.
A high dam with 185 meter above sea level will be built for the Three Gorges reservoir, which will accommodate water of 39.3 billion cubic meters in maximum and its impoundment will reach up to 175 meters in height. The local stress status, medium propriety and regional stress field in and around the reservoir will vary with the impounding and water fluctuation in the reservoir which will probably induce seismicity. In order to detect crustal deformation, tectonic fault displacement, sink of reservoir basin in the area and reservoir-induced seismicity, a monitoring system is set up. The paper introduces the study on monitoring in Three Gorges, of the Yangtze River.
A description method of part information and manufacturing resources information based on the ontology´s concept is introduced. The attributes of part noumenon and feature noumenon are described. The relationships among noumena and their attributes are analyzed. Finally, the practicality of the description method is demonstrated in the CAPP system.
The phase Ⅲ RCC cofferdam construction belongs to the phase Ⅲ diversion works. It is a key item to ensure achievement of the reservoir impoundment, navigation and power generation in 2003 and the guarantee to the safety construction of the follow-up right-bank intake dam section and the powerhouse. Restrained by navigation while construction, the construction site and duration, both the concreting intensity and the rise height of the phase Ⅲ RCC cofferdam exceed the current construction level. In view of these difficulties, a huge amount of research work has been performed by relevant departments and is described in the paper.
The conflict among population, resource and environment requires the manufacturing to develop environmental management strategies. The green supply chain management (GSCM) is an effective way to solve the problem. The concept mcxlel of green supply chain is constructed, and strategic objects of green supply chain management are analyzed based on sustainable development theory. The basic principles of green supply chain management are discussed, which include the intergrowth theory, the cycle theory, the switchover theory and the open system theory.
This paper draws real questions on technological innovation from major engineering practices in China, proposes that innovation is the basic motive force of the development of science and technology. The authors bring out the basic principles of safeguarding technological innovation, propose the new thinking to encourage innovation and the suggestions to reform appraisal regulations and so on.