Though not all active faults will generate strong earthquake, people still turn pale at only mention of them. Strong earthquake will take place only on a fraction of the active faults in a time scale as long as tens or hundreds of years, so we call them the macroseism generating fault. The macroseism generating fault is not merely a line but has a certain width from several meters to tens or hundreds of meters or more. During a strong earthquake, the seismic intensity may increase abruptly by 2 to 3 or more degrees along the fault, so it brings forth much difficulty to anti-seismic design, or nearly makes the design impossible. Off the fault, the seismic peak ground acceleration decreases with distance. In anti-seismic design, the commonly-used seismic ground motion parameters(or the seismic intensity)often have a bigger anti-seismic potential, e.g. a building with a design acceleration of 0. 15g(intensity Ⅶ°)may actually resist a damage of 0. 5g(Ⅸ°). The discovery of macroseism generating fault enables us to deal with the three factors, i.e. the time, location and magnitude, of earthquake prediction from another aspect. When using the"ground motion parameter zoning map" in urban planning, correction and amendment are necessary as for whether or not the macroseism generating fault exists and its influences.
What is discussed here is that the earthquake precursor have their own physical model, which is divided into the load stage, the stage of stalemate, the unload stage, the short stage before occurrence and the quake stage. Up till now, numerous earthquakes that occurred worldwide have proved that the quake-breeding physical model of destructive earthquakes may repeat and reappear. An analytic method is brought forward for tracing the information on the warning signs of an earthquake and predicting earthquakes step by step. Also, earthquake prediction is preactically divided into stages, making it possible to realize the predicting of destructive earthquakes.
This paper contains a brief introduction of the development of the steel bridges at home and abroad. It also introduces the characteristic requiremens of the material used in steel bridges.
his thesis thinks that traditional Chinese medicine is a great treasure house. First, it expounds that the creams of traditional Chinese medicine are rarities of traditional Chinese culture, and traditional Chinese medicine contributes a lot to the multiplication and prosperousness of the Chinese nation. Then, it clarifies the basic characteristics of traditional Chinese medicine. Finally, it points out the way of learning widely from others'strong points and synthesizing innovation for establishing new form medicine system.
Gear preforming by cross wedge rolling is an original question for discussion, parameters such as deformation, temperature field and mechanical performance are looking forward to be researched. This paper ties the advantages of preforming by CWR and the principle of generated gear together, and the die suited for gear rolling has been designed. Based on the finite deformation theory, the coupled thermal-mechanical constitutive model of gear rolling by CWR has been established. Then FEM simulation for the forming process has been developed in MSC. SuperForm, and information gained from the simulation has been analyzed also in detail which provide references for further study of gear rolling by CWR technology.
Based on the developing demand of spacecraft thermal control and thermal management, basic design schemes and analysis models for maintaining thermal control/thermal management system's reliability are developed through classifying and reviewing of common spacecraft thermal systems and devices. Examples are given to show the application patterns and methods of the reliability design schemes and analysis models, which provide a fundamental tool for advanced design and analysis for the reliability of spacecraft thermal control and thermal management system.
In the construction projects invested by Chinese government, the owners are often affected by their personal preference such as taste standpoint or individual achievement when they are making decisions. At the same time, the designer caters to the owner's pleasure for the sake of benefit. As a result, there are too many"face projects" , "achievement projects" in China`s cities. The principal-agent model is used in this article to analyze the change of owners`investment benefit and designers' effort under law-abiding and speculation conditions. It is concluded that the speculation activities can be efficiently reduced by strengthening supervision power and increasing the owners' and the designers' political risk cost.
The fault of wheelset bearing is one of the most important factors which is deangerous to the satfy of the train running. And the key problem that should be solved firstly is the accur ate measurement method for the high speed heavy haul locomotive. Since there are some discontinuity points in the amplitude of the vibration signals when the wheelset bearing is abnormal, a method for analyzing the vibration acceleration signals which come from the wheelset bearing by using the spectrum zoom is prsented. The experiments indicate that the abnormity of wheelset bearing high-accuracy detection can be realized by using this method, and this method can detect the abnormity effectively compared to the commonly used methods.
This paper puts forward a novel image edge detection method based on uniform B-spline with shape parameter by modifying profit and loss data. The original image intensity is modified for decreasing the residual error between smooth image and original image. A smooth surface of the digital image is presented by the new modified data. The edge point is detected by either computing the local extreme of the directional derivative or computing zero crossing of the second order directional derivative of the smooth surface. Experiments demonstrate that this algorithm is simple, accurate and reliable. It can wipe off the bogus edge commendably and process the digital image in real time.
The characteristics of concrete-filled steel bridge piers were presented briefly in the paper. The status of application and research on concrete-filled steel bridge piers was summarized. The prospects of application and changing of its structural type of concrete-filled steel bridge piers were predicted. Order to promote future application and research of the new-style piers for bridge structures in China.
In this paper a new style of polymerase chain reaction(PCR)equipment is studied and the goal of the study is to reduce the cost of micro-reactor PCR chips, improve its reliability and make a hundred of chips working together in the same time. There are no micro-sensors and micro-heaters in the chips. It is the concrete way to reduce the cost of PCR chips and improve the reliability of the chips. So the focus of the study transfers from the design, simulation and processing to the measurement and control of the chips. The measurement and control scheme for the low-cost PCR chips is designed. By selecting several chips as model chips and combining unitized macroscopic control and distributed microcosmic control, the system is able to do temperature cycling control to the chip array which is made of many chips at the same time. The loading effect applied to the temperature field by the temperature sensor and the compensation method for the loading effect are studied. The main idea of this method is to compare the measurement result gained from the temperature field in which two sensors are set with the measurement result gained from the same temperature field but in which one sensor is set, and the difference is the loading effect that one sensor applies to the temperature field. The temperature measurement errors to the liquid internal the model chips are analyzed and synthesized in considerable detail and an intelligent prediction compensation method for dynamic measurement errors is obtained. The uncertainty of indirect to the temperature of PCR liquid in low-cost PCR chips is also assessed. Cascade control strategy is applied to further improving the performance of control system. Its performance in temperature cycling meets the requirements of PCR.
Learning curve is one character function that improves output by the experience accumulation of producer. Learning curve can be used to establish scientific cost plan, improve shop flow scheduling, labor quota and plan, quality, and so on. This paper reviews the research literatures, introduces different forms of learning curve, analyzes their characters, and discusses the future directions of application of learning curve.
Bone marrow mesenchymal stem cells (BMMSCs) were separated by density gradient centrifugation and purified by different adherence speed. BMMSC was identified by flow cytometry analysis and laser confocal microscopy. Cell surface antigen (CSA) CD29, CD44, CD105, CD166 were detected positive expression and CD14, CD34, CD45 were not positive. The positive expression of the nestin, NST, and weakly positive expression of Oct-4 were confirmed by RT-PCR. The cells were verified as the BMMSC by the expression of the CSA and the genes. Using density gradient separation and different adherence speed could harvest high quality BMMSC. This is a simple and reliable method to obtain BMMSC as stem cell used in cell and tissue engineering research.