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In this paper, the solidification behaviors of hypoeutectic grey iron under different vacuum conditions in lost foam casting (LFC) were discussed by using thermal analysis method. In order to reveal unique solidification characteristics in LFC, green sand casting (GSC) is introduced as comprehensive study. To comprehensively investigate solidification process, several groups of continuous cooling curves were taken from the geometrical center of the different thickness section (from 5mm to 45mm) of the stepped test bar in practical pouring experiment for the above two processes. And the first derivative of these cooling curves and key temperature points were evaluated. In this paper, through more complete comparative analysis of cooling curves, vacuum environment in LFC would not only change the filling characteristics of melt, but also importantly effect on the further solidification of melts, thereby effect on solidification processes and structural feature of hypoeutectic grey iron.

A finite element model ships, for example design test condition of the underwater explosion, selection of explosive package quantity is 1000KG TNT, the explosive location along the direction of the ship with the bow, midship and stern, the angle of attack in three exploded cross section have 90 degrees, 60 degrees, 45 degrees, 30 degrees and 0 degrees. According to the current standard to calculate the ship damage radius, critical radius and safety radius of specific values under the effect of underwater explosion, interpolation calculation and draw the envelope. Analysis shows that the vitality of ships and shock-resistance is not only related to the explosive distance, also related to the attack position.

Hierarchical nanostructure Fe3O4/multi-walled carbon nanotubes (Fe3O4/MWCNTs) were prepared by solvothermal process using acid treated MWCNTs and iron acetylacetonate in ethylene glycol as reduction reagent. The materials were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET). The results showed that petal-like hierarchical Fe3O4 grew on MWCNTs and the Fe3O4 nanoparticles had diameters in the range of 55-110 nm. It was a facile approach to grow hierarchical nanoFe3O4.

Employability was the core of college graduates' successful employment influence factors. Based on the USEM model and selecting factors of college graduates' employability and adding latent variables of education resources, research established conceptual model of college graduates' employability. The results of 7 facts showed that the fit indicators of the model proposed by this research had high goodness-of-fit. Finally, the paper analyzed the practical significance of this model.

For EMC simulation, the vector fitting model is transformed into time domain state equation model. Then the system is balanced. Then the reduced model can be obtained by removing the states corresponding to the small HSV (Hankel Singular Values). The order of the reduced model is determined by the singular curvature spectrum. Finally, balanced truncation model reduction method is used on a sample chip PDN (Power Distribution Network) and compared with the performance of the AWE (Asymptotic Waveform Evaluation) method. Simulation results show that the proposed method can operate in a wide frequency range and has smaller error and faster speed.

In this paper, we propose a novel model of three points named TP for location estimation in wireless sensor networks (WSNs) with random deployment of anchor nodes. In this model, we select three anchor nodes which have the strongest received signal strength (RSS) for location estimation, the centroid algorithm and the method of intersection of judgment are used to estimate the location of unknown nodes. To further exploit three nearest intersection points in TP, the enhanced TP (ETP) is proposed. The simulation results show that the proposed models outperform MMSE and BML in terms of the localization accuracy for WSNs. Moreover, the localization accuracy of the proposed models in scenario 2 with random deployment of anchor nodes are better than in scenario 1 with planned deployment of anchor nodes. Additionally, compared with MMSE and BML, ETP and TP can reduce the environmental impact on location estimation.

Through the analysis and comparison of the results of static and dynamic performance testing of a series of laminated steel pieces isolators used in the vibration isolation of warships, in the number and thickness of laminated steel pieces of the same circumstances, laminated steel arc and preload of test samples had a certain impact on the values ​​of static stiffness, dynamic stiffness, damping ratio as well as dynamic and static stiffness ratio.

Shale gas is an important unconventional energy resource. However its only achieved successful commercial exploitation in the United States and Canada. Shale gas well QY1 was carried out in southeast Chongqing.Taking this well as a case, the fracturing design optimization workflow and its practice are described in this paper. The fracturing feasibility of well QY1 was firstly determined by referencing all the physical parameters of target formation. Then the reservoir stress model was revised and reservoir stress profile was established as well. The reservoir simulation software (Eclipse) was applied to build reservoir geological model for predicting the gas production and determine the optimized permeability enhanced area (PEA). The unconventional fracturing model (UFM) was used to optimize the fluid volume and fracturing scale. And the final fracturing plan was made based on the optimized conclusions. This optimization workflow and the good result provide reliable technique support for the development of the shale gas reservoir in this area. Key Words: Shale gas, PEA, Fracture propagation model, UFM, Production predicting model, Optimization

Room-temperature ionic liquids are new emerging green material. They have good chemical and thermal stability, negligible vapor pressure, nonflammability, high ionic conductivity, transparence, and a wide electrochemical window. So the ionic liquid material strongly tempts many researchers. But ionic liquids are usually applied in chemistry and rarely applied in physics. In fact ionic liquids are good photoelectric medium material owing to its well ionic conductivity, transparence. However, in applications, the drive of ionic liquids is the key technic and is also a bottle-neck. Here a kind of electromagnetic drive way is presented, There are not any mechanical moving elements and the drive is bidirectional. Theory and experiments indicate the drive pressure and flow rate are distinct undering a few voltages and 0.5T magnetic flux density. So this drive way can be used as a low power liquid pump. Latency applications in Microfluidics, Optoelectronics and industry are given.

With the development of electronic media and the demand of human, speech communication becomes more and more diversified and important. Face-to-face Speech Communication(FSC) is the most basic form and the flourishing of Electronic Speech Communication(ESC) indicates rejuvenation of oral tradition. This paper aims at demonstrating the similarities and differences between FSC and ESC through literature review and observation. FSC is highly dependent on communication environment while ESC depend upon other non-verbal symbols which determine communicator’s image; in terms of communication content, both of them are full of characteristics of oral language, but have significant differences in information code and language regulation; From the perspective of emotion interaction, FSC pays more attention to face-work while ESC focuses on confrontation performance to create exciting point.

For logic-based distributed fault-tolerant routings, livelock is a troublesome challenge. In this paper, we prove the sufficient conditions which make the fault-tolerant routing PR-WF [1] to be livelock-free. Due to the diversity of fault blocks, it is almost impossible to verify the sufficient condition of livelock-free by a formal method. In this paper, both visual analysis and enumerative simulation methods are taken to prove livelock theorems. In order to avoid livelock, an algorithm is presented to extend fault blocks. Experimental results show that, it has to disable no more than 1.8% no-faulty links to avoid livelock if the true faulty link rate is 10%.

In current study, Sarem, CNGA, Peng-Robinson, AGA8-92DC, BWRS state equations have been researched by analyzing the basic form and developing the numerical methods of compressibility factor. An attempt has been made to develop corresponding computer programs to calculate compressibility factor with these five state equations. The computed results have been compared with Standing-Katz chart. The results show the similar trends and good agreements

In this paper, the research of regeneration of waste EPDM has been done on the basis of a lot of reading of literature and collecting of information. It has neither the pollution of gas emission during the recycling of rubber in dynamic desulfurization tank under high temperature and pressure, nor the high energy consuming during the recycling of rubber using regenerant under normal temperature and pressure. Eventually, the regeneration of waste EPDM under low-temperature became a reality.

Crosstalk between high speed parallel bus signals is one of the most important signal integrity(SI) issues. In this article, a crosstalk simulation method based on full-wave scattering parameters extraction for transmission lines is researched. First, the coupling mechanism between transmission lines is analyzed using S-Parameter network theory and a fast frequency-domain method for crosstalk calculation is introduced. Then based on this method, some basic rules of crosstalk are studied in details and the method is validated by simulation results which agree well with those of RLGC model. At the end of this paper, a practical crosstalk simulation example between high speed data bus signals on a 8-layered printed circuit board is demonstrated step by step.

Liquidus temperature, electrical conductivity and phase composition of Al2O3-CaO-Na2CO3 slag were studied in the paper. The results showed that the minimum value of liquidus temperature was 1429°C when the content of Na2CO3 was 11%. The Al2O3-CaO-Na2CO3 slag of lower liquidus temperature had higher electrical conductivity, and the electrical conductivity of Al2O3-CaO-Na2CO3 slag increased with the increase of temperature. The main phases of Al2O3-CaO-Na2CO3 slag are composed of CaAl2O4, Ca3Al10O18, NaAlO2 and Na2CO3. The addition of Na2CO3 is to be more effective for decreasing liquidus temperature and increasing electrical conductivity in the Al2O3-CaO-Na2CO3 slag system.

Liquidus temperature, electrical conductivity and phase composition of Al2O3－CaO－SiO2－CaF2 System were studied. The results showed that the liquidus temperature of the slag decreased with increasing CaF2 content, and its electrical conductivity increased with increasing CaF2 content and temperature. When the content of CaF2 is 20%, the liquidus temperature is 1469°C. When the contents of CaF2 is 10%，its main phase compositions are composed of Ca5Al6O14、Al2Ca3(SiO4)3、Al2(SiF6)3 and Ca3Al10O18. Ca2AlF7、Ca2Al3O6F becomes more and more with increasing the content CaF2 because of F1- replacing O2- in molten slag.

In this thesis, a kind of jitter is focused on, which is called Native Jitter (NJ) of the Voltage Controlled Oscillator (VCO). The cause of NJ is the high order effect of the transistor itself in the VCO, and almost has no correlation with the control voltage or supply. The detailed analysis of the cause and the evaluation of this NJ is proposed in this paper, and an Inter-locked Dual-loop VCO (ID-VCO) is put forward, in which most of the NJ is eliminated. A test chip of the ID-VCO based on 0.18μm CMOS process is established. Compared with the classical single end VCO, the result shows that the peak to peak value and mean-root-square values of period jitter reduce 15.4% and 16.3%, the same values of cycle-to-cycle jitter reduce 9.82% and 6.98%, respectively.

Use the method of Numerical simulation to different operating parameters and structural parameters of blast air swirl burner . On the basis of it, several evaluation indicators of swirl burners were proposed.

Liquidus temperature, electrical conductivity and phase composition of Al2O3 -CaO-CaF2 slag system were studied. The results showed that the liquidus temperature of the slag decreased with increasing CaF2 content, and its electrical conductivity increased with increasing CaF2 content and temperature. The liquidus temperature is 1468°C when the content of CaF2 is 20%. Its phase composition are composed of CaAl2O4、Ca2Al3O6F、Ca2AlF7 andAlF3. When the content of CaF2 is 10%, there are lots of CaAl2O4. The content of CaAl2O4 decreased with increasing CaF2, but the content of Ca2Al3O6F and Ca2AlF7 increased.

The post-fire behavior of a set of ceramsite concrete filled steel tubes (note as CCST) after exposure to fire are experimentally studied. Effect of the maximum value of fire response temperatures of the tubes and their geometric parameters on the strength and ductility of the specimens were especially discussed. The test results show that the specimens of CCST have higher post-fire bearing capacity and better ductility, there was no obvious descent segment in post-fire load-displacement curves of the most specimens subjected to fire load. It was concluded that the maximum response temperature of specimens has great effect on the post-fire bearing capacity of concrete-filled steel tubes subjected to fire load.

A kind of FGD gypsum from Ningbo Beilun Power Plant of China and fly ash were used as the raw materials with which a complex cementing material was made. Effect of the related factors such as water proportion, mineral admixtures and chemical activators on characteristics of Hemi-hydrate FGD gypsum-fly ash complex cementing material is studied through a number of single factor experiments. The experimental results show that an appropriate amount of admixtures can effectively improve the strength of the Hemi-hydrate FGD gypsum–fly ash complex cementing material presented here. It is concluded that the strength of HFGD-FACM is best as the ratio of HFGD gypsum and fly ash is 1:1 and proper water aggregate proportion is 0.45~0.50.

The computational model of numerical analysis of a suspended pre-stressed steel reticulated shell subjected to fire load is established with using the software Marc. Based on the model presented here, numerical analysis of thermal response and structural response of the pre-stressed steel structure are computed for the key nodes of the structure. The different location of fire source and different space height are considered for analysis of response temperature, displacements and stresses of the pre-stressed lattice shell. It is shown that the air temperatures was much higher than the response temperatures of the nodes of the lattice shell during a quite period of time after a fire takes place, and the temperature of the cable nodes are also less than the air temperature near the nodes. It is also concluded that displacement of the node right above the inner cable is the maximum among the four nodes as the fire source is located at the position under the middle cable.

With the development of network in the society, internet surfing has already become one of the unprecedented living styles for people, especially for youth. However, this kind of living style puts youth in the dilemma between "center and border", "self and others", "unreality and reality", "tradition and rebellion", "creation and destroy", "role and game" and so on. Only when youth handle those relations correctly can they live a colorful and wonderful life.

The computational model of numerical analysis of a suspended pre-stressed steel reticulated shell subjected to fire load is established with using the software Marc. Based on the model presented here, numerical analysis of thermal response and structural response of the pre-stressed steel structure are computed. The different space height and different rise-span ratio are considered for analysis of response temperature, displacements and stresses of the pre-stressed lattice shell under fire for one fire source. It is also shown that displacement of the node right above the inner cable is the maximum among the four nodes presented here as the fire source is located at the position right below the second-ring cable of the structure. It is concluded that the influence degree of space height of the structure on the fire response of the structure is not great, but rise-span ratio has obvious and great effect on displacements and stresses of the pre-stressed steel structure with large span in fire.

Numerical analysis of thermal response and structural response of a suspended pre-stressed steel reticulated lattice shell are conducted for the key nodes of the structure of a gymnasium on software FDS. Two different location of fire source are considered for analysis of response displacements and stresses of the nodes of the pre-stressed lattice shell and three cables. It is shown that the response temperatures of three cables set in the structure have similar variation trend for the fire scene presented here and the fire temperature near inner cable is highest among the three cables. It is concluded that the shell element of center of the structure has largest response stress, and the element above the side cable has larger stress than the shell element above the middle cable when the fire source is located at center of the gymnasium. It is shown that decrease of the pre-stress of the outer cable far away from the fire source is smallest among the three cables set in the structure.

The numerical model for analysis of fire behavior of the spatial pre-stressed steel structure is established based on the software Marc. Analysis of thermal response and structural response of a suspended pre-stressed steel reticulated lattice shell are computed for the key nodes of the structure. For comparison, the air temperatures near the key nodes are also calculated based on the practical formula of large space air temperature rise. The different location of fire source is considered for analysis of response temperature, displacements and stresses of the nodes of the pre-stressed lattice shell. It is shown that the air temperatures obtained from the practical formula was always higher than the response temperatures of the nodes of the lattice shell during a quite long time after a fire takes place. The results show that the displacement of the node near the center of the gymnasium in fire is close to that of the node right above the inner cable, and the displacement of the node right above the outer cable is much less than the result of the center node.

For high power density diesel engine operating characteristics and its unique compact structure, the development of new high power density diesel engine oil referred to the latest diesel engine oil standard GB 11122-2006. Through the comprehensive assessment of physical and chemical properties, the composite of poly a-olefin (PAO) and polymer esters was determined as base oil,and added high-performance additives. This oil developed has clean dispersion, antioxidation, anti-wear , anti-corrosion and other properties. the lubricating oil can well satisfy the performance requirements of high power density diesel engine.

In order to study the fire behavior of the profiled sheet-ceramsite concrete composite floor subjected to fire load, research on fire response and post-fire bearing capacity of a profiled sheet-ceramsite concrete composite floor subjected to dead load, which has no shearing nails, is carried out here through experiment. Based on the experimental results, the fire behavior and post-fire bearing capacity of the floor after exposure to fire are analyzed. It is shown that the failure form of the profiled sheet-ceramsite concrete composite floor after exposure to fire has obvious change compared with the floor not subjected to fire load, but the composite floor subjected to fire still exhibits higher bending capacity, and the ultimate value of the equivalent distributed load is up to 35kN/m2, which may be used as basis of strengthening and repairing of the profiled sheet-ceramsite concrete composite floor after exposure to fire.

In order to study the fire-resistance behavior of the spatial pre-stressed steel structures with large span, the model of numerical analysis of a suspended pre-stressed steel reticulated shell subjected to fire load is established with using the software Marc. Based on the model presented here, numerical analysis of thermal response and structural response of the pre-stressed steel structure are computed for the key nodes of the structure. For comparison, the air temperatures near the key nodes are also calculated based on the practical formula of large space air temperature rise. The different location of fire source is considered for analysis of response temperature, displacements and stresses of the nodes of the pre-stressed lattice shell. It is shown that the air temperatures was much higher than the response temperatures of the nodes of the lattice shell during a quite period of time after a fire takes place, and the temperature of the cable nodes are also less than the air temperature near the nodes. It is also concluded that not the cable nearest the fire source but the other cables around the cable fail to work first in the fire.

Mechanical behavior of a set of ordinary concrete filled steel tubular short column (note as NCSSC) and ceramsite concrete filled steel tubular short column (note as CCSSC) subjected to fire load are experimentally investigated. Effect of the parameters, such as the maximum value of fire temperatures, fire duration on the strength and ductility of the two types of specimens were especially discussed. The test results show that both of the specimens of NCSSC and CCSSC have higher post-fire bearing capacity and better ductility, there was no descent segment in post-fire load-displacement curves of the most specimens subjected to fire load. It was concluded that the maximum response temperature of specimens and fire duration time has great effect on the axial bearing capacity of concrete-filled steel tubular short columns subjected to fire. The maximum longitudinal strain of specimens of CCSSC is less than the corresponding value of the longitudinal strain of NCSSC.

The fire experiment was conducted for three of circular steel tubes protected with two different gypsum fireproof panel and the steel tube without any protective material. The fire response temperature of surface of steel tubes was measured and the axial compressive bearing capacity of the specimens after fire were tested and analyzed. The test results show that gypsum fireproof panel has better fire protection characteristics. It is noted that the variation of temperatures of inner surface of gypsum fireproof panel under fire is consistent with the temperature of outer surface of the steel tube. The maximum difference of temperature between the outer surface of the tube and the furnace space is 150°C as the fire keeps stable for the steel tube without any protection. It is concluded that two of the specimens protected with gypsum fireproof panel have larger post-fire capacity, which means that the gypsum fireproof panel has better effect on fireproof of the steel tube under fire.