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   Science & Technology Review
2010, Vol.28, No. 11
13 June 2010

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Life Phenomenon: An Ever Widening Frontier for Physical, Mathematical, and Computational Sciences

Science & Technology Review. 2010, 28 (11): 3-3. ;  doi:
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Abstract ( 298 )
特别栏目

Science & Technology Review. 2010, 28 (11): 8-8. ;  doi:
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Abstract ( 257 )

Science & Technology Review. 2010, 28 (11): 10-10. ;  doi:
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Abstract ( 289 )

Science & Technology Review. 2010, 28 (11): 12-13. ;  doi:
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Science & Technology Review. 2010, 28 (11): 14-15. ;  doi:
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Science & Technology Review. 2010, 28 (11): 16-17. ;  doi:
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Science & Technology Review. 2010, 28 (11): 125-125. ;  doi:
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Science & Technology Review. 2010, 28 (11): 138-138. ;  doi:
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Science & Technology Review. 2010, 28 (11): 139-139. ;  doi:
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Abstract ( 269 )
封面图片说明

Science & Technology Review. 2010, 28 (11): 8-8. ;  doi:
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Abstract ( 302 )
半月科技风云

Science & Technology Review. 2010, 28 (11): 9-9. ;  doi:
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Abstract ( 314 )
科技事件

Science & Technology Review. 2010, 28 (11): 11-11. ;  doi:
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Abstract ( 302 )
科技工作者建议

Science & Technology Review. 2010, 28 (11): 18-18. ;  doi:
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Abstract ( 380 )
Articles

Calculations of Total Radioactivity Inventory in HTR-PM Reactor Core

Science & Technology Review. 2010, 28 (11): 19-23. ;  doi:
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Abstract ( 430 )
As a new and advanced reactor system of nuclear power plants, the high temperature gas-cooled reactor has received more and more attention for its advantages in enhanced safety and highly economical and modular structure. In China, the first model power plant of the High Temperature Gas-cooled reactor (HTR-PM) is started its construction at Shidao Bay, Rongcheng, Shandong Province. This paper presents calculations of the total radioactivity inventory of HTR-PM core and the analysis of the environmental impact of the plant, using KORIGEN code. Some segments of the code were recompiled to consider the change of spectral indices in input data which reflects the realistic neutron situation in the reactor core. The half-life data of isotopes are updated and corrected. A reasonable flow-line model is built. Finally, the total inventory of radioactivity in HTR-PM reactor core is obtained, which approaches the actual one to provide a basis for safety analysis and management of HTR-PM, and for accounting of nuclear elements.

Fault Detection and Reconstruction for a Nonlinear System Based on Sliding Mode Observers

Science & Technology Review. 2010, 28 (11): 24-28. ;  doi:
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Abstract ( 412 )
With the expansion of control systems in scale, the possibility of fault is getting high. The security and reliability of a control system becomes a key issue. So far, the fault diagnosis for linear systems sees many successes, but that for a nonlinear system remains a difficult problem. The traditional fault diagnosis method based on state observer can not effectively used for nonlinear systems; and its robustness of the diagnosis and localization can not be well ensured when a system has uncertainties and disturbances. In this paper, for the sensor fault diagnosis and for nonlinear systems, a method for fault detection and reconstruction based on sliding mode observers is proposed. The sensors fault is first augmented into actuator faults by introducing integral variants. Then a sliding mode observer is constructed for the augmented system. The stability of the sliding observers is proven by using the Lyapunov stability theory. Finally, the observers are designed by solving the Linear Matrix Inequalities (LMI) and the sensor faults can be reconstructed directly. Numerical simulation shows the effectiveness and accuracy of the reconstruction of the sensor faults using the proposed approach.

Hardware-in-the-Loop Design of Testing and Maintenance Training for a Certain Type of Missile

Science & Technology Review. 2010, 28 (11): 29-32. ;  doi:
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Abstract ( 1222 )
For the testing and maintenance training concerning a certain type of missile equipment, this paper proposes an overall scheme for a hardware-in-the-loop simulation, designs a hardware-in-the-loop simulation adapter based on C8051F040 MCU, and presents the hardware structure and software flowchart of the adapter, including the signal acquisition and serial port communication. A testing and maintenance operation process model is also built based on the extended Petri net, and is implemented by using virtual reality technology. The software structure and the detailed flowchart of the process model are given, for the virtual testing and maintenance environment. As a part of the testing and maintenance simulation training system, in the design of the hardware-in-the-loop simulation, the testing and maintenance object is added to the virtual testing and maintenance environment to improve the fidelity of the simulation training system and to solve the practical training problems at the same time.

A Background Model and the Method of Removing Camera Shake Effects Based on Edge Features

Science & Technology Review. 2010, 28 (11): 33-38. ;  doi:
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Abstract ( 486 )
Outdoor surveillance systems would be subjected to illumination changes and camera shakes to cause changes in the background. This paper proposes a background model and a method of removing camera shake effects based on edge features. The edge features of the background are handy to have a representation of the scene background invariant to illumination changes. Firstly, reliable background edges are extracted by edge detection algorithms from a video sequence. Secondly, the Gaussian Mixture Model (GMM) is employed in the regions near the background edges, while the Temporal Average Model (TAM) is used for other regions. Both the detection accuracy and speed are considered. Finally, to eliminate the false target caused by camera shakes, a method using the reliable background edges is proposed. A background update mechanism is also used. The experiment results show that the detection speed is increased by 50% than the GMM method. The detection accuracy is better than the TAM method. The advantages of the GMM and TAM methods are well combined in the new method. When the camera is shaking, the false alarm rate is reduced by using background edge features. Good detection results are obtained as compared to the GMM and TAM methods. The method can be used for moving object detection in complex scenes.

Disordered Immune-endocrin Network in Hepatocirrhosis Phase of Hepatocarcinoma of Carrying Abnormal Savda Model

Science & Technology Review. 2010, 28 (11): 39-42. ;  doi:
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Abstract ( 448 )

According to the theory of Uighur traditional medicine, male wistar rats were fed with a diet of cold-nature under cool dry environment, stimulated with chronic and interrupted electric foot shocks to establish abnormal savda syndrome rat model in Uighur medicine in three weeks. DEN was used further to establish hepatocarcinoma carrying abnormal savda disease animal model till the hepatocirrhosis occurred. The alterations of IL-1β, IL-6, TNF-α, ACTH and CORT in serum level were monitored. The results show that compared with the normal group the serum levels of IL-1β, IL-6 and TNF-α in the abnormal savda syndrome model group were increased (for IL-1β, P<0.01; for IL-6 and TNF-α, P<0.001); compared with the model control group the serum levels of IL-6 and TNF-α in the abnormal savda syndrome model group were increased (P<0.01); compared with the normal group the serum levels of ACTH and CORT in the model control group, the abnormal savda disease group and the abnormal savda syndrome model group were all increased, with significant mathematical differences, compared with the model control group the serum level of ACTH in the abnormal savda syndrome model group was significantly increased (P<0.05). These findings indicate that the immune-endocrin network was disordered in hepatocirrhosis phase of hepatocarcinoma carrying abnormal savda model. In the process of pathological changes of hepatic tissue in hepatocarcinoma carrying abnormal savda model, DEN is the main induction agent, and abnormal savda hilit is the accelerative factor. In addition, the abnormal savda, disordered immune-endocrin network and DEN are closely related and stimulated with each other.

Effects of Low Intensity Pulsed Ultrasound on Prevention of Disused Osteoporosis

Science & Technology Review. 2010, 28 (11): 43-46. ;  doi:
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Abstract ( 422 )
This paper studies the therapeutic effects of Low-Intensity Pulsed Ultrasound (LIPU) on prevention of disused osteoporosis, by testing on tenotomy and neurectomy rats. A total of 40 male Sprague-Dawley rats were randomly assigned into four groups, each with 10 animals. They are tenotomy groups, which underwent left patellar-tenotomy, with/without ultrasound treatment and neurectomy groups, which underwent left sciatic-neurectomy, with/without ultrasound treatment. The ultrasound treatment groups were treated with 30mW/cm2 pulsed low-intensity ultrasound stimulation for 15 minutes a day on the lateral site of the left legs. The sham ultrasound groups (those without ultrasound treatment) did not receive any ultrasound treatment. All animals were euthanized after 4 weeks. Both tibias of rats were prepared for peripheral Quantitative Computed Tomography (pQCT). Average Bone Mineral Density (aBMD) was measured. For the study of bone histomorphometry of proximal tibia, trabecular bone morphometry measurements were performed on the area beginning 1mm proximal to the growth plate (epiphysis). Total tissue area, trabecular area, and perimeter were measured. These endpoints were used to calculate the trabecular bone volume (BV/TV, %), trabecular width (Tb. Wi, μm), trabecular number (Tb. N, mm) and trabecular separation (Tb. Sp, μm) according to the methods of Parfitt et al. Statistical analysis was performed by using SPSS 11.5 data analysis software. All data were expressed as the mean±SD, and difference were considered significant if P<0.05. The decrease of aBMD in the operated tibia versus non-operated tibia was 16%, and that was 17% in the neurotomy group. In ultrasound groups, aBMD did not decrease significantly in tenotomy group (P>0.05). But difference was found between operated and non-operated tibia in neurotomy group (0.01<P<0.05). Moreover, in neurotomy groups, difference was found in bone loss percentage change between groups with and without ultrasound treatment. There was no difference in tenotomy group. In neurotomy groups, BV/TV of operated tibia decreased significantly for ultrasound group as compared with the group without ultrasound treatment (P<0.01). There were also differences between operated and non-operated tibia in Tb. Wi, Tb. Sp between groups with and without ultrasound treatment (0.01<P<0.05). In tenotomy groups, there was only difference in BV/TV between operated and non-operated tibia in groups without ultrasound treatment. The study confirms the effect of LIPU on the prevention of the bone loss in disuse osteoporosis, especially in the disuse model without nerve injury. And the nerve distributed in the tissue may play an important role. The mechanism of the nerves acting on the bone growth needs further investigation.

Effects of Thymosin on Serum Hormone Levels in Female Mice of Different Ages (Months)

Science & Technology Review. 2010, 28 (11): 47-50. ;  doi:
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Abstract ( 1114 )
After 30 days' subcutaneous injection of different doses of thymosin into the female mice of different ages (1 month, 3 months), serum hormone levels of Follicle-Stimulating Hormone (FSH), Estradiol-2 (E2), Thyroid-Stimulating Hormone (TSH) and Insulin (INS) were detected to determine the effects of thymosin. The results show that for 1 month mice with different doses of thymosin, FSH and E2 levels are decreased significantly or very significantly(P<0.05, P<0.01), TSH levels are increased significantly or very significantly(P<0.05, P<0.01), INS levels are decreased, and high dose thymosin makes a significant difference in INS(P<0.05). For 3 month mice with different doses of thymosin, FSH levels are decreased and high dose thymosin makes a very significant difference in FSH(P<0.01), TSH levels are increased and high dose thymosin makes a significant difference in TSH(P<0.05). E2 and INS levels are decreased with no significant difference. It is concluded that thymosion influences female mice's serum hormone level, which in turn affects its endocrine system.

Comparative Analysis of Trace Elements in Mentally Retarded Children and Normal Children

Science & Technology Review. 2010, 28 (11): 51-53. ;  doi:
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Abstract ( 1199 )
Trace elements are essential for human growth. On the other hand, an excess of some elements can be toxic, leading to disturbances in human growth. Altered trace elements concentration influences the biological growth, leading to changes in the structure of macromolecules, the permeability of cell membranes etc. Mental retardation is one such disease, which can be congenital or acquired. This paper investigates the relationship between the contents of trace elements Zn, Pb, Cu, Fe and the intelligence quotient of the child. By means of atomic absorption spectrometry, the trace element contents in hair and blood of 100 normal and 100 mentally retarded children were determined. These children had no record of chronic or hereditary diseases and are of the age between 5 to 10 years. None of these children had any significant environmental or occupational exposure to metals. It is shown that the contents of Cu, Zn in the hair of normal children are significantly higher than those in mentally retarded children. The content of Fe sees no significant difference. However, the content of Pb in the hair of normal children is significantly lower than that in mentally retarded children. So, the lack of essential trace elements or the excess of toxic metallic elements will effect the development of children's brain and intelligence quotient.

Feasibility Study of Carbonyl Iron Powder as a Novel Mediator of Arterial Embolization Hyperthermia for Liver Cancer Treatment

Science & Technology Review. 2010, 28 (11): 54-58. ;  doi:
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Abstract ( 412 )
This paper explores the feasibility of carbonyl iron powder to be used as a novel mediator of arterial embolization hyperthermia. Based on in vitro morphology study, the particle diameter distribution of the carbonyl iron powder is measured by laser light scattering with particle size analyzer, and the morphology of these particles is observed by Scanning Electron Microscopy(SEM). Mouse fibroblast L-929 cells are cultured in the medium of extraction of carbonyl iron powder. The cytotoxicity is graded by the generally accepted standard. In in vitro heating experiment, different doses of carbonyl iron powder/Lipiodol suspension are heated in an alternating magnetic field. The influences of the doses of suspension and the magnetic field are observed. As animal models, the normal New Zealand half lop rabbits are treated with arterial embolization hyperthermia by using the suspension. Cytotoxicity study demonstrates that Carbonyl Iron Powder (CIP) shows good biocompatibility. The heating profiles of in vitro and in vivo experiments reveal that CIP possesses the ideal property with inductive heating characteristics under the alternative magnetic field and it does not affect the normal temperature of animal models. These findings suggest that CIP is a very promising mediator candidate of arterial embolization hyperthermia for clinical applications.

B-ultrasound Image Registration of HIFU Monitoring Based on Ultrasonic Speckle

Science & Technology Review. 2010, 28 (11): 59-63. ;  doi:
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Abstract ( 445 )
The existence of phantoms and other ultrasound noises in Ultrasound-Guided HIFU systems' B-mode ultrasound images will hamper the B-mode ultrasound image registration and the locating of the target. In order to solve this problem, this paper proposes a new method of B-mode ultrasound image registration based on the phase correlation of ultrasonic speckle. Firstly, under the principles and the pseudorandom feature of the speckle, the speckle images and registration, the B-mode ultrasound images are picked up by using the phase correlation of ultrasonic speckle through the moving values of images, on the platform of Maltab 7.0. Secondly, the direct registration of the phase correlation is compared with the registration of the speckle in B-mode ultrasound images. Thirdly, the results of registration are analyzed and the measurement is made of the similarity degree. It is shown that the phase correlation of the speckle could achieve the image registration among the B-mode ultrasound images with phantoms and noises. This registration method enjoys a high robustness and accuracy, and is better than the direct registration of phase correlation. The feasibility of the registration based on speckle is demonstrated by experiments.

Calculation of Reservoir Irreducible Water Saturation Based on NMR Experiment and Mercury Penetration Experiment

Science & Technology Review. 2010, 28 (11): 64-67. ;  doi:
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Abstract ( 496 )
In order to calculate the irreducible water saturation of sandstone reservoir in a certain area in Xinjiang, 142 sandstone rock samples are selected from six wells for experimental Nuclear Magnetic Resonance (NMR) and mercury penetration measurements. According to the result of NMR, using methods of T2 spectrum area ratio, weighing, Spectrum Bound Volume Irreducible(SBVI), unified T2cutoff, to get water saturation, it is seen that the weighing method and the T2 spectrum area ratio method are better, and the two methods are used to build irreducible water saturation model of sandstone reservoir in the study area. Based on NMR experiments measurements, all application conditions of irreducible water saturation derived from mercury intrusion capillary pressure experiments are studied. The studies suggest that for rock samples with the porosity of less than 15% and the permeability of less than 0.1×10-3μm2, the displacing force of 6.897×10-3MPa can drive all movable water, and that the water saturation derived from mercury penetration experiments is the true irreducible water saturation. For rock samples with porosity greater than 15% and permeability less than 0.1×10-3μm2, the displacing force of 6.897×10-3MPa can only drive some movable water, and the water saturation derived from mercury penetration experiments is not the true irreducible water saturation. Under the condition of reservoir with high porosity and permeability, the buoyancy generated by the difference of oil-water density in reservoir conditions which is equal to the capillary pressure in this paper, the water saturation obtained in pure oil conditions is the true irreducible water saturation.

Sedimentary and Diagenetic Evolution Pattern of Reservoir Bed of Carbonate Rock in Jingbian Gasfield of Ordos Basin

Science & Technology Review. 2010, 28 (11): 68-73. ;  doi:
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Abstract ( 1534 )
Evaporation tidal flat facies are developed in the mid gas field of Ordos Basin. They can be subdivided into 7 microfacies, including mud-dolostone flat of the supralittoral zone, gypseous depression of the supralittoral zone, gypseous dolostone flat of the supralittoral zone, algae-dolostone flat of the intertidal zone, mud-dolostone flat of the intertidal zone, grain bank of the intertidal zone and limestone flat of the subtidal zone. Core observation and thin section analysis indicate that the diagenesis of reservoirs in the syngenesis diagenetic environment, freshwater diagenetic environment and buried diagenetic environment include dolomitization, dissolution, filling cohesion, fracture, replacement, compaction-pressure solution, recrystallization, breccia, etc. Based on the analyses of sedimentary facies and the effect of diagenesis on porosity and permeability characteristics of reservoirs, the sedimentary-diagenetic evolutions of carbonate reservoirs are divided into 4 periods, namely sediment-syngenesis diagenesis period, embedding diagenesis period, near floor, uplift-weathering period and late embedding diagenesis period. This unique evolution pattern constitutes vertical 5-layer reservoir architecture, including 2 high porous layers and 3 low porous layers, alternatively distributed. M51 1~M53 1 and M54 1a high porous layers are under the control of the paleokarst in sediment-syngenesis diagenesis period, uplift-weathering period and the microfacies of gypseous dolostone flat, M53 2~M53 3, M54 1b~M54 3b and M55 low porous layers are under the control of mud-dolostone flat, gypseous depression and limestone flat.

Application of Gray Logistic I/II Models in Subsidence Prediction in Mine Exploitation

Science & Technology Review. 2010, 28 (11): 74-79. ;  doi:
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Abstract ( 1263 )
After the exploitation of underground coal resources, the cracking, subsidence, deformation and other geological disasters may occur in the surface because of the instability of overlying strata, the collapse and the re-compacting. The traditional methods to deal with coal mine subsidence include geological methods, field monitoring, physical and numerical simulations and others, but they are often costly and time consuming, and some parameters are very difficult to identify. In order to obtain accurate information about the ground subsidence in coal mining, the mining-induced stress-relief principle and the "three-zone" model are applied in this paper, and the coal mining subsidence in Tuzhu Coal Mine of Jinzhushan Mining Company is studied. The occurrence mechanism and characteristics of surface cracks and settlement in underground coal mining are analyzed. It is suggested that: (1) when exploiting the shallow coal seams with a large estimate of vertical cracks which would directly affect the surface, one should make settlement prediction on the basis of theoretical analysis and field observation methods, to obtain timely effective security warning information; (2) when exploiting the deep coal seams with a large estimate of vertical cracks which do not affect the surface, one should, on the basis of the actual observation data, establish gray Logistic I/II models to predict the land subsidence, and without the need to carry out the practical monitoring. Practical verification and model accuracy test show that the Grey Logistic I/II models can make accurate predictions, with a good agreement between the predictive value and actual value. It can provide effective and accurate information, and also can provide an important reference for the reclamation planning of surface environment.

Crashworthiness Analysis and Optimization of Thin-walled Tube with Pyramidal Folding Patterns

Science & Technology Review. 2010, 28 (11): 79-85. ;  doi:
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Abstract ( 454 )
Thin-walled structures are often used as energy absorbers to dissipate the kinetic energy of impacting in case of accident. In order to improve the crashworthiness of thin-walled structures, the pyramidal folding pattern is added to the smooth surface of traditional cylindrical shell. LS-DYNA is adopted to analyze the new tube's crashworthiness with explicit Finite Element (FE) technique. Fibonacci Search method is used to search the optimal number of sides of polygon of the new model's section. With the height and obliquity of the pattern as optimization variables, the absorbed energy as the optimization objective, the optimization model is built. Response Surface Method is used to obtain an approximation of the implicit quadratic function to make the optimization objective explicit. And then, the optimization problem can be solved. Take 40mm-radius tube with pyramidal folding patterns as an example, the optimization results show that, when the side number of the section polygon is 11, the pattern's height is 80 mm and the distance from pattern peak to axis is 38.92mm, the pyramidal folding pattern tube has the best ability in absorbing energy. Compared with the traditional smooth cylindrical shell, the energy-absorption ability is improved by 31.88%. The new folding pattern structure proposed in this paper can be applied in designing practical energy absorption components. The directions for further study are suggested.

A Vortex-conducted Micromixer Dirven by Electroosmosis

Science & Technology Review. 2010, 28 (11): 86-91. ;  doi:
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Abstract ( 383 )
By taking electroosmosis as the driving force, a micrometer-range micromixer based on vortex-conducted is presented. In the design, a mixing quadrate antrum is placed to be a mixing container, in which the upside and underside wall is placed in a stable horizontal electric field, the electroosmosis flow is formed for the double electrical layers on the inner wall sides. The electroosmosis flow can drive its nearby fluid to move in a certain direction. However, the left and right sides of the mixing quadrate antrum are closed, and there is no electroosmosis taking place, so according to conservation of mass theory, some part of fluid will flow in a reverse direction contrastively to that of electroosmosis flow. By this means, some annular flow configuration are formed, that is, some shapes of vortexes can be created. Based on the above principle, two mixing modes of single-vortex mode and double-vortex mode are studied quantificationally with numerical simulation to discuss the performances of the mixer, especially of the stable and the dynamic mixing characteristic. It is proved with the numerical model that the proposed micromixer can perform high-efficiency, continuous and stable mixing, which has those advantages of short mixing channel, simple structure and convenient operation; as to the two mixing modes, the double-vortex mode is more significative in practical case.

Stability Degree of Excavation in Clay Soil

Science & Technology Review. 2010, 28 (11): 91-93. ;  doi:
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Abstract ( 457 )
Stability of the tunnel is a very important issue in geotechnical engineering. First the factor of safety is introduced into the assessment of stability in the geotechnical engineering, and then the concept of stability degree is defined. Various kinds of the stability degrees of tunnel are discussed, including those with and without consideration of earth weight and that related with support strength of tunnel. Then with a variable tunnel model of failure proposed by Davis's as an example, the block body velocity field and the stress distribution are obtained, based on the work-energy theorem, and the stability degree is calculated. According to measured data on the site, the site stability degree is obtained. The theoretical stability degree can be obtained by analysis. These three different stability degrees are compared when the value of site stability degree is greater than the theoretical value, then the tunnel would fail; when the value of site stability degree is equal to the theoretical value, then the tunnel is in a critical failure state; when the value of site stability degree is smaller than the theoretical value, then the tunnel is in a stability state. According to different circumstances, with the use of different expressions of the stability degree of the tunnel, the tunnel stability can be assessed.

Dynamics Analysis of the Linkage Mechanism for Beam Pumping Unit Based on Multi-parameter Friction Model

Science & Technology Review. 2010, 28 (11): 94-97. ;  doi:
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Abstract ( 399 )
In recent years, the friction model theory and its application have attracted a considerable attention. In addition to the traditional Coulomb friction model, other multi-parameter friction models such as Coulomb+hyperbolic tangent friction model and exponent hyperbolic tangent friction model are also applied to the dynamic analysis of mechanisms. This paper discusses the physical meaning and the selection of parameters of multi-parameter friction models. The relationship between Striebeck velocity and coefficient k in the exponent hyperbolic tangent friction model is analyzed. Based on the exponent hyperbolic tangent friction model, the nonlinear dynamic equation of a linkage mechanism for beam pumping unit is established and is then solved by using the numerical iterative method. The curve of the driving torque acting on the crank against the mechanical efficiency of this system is obtained. The theoretical analysis result agrees with the actual phenomenon. It is shown that the exponent hyperbolic tangent friction model is more precise than the Coulomb friction model for describing the energy dissipation in the dynamic simulation of the mechanisms.

Development of SCR Post-treatment for Vehicle Diesel Engine to Meet the China Stage IV Emission Norms

Science & Technology Review. 2010, 28 (11): 98-102. ;  doi:
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Abstract ( 554 )
The selective catalytic reduction is one of the most efficient technologies for NOx reduction. The experimental investigation was conducted on a six-cylinder diesel engine with electronically-controlled cam-actuated unit pumps. The particulate mass of the diesel engine is greatly decreased to meet the China stage IV emission norms by a proper modification of the combustion system. In order to reduce the serious NOx emission, a dosing controlling unit with open loop strategy is developed. The urea solution with concentration of 32.5% is induced into exhaust pipe by using the dosing injection system and the controlling unit. Thus, the NOx reacts with ammonia from pyrogenation of urea and then they are transformed into H2O and N2. Because of high rate of NOx conversion, the open loop strategy for dosing of urea solution is sufficient for meeting the China stage IV emission norms. Firstly, the maps of NOx emission, the exhaust temperature, the exhaust flow and the reduction of NOx per unit urea solution were acquired in the engine calibration tests, and saved into the flash memory of the dosing controlling unit. Then one can calculate the quality of urea solution to be induced into the exhaust pipe by using the maps, the current speed and torque percent of the diesel engine as well as the inlet and outlet of the catalyst. Moreover, the performances of NOx conversion, NH3 slip and urea solution consumption of the selective catalytic reduction post-treatment were investigated in the European Steady Conditions (ESC) and European Transient Conditions (ETC). The results show that, NOx conversion over 65.2% and 65.3% can be achieved in the ESC and ETC tests, respectively, while NH3 slip is below 5ppm. On the basis of SOF analysis, the PM reduction is the result of SOF reduction with SCR catalyst. Also, in the analysis of the urea solution consumption in the ETC test, a heavy duty truck with the diesel engine in the test will consume 2 liter urea solution with concentration of 32.5% per 100 kilometers under the controlling of the dosing controlling unit.
Reviews

Research Progress in Degradation of Indoor Pollutants by Nanocatalysts

Science & Technology Review. 2010, 28 (11): 103-110. ;  doi:
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Abstract ( 577 )
The harm effects of environmental pollution, especially, indoor air pollutants on human health have been attracting more and more attention in recent years. One of important topics of environmental management is how to effectively eliminate indoor air pollutants. In these aspects, nanocatalysts show outstanding effects and promising applications. The basic principle of photocatalysis reaction of the nanomaterials is discussed and the research progress in nanocatalysts of metal nanoparticles, metal oxide nanoparticles, and composite nanoparticles of metal oxides developed for degradation of varied indoor air pollutants is reviewed in this paper. The advantages and disadvantages of these nanocatalysts are discussed. Noble metals show a very good effect in degradation of indoor air pollutants, but the high price hinders its wide application. The photocatalytic degradation process of indoor air pollutants of oxide nanomaterials requires the light, and the catalysts show a good effect after being supported by the precious metal. Catalytic degradation of indoor pollutants of the oxide and mixed oxides nanomaterials shows good catalytic performance and development prospects. The future developments and potential applications of nanocatalysts for degradation of indoor air pollutants are pointed out.

Recent Development in Acupuncture Treatment for Female Dysgenesia

Science & Technology Review. 2010, 28 (11): 111-115. ;  doi:
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Abstract ( 459 )
Acupuncture has a long history in treating gynecological disease in China as a traditional therapy. Acupuncture treatment for female reproductive system diseases has acquired a legitimate status in western medicine since the 1980s. The academic achievements about acupuncture treatment are now generally accepted by international community of learning. This paper reviews the recent development of acupuncture treating female dysgenesia both at home and abroad, especially for IVF-ET and polycystic ovarian syndrome, including the effect of acupuncture on embryo nidation and pregnancy rate in IVF-ET, the study on mechanism of acupuncture for PCOS, the clinical curative effect of acupuncture on PCOS anovulation. An analysis is also made on the international competition, the existing problems at home and prospective directions.

Science & Technology Review. 2010, 28 (11): 116-116. ;  doi:
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Abstract ( 288 )
科技评论

Science & Technology Review. 2010, 28 (11): 117-117. ;  doi:
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Science & Technology Review. 2010, 28 (11): 120-120. ;  doi:
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Focus

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走向职场

Science & Technology Review. 2010, 28 (11): 126-126. ;  doi:
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