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   Science & Technology Review
2010, Vol.28, No. 03
13 February 2010

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Metrology and Its Social Function

Science & Technology Review. 2010, 28 (03): 1-1. ;  doi:
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Abstract ( 383 )
特别栏目

Science & Technology Review. 2010, 28 (03): 8-8. ;  doi:
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Abstract ( 384 )

Science & Technology Review. 2010, 28 (03): 10-10. ;  doi:
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Abstract ( 373 )

Science & Technology Review. 2010, 28 (03): 12-13. ;  doi:
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Abstract ( 373 )

Science & Technology Review. 2010, 28 (03): 14-15. ;  doi:
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Abstract ( 366 )

Science & Technology Review. 2010, 28 (03): 16-17. ;  doi:
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Abstract ( 382 )

Science & Technology Review. 2010, 28 (03): 125-125. ;  doi:
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Abstract ( 362 )

Science & Technology Review. 2010, 28 (03): 138-138. ;  doi:
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Abstract ( 329 )

Science & Technology Review. 2010, 28 (03): 139-139. ;  doi:
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Abstract ( 325 )
封面图片说明

Science & Technology Review. 2010, 28 (03): 8-8. ;  doi:
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Abstract ( 337 )
半月科技风云

Science & Technology Review. 2010, 28 (03): 9-9. ;  doi:
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Abstract ( 429 )
科技事件

Science & Technology Review. 2010, 28 (03): 11-11. ;  doi:
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Abstract ( 376 )
科技工作者建议

Science & Technology Review. 2010, 28 (03): 18-18. ;  doi:
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Abstract ( 437 )
Articles

A Zoomorphic Set of Ternary Complex Numbers

Guan-Ping YANG
Science & Technology Review. 2010, 28 (03): 19-23. ;  doi:
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Abstract ( 520 )
This paper studies 3D fractal geometry by using the method of the ternary complex number. Based on the definition of the ternary complex numbers and their operation rules, an infinite set of ternary complex numbers is defined according to the rule of Mandelbrot set. Some sample sets are extracted from the set with as high precision as possible, to portray exterior images under the control of the computer software. With observation and analysis, it is shown that its 3D geometric solid is in a shape of an animal. Almost every part of it seems rational, such as the head, tail, back, abdomen and four limbs. Its facial features are idiographic, with eyes equipped by eyeball, eyehole and eyelid. The whole body has some similar subsets around, and each of these subsets itself also has similar subsets around. This similarity differs from the geometrical similarity, but resembles the similarity of biologic heredity. If one increases the density of sample points, more accurate complicated structures can be seen. The zoomorphic fractal solid is located near the origin in Euclid space, its lineal measure is about 2.3. All these natural peculiarities and the details can be seen from the figures.

Standby System Reliability Model of the Neclear Power Plant and Its Parametric Evaluation Methods

ZHANG Yongfa;TONG Juanjie;ZHOU Yu
Science & Technology Review. 2010, 28 (03): 24-28. ;  doi:
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Abstract ( 492 )
Because the standby equipment is affected by demand stress and standby stress simultaneously, its reliability model is diverse. Firstly, the characteristics of two essential models—standby failure model and demand failure model is analyzed; And then, the expression and applicability is presented, and the fundamental using principles are provided; Next, the evaluating methods of the model parameters is researched, after that three methods corresponding to the generic database and special data are advanced. Finally, the using advice of the model and its evaluating methods in domestic nuclear power plants are proposed.

Applications of Parametric Modeling Method Based on Secondary Development of UG in Optimization Design

Science & Technology Review. 2010, 28 (03): 29-32. ;  doi:
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Abstract ( 476 )
In engineering design problems involving the geometrical model optimization, the current two methods used in the parametric modeling suffer some drawbacks in the process of automation and complex geometry treatment. According to the characteristics and requirements of the optimization task with the geometry modeling link, a parametric modeling method based on secondary development of UG is proposed. A model-updating program is developed with UG/Open API external mode and MFC. A new geometry model is created by modifying the expressions and updating model of the template file with external parameters, and the necessary characteristic geometric parameters are exported. The program can be run independently without UG environment and integrated in a third-party optimization platform, with the analysis process in the optimization task as a black box, the design parameters as input data and the geometrical model and characteristic geometric parameters as output data. The example shows that the method and the program can effectively applied to engineering optimization design. It can also be used in a CAE system and multidisciplinary design optimization framework as a parametric modeling module.

A Sub-Space Distance Rule based Method for the Estimation of the Number of the Source

XU Ce;ZHANG Xinhua;XIONG Xin
Science & Technology Review. 2010, 28 (03): 33-36. ;  doi:
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Abstract ( 512 )
The estimation of the number of sources is an important problem in array signal processing and it is also a problem for sonar detection. Based on the principle of the eigen sub-space, a new algorithm is proposed for the estimation of the number of sources. The proposed algorithm makes use of the blind source separation and is based on the sub-space distance rule. The blind source separation offers the eigen vector to the new algorithm, and the sub-space distance rule is the fact that if the source number estimation is right, the signal sub-space and the noise sub-space would be in an orthogonal relation, with the distance between the signal sub-space and the noise sub-space taking the minimum value. Based on that rule, the sub-space cost function is built. The simulation data and pool test data are used to analyze the performance of the proposed algorithm and the minimum description length method, based on the information criteria. It is shown that the algorithm can provide the true number of sources in both simulation data and pool test data and with a good performance in low SNR in the simulation data. Compared with the minimum description length method, the proposed algorithm is more robust in the pool test data.

Hazard of Thermal Explosive of Dicumyl Peroxide

Science & Technology Review. 2010, 28 (03): 37-40. ;  doi:
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Abstract ( 473 )
In order to prevent and reduce the fire explosion accidents in the process of manufacturing Dicumyl Peroxide (DCP), the thermal hazard of DCP, DCP/20% sodium carbonate and DCP/20% phenol are studied by the Accelerating Rate Calorimeter(ARC) under adiabatic environment. Their thermal stability characteristics, such as the onset exothermic temperature, the maximum temperature rise rate and the time-to-maximum rate, and the exothermal curves, were obtained. The test data were corrected by thermal inertia factors. The compatibility of DCP/20% sodium carbonate and DCP/20% phenol was calculated by using the theoretical model, consisting of two criteria: the initial exothermic temperature and the average acceleration. It can be seen from the results that the initial exothermic temperature of DCP, DCP/20% sodium carbonate and DCP/20% phenol are 97.47, 106.40 and 115.59℃, respectively. And the maximum temperature rise rates are 65.15, 2.15 and 3.44℃·min-1, respectively, and the average accelerations are 0.2977, 0.0077 and 0.0127. Sodium carbonate and phenol have a good compatibility with DCP as catalysts in industrial yields; however, compared with phenol, sodium carbonate performs much better in manufacturing DCP.

Electroluminescent Characteristics of a Novel Red-fluorescent Dye ACY Doped PVK System

Science & Technology Review. 2010, 28 (03): 41-45. ;  doi:
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Abstract ( 502 )
Using a doping system of PVK and ACY with various weight ratios, Organic Light-Emitting Devices (OLEDs) with a structure of Indium-Tin-Oxide (ITO)/poly(N-vinylcarbazole) (PVK):[7-diethylamino-3-(2-thienyl)chronmen-2-ylidene]-2,2-dicyanoviny-lamine (ACY)/tris(8-quinolinolato) aluminum (Alq3)/Mg:Ag by the spin coating method were fabricated. The device spectra characteristics and the distinct features of the device performance were studied, including the luminance-voltage and current density-voltage characteristics of the OLEDs. It is demonstrated that the high electroluminescent performance could be obtained by choosing a concentration proportion of PVK:ACY of 1000:7. In the EL spectra of the OLEDs, the red and green fluorescences of ACY and Alq3 appear. The EL spectra intensity decreases initially and then increases to a maximum with the enhancement of the doping concentration. Moreover, the molecular structure, sterical hindered structural moieties are discussed and the Energy Transfer (ET) theory is used to analyze the EL spectra characteristics of ACY doped OLEDs.

Influencing Factors of Hydroxyl Production in Orifice-typed Cavitation Reactor

ZHAI Lei;DONG Shouping;FENG Gaopo;MA Honglian;GENG Dai
Science & Technology Review. 2010, 28 (03): 46-50. ;  doi:
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Abstract ( 676 )
The cavitation associated with the formation, growth and the collapse of micro-bubbles leads to the generation of very high pressures and temperatures locally, which can cause a series of physical and chemical reactions. The molecular link of hydrone in the solution is broken by the energy released from the high pressures and temperatures in hydrodynamic cavitation, which would generate the hydroxyl (·OH) radical. Therefore, the energy released in hydrodynamic cavitation can be used to enhance some chemical reaction, as a new approach of energy utilization. In addition, the production of hydroxyl radical reflects the strength and effect of cavitation. The influencing factors of ·OH production of hydrodynamic cavitation are investigated in this paper in order to increase the production of ·OH and find the best cavitation reaction conditions. Multi-hole orifices are used as the reactor of hydrodynamic cavitation. Methylene Blue (MB) is used as the catcher for hydroxyl radicals induced in hydrodynamic cavitation. An ultraviolet-visible spectrophotometer is used to measure the amount of induced hydroxyl radicals. The relations between ·OH production and MB solution strength, inlet pressure, solution temperature, mixing velocity of oxygen are analyzed. The experimental results show that the experimental method mentioned above is an efficient approach to quantitatively analyze the relationship between the production of ·OH and the cavitation intensity or the cavitation effect. The catching ratio to the ·OH is basically constant under the condition that the MB solution strength is in the range of 16 to 19μmol/L for the ideal sensibility and accuracy of catching ·OH. The production of ·OH is the highest under the condition that the inlet pressure is equal to 0.2MPa, the solution temperature is equal to 30℃ and the mixing velocity of oxygen is equal to 45L/h. In addition, under adequate structural parameters, the production ·OH is approximately linearly related with the reaction time of cavitation. The production of ·OH can be raised through adjusting the inlet pressure, solution temperature, mixing velocity of oxygen, reaction time and other macro-parameters, as in the optimal cavitation conditions.

Analysis of Bacterial Diversity of Gravel Contact Oxidation Reactor by 16SrDNA Sequencing

Science & Technology Review. 2010, 28 (03): 51-54. ;  doi:
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Abstract ( 553 )
Microbes are important members in a biological treatment system, especially, in the gravel contact oxidation reactor filled with crushed stone globular aggregates as carriers, which is discussed in this paper. By means of molecular biology techniques, for the gravel contact reactor, in its typical area, including the surface biological membrane of gravel, internal sludge of gravel and bottom sludge of the reactor, after DNA extraction, PCR and cloning, 16SrDNA sequence determination, the bacterial diversity is analyzed. The results indicate that the reactor bacterial communities are composed of aerobic bacteria group and anaerobic bacteria group. The dominant members are respiratory metabolized microbes Pseudomonas and fermentative metabolized microbes Bacteroidetes bacterium/Cytophaga. Non-dominant members in the aerobic group include α-, β-, and γ-Proteobacterium, Nitrosospira, Chlamydia, Gluconobacter and Agrobacterium. Anaerobic members are Spirochaeta Sp., delta preobacterium, Denitrifying bacterium. In addition, to reduce the growth of biomass, the slow-growth bacterial group is also a feature group in this reactor. The existence of biodiversity is the key of the sludge reduction.

Preparation and Property of Sodium Alginate-Kaolin/P(AA-AM) Super Absorbent Resin

LIN Jian;MOU Guodong;LI Wei
Science & Technology Review. 2010, 28 (03): 55-58. ;  doi:
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Abstract ( 1425 )
Currently, the studies of Super Absorbent Resins (SAR) are focused on homopolymers. But with their development, the defects of some products have gradually cropped up, such as high cost, low strength, slow water-absorption rate, insufficient amount of water-absorption, poor salt-tolerant performance. So people have to use copolymerization or graft copolymerization of two or more monomers or to add cheap fillers to improve the comprehensive performance of SAR and reduce the production costs. In this study, a salt-tolerant super absorbent resin was obtained by crosslinking copolymerization, using acrylicacid, acrylamide, sodium alginate and kaolin. Aqueous solution polymerization method was used for improving properties of super absorbent resin, which would be affected by the amount of crosslinking agent, initiator, kaolin, acrylamide and drying condition, and so on. It is shown that the water absorption rate can reach 895g/g, and the salt absorption rate can reach 85g/g. Super absorbents were also synthesized by copolymerization of acrylic acid, acrylamide, sodium alginate and kaolin, to improve the absorbency properties. The results show that with K2S2O8 as the initiator, the dosage of 0.8%~1.2%, the temperature of 65~75℃, the neutralization degree of acrylic acid of 60%, the reaction time of 4 hours, good absorbency properties are obtained. When the neutralization degree of acrylic acid, the temperature, the reaction time, the monomer concentration and the dosage of crosslinker are appropriately adjusted, the anti-ultraviolet properties are also

Experimental Study of Horizontal Gas-water Flow Pattern During Production Well Logging

LU Jing;WU Xiling;HUANG Zhijie;WANG Jieyi;PENG Yuanping;HE Fengjiang
Science & Technology Review. 2010, 28 (03): 59-62. ;  doi:
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Abstract ( 564 )
In order to study the characteristics of flow distribution changes and the factors affected by Production Logging Tool (PLT) on the gas-water two-phase flow during production well logging in horizontal wellbores, a flow-loop was built. An experimental test matrix designed to collect a maximum amount of data on the gas-water two-phase flow in horizontal wellbores was conducted on this transparent flow-loop of 16 m long, using air and tap water. Every measurement was strictly carried out in a steady-state gas-water mixed flow, by using production well logging tool-string. All flow patterns observed in these experiments were recorded by camera; all actual air and water flow rates were measured, respectively, by flowmeters located along the flow-loop. A well logging flow regime map that shows the gas-water flow patterns observed in these experiments was obtained according to these two parts of information. On the map, the variation trends of the gas-water two-phase distribution are similar to observations in ordinary fluid dynamics experiments, which means that the gas-water two-phase flow may well describe the general features in production well logging, but with its unique characteristic distribution interfered by measurements of the PLT and displayed on the flow regime map in the form of the boundaries shift. The results provide some insight for understanding the distribution of the gas-water two-phase flow during production well logging in horizontal wellbores.

Validation of a Temperature Rise Model of DC Permanent Magnet Motor

Science & Technology Review. 2010, 28 (03): 63-65. ;  doi:
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Abstract ( 548 )
Since the energy loss of a motor not only reduces its efficiency, but also leads to temperature rise in the motor, as represented by the difference between the motor temperature and the ambient temperature. The temperature rise will accelerate the aging and damage of the motor insulation component and reduce the life of the motor. Therefore, the prediction of the motor temperature rise is very important. In this paper, a temperature rise model for DC permanent magnet motors is proposed, where an exponential relation is assumed between the temperature rise and the time. The motor temperature rise curve is obtained by fitting the relation with the measured data, and compared with the measured temperature rise curve in the carbon brush of the motor, which verifies the accuracy of the fitting temperature rise curve. This model can be applied to monitor the motor real-time temperature rise. As the window lift motor works as a repeated short-term motor, this paper studies the short-term working system with the motor heating and cooling model.

Numerical Realization of Soil-cable Interaction Characteristics and Its Validation

PENG Wenxiang;YIN Quan
Science & Technology Review. 2010, 28 (03): 66-69. ;  doi:
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Abstract ( 487 )
The characteristics of soil-cable interaction as well as the numerical realization of the cable element and its validation are studied in this paper. The mechanism of the soil-cable interaction is analyzed and the numerical modeling is done for the cable element. In situ-monitoring tests are carried out to obtain the reinforcement force of the cable, the numerical calculation model is built for the reinforcement force and the results are compared. It is shown that (1) with the time, the reinforcement force of the cable increases gradually until the excavation of the foundation is finished, and then the reinforcement force will tend to be constant; (2) the maximum reinforcement force from the numerical calculation is 259.0kN and that from the in situ-test is 229.4kN, and similar relations between the reinforcement force and time are obtained. The analysis results validate the numerical model.

Identification and Paleogeographical Implications of Middle Triassic Carbonate Slope in Xiacheng—Shaijingtan Area, West Qinling Mountains

Science & Technology Review. 2010, 28 (03): 70-75. ;  doi:
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Abstract ( 467 )
The carbonate platform slope is a slope break zone between the carbonate platform and the deep-sea basin. The deposition and the deformation of sediments are controlled by gravity. Its study has important palaeogeographical implications and economic significance. A great number of carbonate debris flows, syndepositional faults and truncation structures have been found in Middle Triassic in Xiacheng. Also, carbonate debris flows exist in flysches of Middle Triassic Gulangdi Formation in Shaijingtan. In order to reconstruct the paleogeographical environment in this area, the carbonate microfacies are analyzed, with identifications and discussions. The analysis on these sediments and sedimentary structures reveals that a continental slope exists from SEE to NWW along Xiacheng—Shaijingtan in Middle Triassic. They are mostly deep-water carbonate sediments in Xiacheng and terrigenous clast in Shaijingtan. This slope is nearly a carbonate platform in NNE, and has a transition to deep-sea sediments in SW.

Optimization of EST-SSR System on Heading Chinese Cabbage and Primer Screening

Science & Technology Review. 2010, 28 (03): 76-81. ;  doi:
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Abstract ( 1281 )

The aim of this paper is to optimize the EST-SSR system on heading Chinese cabbage, and select a certain amount of primer pairs using the optimized system. L16(44) orthogonal design is used in the system optimization, and the concentrations of the main factors are studied to build the best system. The results show that the different levels of each factor have some effects on the results of EST-SSR, with the effect of the primer concentration being the greatest, those of dNTP and Taq DNA polymerase the next, and that of the concentration of DNA template the minimal. The optimized system(20?滋L) is: 2.0?滋L 10×PCR Buffer with Mg2+, 70ng DNA template, 250?滋mol/L dNTP, 1.0?滋mol/L primer, and 0.5U Taq DNA polymerase. One hundred and twenty-six primer pairs are designed according to the EST sequences of heading Chinese cabbage, and EST-SSR PCR is amplified by using the above primer pairs and optimized system, with nineteen primer pairs being selected based on their reproducible and polymorphism, which could be used for further research.

Effects of Immune Regulation of Abnormal Savda Munziq Granular on Immune Suppressed Mice

Science & Technology Review. 2010, 28 (03): 82-86. ;  doi:
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Abstract ( 466 )
This paper investigates the effects of abnormal savda munziq granular on nonspecific immunity, humeral immunity, cell immunity functions of cyclophosphamide induced immune suppressed mice. 84 qualified mice were randomly divided into 6 groups with 14 in each group: normal control group, model group, groups of abnormal savda munziq granular for high, medium, low dosages and the control group. Except for the normal control group, mice in all other groups were made immune suppression models by using cyclophosphamide(75mg/kg, OD). Abnormal savda munziq granular was orally administered for 14 days, once a day. The mononuclear phagocyte englobement function, the quantity of T cell subpopulation in peripheral blood, NK cyto-active, interleukin-1 and interleukin-2 activity, TNF-α activity, serum hemolysin(CH50), delayed allergy were monitored. Three groups of abnormal savda munziq granular were found to have made remarkable improvement in the mononuclear phagocyte englobement function, the quantity of T cell subpopulation in peripheral blood, serum hemolysin, delayed allergy (P<0.05). The IgM and IgG values were also improved remarkably(P<0.05). In the groups of abnormal savda munziq granular, the NK cyto-active, and TNF-α, activities were remarkably improved for the medium dose and the high dose groups. There was a tendency in abnormal savda munziq granular groups of increasing the activities of IL-1 in lower dose group and those of IL-2 in medium dose group (P<0.05). Abnormal savda munziq granular could improve the immunological function of immune suppressed mice.

Principal Component Neural Network Prediction Model for Incidence of Upper Respiratory Tract Infection

Science & Technology Review. 2010, 28 (03): 87-89. ;  doi:
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Abstract ( 600 )
In the medical field, due to the fact that diseases are often affected by many factors, it is difficult to use a structural causal model, while on the other hand, it would be effective to establish a dynamic model, based on their own time-series changes. To predict the number and incidence of diseases, because meteorological factors, the monthly average atmospheric pressure, monthly mean temperature, monthly mean relative humidity, monthly average wind speed, the monthly average precipitation are strongly correlated between themselves and with very high dimensions, the accuracy of the Radial Basis Function (RBF) neural network prediction may be very low. To solve this problem, this paper proposes the use of the Principal Component Analysis (PCA) method to reconstruct the original input space and, based on the contribution rate of all main components to determine the network structure, which will effectively solve the problem of low prediction accuracy. The incidence data of upper respiratory tract infection, from August 2001 to September 2006, in Wuwei City of Gansu Province are used to validate the method. The clinical characteristics in each time period should be duly considered in order to carry out a more focused health prevention and treatment and to effectively reduce the hazards to human bronchial pneumonia.

Dust Control Technologies Under the New Emission Standard for Thermal Power Plants

Science & Technology Review. 2010, 28 (03): 90-95. ;  doi:
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Abstract ( 803 )
The progress of dust control technologies for thermal power plants accompanying with the successive revisions of emission standards are reviewed in this paper. Electrostatic precipitator (ESP), Bag Filter (BF) and ESP-BF integration (COPAC) are among those technologies adopted for meeting these standards. It is pointed out that to design the ESP with a migration velocity, it is not enough to consider only the dust resistivity and the chemical composition, which would involve a large error. One has to consider the influences of dust mineral composition and other properties such as microstructure, infiltration, adhesion, particle size distribution and apparent density, as well as the coal combustion method, furnace temperature, and combustion atmosphere. It is recommended to use the Specific Collection Area(SCA) of the ESP as an index of the dust precipitability for different fly ashes, produced from different coal combustions. Based on technical and economical comparisons between ESP, BF and COPAC, the following suggestions are made. (1) In case of stable coal supply, the ESP is preferred, when SCA<160m2/(m3·s-1) in order to meet the emission standard; (2) COPAC is preferred, when SCA≥160m2/(m3·s-1) is required with a variety of or changeable coal supplies or in case when it is necessary to obviously improve the existing ESP performance in order to meet the emission standard. COPAC can also collect M10 and PM2.5 fine particulates in the same manner as BF. (3) BF is preferred when SCA≥160m2/(m3·s-1) is required and in case of low sulfur coal, low inlet dust concentration, uniform gas/dust distribution and even air leakage.

Comparison of Organic Matter Concentration in Wastereater Between Different Drainage Systems in Districts Affected by Tidal River

Science & Technology Review. 2010, 28 (03): 96-99. ;  doi:
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Abstract ( 477 )
Investigation on concentrations of COD of different kinds wasterwater in a city affected by tidal river in the Pearl River Delta area was carried on. And COD of the wastewater in the city, 272mg/L, was worked out. The COD Concentration of wastewater in separate system, 191mg/L on average, was significantly higher than that in combined sewerage system, 137mg/L on everage. COD concentration in combined sewerage system decreased as the river level increased, appearing significant negative correlation. The partial correlation coefficient was -0.8432. However, COD concentration in separate system appeared no correlation to the river level. In district affected by tidal river, separate system could prevent river water from backing up into the sewerage system more efficiently than combined sewerage system. On behave of the operation of wastewater treatment plants, separate system was more sutible than combined sewerage system for district affected by tidal river. References were provided for drainage systems choosing in the Pearl River Delta area.

Modeling of the Effects of EGR on Combustion of a Diesel Engine

Science & Technology Review. 2010, 28 (03): 100-104. ;  doi:
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Abstract ( 1336 )
Exhaust Gas Recirculation(EGR) is a common way to control in-cylinder NOx production and is used in most modern direct injection diesel engines. However the influence of EGR on NOx and Soot is not perfectly understood. In order to analyze the characteristics of EGR, a model of diesel engine based on the GT-POWER is established. Based on the basic structure of diesel engine, the model is a 1D fluid-dynamic engine cycle simulation model of TDI diesel engine with EGR system. The influences of EGR on combustion of the diesel engine are investigated in a constant inlet boost pressure and constant inlet air fuel ratio condition. In the condition of constant inlet boost pressure and constant EGR temperature, along with the rise of the EGR ratio, the rise ratio of the in-cylinder pressure reduces, the highest in-cylinder pressure drops, the start of combustion delays, the peak rate of heat release becomes higher. The EGR makes the Soot lifts and the Brake Specific Fuel Consumption comes down. In the condition of constant air fuel ratio and the EGR temperature, in the wake of the rise of EGR ratio, the in-cylinder pressure becomes higher, which makes the start of heat release shifting to an early time. The delay of heat release due to EGR is compensated by the rise of in-cylinder pressure. The characteristics of the inert gases in the exhaust gases become a secondary factor. EGR reduces the combustion efficiency. The rate of heat release becomes lower. The combustion temperature of in-cylinder comes down. The small EGR ratio can improve the emission. So, the effect of EGR at different boundary conditions is different. The control strategy of EGR with air fuel ratio as the controlling target is defective. One should adopt the control strategy with both inlet air mass flow and EGR ratio as controlling targets. In the condition of constant EGR ratio, the rise of EGR temperature shortens the ignition delay. The start of combustion shifts to an early time, and the rate of heat release comes down. The in-cylinder temperature and the emission of NOx rise, however, the emission of Soot improves. Dynamic property and economical efficiency deteriorate. In order to make a perfect EGR control system, the EGR temperature should also be controlled.
Reviews

JIANG Xingwei;SONG Qingtao
Science & Technology Review. 2010, 28 (03): 105-111. ;  doi:
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Abstract ( 626 )
A wide variety of geophysical information including Sea Surface Temperature (SST), Ocean Vector Winds (OVW), Sea Surface Height (SSH) and Sea Surface Salinity (SSS) can be retrieved by satellite-borne microwave sensors. Cloud is nearly transparent to microwave, and the availability of all-weather microwave satellite measurements has overcome many limitations of traditional optical and infrared measurements. The China ocean satellite 2 (HY-2A), scheduled to be launched in 2011, with primary objective of measuring SST, SSH and OVW, will significantly increase the sampling frequency over the global oceans while working together with other operational microwave satellites. This paper reviews the up-to-date ocean microwave satellite missions, outlines the future microwave missions and new technologies used to overcome limitations of the current microwave sensors, and addresses the importance of multi-dimensional observing system that combines high-resolution microwave (China's ocean satellite 3, HY-3), optical and infrared sensors as well as traditional measurements over the coastal and global oceans. It is concluded that (1) microwave measurements of SST are especially suitable for resolving mesoscale structure associated with the western boundary current systems (e.g. the Gulf Stream, the Agulhas Current) and their eastward extension into the interior ocean, where significant amount of clouds typically exist; (2) microwave measurements of surface wind are critical in understanding the mesoscale interaction processes near the oceanic fronts, and surface wind is an important physical parameter in improving the marine environmental forecasting skills; (3) microwave measurements of sea surface height have revolutionized our understanding of ocean circulations and large scale ocean wave theories. Finally, it is suggested that sustained microwave observations with resolution and accuracy at least as good as AMSR, QuikSCAT and TOPEX/Poseidon are required to understand the implications of short-term and long-term climate variability.

Research Progress of Sludge Treatment and Disposal with Microwave

DONG Yu;TANG Bing;XU Yichun;ZHOU Ziyou
Science & Technology Review. 2010, 28 (03): 112-115. ;  doi:
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Abstract ( 548 )
The sewage sludge produced by municipal wastewater treatment plants contains a large number of unstabilized pathogenic microbes and other toxic and harmful substances. The sludge treatment and disposal is a widely concerned problem. This paper reviews the current state of the treatment and disposal for sewage sludge both at home and abroad. The technology of sludge treatment using microwave is discussed. Microwave is a high-efficiency heating technique, its use for sludge treatment and disposal can make quick sludge heating and hydrolysis, that will improve the sludge dewatering and anaerobic digestion capability. On the other hand, the microwave treatment technology does not involve any chemical agents and will not introduce any new pollutants or toxic substances into the sludge, therefore, will make the subsequent processing more efficient. Some representative sludge treatment technologies with microwave are analyzed, including the pyrolysis of sewage sludge by direct microwave heating to keep out of the air and to obtain gas, liquid fuel products; the disruption of sludge cell wall and extracellular substance using microwave heating to improve the biodegradability of sludge for anaerobic digestion; and the treatment of sludge by microwave together with other physical or chemical methods. The principles of these technologies are focused, and some proposals for the future research and development of the sewage sludge treatment using microwave are suggested.

Science & Technology Review. 2010, 28 (03): 116-116. ;  doi:
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科技评论

Science & Technology Review. 2010, 28 (03): 117-117. ;  doi:
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Focus

Science & Technology Review. 2010, 28 (03): 118-119. ;  doi:
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主编心语

Science & Technology Review. 2010, 28 (03): 125-125. ;  doi:
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Abstract ( 384 )
走向职场

北京大学科学研究部;科技部国际合作司
Science & Technology Review. 2010, 28 (03): 126-126. ;  doi:
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Science & Technology Review. 2010, 28 (03): 127-127. ;  doi:
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Science & Technology Review. 2010, 28 (03): 128-132. ;  doi:
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Science & Technology Review. 2010, 28 (03): 133-137. ;  doi:
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Abstract ( 348 )

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