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   Science & Technology Review
2009, Vol.27, No. 0915
13 August 2009

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The Longest Total Solar Eclipse of 2009 in the Yangtze River Basin, China

Science & Technology Review. 2009, 27 (0915): 3-3. ;  doi:
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Abstract ( 516 )
特别栏目

Science & Technology Review. 2009, 27 (0915): 8-8. ;  doi:
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Abstract ( 492 )

Science & Technology Review. 2009, 27 (0915): 10-10. ;  doi:
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Abstract ( 509 )

Science & Technology Review. 2009, 27 (0915): 11-11. ;  doi:
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Abstract ( 505 )

Science & Technology Review. 2009, 27 (0915): 12-13. ;  doi:
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Abstract ( 463 )

Science & Technology Review. 2009, 27 (0915): 14-14. ;  doi:
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Abstract ( 525 )

Science & Technology Review. 2009, 27 (0915): 15-15. ;  doi:
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Abstract ( 534 )

Science & Technology Review. 2009, 27 (0915): 16-16. ;  doi:
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Science & Technology Review. 2009, 27 (0915): 17-17. ;  doi:
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Abstract ( 540 )

Science & Technology Review. 2009, 27 (0915): 18-18. ;  doi:
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Abstract ( 543 )

Science & Technology Review. 2009, 27 (0915): 117-117. ;  doi:
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Science & Technology Review. 2009, 27 (0915): 124-124. ;  doi:
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Abstract ( 590 )

Science & Technology Review. 2009, 27 (0915): 125-125. ;  doi:
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Abstract ( 509 )
封面图片说明

Science & Technology Review. 2009, 27 (0915): 8-8. ;  doi:
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Abstract ( 541 )
半月科技风云

Science & Technology Review. 2009, 27 (0915): 9-9. ;  doi:
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Abstract ( 581 )
Exclusive

Ionospheric TEC Measurement with VLBI and GPS During the Total Solar Eclipse of 22 July 2009

Science & Technology Review. 2009, 27 (0915): 19-24. ;  doi:
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Abstract ( 647 )
The longest total solar eclipse during the 21st century, occurred over China at latitudes of about 30°N in the morning of 22 July 2009, provides a unique opportunity to investigate the influence of the sun on the earth upper ionosphere. For Shanghai is located near the central line of the total eclipse belt, a VLBI experiment for ionospheric Total Electron Content (TEC) measurement has been carried out with participation of Shanghai, Urumqi and Kashima stations. Meanwhile, a number of GPS receiving system are also used in the experiment. The background and methodology for the experiment are briefly described, followed by the introduction of observation details and data processing procedure. Based on the cross correlation results, good fringes have been detected on the Shanghai-Urumqi baseline with the 2 dimensional fringe search technique, which indicate that the VLBI measurement of TEC was performed successfully. The data analysis of a single GPS station led to a preliminary result which shows the sudden decrease in TEC at the time of maximum eclipse. We expect to acquire the first VLBI results for TEC measurement, and compared with the results from GPS observations.

Progress in Research on the Variability of Sgr A*

Science & Technology Review. 2009, 27 (0915): 25-34. ;  doi:
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Abstract ( 650 )
There is compelling evidence that Sgr A*, the extremely compact radio source at the dynamical center of the Galaxy, is associated with a four million solar masses massive black hole. This paper deals with the temporal variability observed in the emission from Sgr A*. The total flux density variation has been puzzling ever since the discovery of Sgr A* in 1974. At radio bands, Sgr A* appears to have significant fluctuations in flux density at shorter centimeter wavelengths and the fractional variation appears to be higher toward the short wavelengths. This trend continues toward higher frequency bands including millimeter, sub-mm, near-infrared and X-ray wavelengths. The observed outbursts exhibit a typical time scale of hours at mm/sub-mm, less than an hour at near-infrared and X-rays. Both Chandra and XMM-Newton X-ray observatories have detected some very strong and highly variable flares from Sgr A*. These observations provide unique constraints on the emission geometry of Sgr A*, and can be use to study the origin of the variability of Sgr A*. Some multi-frequency observations of Sgr A* have detected flares simultaneously at both near-infrared and X-ray bands, and a time delay of the radio flare emission with respect to those at near-infrared and X-rays. These measurements of time delay seem to favor the adiabatically expanding plasmon model. However, more reliable simultaneous multi-frequency campaign is still needed to well establish the relationship between flaring emission at various wavelengths before we can distinguish different theoretical models.
Articles

Application of Intracranial Electrode in the Surgery for Children with Drug-resistant Frontal Epilepsy

Science & Technology Review. 2009, 27 (0915): 35-38. ;  doi:
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Abstract ( 670 )
The application of intracranial electrode in the surgery for children with drug-resistant frontal epilepsy with negative MRI is discussed. Retrospective analysis is conducted of 40 cases of children patients in the surgery treatment for drug-resistant frontal epilepsy in our ward between June 2006 and August 2008. Considering the children's seizure manifestations and scalp video electroncephalogram, the intracranial electrode is planted in suspected epileptogenic zones, then based on ECoG and/or cortical stimulation, the real epileptogenic zones are identified. All the patients received surgery treatments to remove epileptogenic zones. The frontal epilepsy was confirmed for all patients. Frontal lobectomy was performed on 12 cases, frontal lobectomy combined with local epileptogenic cortex resection and/or bipolar coagulation of the codex was performed on 8 cases, local epileptogenic cortex resection and/or bipolar coagulation of the codex was performed on 7 cases. Lateral frontal lobectomy combined with local epileptogenic cortex resection and/or bipolar coagulation of the codex was performed on 7 cases. Medial frontal lobectomy combined with local epileptogenic cortex resection and/or bipolar coagulation of the codex was performed on 6 cases (with 3 cases of additional corpus callostomy). There were no severe complication mortality. Patients were followed up for 20 to 36 months. The curative effects were analyzed with Wilson standard in postop, with fineness rate of 80%, 8 cases (20%) were free from seizure, a significant reduction of seizure attack was found in 14 cases (35%), 10 cases (25%) saw a reduction of seizure attack, no change was observed in 8 cases (20%). Therefore, the children frontal epilepsy can be well treated by epileptogenic zones resection, corpus callostomy, bipolar coagulation and frontal lobectomy or by 2 and more methods combined after a precise identification of the epileptogenic zone.

TO INVESTIGATE THE EFFECT OF CRYPTOTANSHINONE ON INSULIN RESISTANT OVARIAL GRANULAR CELLS BY DNA MICROARRY

Science & Technology Review. 2009, 27 (0915): 39-43. ;  doi:
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Abstract ( 651 )
The mechanism of Cryptotanshinone in treating ovary insulin resistance is identified in this paper. The ovarian granulose cells from porcine follicles were isolated and cultured in vitro, and insulin resistance was induced by treatment with Wortmannin. The cells were divided into 4 groups, the blank control group cultured with DMSO, the Wortmannin group cultured with Wortmannin 250 nmol/L, the Cryptotanshinone group cultured with Wotrmannin 250 nmol/L as well as 0.02 g/L Cryptotanshinone. After being incubated for 48 h, the total RNA was isolated from cells, and the differently expressed genes were screened from them by the gene chip technique. Then they were analyzed by molecule annotation system to get differential gene expression profiles and pathways of the four groups. The results show that 42 differential genes are screened through the channel gene chip technique, including 22 down-regulation genes and 20 up-regulation genes. These differential expression genes have various biological functions, such as lipid metabolism, intercellular signal transmission and so on. And the Cryptotanshinone may improve ovary insulin resistance by adjusting many genes and signal pathway. It is implied that Cryptotanshinone may be used to treat endocrine disease and reproductive barrier of polycystic ovary syndrome.

Influence of Bacterial Endotoxin on Survival Rate and Birth Rate of Genetic Immunised Mice

Science & Technology Review. 2009, 27 (0915): 44-47. ;  doi:
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Abstract ( 1527 )
As a third generation vaccine, the nucleic acid vaccine is easy to operate, and of low cost. However, there are some intrinsic risks involved, such as bacterial endotoxin, which should be studied and avoided. Bacterial endotoxin is contained in the outer layer surrounding cell wall of Gram negative bacteria. After being released in vivo, it can cause many pathological changes, such as fever and shock. Some previous in vitro studies show that endotoxin had bad effects on reproductive system of mice. This paper presents experimental studies on the effect of endotoxin on the survival rate and birth rate of immunised mice in vivo. In the experiment, two types of pCR3.1-Sry were extracted by two different methods and used to immunise mice. One method uses the general method, and the other uses a reagent kit. Their difference lies in the fact whether the endotoxin is removed or not. And, their purity and concentration were analyzed and controlled by agarose gel electrophoresis and spectrophotometry. At the same time, sterile ddH2O was injected into mice as control. Then, the immunising and mating tests of mice were carried out. Molecular biological results show that two types of nucleic acid vaccine were at proper concentration and high purity too. The immunity and statistical results show that compared with the group whose endotoxin was removed, the survival rate and the birth rate of the group with endotoxin were severally decreased from 93% to 84% and from 87.5% to 35.7%, respectively. At the same time, data for endotoxin-removed group is close to the control group. All the results indicate that endotoxin interfused in the nucleic acid vaccine has adverse effect on immunised mice, especially, on the reproductive system.

Experiment Simulation of Micro-anisotropy of Yanchang Formation in F110-well Area in Panlong Oilfield

Science & Technology Review. 2009, 27 (0915): 48-51. ;  doi:
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Abstract ( 634 )
Using an authentic sandstone micro-model, the flowing of oil and water was experimentally simulated in reservoirs. The micro-anisotropy was found to be an important factor in the distribution of remaining oil and the exploitation of the oilfield. The micro-anisotropy and its effect on the distribution of the remaining oil in Yanchang formation in the studied area are experimentally studied in this paper. The results show that the micro-anisotropy of Yanchang formation reservoirs is outstanding. A better quality of reservoirs is found to be related to more outstanding micro-anisotropy. Diagenesis and pore structure are the most important factors for micro-anisotropy, which, in turn, is responsible for oil displacement and forming of remaining oil, directly due to fingering flow. There are four main types of pores. They are remaining primary pore, dissolution pore, micro-crack and the micro-pore among crystals. The flow characteristics of the four pore types are quite different. The studies on the four main types of pore structures for Yanchang formation reservoirs suggest that it is better to conduct waterflooding development based on the remaining primary pore type and the dissolution pore type; or based on the micro-crack type; or based on the type of micro-pore among crystals.

Evaluation of Low Resistivity Oil Zone in YSM Oilfield

Science & Technology Review. 2009, 27 (0915): 52-55. ;  doi:
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Abstract ( 595 )
Based on a geological analysis and the drilling features, the genesis of low resistivity reservoir in YSM oil field is studied. It is concluded that the low resistivity reservoir oil comes mainly from five causes, that is, high irreducible water saturation, high clay content, thin layer of low resistivity reservoir, effect of high salinity and high-density slurry. Especially, the thin layer and high bound water saturation are the main causes of low resistivity reservoir in this area. This paper considers mainly these two aspects. According to the actual conditions of YSM oil field, a qualitative evaluating method for low resistivity reservoir is proposed, which includes the regional structure contrast method and the spontaneous potential decrease coefficient method. With the actual testing situation, the low resistivity reservoir can be interpreted well by the regional structure contrast method. The spontaneous potential decrease coefficient method is first applied to the area, with good results. At the same time, the quantitative evaluation method is used with a dual water model that considers the high bound water saturation. The dual water model is effective for the low resistivity reservoir due to the lithology and the additional electrical conductivity from clay minerals. Meanwhile, a high-resolution logging data processing technology is put forward, mainly for reservoirs with complex lithology.

Experimental Study of Water-oil Two-phase Fluid Flow in Low Permeability Reservoir by Nuclear Magnetic Resonance

Science & Technology Review. 2009, 27 (0915): 56-58. ;  doi:
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Abstract ( 661 )
A low permeability reservoir features fine throat and complex porous structure, which an artificial micro pore model can not well represent. A water flooding experiment was carried out with the real core and simulated oil without hydrogen. The water-oil two-phase fluid flow was studied using the technique of nuclear magnetic resonance, to obtain the distribution of irreducible water, irreducible oil and produced oil in cores of different porosity during drainage and imbibition, and to reveal the formation mechanism and imbibition mechanism quantitatively during the water displacement. The results show that the bigger the pore radius is, the lower the irreducible water saturation will be; the main reservoir space of low permeability reservoir is a medium with pores of more than 0.1 μm in radius; residual oil is mainly distributed in mid-small pores; and imbibition is significant in low permeability reservoir.

Experimental Studies on Large Rock Socketed Pile's Confining Bearing Properties in the Pile Bottom

Science & Technology Review. 2009, 27 (0915): 59-63. ;  doi:
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Abstract ( 602 )
The estimation of the rock-socketed piles' confining bearing capacity by empirical methods always involves large error. So an in-situ method is preferred in important engineering projects. The experimental studies on large rock socketed pile's confining bearing capacity properties were carried out in the dug piles' bottom at construction zone C of Guangzhou new television station tower site. The short concrete piles were used to simulate the real piles, and the confining friction force between the short pile and the rock mass was determined. The compressive friction tests and the pulling out friction tests were conducted, and the confining friction forces between the short pile and the rock mass were used to determine confining friction parameters. The tests results show that the piles' confining friction properties are quite different under the compressive force conditions and under the tensile force conditions, and the compressive friction characteristic value is always larger than that of the pulling out friction. According to the tests analysis, a tensile partial coefficient may be defined for the pile's pulling out resistant force computation to achieve a larger safety factor in important buildings. In this new television station tower site project, the tensile partial coefficient is about γ in the range of 1.5~2.0, and the tests results provide a useful reference for important building constructions.

Determination of the Shear Strength Parameters of Rock Mass Based on Nonlinear Failure Criterion

Science & Technology Review. 2009, 27 (0915): 64-66. ;  doi:
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Abstract ( 644 )
The prediction of the shear strength is an important part in the analysis for rock mass stability. The shear strength parameters of the rock mass are described by the Hoek-Brown nonlinear failure criterion in this paper. And a transformation procedure from the Hoek-Brown parameters to the Mohr-Coulomb parameters is proposed. In the transformation procedure, the theoretical analysis and data fitting method are used. The influences of each parameter in the nonlinear failure criterion on the shear strength parameters are analyzed. It is shown that the relationship between the shear strength parameters and Hoek-Brown criterion parameters can be determined by fitting a large amount of data. With the increase of geological strength index GSI, the shear strength parameters c and ?准 increase gradually. The effect of cohesion on the rock geological strength index is more sensitive to the friction angle. But their variations with the mi are not that large, which indicates that the GSI has a larger effect on the rock strength than on mi. The results can give some guidance for the real practice.

Calculation of Water Temperature State and Amount of Surplus Water for Original Subgrade in Frost Regions

Science & Technology Review. 2009, 27 (0915): 67-70. ;  doi:
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Abstract ( 655 )
Water temperature state of an old subgrade in frost regions might change significantly when it is widened. If old water temperature state is not accurately analyzed and calculated, all kinds of damages of subgrade and pavement in the joints between the old places and new places may become possible. This paper analyzes different water temperature states in widening subgrade, as connection between the original and widening subgrades in the frost regions. One may identify the beginning stage, stagnant stage, freezing stage, saturated moisture stage and complete melting stage on the basis of previous studies. The calculation formula for the amount of surplus water is derived with the help of the seepage theory of soil, and some technological measures are proposed to improve the water temperature state and to keep the subgrade in a middle-wet state. The results show that these measures and formulas can help to reduce various kinds of damages of subgrade and pavement in the joints.

Intent Reduction and Classification Rules Mining

Science & Technology Review. 2009, 27 (0915): 71-75. ;  doi:
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Abstract ( 596 )
The concept lattice is accurate and complete in the knowledge representation, and it is an effective tool for data analysis and knowledge discovery. Classification rule mining based on the concept lattice in an efficient way is a challenging task. At present, there are many extraction algorithms for classification rule based on the concept lattice, but the number and form of extracted rule can not achieve satisfactory results. This paper focused on classification rule mining using intent reduction of the formal concept. It proposed an incremental way to compute intent reduction by adding object to the formal context one by one. Through modifying the incremental computation of the intent reduction of concepts, new algorithms are developed to compute the intent reduction, and then definitions of the exact classification rule base and the approximate base are given. On the basis, two algorithms for the exact and the approximate mining bases are designed. In the algorithms, only those concepts that concern the classification rule mining need to be considered in compute their intent reduction. Furthermore, the use of classification rule bases reduces the total number of classification rules that need to be extracted. In order to verify the data mining methods of classification association rules which were put forward in this research, the algorithms mentioned above were implemented by using C++. Finally, empirical experiments on UCI data demonstrated the efficiency of these algorithms in the mining of affirmative classification rules and approximate classification rules using intent reduction.

Ranging Method for Indoor Mobile Robot Based on Active RFID Signal Strength

Science & Technology Review. 2009, 27 (0915): 76-79. ;  doi:
Full text: HTML (0 KB)  PDF  (443 KB)  ( 492 )
Abstract ( 696 )
In order to use a geometric method to locate the indoor mobile robot, this paper proposes a method of active RFID signal strength for ranging. Based on the characteristics of wireless signal propagation and the principle of Received Signal Strength Indication (RSSI) ranging, a logarithm-normal distribution propagation loss model is established. An experiment system is built by using HR-6020C reader and WS-HT06 tags, with the reader fixed as the base station, and the tags sending the signal continuously as the mobile agents. The relationship between distance d and the RSSI value is obtained through the experiment. The signal strength of a reference point and the scale factor are determined in calibration. Ranging precision factors are analyzed through the active RFID system. The influencing factors include the position, number of tags and the experiment environment. The test results show that the maximum deviation in the 3 m range is 41.68 cm, which can meet the positioning precision requirements for indoor mobile robots.

Effect of Annealing Temperature on Sputtered ZnO Thin Film

Science & Technology Review. 2009, 27 (0915): 80-82. ;  doi:
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Abstract ( 651 )
Highly C-axis oriented nano-ZnO thin film was manufactured by RF-magnetron sputtering technique on a normal glass base. The influence of the heat treatment temperature on the ZnO thin film's morphology, microstructure and the residual stress is studied by the Scanning Electron Microscope and X-ray diffraction apparatuses. During the sputtering process, due to various factors, there may be residual stresses in thin films, which are usually to be reduced by heat treatment. It is shown that the films' quality can be significantly improved by post-deposition heat treatment. With the heat treatment, the crystal grains become larger, more compact and better-proportioned. Therefore, the surface of the thin film becomes smoother as well as with distinctly fewer holes. The spacing of crystal plane(002) and the residual stress of all the samples are clearly reduced, as compared with those ZnO samples not heat treated. Firstly, the spacings of crystal plane(002) and residual stresses are reduced when the heat treatment temperature is raised and before it reaches the minimum at 450℃. Then, some of the crystal grains grow excessively and the smoothness and the compact level are reduced and the spacings of crystal plane(002) and the residual stress are increased when the annealing temperature rises higher than 450℃. It is concluded that ZnO thin film's surface morphology microstructure and residual stresses are significantly improved at the annealing temperature of 450℃, which is very effective in the removal of the residual stress in thin films. Therefore in the process of preparing ZnO thin films by magnetron sputtering technique, oxygen could be introduced into the film by post-deposition heat treatment in the ambient atmosphere.

Accident Analysis by Phase-mission Methods in Nuclear Plant

Science & Technology Review. 2009, 27 (0915): 83-86. ;  doi:
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Abstract ( 649 )
Probabilistic Safety Assessment (PSA) is a systematic engineering evaluation technology, widely used in the nuclear power plant safety evaluation. In PSA, the Event Tree(ET) and Fault Tree (FT) are commonly used. However, it is common that a mission in different phases is executed by different systems or function modules in an engineering project. Conventional ET/FT are static analysis methods based on Boolean logic technology, not flexible enough to handle the dynamic problems directly, e.g. to change the accident scenario evolution at different stages. Sometimes the accurate timing of the events is important for the accident sequence development. The method to evaluate the accident sequence in different phases can be used to solve the problem. The basic idea of this method is to convert the multi-phase system to several single-phase systems to be analyzed separately, and then the results are combined to get the final consequence. Reliability diagram and event tree are two of the important analysis methods for phased analysis. In this paper, they are used to analyze the accident of loss of the main feed water in different phases. It is shown that to improve the reliability of execution process, U1 can help to reduce the probability of core damage in this accident. At last, the applicability of the two methods are discussed briefly. In the reliability diagram, since the real condition of the accident cannot be reflected completely, the illogical cut set should be deleted by hand. In the event tree, since the logical order can be partially reflected, the illogical cut set can be avoided. The two methods are both based on FT or ET eventually, so the accident development with the time cannot be described entirely, and the result is conservative. When the mission time is short, this deviation can be accepted.

Energy Efficiency Evaluation Based on Data Envelope Analysis for a Railway Station

Science & Technology Review. 2009, 27 (0915): 87-91. ;  doi:
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Abstract ( 683 )
The objective of this research is to evaluate the energy efficiency for a railway station, based on an energy efficiency analysis. Firstly, the influencing factors of passenger's comfort extent in the waiting environment and the economic benefit of the railway station are analyzed and an output index system is established. Secondly, various energy consumption factors form the input index system. On the basis of DEA model, with linear programming methods, the total efficiency, the pure technology efficiency, the scale efficiency and the relative order are obtained. Methods are proposed to turn a non-DEA efficient railway station into a DEA efficient one. Then the crosscut efficiency between different railway stations are compared. According to the results, the final ordered list of all stations based on energy efficiency and passengers' comfort extent is obtained, with some important and useful suggestions for improving the railway station energy efficiency. Some proposals are given for improving the transportation quality and comprehensive competitiveness.

Micromechanical Model for Crazing in Toughened Polystyrene

Science & Technology Review. 2009, 27 (0915): 92-96. ;  doi:
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Abstract ( 571 )
Crazing is a kind of mechanism in toughening polystyrene by particles. In this paper, an independent elastomer particle unit is selected, and holes are embedded into the matrix (with cavities being represented by circular holes). Their diameter and distance are the same as cavities in crazing plane and the diameter of fibril. The crazing model is used to simulate the 1% strain crazing process with the finite element method. It is shown that the crazing initiates near the elastomer equator firstly, and is extended to the tangential direction. As the load increases, the fibril near the equator of elastomer is the first to reach the fracture critical value, then eventually crazing turns into crack. In this process, the fibril growth is in the direction of a certain angle with the load, which agrees with the experimental observation. From the elastomer with ?兹=30°, the molecular chains start to shrink because of the deformation of elastomer, then follows the materials contraction.

Simulation of Gain Characteristics of Erbium Ytterbium Adulterates Fiber Waveguide Amplifier and Functional Optimization

Science & Technology Review. 2009, 27 (0915): 97-100. ;  doi:
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Abstract ( 661 )
Optical integration is the development trend of modern optical communication technologies. Waveguide amplifier is a new type of integrated optical devices, after the semiconductor laser amplifiers and the erbium-doped fiber amplifiers. The use of rare-earth element ytterbium due to some salient features of the as-sensitized elements can improve the performance of the erbium-doped waveguide amplifier. EY-CDWA, due to its high gain per unit length and the easiness to be integrated, can very easily be integrated with any device. Optical integration paves a way for a wide range of active components. Therefore, EY-CDWA is being paid more and more attention. This paper analyzes the impact of various factors on the gain of amplifiers and how to improve the amplifiers. The analysis of co-doped Yb-doped structure in the system-level forms the basis of the relevant transition by solving the rate equation and the amplifier transfer equation. A gain model is built for EY-CDWA with related formula for the gain. Gain characteristics are simulated. The waveguide length, pump power and other related conditions are optimized with respect to the amplifier gain. With a parameter optimization program, the amplifier pump wavelength, pump power and gain are optimized at the same time, with the maximum gain in the best length. The theoretical model can be applied to the actual production of the Yb-Er co-doped Al2O3 optical waveguide amplifier, with a good agreement with the experimental data. Analysis of the impact of various factors on the gain of amplifier improves the methods and helps to develop a more reasonable parameter optimization program.

Fault Detection for Bearings Based on Signal Lipschitz Spectrum Entropy

Science & Technology Review. 2009, 27 (0915): 101-103. ;  doi:
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Abstract ( 625 )
It is known that the wavelet-singular point detection-based method is sensitive to noises; to solve this problem, a method of fault detection for bearings based on wavelet transform modulus maximum Lipschitz spectrum entropy is proposed by combining wavelet analysis with entropy theory, including the detection scheme of bearing vibration faults and the threshold selection method based on swarm intelligence. The proposed method is compared with the methods based on wavelet energy spectrum and wavelet packet energy spectrum entropy and the wavelet-singular point detection-based method in the experiments. The results show that the proposed method is particularly well adapted to describe fault characteristics and fault diagnosis, which outperforms the other three methods in terms of detection time and detection rate.

Detection of Specific Dehydrogenase Activity for Evaluating the Hydrogen-producing Activity of Flocs in Anaerobic Fermentation Process

Science & Technology Review. 2009, 27 (0915): 104-108. ;  doi:
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Abstract ( 1398 )
The ratio between Mixed Liquor Volatile Suspended Solid (MLVSS) and Mixed Liquor Suspended Solid (MLSS), the specific hydrogen producing rate by MLVSS and the COD removal rate are normally used to evaluate the hydrogen-production efficiency of anaerobic activated sludge in fermentation processes, but they suffer from some drawbacks. In order to evaluate the hydrogen-production efficiency of anaerobic activated sludge in fermentation processes, a detection method using iodonitrotetrazoliumchloride (INT) is proposed and optimized for detecting the specific dehydrogenase activity in the flocs. The correlation between dehydrogenase activity and the specific hydrogen production rate of the activated sludge is analyzed. The results show that the optimal conditions for detecting INT-dehydrogenase activity are as follows. A 2.8 mL reaction system, including 0.3 mL sludge sample with a mixed liquor volatile suspended solids of 3.5 ~ 12.5 g/L, 1 mL 19.8 μmol/L INT and 1.5 mL sodium acetate buffer with a pH of 5, is put in dark for 30 min under 45℃ with oscillation. Concentrated sulfuric acid of 98% is used as the reaction termination agent, while the anhydrous ethanol is used as the extraction solvent. The absorbance is measured at 438 nm. The dehydrogenase activity of the activated sludge is very highly correlated with its specific hydrogen production rate, excellently reflecting the hydrogen-producing activity.
Reviews

Research and Application of Minimally Invasive Biomedical Technology for Disease Diagnostics

Science & Technology Review. 2009, 27 (0915): 109-115. ;  doi:
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Abstract ( 784 )
Modern medical imaging diagnosis and blood-test technologies now play critical roles in the diagnosis of diseases. However, it is still difficult to detect in vivo target tissues in human body, as a result most medical cases with relatively higher diagnostic accuracy are already in advanced stages now. Given its minimally invasiveness and relatively higher accuracy, minimally invasive diagnostics may solve this problem. This article systematically reviewed and discussed the current situation of modern minimally invasive diagnostic technology, introduced its categories and applications as fully as possible, analyzed in depth the critical scientific problems involved, and discussed the prospect of this field along with the development of micro/nanotechnology. It is likely that compared with non-invasive and invasive diagnostics, minimally invasive diagnostics in vivo is equipped with both the former's least injury to patients and the latter's higher accuracy. A full exploration of minimally invasive diagnostic technology will bring about breakthrough of a series of researches fields, which will lead to a more widely application of such technology.

Science & Technology Review. 2009, 27 (0915): 116-116. ;  doi:
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Abstract ( 504 )
Focus

Science & Technology Review. 2009, 27 (0915): 118-119. ;  doi:
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Abstract ( 590 )
科技评论

Science & Technology Review. 2009, 27 (0915): 120-121. ;  doi:
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Abstract ( 571 )

Science & Technology Review. 2009, 27 (0915): 122-122. ;  doi:
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Abstract ( 530 )

Science & Technology Review. 2009, 27 (0915): 123-123. ;  doi:
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Abstract ( 474 )
主编心语

Science & Technology Review. 2009, 27 (0915): 125-125. ;  doi:
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Science & Technology Review. 2009, 27 (0915): 126-126. ;  doi:
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Science & Technology Review. 2009, 27 (0915): 127-127. ;  doi:
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Science & Technology Review. 2009, 27 (0915): 128-132. ;  doi:
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Science & Technology Review. 2009, 27 (0915): 139-140. ;  doi:
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