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   Science & Technology Review
2009, Vol.27, No. 0921
13 November 2009

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Discussion on China Association for Science and Technology Science

Science & Technology Review. 2009, 27 (0921): 1-1. ;  doi:
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Science & Technology Review. 2009, 27 (0921): 5-6. ;  doi:
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Science & Technology Review. 2009, 27 (0921): 19-23. ;  doi:
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China Association for Science and Technology (CAST) entrusted Institute of Policy and Management, Chinese Academy of Sciences (CAS) to conduct a survey on the Science and Technology Award for Chinese Youth during the period from 2006 to 2007. Through historical data analyses, questionnaires, interviews and informal discussions, the distribution of award winners, the functions of the award, the award index and its evaluation procedures are surveyed and analyzed. The Science and Technology Award for Chinese Youth is awarded with research or academic achievements, academic quality, development potential as important evaluation indexes, and its functions include selection, promoting, guiding and radiating. The results show that 83.27% of award winners consider that the Science and Technology Award for Chinese Youth plays an important role in achieving more outstanding achievements. 87.27% of evaluation experts and 94.32% of recommending institutions are satisfied with the role of the award. 96.23% of award winners, 89.90 percent of evaluation experts and 75.00% of recommending institutions are satisfied with equity of the election, 96.33% of award winners, 89.90% of evaluation experts and 76.14 percent of recommending institutions are satisfied with fairness of the election, and 93.80% of award winners, 80.00% of evaluation experts and 76.14% of recommending institutions consider the election scientific. Award winners, evaluation experts and recommending institutions basically have a consensus on the general influence of the Science and Technology Award for Chinese Youth, and consider that besides the direct effect on award winners, the Science and Technology Award for Chinese Youth has positive influences on young scientists, the national innovation system, science and education communities, and the social economy development.

Science & Technology Review. 2009, 27 (0921): 8-8. ;  doi:
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Science & Technology Review. 2009, 27 (0921): 139-140. ;  doi:
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Science & Technology Review. 2009, 27 (0921): 11-11. ;  doi:
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Science & Technology Review. 2009, 27 (0921): 18-18. ;  doi:
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Preparation and Self-assembly of Biocompatible Polyrotaxane and Hemolysis Evaluation of Amphotericin B After Being Loaded by the Self-assembly

Science & Technology Review. 2009, 27 (0921): 24-31. ;  doi:
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Abstract ( 851 )
A kind of novel amphiphilic triblock copolymers containing polyrotaxane (PR) as a central block was synthesized via the ATRP of poly(ethylene glycol) methyl ether methacrylate (PEGMA) initiated with polypseudorotaxanes made from a distal 2-bromopropionyl end-capped Pluronic F127 with a varying amount of β-CDs in the presence of CuCl/N,N,N',N'',N''- pentamethyldiethylenetriamine(PMDETA) at 25℃ in an aqueous medium. The structure of the resulting copolymers was characterized in detail by 1H-NMR, GPC and DSC analyses. As a typical sample, F-30β-CD-60 was found to be self-assembled into nano-sized aggregates in water. Its critical aggregation concentration was estimated by the fluorescence probe technique. The transmission electron microscopy images further revealed that the sizes of the polymeric micelles of this selected copolymer were in nano-scale and smaller than those of the blank brush-like block copolymer. These nano-sized particles showed a great potential to be used as carrier for the controlled release of Amphotericin B(AmB) with 8.7% drug-loading content and 87 % drug-loading efficiency. And it is also true that the hemolysis of AmB has been significantly decreased after being loaded by the self-assembly.

Millimeter-wave intervention chondrocyte role of β-catenin activity mechanism

Science & Technology Review. 2009, 27 (0921): 32-38. ;  doi:
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Abstract ( 648 )
To investigate the millimeter wave chondrocyte intervention activity of β-catenin and its mechanism. Methods: SD rats with knee joint cartilage, the establishment of in vitro cultured chondrocyte, identification of toluidine blue staining. No. 2 on behalf of chondrocyte culture 48h, serum-free DMEM with hunger 24h, randomized, using different times after the intervention of the millimeter wave detection of the indicators. Results: The intervention in each group before and after the chondrocyte of type Ⅱ collagen expression and stability can be sustained; experiment 2, experiment 3 groups of chondrocyte β-catenin, CKIε expression was significantly higher than the normal group, experimental group 1 (P <0.05, P < 0.01), experiment 2, experiment 3 groups of chondrocyte l, GSK-3β expression was significantly lower than the normal group, experimental group 1 (P <0.05, P <0.01). Conclusion: The millimeter wave may be induced by transcriptional synthesis of chondrocyte, β-catenin, CKIε, inhibit the expression of GSK-3β, thereby promoting synthesis of β-catenin, inhibit decomposition of chondrocyte to enhance β-catenin activity.

rAAV1-mediated Gene Over-expression of VEGF-165 and Angiopoietin-1 in Rat Cerebral Ischemia Model: An Investigation on Its Efficacy and Possible Mechanisms

Science & Technology Review. 2009, 27 (0921): 39-49. ;  doi:
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Abstract ( 694 )
To examine the effects of intra-ventricular pre-treatment with a combination of recombinant Adeno-Associated Virus vectors encoding VEGF (rAAV1-VEGF) and Ang-1 (rAAV1-Ang-1) on early stroke in a rat model of transient Middle Cerebral Artery Occlusion (tMCAO), rAAV1-VEGF/rAAV1-Ang-1 or rAAV1-VEGF/rAAV1-null vector were delivered into the lateral ventricle of each rats. After eight weeks later, the rats were subjected to tMCAO for two hours. During the early stages of ischemic reperfusion, VEGF and Ang-1 expression levels, Blood Brain Barrier (BBB) permeability and cerebral microvessel density were determined and compared statistically between groups. Cerebral infarct volume and modified Neurological Severity Scores (NSS) were also determined to evaluate the therapeutic efficacy of rAAV1-VEGF/rAAV1-Ang-1. The results show that the intra-ventricular application of rAAV1-VEGF/rAAV1-Ang-1, eight weeks before tMCAO, results in VEGF and Ang1 overexpression, and significantly reduces Evans blue permeability following ischemia (P<0.05). The microvessel density in the peri-infarct zone is significantly increased in the rAAV1-VEGF/rAAV1-Ang-1 group as compared with the rAAV1-VEGF/rAAV1-null group(P<0.05). Cerebral infarct volume and NSS in the rAAV1-VEGF/rAAV1-Ang-1 group are significantly decreased as compared decreased as compare0d with the rAAV1-VEGF/rAAV1-null group (P<0.05). It is concluded that, in cerebral ischemia, the combination of Ang-1 and VEGF could be used early to promote the formation of mature neovessels and protect the injured cells, without inducing the side effects on BBB permeability. Early intra-ventricular injection of mixed rAAV1-VEGF and rAAV-Ang-1 may be a favorable therapeutic strategy in gene therapy for stroke.

Synthesis and Characterization of Cross-Link and Anticoagulant Heparinized Four-arm Star-shape Poly(ε-caprolactone) and its Preliminary Electrospinning Study

Science & Technology Review. 2009, 27 (0921): 50-55. ;  doi:
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Abstract ( 581 )
Four-arm star-shape poly(ε-caprolactone)s were prepared by Ring Opening Polymerization(ROP) with pentaerythritol/Stannous octoate as the initiator system. Photocurable and heparinized four-arm star-shape poly(ε-caprolactone) (PCL) was synthesized by covalently attaching acryloyl chloride and heparin to the ends of four-arm star-shape poly(ε-caprolactone)s. The resulting polyester was also cross-linked under UV light with good mechanical properties. The properties of the four-arm star-shape poly (ε-caprolactone)s were tested by using GPC, IR and 1H-NMR. The results of static contact angle and water absorption show that this heparinized PCL has better hydrophilic quality than its counterpart. The heparin content on the surface of this PCL was characterized by UV. The anticoagulant characteristics in vitro were evidenced by APTT test and the time of APTT test was obviously prolonged. The results of APTT test show that the heparinized material enjoys anticoagulant properties. The resulting polyester may also be cross-linked under UV light by adding an appropriate amount of photo-initiator. The results of mechanical tests show that the tensile strength is improved significantly after the exposure to the UV light. A preliminary study on its electrospinning properties was also carried out. The material can successfully be electrospun into tubular scaffolds with an ultrafine fiber structure. The cross-linked and anticoagulant heparinized four-arm star-shape poly (ε- caprolactone) enjoys a good application prospect in the field of vascular tissue engineering.

A Dynamic Programming Algorithm for Mass Segmentation on Mammograms Based on Contour Supervision

Science & Technology Review. 2009, 27 (0921): 56-60. ;  doi:
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Abstract ( 691 )
Mass segmentation plays a crucial role in Computer-Aided Diagnosis (CAD) systems on mammograms. Good segmentation result can better reflect the pathological characteristics of mass. And it can provide basis for the subsequent feature extraction and classification of suspicious region. At present, lots of literatures of mass segmentation have been proposed. Dynamic Programming (DP) based mass segmentation algorithm uses edge information as well as the priori knowledge of grey level and size information of mass. But the traditional DP based algorithm has low adaptability and robustness in mammograms. In order to overcome these shortcomings, an improved dynamic programming method was presented. Firstly, the Contrast Limited Adaptive Histogram Equalization (CLAHE) was used to improve contrast of Region of Interest (ROI) about mass. And the Gaussian mask was used to mask the surrounding tissues. Then, transform the ROI into polar coordinate and calculate the local cost matrix combining the edge, grey level and size information of mass. And the cumulative cost matrix was calculated using the local cost matrix. Finally, in the process of contour tracing based on dynamic programming, the contour supervision mechanism was introduced to avoid the contour departure, which is caused by the low contrast and the influence of surrounding tissues. The segmentation results of improved algorithm are compared with the traditional algorithm. The experimental results show that the introduction of Gaussian mask and contour supervision can effectively mask the surrounding tissue and avoid the contour departure. The proposed algorithm improved the segmentation accuracy. It is more robust than the conventional methods.

Degradation and Histocompatibility of Bacterial Cellulose

Science & Technology Review. 2009, 27 (0921): 61-66. ;  doi:
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Abstract ( 744 )
Bacterial Cellulose (BC) used in tissue engineering is studied in this paper, with the focus on the effects of bacterial cellulose on rhagiocrine cell and the structural changes of materials owing to tissue cells entering. To study the in vivo degradation and histocompatibility of BC, BC with the size of 5 mm×10 mm×1 mm was implanted in the subcutaneous tissue back of mature Wistar rats. After a period of time, BC was taken out and cleaned out with Sodium Dodecyl Sulfate (SDS), Phosphate Buffer Solution (PBS) and distilled water. And then the net BC taken out in different times was detected and analyzed by XRD, SEM and FTIR. At the same time, the corresponding subcutaneous tissue was fixed and observed under Transmission Electron Microscope (TEM). The interface of materials and organization tissue was observed by TEM to investigate the condition of histiocyte growing into 3D network of materials. The materials were taken out from the tissue after BC was implanted for several months. It is found that the crystallinity of BC is stepped down and C—O bond characteristic absorption peak broadened. Moreover, calcium phosphate salts were found deposited on the nano-fibril of BC after implanted for 6 months. Bacterial cellulose had good histocompatibility with subcutaneous tissue of back. Fibroblasts as well as blood vessel could migrate up to 30 ?滋m into the fibrous network after 6 months of implant.

Preparation and Characterization of Dextran Coated Superparamagnetic Iron Oxide Nanoparticles for Medical Applications

Science & Technology Review. 2009, 27 (0921): 67-71. ;  doi:
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Abstract ( 841 )
Nano magnetic particles are extensively used in both clinical diagnostics and basic researches for its distinct features, such as cell separation, immune recognition, contrast reagents in Magnetic Resonance Imaging (MRI). This paper proposes a method of preparing magnetic nanoparticles in the aqueous phase, which can be heated in an alternating magnetic field. Through orthogonal experiments, the relationship between particle diameter and reaction condition (dose of ammonia, iron salt, dextran and temperature) is optimized. The size of magnetic nanoparticles and their distribution, the relationship between dextran shell and iron oxide core, the magnetic characteristics are measured. The dextran coated iron oxide nanoparticles prepared in this way can be stored in room temperature for several months without any change of properties.

Investigation on Tumor Growth in Relation to Entropy Under Long-term Hyperthermia Environment

Science & Technology Review. 2009, 27 (0921): 72-76. ;  doi:
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Abstract ( 696 )
The abruption and modality rate of cancer is growing every year in the world. And the therapeutic means are far from a thorough heal of the disease. Both the causes of the disease and the mechanisms underlying its metastasis are still under investigation. Hyperthermic treatment can cause complete and selective destruction of malignant cells. To understand how heat affects tumor, entropy is used to characterize the structure or the assemble degree of a living system in thermal dynamics. The flow of entropy between tumor and normal cells from the reference point of entropy is calculated. Entropy flows resulting from external energy (heat), diffusion current, chemical reaction rate and velocity gradient coupled with viscous stress, are analyzed both quantitatively and qualitatively. The results show that the long-term hyperthermia environment can increase the positive entropy of the system and finally inhabit the growth of tumor. The analysis provides a new method for study of the relationship between the tumor growth and the environment, and a possible alternative cancer treatment.

EMG Analysis Based On The Entropy Theory And Complexity Measure

Science & Technology Review. 2009, 27 (0921): 77-81. ;  doi:
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Abstract ( 1515 )
Electromyography(EMG) finds more and more application areas, such as the workload evaluation and the robotic control. The key is the feature analysis and extraction. Various methods for the analysis of the EMG can be grouped into the linear methods and the nonlinear methods. The methods based the entropy theory and the complexity are among the nonlinear methods. The entropy methods include various entropy calculation algorithms, and the Renyi Entropy and Wavelet Entropy are the typical methods. In this paper the EMG are obtained from two volunteers while they are doing the push-up exercise, and the measures of the Renyi entropy, Wavelet entropy and LZC complexity are calculated. In the algorithm, the segments of the EMG are made to achieve better analysis results. The complexity of the EMG is reflected by these measures, as is validated by analysis. The value of the wavelet entropy implies the power of the EMG, and a higher power is obtained for the muscle fiber concentrated discharge, and so the complexity is decreased. The results from the Renyi entropy and LZC are the same. With these methods, the EMG is divided into several segments based on the muscle fatigue and EMG complexity. The results show that with these methods the EMG is a promising research field in the future, and these measures can also be applied to muscle fatigue.

Algorithm for Base Function Generation Based on Adaptive Multi-threshold

Science & Technology Review. 2009, 27 (0921): 82-85. ;  doi:
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Abstract ( 663 )
With the ability of sensing the electromagnetic environment, the Transform Domain Communication System (TDCS) can avoid jamming, with an excellent performance of anti-jamming. The base function generation is the core in the algorithms of TDCS. After an analysis od shortcomings of existing algorithms for base function generation, an algorithm of using adaptive multi-threshold in the base function generation is proposed in the paper for the TDCS. The algorithm uses a multi-structure, making the traditional adjudicate result more refined to reflect the difference of channel quality more accurately, based on the traditional binary adjudicate. The theoretical analysis shows that the algorithm of generating base functions based on adaptive multi-threshold can overcome the shortcoming of the traditional threshold estimation algorithm of bad adaptability with respect to channel circumstance. And the threshold design of the algorithm is simple, with good interference suppression performance.

A Method of Liquid Water Content Measurement in Icing Wind Tunnel

Science & Technology Review. 2009, 27 (0921): 86-90. ;  doi:
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Abstract ( 730 )
Liquid Water Content (LWC) is an important parameter in the process of aircraft icing. Ice shape and type can be greatly affected by LWC. For a valid icing wind tunnel test it is necessary to obtain the value of LWC before test. The present paper proposes a method to measure LWC in an icing wind tunnel, which combines both numerical and experimental results. Firstly, droplet trajectories are computed with a Lagrangian method to obtain the total collection coefficient of water droplet. Secondly, ice mass is computed, and the curve relating LWC with ice mass is obtained. Lastly, the experimental results of ice mass are used to determine the value of LWC from the curve. It is a convenient and economical method to measure LWC without the need of expensive and complex devices and with only an instrument for mass measurement. The value of LWC, in an icing wind tunnel with a 0.3 m×0.2 m test section, is then obtained. The results from test speeds of 25 m/s and 35 m/s are found in agreement, with a difference of not more than 0.01 g/m3, which validates the method. The study shows that when one nozzle is opened, the LWC value in the 0.3 m×0.2 m icing wind tunnel is about 0.15 g/m3.

An Object-Oriented Optimal Scale Choice Method of High Spatial Resolution Remote Sensing Image

Science & Technology Review. 2009, 27 (0921): 91-94. ;  doi:
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Abstract ( 663 )
The traditional pixel-based information extraction and classification method is not suitable for processing high spatial resolution remote sensing images because it only focuses on spectral information and ignores information concerning texture, shape and structure related with adjacent pixels. The object-oriented information and classification extraction approach can solve this problem, with the basic unit being the image object, which enjoys good integrity and uniqueness in a multi-scale segmentation algorithm. The related experimental researches show that it is necessary to extract the region of interest in optimal scale images. In view of this, the RMAS method is based on analysis of the limitations of two optimal scale selecting methods, according to the best classification principle as "homogeneity in class, heterogeneity between classes". This method makes the heterogeneity in class the minimum and that between class the maximum when RMAS is the maximum, so the segmentation scale is optimal. According to the principle of the highest information extraction accuracy based on the optimal scale, the experiment has verified the feasibility of this method and the classification results are found to be better. It is shown that several local peaks appear in the curve of RMAS and that the optimal scale is relative and usually in a range of values. So, it is difficult to extract information using only one scale for the class with a large area. The optimal scale should be very carefully chosen according to specific application cases.

Model of Cold AFFF Foam Spreading on the Circular Oil Surface under Gentle Application

Science & Technology Review. 2009, 27 (0921): 95-98. ;  doi:
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Abstract ( 1058 )
The development of the Aqueous Film Forming Foam (AFFF) heralds a revolution in the study on fire fighting foams. Fluorosurfactants are added in the AFFF to facilitate the spread of a thin film of water on oil fire. In fighting against fire, time is a very important parameter, which decides whether the damage can be effectively controlled. The spreading process is closely related with the fire fighting time. If foams spread quickly, the cover area will be large and the burning resistant ability can be improved. Since there is a foam drainage, in the model it is assumed that the AFFF foam spreading process is in a quasi steady state and the drainage will not affect the flow within a short time. The main driving force is the hydrostatic pressure and the viscosity shear between the AFFF foam and the oil interface. The foam spreading distance and the foam height are obtained based on the continuity equation and the momentum equation. The calculation results based on the model show that with a larger AFFF flux and a longer time, we will obtain longer spreading distance. With given AFFF and oil, the viscosity shear between AFFF foam and oil interface is the main parameter. In the test, it is found that resistance of the channel can also affect the spreading distance, by which the distance can be reduced. The AFFF drainage will also reduce the spreading distance. In order to improve the model, the resistance of the channel and the AFFF drainage are to be considered. A good model for a cold AFFF foam spreading on the circular oil surface under a gentle application is necessary for the AFFF foam to be used on large area oil fire, to predict the fire fighting time.

A Method of Dangerous Goods Depot Fiber Optic Passive Monitoring of Temperature and Humidity

Science & Technology Review. 2009, 27 (0921): 99-102. ;  doi:
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Abstract ( 609 )
Against the risk of explosive atmospheres Explosive materials storage temperature and humidity testing has been used from time to time manual reading mode, the workload, it is not easy to manage and the current domestic non-relevant and applicable to the environmentally friendly products, active devices can not be used to automate tests, presents a unique conversion method: the use of traditional wet and dry bulb thermometer shows the temperature and humidity on the scale, the method of optical hygrometer on the temperature and humidity values into a light intensity value (light signal), and to optical fiber to send out, using passive testing microcontroller processing temperature and humidity sensors are implemented. Namely, using optical fiber collimator and a combination of temperature and hygrometer to monitor temperature and humidity need to set the scope of optical fiber collimator placed in the middle of grating, optical fiber end face of the launch optical expansion swept up in a uniform parallel light through the hygrometer, at the receiving end so that the parallel light beam is then focused back to optical fiber end face. This method is its low cost, test results basically meet the requirements to solve the state material reserves, military, scientific research and production units and other inflammable and explosive dangerous goods depot in temperature and humidity monitoring.

Sliding Mode Control Strategy of DFIG in Wind Power System

Science & Technology Review. 2009, 27 (0921): 103-106. ;  doi:
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Abstract ( 1537 )
Wind power is a clean and renewable energy, and its exploitation is developing rapidly across the world. The Variable Speed Constant Frequency (VSCF) wind power generation system requires the Double Feed Induction Generator (DFIG) to have high response speed as well as good robustness. The DFIG will be affected both by internal disturbance of parametric variations and external disturbance of the load torque oscillation. The dynamics of the current response of the present PI controlled rotor may be in bad conditions. In addition, the above disturbances reduce efficiency and stability of the wind turbine. Slide Mode Control (SMC) is a kind of nonlinear control methods based on state space and is independent of object parameters and disturbances. Compared with PI control, SMC has a faster response, and is insensitive to the parameter variations and disturbances. This paper proposes a sliding-mode variable structure controllerI, as an integral action under exponential approximation law. The controller uses the boundary-layer design to reduce the vibration of the sliding-mode control. The simulation indicates that the dynamic performance and the anti-interference ability of DFIG are improved. The vibration is effectively reduced by adopting this control strategy with a simple design process and easy implementation.

Research Advances of Carbon Nanotube-based Gas Sensors

Science & Technology Review. 2009, 27 (0921): 107-110. ;  doi:
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Abstract ( 997 )
Carbon nanatubes(CNTs) have potential applications in the selective and rapid detection of various gas species due to their special electrical, mechanical, physical, chemical performance . In recent years, researches on the application of CNTs in gas sensing have made a great progress. CNTs-based gas sensors enjoy many good features, such as small size, the capability of working at room temperature, high sensitivity, and short response time. This paper reviews the recent progress on the development of intrinsic CNTs-based gas sensors, the functionalization of CNTs-based gas sensors and the applications in human breath, with the focus on how to improve the sensing performance(sensitivity,selectivity ,response time and reproducibility) and increase the gas species of detecting through the rational functionalization of CNTs with different materials(organic polymers ,metals and metal oxides) .The new desorption method besides heating and ultraviolet radiation, the selective detection for specific gas in the complex surroundings, the technology of CNTs-based gas sensor arrays, and the implementation of commercial gas sensor devices will be issues for future reseaches.

Working Mechanism of Space-based Infrared Detector for Early Warning and Its Combat Modes

Science & Technology Review. 2009, 27 (0921): 111-115. ;  doi:
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Abstract ( 699 )
The Space-Based Infrared Detector for Early Warning (SBIRDEW) is the most important payload of an early warning satellite. By detecting the infrared radiation of the exhaust plume of a rocket engine, the SBIRDEW searches and tracks targets, mostly missiles or rockets. The purpose and characteristics of the SBIRDEW, and its development trends are reviewed in this paper. The choice of the operation band is a key issue in the design of an infrared system. The very far infrared spectrum, in which the SBIRDEW works, is analyzed. It is pointed out that the absorption of the earth atmosphere is the most important factor that influences the choice of the operation band of the SBIRDEW. The SBIRDEW usually adopts the Focal Plane Array (FPA) infrared sensor based of Time Delay Integral (TDI) technology. The working mechanism of SBIRDEW is briefly analyzed. There are two main detecting modes, scanning and starring modes. Their principles, advantages and disadvantages are discussed. The two types of detectors will be used jointly in the space-based early warning mission in future. Theoretically, the SBIRDEW can be destroyed and avoided. The passive and active measures in combat are discussed.

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