08 September 2013, Volume 31 Issue 25
    

  • Select all
    |
    Articles
  • LIAN Tongshu
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    This paper is to issue a new theorem in the field of the theory of adjustment for reflecting prisms:Theorem of Adjustment for Reflecting Prisms.First, an embryonic form of this theorem called the "cosine law and two-vector subtraction rule", referred only to the image lean has been discussed relatively in detail, although it was created by the author 40 years ago. And then its follow-on evolving process including five times of going up has been briefly described. Finally an exact and clear definition of the theorem is given.
  • ZHU Chuangang;DING Yifeng;XU Faqiang
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Diffusion of arsenic atoms affects the quality of interface magnetic integrated device and the physical properties of the structure. A method was put forward to improve the interface magnetism by passivation process. The valence band spectrum and core level spectrum were measured by synchrotron radiation photoemission. Experimental results confirm interface diffusion of As atoms. The result was compared with that from Fe/GaAs without passivation and it is confirmed that passivation has attenuated diffusion of arsenic atoms; Fe 3d band is expanded by exchange-splitting interaction, showing the Fe film in good magnetic order and the magnetism of Fe film has been enhanced. According to the large exchange splitting in valence band spectra and the related results, it can be concluded that passivation technology can be used to improve the quality of integrated magnetic devices.
  • ZHENG Li;PENG Youxin;BU Xueqin;FENG Kang
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    The design of anti-icing system is in term of the meteorological conditions causing aircraft icing during flight. The physical simulations on meteorological conditions and standards, the surface simulation equipments and mothdologies involved in fight icing are reviewed. To meet the features of climate and types of aircraft in China, the principles to set the appropriate meteorological conditions for anti-icing system design, and experimental plans made for the typical freighter, helicopter and fighter are put forward. Combined with the domestic design and experiment of Icing Wind Tunnel(IWT), critical techniques are presented, e.g., its inner temperature, wind speed and the reproducing of the cloud and fog. During the experiments, a closed-loop controlled refrigerating system is employed to keep a low temperature condition, and a wind turbine system is used to generate airflow with high speed, and a fog spray system is applied to produce the artificial cloud, and the liquid water content and the cloud particle diameter can be controlled by adjusting the water pressure, the air pressure and the quantities of the operative nozzle. Further, the apparatuses and methods are discussed and compared for the correct observation on Liquid Water Content (LWC), Median Volume Diameter (MVD) and uniformity of the cloud and fog.
  • LIU Yong;WANG Baomin;WANG Xin;HAN Yuntao
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Scheme selection is a Multiple Attribute Decision Making (MADM) problem. The Uncertain Linguistic MADM (ULMADM) method is generally studied and widely used. The key point for this kind of decision making is the aggregation algorithm. It is necessary to compare and rank uncertain linguistic variables in the process of decision making. To overcome the error occuring in the existed ranking model, a new model that can accurately calculate the possibility degree is presented, which guarantees that the subscript value of an uncertain linguistic variable is subject to uniform distribution. During the aggregation algorithms, the uncertain linguistic hybrid geometric mean (ULHGM) operator is of good applicability. This operator deals with the weight of a datum itself ahead of the position weight, so it might allocate counterproductive position weights to experts' original opinions. To avoid this, its aggregation process is improved, and it directly allocates position weights to experts' original opinions. The ULHGM operator needs twice exponential weight operations to complete aggregation, but the improved ULHGM (IULHGM) operator only needs once, so the improved algorithm is more convenient. Then the scheme selection method based on ULWGM operator and IULHGM operator is formulated. Finally, taking the selection of the maintainability design scheme of a certain shipborne gun as an example, the experts' evaluation data are aggregated by IULHGM operator and ULHGM operator, respectively, which lead to different scheme ranking results, and the cause is analyzed. The case shows that the aggregation algorithm of IULHGM operator is more accurate and reasonable than that of ULHGM operator.
  • LUO Yaodong;LUO Bing
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    In blasting operation, energy of blasting seismic transferrs differently due to differences in rock structure and construction. In order to control blasting seismic effect effectively, the borehole stress-strain of blasting process is researched by the theoretical study and model test. The relationship of the hole length between duration of vibration and peak strain is investigated respectively. Meanwhile, the seismic effect is compared in different intervals between the shallow hole and deep hole. In addition, amplitude, frequency and duration of vibration are also comprehensive compared. The results show that air interval charge can decrease the blasting seismic effect, and reduce the impact and backlash. Moreover, compared with three loading modes, the vibration reduction is up to 10%-25%. Concretely, the vibration reduction effect is the best through the air interval charge in bottom of hole, and the upper is followed. Blasting seismic effect is maximum in the middle of air-spaced.
  • YANG Bing;LI Jingsong;QI Chengxiang;FENG Xiang
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    For horizontal wells with high water cut, water shutoff operations should be conducted to improve the oil production. But not all the wells with high water cut are suitable for water shutoff. To select the most suitable horizontal well to conduct water shutoff operation, various factors related to well production should be considered. On the analysis of waterflood impact factors, geological parameters and production factors are selected, which have great impact on horizontal well waterflood in building the decision-making system for reservoir with bottom water. Expert system with uncertainty representation method was used for characterizing the filter index. In building the optimized horizontal well water shutoff decision-making model, fuzzy mathematical comprehensive evaluation technology and variable weights evaluation method is used. Using this model, the wells having greater potential to conduct water shutoff operation can be figured out. The case study shows that, in this method all the factors affecting waterflood is considered and negative effect of singular factor on well selection decision-making is avoided, which can make the water shutoff well selection more scientific and logical.
  • LIU Haiyan;WANG Xi;ZHONG Gansheng;LI Yiwen;LIU Jia;OU Lina;LIU Yunxiang;GAO Yuan
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Though comparing the toxicity of the Gansuibanxia soup, Gansuibanxia soup with Zhigancao removed, Gansuibanxia soup with Cugansui removed, Gansuibanxia soup with Zhigancao and Cugansui removed, and Zhigancao, Cugansui and the compatibility of Zhigancao and Cugansui, the toxicity of single herbs, anti-drug combinations, and the compound containing anti-drug combination is evaluated by dismantling the compound containing anti-drug combination of Gansui and Gancao. The Kunming male mice of 18-20g were randomly divided into a blank group, Gansuibanxia soup group, Gansuibanxia soup with Zhigancao removed group,Gansuibanxia soup with Cugansui removed group, Gansuibanxia soup with Zhigancao and Cugansui removed group, Zhigancao group, Cugansui group and the compatible group of Zhigancao and Cugansui. The blank group was administered with distilled water and other groups were administered with related drugs. For each group, LD50 is obtained in this way: The drugs are continuously administered for 28 days, to cause half of the lethal to evaluate the toxicity. The results show that the values of LD50(n) for the compatible group of Zhigancao and Cugansui, the Zhigancao group, the euphorbia and pinellia soup group are: 44.21, 48.26, 51.01g crude drug·kg-1, and for other experimental groups, the half lethal dose is not reached in the case of the continuous administration for 28 days. It is suggested that the Gansuibanxia soup with Gansui and Gancao removed, the anti-drug combination or individually with Gansui or Gancao removed, alone do not show the cumulative toxicity, while for the two flavor combination of anti-drug application in the compound, the LD50(n) value has an increasing trend.
  • DONG Dan;WU Huiling;ZHANG Taotao;LIU Weicheng
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Streptomyces lydicus strains A02 is isolated from the soil of suburban vegetable and forest fields in Beijing (China), which is capable of producing natamycin and has proved to be a potential biocontrol agent to several plant fungal diseases. In order to clone the biosynthetic gene clusters and regulate genes of natamycin, the genomic DNA of Streptomyces lydicus A02 is extracted and partially digested with HindIII and BamHI to increase the yield of natamycin by gene modification, the 97-194kb and 48.5-97kb high molecular weight DNA are extracted and ligated to pCC1BAC. The ligation mixtures were transformed into EPI300 competent cells. A total of 800 and 1500 colonies are obtained by white-blue screening. The analysis of enzyme digestion shows that the average size of the insert fragments are about 133kb and 65kb, and the frequency of clones without inserts is less than 1%. The libraries can cover 12.28 times and 11.25 times of genome if the Streptomyces lydicus A02 contains 8Mb chromosome. Therefore, the probability of screening the target fragment from the libraries is more than 99.99%. This BAC library will be an important resource used in gene cloning, the secondary metabolic pathways and new antibiotics.
  • WANG Hui;GUO Feng;GUAN Chao;DUAN Yuxi;BAI Hongzhi
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    To explore an easy, rapid and economical approach for extracting rice (Oryza sativa L.) genomic DNA for SSR (Simple Sequence Repeat) analysis, half-grain dry seed of rice Shennong265 is taken as tested material, just one step was used for cell lysis by SDS buffer, and the operation of RNA digestion was integrated into protein extraction. During this process, the SDS concn was 0.5% (W/V), water bath time was 10min, extraction with chloroform/isoamyl alcohol was used. High quality genomic DNA from rice seed was obtained simply and quickly. In this paper, the results of agarose gel electrophoresis all showed that the purity and integrity of the isolated DNA were satisfying; the amplified bands were clear as well as good in repeatability and stability, indicating that it can be used in SSR marker analysis. This is a time-saving method for extraction of genomic DNA, and can be effectively applied in genetic diversity analysis of rice seed and marker aided breeding activity.
  • WANG Chongtao;LI Shaokun
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Based on the analysis of typical characteristics and inherent law of high-yielding corn (≥15000kg/hm2)fields in China, the way of breaking through of the yield reaching 15000kg/hm2 and the key technologies are put forward. The results show that harvest ears is the most important factor in yield components factors. Under the conditions of the present production, the optimal yield components mode are planting density per hectare (70755-101250 plants), ear number per hectare (7.01×104-10.09×104 ears), grain number per ear (453-642 grains), 1000-grain weight (323.0-414.9g), kernel weight per ear (162.5-236.2g), and 35°N-44°N can be regarded as corn high-yielding belt of China. Furthermore, the main technical ways for breakthrough of the corn yield are given, including selection of mid-late maturity hybrids with high population tolerant, higher population, wider use of chemical fertilizers to meet nutrient demands, intensive management, delay harvest, creating high-quality population, prolonging accumulating time of dry matter after flowering and increasing transfer rate of organ to grain, and taking full advantage of light-temperature resources.
  • Reviews
  • CHEN Jian
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    An explosive source is the most commonly used excitation source in seismic exploration. Studies on the characteristics of explosive source play an important role in improving energy and resolution of seismic waves. In this paper, the progress of components and structures of explosive charge are reviewed. Then the practical application value and limitation are commented and the potential future research directions are pointed out. The basic requirement of explosive source for seismic exploration is introduced, and the method of formulation design of explosive to improve seismic wave energy is analyzed and four main charge components during the last twenty years are summarized. On the other hand, the design principle and mechanism of charge structure including multi-level-delayed charge, low detonation velocity and elongated charge, shaped charge, multi-well shot arrays charge and screwing charge are introduced, respectively, and the application effect and scope of each type of explosive structure are analyzed, and looks forward to the prospect of explosive source in the future.
  • LIU Gang;LIU Pengtao;HAN Jinliang;CHEN Chao
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Applying cold production to heavy oil reservoirs is one of the hottest technologies of the present oil exploration, which can improve the yield of oil wells substantially. However, excessive sanding can damage the production equipment while excessive sand prevention can decrease the efficiency of the yield. Both of them in actual production can bring problems. In order to seek the optimal solutions in sand production and sand prevention, and achieve sand management in oil wells, a set of sand monitoring systems for real time monitoring are needed to show sand information continuously and effectively to provide optimal strategy. According to the research of sand monitoring technology worldwidely, different sand monitoring methods such as ultrasonic methods, ER methods, surface monitoring and underground monitoring, equipments such as ClampOn system, CorrOcean system and Landy system, and signal processing methods such as FFT, WT and EMD are introduced. Characteristics of these methods and facilities are analyzed, and the importance of sand monitoring and the development trends of sand monitoring are put forward.