13 October 2009, Volume 27 Issue 0919

    

• Select all
  |

卷首语
• Select
  Scramble for the Seabed and Historical Duty of Scientists

  . 2009, 27(0919): 1-1.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
Articles
• Select
  Continuous-thrust Optimal Orbital Avoidance

  . 2009, 27(0919): 19-23.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  The nonlinear programming method is used to study the continuous-thrust minimum-time and the minimum-fuel-consumption orbital avoidance in this paper. During the spacecraft mission lifetime, a encounter with other space objects is possible and to avoid collision, some maneuver strategy is required. The optimal orbital avoidance is a typical trajectory optimization problem with path constraints, but is difficult to be solved by indirect methods. The dynamics of the spacecraft is described by the modified elements. Given the optimal parking orbit, the orbital avoidance mission is divided into transfer and roundtrip phases. Considering the minimum-time or the minimum-fuel-consumption performance, the optimal orbital avoidance problem can be formulated. Furthermore, the nonlinear programming method is applied to deal with the two phase orbital transfer problem. The simulations demonstrate that the minimum time/fuel-consumption orbital avoidance mission is well accomplished. The simulation results also show that the spacecraft flies around the earth with the maximum thrust magnitude during its whole time history both in the minimum-time and the minimum-fuel-consumption cases.
• Select
  Severe Accident Sequence Screening Criteria for Nuclear Power Plant

  . 2009, 27(0919): 24-27.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  Severe accidents prevention and mitigation is an important safety issue for new generation Nuclear Power Plant (NPP). This paper mainly focuses on the severe accident dominant sequences screening criteria when performing NPP severe accident management and study, including qualitative and quantitative criteria and their understanding. On this basis, a set of severe accident dominant sequence screening criteria is recommended for Chinese nuclear power plant severe accident study. Using this set of criteria to Advanced Passive Pressurized water reactor (AP1000) standard design is also attempted to show criteria's applicability. It is shown that severe accident sequence screening criteria should be described both qualitatively and quantitatively. From the qualitative point of view, the selection of severe accidents should be based on nuclear power plant state definition. Sequences which may lead to core damage or containment bypass and have most serious consequences in the range of beyond design basis accidents should be selected. From the quantitative point of view, absolute and relative values corresponding to severe accidents risk should be identified. At the same time, steep side effect combined with the outcomes of deterministic analysis and engineering experience should be considered. The screening results derived from the proposed screening criteria application on advanced reactor AP1000 are basically consistent with that given in AP1000 probabilistic safety assessment report.
• Select
  Difficulties and Countermeasures for Construction of the River-crossing Tunnel Along the South Tibet Road

  . 2009, 27(0919): 28-32.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  Based on the geological condition, surrounding environment and engineering characteristics of the river-crossing tunnel along the South Tibet Road in Shanghai, this paper analyzes the construction difficulties and potential risks, which involve many factors: complicated geological conditions, variable soil thickness, crossing of the Huangpu River and metro M8, the curved excavations. The related technologies were studied, concerning the large slurry balance shield for excavating river-crossing tunnel and traversing operational tunnels under conditions of practical construction. The results indicate that it is possible to prevent leaking of slurry, keep slurry balance on the excavation face and control the settlement of operational tunnels by controlling pressure and volume of slurry in real-time and keeping an appropriate speed of excavation. The coordinative platform is composed of the guidance system and the information management system for information to be integrated and shared, which improves automation and effective management level of shield construction. The technologies of designing and producing large slurry balance shield can also be used for similar constructions in future.
• Select
  Optimal Design of GTEM Cell Connector

  . 2009, 27(0919): 33-37.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  Gigahertz Transverse Electro Magnetic (GTEM) transmission cell is widely used in the field of electromagnetic compatibility tests. The transition connector of GTEM transmission cell is closely related with the performance of the transmission cell. The transition connector as a transition of the conversion component between the circular coaxial transmission line and the rectangular coaxial line connects the coaxial transmission line and the main body of the GTEM transfer chamber. If there is a structural discontinuity at the transition connector, it would make the characteristic impedance and the transmission cell mismatch and cause the phenomenon of electromagnetic wave reflection and high-order modes, deteriorating the transmission performance of the transmission room. According to the technical requirements of GTEM transmission cell, it should in principle be a continuous transmission system of impedance. To design the shape of the transition joint's outer surface of the inner conductor and the inner surface of the outer conductor simultaneously, the outer surface of the inner conductor and the outer conductor of the inner surface could smoothly transit, and the transition joint's characteristic impedance could match with the system. To design the connected parts between two ends and standard coaxial line and ax-shaped pieces, the smoothly connected surface, with minimized mutations should be ensured. According to the designed calculation data, the precise three-dimensional model is constructed through the SolidWorks. Three-dimensional model is imported into HFSS to be simulated and tested. So, it provides an effective design method to ensure the constancy of impedance characteristics of the transition joints. The mathematical model could be imported directly into the electromagnetic simulation software for easier further analysis. The inside and outside of the conductor' three-dimensional structure model could be imported into CNC to ensure the accuracy of conductor surface on both sides.
• Select
  Measuring Device for Output Error of the Solar Sensor

  . 2009, 27(0919): 38-41.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  The device for measuring output error is simple in principle and with a low cost. It can meet most requirements of the measurement accuracy for the solar sensor. Its development is a sub-project of the project of the satellite dynamic simulator, as one of the important problems before the study and test of the satellite dynamic simulator, to measure the output error of the solar sensor. A design of the device is presented in this paper. It is based on the powerful ARM7 microchip controller. The high precision digital two-axis electric rotating platform is used to change the input angle. The ARM microchip controller is used to control the rotating angle and the rotating speed. A specific solar simulator is used as the light source of the solar sensor. The output angle of the solar sensor is transferred to the PC by the wireless URAT communication module. The error curve is obtained while comparing the changed angle of the rotating platform with the output angle from the solar sensor. The sources of the error of the device are reduced greatly. The main error sources are from the rotating platform and the solar simulator. The accuracy of the rotating platform reaches 0.001 25 mm per degree. The accuracy of the device can be in arcsec level if the surrounding is at a perfect state.
• Select
  Optimization Design of Ad hoc Routing Protocol for the Communication of Lunar Exploration Multi-robots System

  . 2009, 27(0919): 42-46.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  Mobile ad hoc networks are a kind of self-organizing and self-reconfiguring networks. They can be established anytime and anywhere without the presence of stationary radio stations or fixed infrastructures. Thus they are regarded as an effective support tool for the communication of a lunar exploration multi-robots system. Generally speaking, there are two issues, the efficient energy conservation and the real-time communication, that are important for the lunar exploration multi-robots system. However, these two issues do not have a satisfactory answer with concurrently existing Ad hoc routing algorithms. Hence, an optimization design of the routing protocol is the key for the Ad hoc networks with the objective of the energy conservation and the constraint of the real-time communication. For that purpose, a node's energy consumption model is built based on the analysis of the network topology of the communication system. Then, a mathematical model is proposed to carry out the optimization for the optimal path. Moreover, a new power-aware routing scheme is presented based on the Dynamic Source Routing (DSR) according to the engineering requirements of the lunar exploration multi-robots communication system. With constraints of hops, total transmission power, and node's remaining energy, the modified distributed Bellman-Ford algorithm is employed to find the optimal path. Simulation results show that the routing protocol designed in this paper performs better for the lunar exploration multi-robots system than others.
• Select
  ARM Embedded System Reliability Fuzzy Comprehensive Evaluation Method

  . 2009, 27(0919): 47-51.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  According the IEEE definition, the embedded system is a device used to control, monitor, or assist the operation of equipment, machinery or plants. The embedded system usually supports real-time task, provides storage area protection, extends processor architecture and with very low power consumption. Based on these features, people have developed various kinds of embedded systems. Among them, ARM embedded system is the most important one and is applied widely in many areas, especially in safety critical system, where its reliability determines the reliability of the system. In order to ensure and enhance the reliability of the ARM embedded system, this paper proposes a fuzzy comprehensive evaluation method to realize a more overall and more accurate assessment of the reliability of the typical ARM embedded system. According to the characteristics of functions, the overall ARM embedded system is divided into different modules, including three parts: the hardware part, the software part and the system extension part. Because each module has different impacts on the reliability of the entire system, it is necessary to distinguish the different important level of the ARM embedded system modules. Based on the different important level of the ARM embedded system modules, the evaluation architecture is established, which is divided into three layers, a fuzzy method is introduced to solve the quantitative or qualitative problems. To deal with the matrix inconsistency problem, a fuzzy matrix transformation is used, to get the fuzzy consistency matrix. The evaluation matrix is constructed from the bottom to the top layers, and the rating column vector is combined to get the whole system reliability. Vertical missile launch control system based ARM is a safety critical system, with high reliability requirements. This model is put into application for the ARM embedded system reliability evaluation. The results show that the evaluation model gives an effective method to assess the ARM embedded system reliability.
• Select
  Alluvial Fan Conglomerate Reservoir Sedimentary Characteristics of Lower Karemary Formation in the 6th District of Karemary Oilfield

  . 2009, 27(0919): 52-56.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  By using the core, geological, and log data, alluvial fan conglomerate reservoir sedimentary characteristics of Lower Karemary Formation in the 6th District of Karemary Oilfield were studied and the distribution patterns of sandbodies were analyzed. The results show that Lower Karemary Formation is the alluvial fan face. The 6th District is located on a single fan. Sedimentary characteristics of each subfacies were analyzed on the basis of subfacies subdivision. The study shows that the inner fan is composed mainly of conglomerate, the middle is composed mainly of microconglomerates and gritrock, and the outer fan is composed mainly of fine sandstone. There are three distribution patterns of sandbodies:sheet pattern in inner fan, broad band pattern in middle fan and narrow band pattern in outterfan. The study of sedimentary characteristics and distribution patterns of sandbodies of each subface offer some geological guidelines for oilfield development.
• Select
  Study on the Field Oriented Control Based on Dual Y Shift 30° Permanent-Magnet Synchronous Motor

  . 2009, 27(0919): 57-60.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  Dual Y shift 30° Permanent-Magnet Synchronous Motor (PMSM) enjoys many good qualities. Due to its structural characteristics, there is no induction motor slip frequency current. In the field-oriented control of a process, one does not need to observe the flux linkage. Therefore, the permanent magnet synchronous motor field-oriented control is simple. But the field-oriented control method relies on a precise mathematical model of the motor. This paper uses the mathematical model of dual Y shift 30° PMSM to implement a six-phase high-performance permanent magnet synchronous motor electromagnetic torque control by the field oriented control method in a simulation. Permanent magnet synchronous motor is based on the six-phase static coordinate system of the mathematical model. With coordinate transformation, the mathematical model of a permanent magnet synchronous motor in the two-phase rotating coordinate system is established. Compared with the six-phase static coordinate system, the two-phase rotating coordinate system is greatly simplified, with reduced number of lower-order differential equations, and the straight chain and the cross-axis magnetic flux axis are no longer related with the angle. Based on the id=0 field oriented control, the decoupling control of dual Y shift 30° permanent-magnet is realized under this mathematical model. Simulation results show that a steady speed and torque can be obtained by this control method. This control scheme is very suitable for a multi-phase PMSM control system.
• Select
  Magnetoelectric Conversion Analysis of Layered Magnetoelectric Composite Materials

  . 2009, 27(0919): 61-64.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  In this paper, a L-T model of layered magnetoelectric composite materials is presented, which, based on piezoelectric effect and piezomagnetic effect constitutive equation, using the method of equivalent scheme, is used to analyze the magneto-ionic voltage coefficient of the composite materials, and to obtain various relations among physical parameters of the composite materials. Then a numerical computation is made of the materials magnetoelectricity response, and results are compared with those of interrelated finite-element experiments to obtain the magnetoelectricity response simulation result and the mechanical coupling in a composite where a magnetostrictive component is laminated with a piezoelectric one to achieve a giant magnetoelectric effect. It is shown that the direction of the applied magnetic field and the restriction upon the laminated composite affect the magnetoelectric coefficient markedly. It is found that the magnetoelectric voltage coefficient in the static method is quite close to that in the equivalent circuit approach, and it increases with the increase of the magnetostricive/piezoelectric thickness ratio. So a clear relationship is found between voltage and magnetic intensity, which provides a theoretical tool for the preparation and optimization of magnetoelectric materials. A new technology is developed in the field, for the environmental energy harvesting with the composite materials. Based on the simulation results, more studies will be carried out on using magneto electric materials as sensors.
• Select
  Visible Modeling and Estimation of Reserves for Tungsten Deposit

  . 2009, 27(0919): 65-68.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  Using the mine software Surpac to set up the geological database, the 3D model of orebody and the block model of orebody, the visualization is realized for the three dimensional models of surface, fault, stratum, and orebody. The data of borehole samples are combined and analyzed according to geological data. Through the three-dimensional variogram calculation and fitting, a variogram model is constructed. All information on the effective structure is summarized quantitatively. The ordinary Krigemethod and the distance power inverse ratio-method are used to analyze and estimate the orebody grade and reserves. The evaluation results of these two methods are analyzed and compared with the calculation results of the traditional geological block method. It is shown that the mine surface and the underground geological structure of the spatial relations and relevant ore-rock information can be completely and accurately displayed by the visualization of three dimensional models. At the same time an effective basis can be provided for the deposit exploitation and dynamic management of production. The 3D model established for the deposit and the estimation method of grade and reserves measurement is reliable and useful for the study of reserve estimation. It not only helps the development of traditional mining methods, but also plays an important role in the digitized process of the mine enterprises in China.
• Select
  Safety Assessment of the Spontaneous Combustion Tendency of Sulfide Ores Based on AHP and SPA

  . 2009, 27(0919): 69-73.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  The prevention and the control of the spontaneous combustion of sulfide ores are always a major safety issue for sulfide ore deposits. It is very important to exactly measure the spontaneous combustion tendency of sulfide ores, in order to ensure the safety of miners' life, maintain the normal production of the mine and make good utilization of the natural resources. The spontaneous combustion tendency of the ore samples were identified by a multi-factor method. The chemical composition analysis, mineral analysis, and mineral sampling of water-soluble iron ions were carried out to obtain the sulfate ion content against oxidation time, self-heating index, indicators of spontaneous combustion. A structural chart of spontaneous combustion tendency of the sulfide ores is established. The grades based on the tendency factors of the sulfide ores are identified by AHP. The oxidation indicator, indicator of self-heating and spontaneous combustion indicator based on calculations are selected to determine the spontaneous combustion tendency of the sulfide ores. The relationship between the spontaneous combustion tendency of indicator values and the number of classification standards are further analyzed and evaluated. Finally, the degree of oxidation and the classification are obtained according to the set pair trend of the samples, the quantitative results of the safety assessment are also obtained. The experiments show that No. 8, No. 3 ore bodies have a tendency of the spontaneous combustion. Those results are in line with the mine site's actual assessment. The results provide a theoretical basis for adopting measures against spontaneous combustion of sulfide ores.
• Select
  Study on Paper Deinking Sludge Fiberboard Using Urea Formaldehyde Resin

  . 2009, 27(0919): 74-78.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  The pyrolysis properties of Urea Formaldehyde (UF) were studied by synchronization thermal analyzer. The paper deinking sludge was used as the main raw materials for paper sludge fiberboard. The influence of density, resin content, temperature, time on mechanical properties of paper deinking sludge fiberboard was investigated. The results show that the suitable hot press temperature is 110～200℃. The suitable content of NH4Cl is 0.5%. The modulus of rupture of paper sludge fiberboard is 1.99～18.33 MPa, with an average value of 8.21 MPa. The modulus of elasticity of paper sludge fiberboard is 0.46～3.22 GPa, with an average value of 1.57 GPa. The internal bonding strength of paper sludge fiberboard is 1.58～3.15 MPa, with an average value of 2.25 MPa. The internal bonding strength after boiling and drying experiments of paper sludge fiberboard is 0.66～1.71 MPa, with an average value of 1.14 MPa. The thickness swelling rate of water absorption of paper sludge fiberboard is 4.36%～7.69%, with an average value of 5.54%. The density, resin content, temperature, time show different influences on mechanical properties of paper sludge fiberboard. The density has the maximum influence by range analysis. The influence of density, resin content and temperature on mechanical properties of paper sludge fiberboard is significant by SAS analysis.
• Select
  Comparison of Spatial Structure for Natural and Semi-natural Mixed Forests in Jingouling Forestry Farm, Jilin Province of China

  . 2009, 27(0919): 79-84.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  Three indices (uniform angle index, mingling index and neighborhood comparison ratio) are used to describe and compare the spatial structure of the natural mixed forest undisturbed by human activities and the semi-natural mixed stand of larch (Larix olgensis)-spruce(Picea jazoensis)-fir(Abies nephrolepis) which only exists in the over-logged forest of Changbai Mountains. Results indicate that two stands have the same uniform angle index of 0.52, with tree distribution being clustered. The average mingling index of the semi-natural mixed forest of larch-spruce-fir is 0.64, with moderate mixed characteristics; the coniferous trees (esp. spruce) in the stand are dominant as seen from the neighborhood comparison ratio based on Diameter at Breast Height (DBH), while the Korean pine(Pinus koraiensis) is in polarization and inferior position. The average mingling index of the natural mixed forest is 0.83 and higher than that of the semi-natural mixed forest of larch-spruce-fir, with intense mixed characteristics and higher stability; hardwood trees in the stand are dominant as seen from the neighborhood comparison ratio based on DBH, while the coniferous trees are in inferior position except spruce. The results could be used to optimize the spatial structure and near natural management of the over-logged forests and plantations.
• Select
  The Light-weight Door Design Based on the Vehicle Safety

  . 2009, 27(0919): 85-89.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  The lateral collision of a car is analyzed in this paper and the strength and design of its deformable barrier and columns are considered. The conditions of the simulation are the same as in the European New Car Assessment Programme (Eruo-NCAP). The influence of the strength and thickness of the door sheet on the safety of the car is discussed and analyzed. The result suggests that the strength and the thickness of the door sheet metal parts are not the key for safety in side impact crash of lateral columns. The central door reinforcement should not be too strong. The door inner panel strength and thickness is the key with respect to the amount of intrusion into the car. This analysis also shows that through the rational distribution of the strength and thickness of the door sheet metal, the door can be lighter by more than 10% as compared with its current weight.
• Select
  Effect of Uygur Medicine Hyssopus officinalis L. on Serum Eotaxin-2, Eotaxin-3 and sP-selectin Level of Asthma Rats

  . 2009, 27(0919): 90-93.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  The Uygur medicine Hyssopus officinalis L. on serum Eotaxin-2, Eotaxin-3 and sP-selectin levels of asthma rats is studied for the mechanism of its treatment of asthma. The test rats were randomly divided into normal control group, asthma model group and dexamethasone group and Hyssopus officinalis L. high and low dose group. They were sensitized with OVA, Al(OH)3 and DPT vaccine, and then were challenged with inhalation of aerosolized OVA solution for preparation of asthma model. The levels of serum Eotaxin-2, Eotaxin-3 and sP-selectin were determined with ELISA. The results show that as compared with model group, the number of EOS in BALF of the treatment groups is significantly reduced, and serum levels of Eotaxin-2 are decreased significantly (P<0.05). Compared with Hyssopus officinalis L. low-dose treatment group, the number of EOS in BALF is significantly reduced for the high dose group, and the serum levels of Eotaxin-2 are decreased significantly (P<0.05). The number of EOS in BALF and the serum levels of Eotaxin-2 are closely related (r=0.829). The EOS has a positive relationship with the serum Eotaxin-3 and sP-selectin levels (r=0.635, 0.348), P＜0.05. The serum Eotaxin-2 level has a positive relationship with the Eotaxin-3 sP-selectin levels (r=0.447, 0.362, P＜0.05). It is concluded that Eotaxin-2, Eotaxin-3 and sP-selectin may be in a mutual coordination, to aggravate the inflammatory response of asthma. Hyssopus officinalis L. may inhibit the secretion of Eotaxin-2, reducing the inflammatory response of asthma.
• Select
  Antiproliferative Activity of Individual Herbs of Abnormal Savda Munziq on HL-60 Cells

  . 2009, 27(0919): 94-98.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  Abnormal Savda Munziq (Patent no. C082130082.8) is a herbal formula composed of ten medicinal herbs, namely Glycyrrhiza uralensis, Ziziphus jujuba, Cordia dichotoma, Anchusa italica, Adiantum capillus-veneris, Euphorbia humifusa, Foeniculum vulgare, Lavandula angustifolia, Melissa officinalis and Alhagi pseudoalhagi. It is used in traditional Uighur medicine for the treatment and prevention of cancer, diabetes and cardiovascular diseases. This paper studies the antiproliferative activity of individual herbs of Abnormal Savda Munziq(except Alhagi pseudoalhagi) on HL-60 cells. Cell viability of HL-60 cells exposed to CH2Cl2 extract and MeOH extract of each herb was determined by the trypan blue exclusion method after 24 h, 48 h and 72 h of incubation (37°C, 5% CO2), respectively. As a result, except for Foeniculum vulgare, CH2Cl2 extracts of all herbs significantly reduce the viability of HL-60 cells (P<0.05); MeOH extracts of only two herbs, namely Glycyrrhiza uralensis and Euphorbia humifusa, significantly reduce the viability of HL-60 cells (P<0.05). The cell viability of cells exposed to CH2Cl2 extract of all herbs was shown to be significantly lower than that of cells exposed to its MeOH extract (P<0.05). The results clearly show that the CH2Cl2 extracts of eight herbs, namely Cordia dichotoma, Euphorbia humifusa, Adiantum capillus-veneris, Glycyrrhiza uralensis, Ziziphus jujuba, Lavandula angustifolia, Anchusa italica, Melissa officinalis and the MeOH extracts of two herbs, namely Glycyrrhiza uralensis and Euphorbia humifusa, have in vitro antiproliferative activity on HL-60 cells. The antiproliferative activity of CH2Cl2 extract of each herb is stronger than that of its MeOH extract.
• Select
  Significance of Expression of IGF-I, OPN and PTEN Protein in Non-small Cell Lung Cancer

  . 2009, 27(0919): 99-103.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  To investigate the expressions of IGF-I, OPN and PTEN and their correlation with prognosis in Non-Small Cell Lung Cancer (NSCLC), immunohistochemical staining was used to identify the expression of IGF-I, OPN and PTEN in 61 cases of NSCLC and 30 cases of adjacent non-cancer tissues. In NSCLC cases, the expressions of IGF-I and OPN were higher than those in the adjacent non-cancer tissues (P＜0.05). The positive rates of IGF-I were closely correlated with the stage of tumor and lymph node metastasis. The positive rates of OPN were closely correlated with the grade of differentiation, lymph node metastasis and TNM staging. In NSCLC cases, the expression of PTEN was lower than those in the adjacent non-cancer tissues (P＜0.05), the positive rates of PTEN was closely correlated with size of tumor, the grade of differentiation and lymph node metastasis (P＜0.05). The expression of IGF-Iwas correlated positively with that of OPN (P＜0.05). The expression of IGF-I and OPN were correlated negatively with that of PTEN (P＜0.05). It is concluded that the expressions of IGF-I, OPN and PTEN are related to the occurrence and progression of NSCLC. And they may serve a valuable index for diagnosing the malignant extent and prognosis of lung cancer
• Select
  Photocatalytic Degradation of Methylene Blue Solution by TiO2 Particles Doped Zn2+

  . 2009, 27(0919): 104-107.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  Printing and dyeing waste water is one of the key concerns of sewage treatment. The methylene blue is the typical organic pollutant in dyeing waste water. The methylene blue solution will be degraded by TiO2 particles doped Zn2+ as the photo-catalyst. The XRD pattern analysis shows that the doped ion Zn2+ has changed the ratio of anatase to rutile. Parameters during the preparation of the catalyst affect the photocatalytic degradation rate of methylene blue greatly. The pure TiO2 calcined performs the best at 450℃. The TiO2 doped Zn2+ calcined performs the best at 500℃. That catalyst dosage should be neither too high nor too low, which is not conducive to the improvement of photocatalytic activity. The degradation ratio of methylene blue is the highest when the concentration of catalyst is 1 g/L. The photocatalytic activity of catalyst is relatively high when the concentration of Zn2+ is 0.5%. As the doping amount of Zn2+ further increases, the photocatalytic activity is decreased. It becomes more difficult for ultraviolet light to reach the catalyst surface when the concentration of organic compounds is high. The utilization efficiency of light, is reduced, so the catalyst activity is getting lower. The degradation is relatively fast when the methylene blue initial concentration is 5 mg/L.
Reviews
• Select
  Ecological Impact of Ocean Acidification

  . 2009, 27(0919): 108-111.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  Approximately one-half of the carbon dioxide (CO2) produced by fossil fuel burning and cement production as a result of human activities during the past 200 years is being taken up by the oceans. This absorption process is chemically changing the oceans, in particular, increasing its acidity. It is reported that the uptake of CO2 has led to a reduction of the pH value of surface seawater of 0.1 units, equivalent to a 30% increase in the concentration of hydrogen ions. If global emission of CO2 from human activities continues to rise at the current rates, the average pH value of the oceans could fall by 0.5 units (equivalent to a three fold increase in the concentration of hydrogen ions) by the year 2100. This pH value would be lower than that has been experienced for hundreds of millennia and, critically, this rate of change is probably hundred times greater than at any time over this period. The evidence suggests that acidification of seawater would damage the calcifying organisms but it is unclear how that will affect stability of ecosystem and human health. The increasing fragility and sensitivity of marine ecosystems need to be taken into consideration during the formulation of any policies about their conservation, sustainable use and exploitation, or the communities that depend on them. Actions need to be taken now to reduce global emissions of CO2 to the atmosphere to avoid the risk of irreversible damage to the oceans. No option that can make a significant contribution should be ignored.
• Select
  Progress of Discoloration of Dyeing Wastewater

  . 2009, 27(0919): 112-115.

  Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save

  The research progress of printing and dyeing wastewater treatment methods is reviewed in this paper, which include the biological treatment method, chemical oxidation method, adsorption method and electrochemical method. The new wastewater treatment technology such as the discharge plasma technology, supercritical water oxidation technology, membrane separation technology and ultrasound technology are discussed. The dye wastewater treatment technology is specially addressed. Chemical oxidation technique is widely used and usually as a pretreatment before biological treatments. Adsorption technique is efficient and does not destroy the structure of dye molecules, while the dye can be recycled. Electrochemical techniques not only can remove heavy metal ions, but also can remove Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD) and Total Suspended Solids (TSS), with a good effect on the decolorizing dye. Supercritical water oxidation can completely discolor noxious organics so as to avoid the secondary pollution, with a fast reaction rate and a wide application. Membrane separation technique is efficient and energy saving, which reuses waste water and recycles useful substance. Ultrasonic technique has a fast reaction rate and can be used in various operating conditions. It not only can be used alone but also be combined with other methods.