Hall thruster is a type of electric propulsion thruster which is often regarded as a moderate specific im- pulse space propulsion technology and is used primarily for station keeping and orbit maintenance tasks. Magne...Hall thruster is a type of electric propulsion thruster which is often regarded as a moderate specific im- pulse space propulsion technology and is used primarily for station keeping and orbit maintenance tasks. Magnetic field is the most important aspect in Hall thruster＇s design. Each time the performance improvement of Hall thrusters is accompanied with the regeneration of magnetic field design. Now, all the maior space nations treat the magnetic field design as the key technology for Hall thrusters, and many Hall thrusters have emerged in recent years, for example, BPT-4000 and NASA- 173M. In China, based on magnetic focus technology, the Beijing Institute of Control Engineer- ing （BICE） has been developing Hall thrusters ranged from hundreds of watts to 5 kilowatts, including the IS00 W HEP- 100MF and the 5 kW HEP- 140blF Hall thrusters. This paper briefly reviews the development of the HEP-XXMF series Hall thruster. The principle of the Hall thruster, the design methods and the current status of HEP-100MF and HEP- 140MF are discussed in the paper.展开更多
Green design horizon, explore the hand-painted rendering performance techniques,from conception to take as, composition distribution, global and local processing, local expansion method, the performance of rendering a...Green design horizon, explore the hand-painted rendering performance techniques,from conception to take as, composition distribution, global and local processing, local expansion method, the performance of rendering and other aspects of analysis and propose countermeasures. Accumulation of professional material for designers and nutrients at the same time, raise awareness of the environment, space and natural understanding, To improve the aesthetic horizon, hand-painted rendering green design and students ability to innovate education is of great significance.展开更多
Fructo-oligosaccharide （FOS） is a type of dietary fiber. It can not be digested by enzymes in the body. It also helps to improve a digestion in the intestine, an excretion system and prevent the cancer. Jerusalem ar...Fructo-oligosaccharide （FOS） is a type of dietary fiber. It can not be digested by enzymes in the body. It also helps to improve a digestion in the intestine, an excretion system and prevent the cancer. Jerusalem artichoke is scanned and analyzed by High Performance Liquid Chromatography （HPLC） for quantity of FOS. They are selected for extraction and drying process. Studies on the extraction for a powder making, the conditions are optimum for maximum yield. Experiments manage using a factorial real 2 × 4 × 6 in 2 blocks of Randomized Complete Block Design （RCBD） models. The first factor studies on two types of solvent. The second factor is the four levels of temperature in the extraction with water at 25 ℃, 35 ℃, 50℃ and 60℃ for 30 min. The third factor is the ratio of sample per solvent as 5, 6, 10, 15, 20 and 30 times. The data and comparison of average is analyzed by Duncan＇s New Mutiple Range Test at the significant level 0.05. The concentrated extracts are processed to powder by freeze drying, a hot air and vacuum drying. Optimal conditions control the temperature and time by heating in both vacuum and conventional oven. The results of temperature on the extraction are significantly different at a = 0.05. In drying process with high temperature, the color of product is more yellow （b） and less white （L）. The difference of color value is statistically significant at level a = 0.05. The sensory evaluation of food products are added the extracted powder and attribute by panelist. High level acceptance of product is aspectual about texture and flavor. FOS is the trend of functional foods for health. It is focus on low energy and on obesity including increasing the absorption of calcium.展开更多
Landscape design for a green community should be favorable for the ambient ecological environment and for enhancement of both the local climate of a residential area and the environmental quality of life. This paper p...Landscape design for a green community should be favorable for the ambient ecological environment and for enhancement of both the local climate of a residential area and the environmental quality of life. This paper presents optimization methods for plant landscape design that take account of results of comparisons of noise reduction effects, heat island temperature decreases and effects on ventilation. These methods are based on different plant configurations and various luminous environments, such as exterior sunshine and shaded areas after the simulation of exterior luminous, acoustic and thermal environments of a residential area using the analytic software ECOTECT, CADNA/A, and PHEONICS. Three different types of residential buildings are simulated including a faculty apartment in the Xixi Campus of Zhejiang University, the Huaqing Villa and the Gangwan Jiayuan faculty apartment of Zhejiang University, China, based on green building design theory. In addition, the methods and process flow of landscape design of green residential areas are also described for the improvement of the exterior physical living environment.展开更多
Sedimentary pigments are useful proxy indicators of phytoplankton biomass, community structure, primary productivity and human influence in lacustrine and oceanic ecosystems. Pigments are relatively labile due to thei...Sedimentary pigments are useful proxy indicators of phytoplankton biomass, community structure, primary productivity and human influence in lacustrine and oceanic ecosystems. Pigments are relatively labile due to their complex chemical structures, which makes the extraction and analysis of sedimentary pigments challenging. In addition, it is important to select appropriate methods to study sedimentary pigments in regions which lack previous investigations. In this study, we adopted the L9（34） orthogonal design to develop methods of extraction and HPLC （high performance liquid chromatography） analysis of sedimentary pigments at two lakes on the Tibetan Plateau： meromictic lake-Dagze Co and dimictic lake-Jiang Co. The orthogonal design comprises 9 combinations of various parameters for extraction and HPLC analysis. The results show that the type and volume of solvent are the most important factors for pigment extraction, and the mobile phase and column selection are the most important for HPLC analysis. For the study sites, we found that the best methods to extract sedimentary pigments are as follows： the use of a mixture of acetone：methanol：water （80： 15：5, v：v：v） as the extraction solvent; sol- vent/sample ratio of 10 mL/g; sonication for 30 s and standing extraction for 6 h. The best methods for HPLC analysis are as follows： Zorbax Eclipse plus C8 column with mobile phase A, methanol：acetonitrile：0.25 M aqueous pyridine （50： 25：25, v ： v ： v） and mobile phase B, methanol： acetonitrile： acetone （20： 60： 20, v： v： v）; pH of mobile phase A adjusted to 6 with acetic acid; and HPLC column temperature maintained at 40~C. The study provides an experimental basis for future investigations of past changes in primary productivity and the response of lake ecosystems to climate change and human activities on the Tibetan Plateau.展开更多
文摘Hall thruster is a type of electric propulsion thruster which is often regarded as a moderate specific im- pulse space propulsion technology and is used primarily for station keeping and orbit maintenance tasks. Magnetic field is the most important aspect in Hall thruster＇s design. Each time the performance improvement of Hall thrusters is accompanied with the regeneration of magnetic field design. Now, all the maior space nations treat the magnetic field design as the key technology for Hall thrusters, and many Hall thrusters have emerged in recent years, for example, BPT-4000 and NASA- 173M. In China, based on magnetic focus technology, the Beijing Institute of Control Engineer- ing （BICE） has been developing Hall thrusters ranged from hundreds of watts to 5 kilowatts, including the IS00 W HEP- 100MF and the 5 kW HEP- 140blF Hall thrusters. This paper briefly reviews the development of the HEP-XXMF series Hall thruster. The principle of the Hall thruster, the design methods and the current status of HEP-100MF and HEP- 140MF are discussed in the paper.
文摘Green design horizon, explore the hand-painted rendering performance techniques,from conception to take as, composition distribution, global and local processing, local expansion method, the performance of rendering and other aspects of analysis and propose countermeasures. Accumulation of professional material for designers and nutrients at the same time, raise awareness of the environment, space and natural understanding, To improve the aesthetic horizon, hand-painted rendering green design and students ability to innovate education is of great significance.
文摘Fructo-oligosaccharide （FOS） is a type of dietary fiber. It can not be digested by enzymes in the body. It also helps to improve a digestion in the intestine, an excretion system and prevent the cancer. Jerusalem artichoke is scanned and analyzed by High Performance Liquid Chromatography （HPLC） for quantity of FOS. They are selected for extraction and drying process. Studies on the extraction for a powder making, the conditions are optimum for maximum yield. Experiments manage using a factorial real 2 × 4 × 6 in 2 blocks of Randomized Complete Block Design （RCBD） models. The first factor studies on two types of solvent. The second factor is the four levels of temperature in the extraction with water at 25 ℃, 35 ℃, 50℃ and 60℃ for 30 min. The third factor is the ratio of sample per solvent as 5, 6, 10, 15, 20 and 30 times. The data and comparison of average is analyzed by Duncan＇s New Mutiple Range Test at the significant level 0.05. The concentrated extracts are processed to powder by freeze drying, a hot air and vacuum drying. Optimal conditions control the temperature and time by heating in both vacuum and conventional oven. The results of temperature on the extraction are significantly different at a = 0.05. In drying process with high temperature, the color of product is more yellow （b） and less white （L）. The difference of color value is statistically significant at level a = 0.05. The sensory evaluation of food products are added the extracted powder and attribute by panelist. High level acceptance of product is aspectual about texture and flavor. FOS is the trend of functional foods for health. It is focus on low energy and on obesity including increasing the absorption of calcium.
基金Project (No. R1080363) supported by the Zhejiang Provincial Natural Science Foundation of China
文摘Landscape design for a green community should be favorable for the ambient ecological environment and for enhancement of both the local climate of a residential area and the environmental quality of life. This paper presents optimization methods for plant landscape design that take account of results of comparisons of noise reduction effects, heat island temperature decreases and effects on ventilation. These methods are based on different plant configurations and various luminous environments, such as exterior sunshine and shaded areas after the simulation of exterior luminous, acoustic and thermal environments of a residential area using the analytic software ECOTECT, CADNA/A, and PHEONICS. Three different types of residential buildings are simulated including a faculty apartment in the Xixi Campus of Zhejiang University, the Huaqing Villa and the Gangwan Jiayuan faculty apartment of Zhejiang University, China, based on green building design theory. In addition, the methods and process flow of landscape design of green residential areas are also described for the improvement of the exterior physical living environment.
基金supported by National Key Basic Research Programs of China (Grant No. 2012CB956100)the National Natural Science Foundation of China (Grant Nos. 41072120 & 41321061)
文摘Sedimentary pigments are useful proxy indicators of phytoplankton biomass, community structure, primary productivity and human influence in lacustrine and oceanic ecosystems. Pigments are relatively labile due to their complex chemical structures, which makes the extraction and analysis of sedimentary pigments challenging. In addition, it is important to select appropriate methods to study sedimentary pigments in regions which lack previous investigations. In this study, we adopted the L9（34） orthogonal design to develop methods of extraction and HPLC （high performance liquid chromatography） analysis of sedimentary pigments at two lakes on the Tibetan Plateau： meromictic lake-Dagze Co and dimictic lake-Jiang Co. The orthogonal design comprises 9 combinations of various parameters for extraction and HPLC analysis. The results show that the type and volume of solvent are the most important factors for pigment extraction, and the mobile phase and column selection are the most important for HPLC analysis. For the study sites, we found that the best methods to extract sedimentary pigments are as follows： the use of a mixture of acetone：methanol：water （80： 15：5, v：v：v） as the extraction solvent; sol- vent/sample ratio of 10 mL/g; sonication for 30 s and standing extraction for 6 h. The best methods for HPLC analysis are as follows： Zorbax Eclipse plus C8 column with mobile phase A, methanol：acetonitrile：0.25 M aqueous pyridine （50： 25：25, v ： v ： v） and mobile phase B, methanol： acetonitrile： acetone （20： 60： 20, v： v： v）; pH of mobile phase A adjusted to 6 with acetic acid; and HPLC column temperature maintained at 40~C. The study provides an experimental basis for future investigations of past changes in primary productivity and the response of lake ecosystems to climate change and human activities on the Tibetan Plateau.
