The seasonal variations in biomass, abundance, and species composition of plankton in relation to hydrography were studied in the saline Bange Lake, northern Tibet, China. Sampling was carried out between one to three...The seasonal variations in biomass, abundance, and species composition of plankton in relation to hydrography were studied in the saline Bange Lake, northern Tibet, China. Sampling was carried out between one to three times per month from May 2001 to July 2002. Salinity ranged from 14 to 146. The air and water temperature exhibited a clear seasonal pattern, and mean annual temperatures were approximately 4.8℃ and 7.3℃, respectively. The lowest water temperature occurred in winter from December to March at-2℃ and the highest in June and July at 17.7℃. Forty-one phytoplankton taxa, 21 zooplankton, and 5 benthic or facultative zooplankton were identifi ed. The predominant phytoplankton species were Gloeothece linearis, Oscillatoria tenuis, Gloeocapsa punctata, Ctenocladus circinnatus, Dunaliella salina, and Spirulina major. The predominant zooplankton species included H olophrya actra, Brachionus plicatilis, Daphniopsis tibetana, Cletocamptus dertersi, and A rctodiaptomus salinus. The mean annual total phytoplankton density and biomass for the entire lake were 4.52×10^7 cells/L and 1.60 mg/L, respectively. The annual mean zooplankton abundance was 52, 162, 322, and 57, 144 ind./L, in the three sublakes. The annual mean total zooplankton biomass in Lakes 1–3 was 1.23, 9.98, and 2.13 mg/L, respectively. The annual mean tychoplankton abundances in Bg1, 2, and 3 were 47, 67, and 654 ind./L. The annual mean tychoplankton biomass was 2.36, 0.16, and 2.03 mg/L, respectively. The zooplankton biomass（including tychoplankton） in the lake was 9.11 mg/L. The total number of plankton species in the salt lake was signifi cantly negatively correlated with salinity.展开更多
2005年,一款冠以“Big Bang”之名的腕表系列出现在大众的视野中,the Big Bang是物理世界中对于物质与时间起源的定义。HUBLOT宇舶表以big bang为名,不难看出其背后深藏的野心,这将是一个足以改变品牌制表理念的腕表系列。如今20年过去,...2005年,一款冠以“Big Bang”之名的腕表系列出现在大众的视野中,the Big Bang是物理世界中对于物质与时间起源的定义。HUBLOT宇舶表以big bang为名,不难看出其背后深藏的野心,这将是一个足以改变品牌制表理念的腕表系列。如今20年过去,Big Bang系列不仅为品牌开创了崭新的发展篇章,更深刻影响了当代制表业的整体发展路径。展开更多
We put forward an enlightening view on repulsive force between antimatter:Antimatter repels each other,and the repulsive force is proportional to the product of their masses and inversely proportional to the square of...We put forward an enlightening view on repulsive force between antimatter:Antimatter repels each other,and the repulsive force is proportional to the product of their masses and inversely proportional to the square of the distance between them;There is no gravitational or anti-gravitational interaction between antimatter and positive matter.As their applications,we explain the Big Bang process in a new light.展开更多
In July,the Ali CMB Polariza〓〓tion Telescope(AliCPT)of〓〓ficially released high-quality maps of 150 GHz radiation from the Moon and Jupiter.The quality of these images not only validates the exceptional performance...In July,the Ali CMB Polariza〓〓tion Telescope(AliCPT)of〓〓ficially released high-quality maps of 150 GHz radiation from the Moon and Jupiter.The quality of these images not only validates the exceptional performance of the core instrument of AliCPT-1 but also signifies the successful completion of its first-stage con〓〓struction.展开更多
A team of researchers from the Beijing Normal University,the Institute of High Energy Physics(IHEP)under the Chinese Academy of Sciences(CAS),and the National Astronomical Observatories,CAS(NAOC),reported in Nature As...A team of researchers from the Beijing Normal University,the Institute of High Energy Physics(IHEP)under the Chinese Academy of Sciences(CAS),and the National Astronomical Observatories,CAS(NAOC),reported in Nature Astronomy on January 23,2025 their discovery of an X-ray flash about 12.5 billion lightyears away.The signals burst out only 1.2 billion years after the Big Bang,when our 13.8-billion-year-old universe was still in its infancy,and a science satellite swiftly recorded them.展开更多
INFOCUS|Listening to Echoes of Big Bang According to Inflation theory,a violent expansion in the wake of the Big Bang that stretched the spacetime from an extremely condense point to a cosmological scale,could have es...INFOCUS|Listening to Echoes of Big Bang According to Inflation theory,a violent expansion in the wake of the Big Bang that stretched the spacetime from an extremely condense point to a cosmological scale,could have estab lished the initial conditions that determined the subsequent evolution of our universe,sowing the seeds for the universe’s large-scale structure,like galaxy clusters.This very inflation could have also triggered the first ripples in our cosmos,the primordial gravitational waves(PGWs).Therefore,listening to such echoes of the Big Bang,we might better understand the early cosmos and its subsequent evolution.展开更多
Based on the mass-energy equation of special relativity and the assumption of the helical motion of light speed in cosmic space,we have theoretically demonstrated the true implications of Planck’s physical quantities...Based on the mass-energy equation of special relativity and the assumption of the helical motion of light speed in cosmic space,we have theoretically demonstrated the true implications of Planck’s physical quantities:Planck length and time represent the step size and period of the helical motion of light speed in the earliest cosmic space following the Big Bang;Planck energy constitutes the minimum energy unit associated with this spatial helical motion;Planck mass is the mass derived from this minimum energy unit.In accordance with the expression of Planck time,we have derived the relationship formula between gravitational acceleration and the speed of light,thereby uncovering an inevitable intrinsic connection between the gravitational field and the electromagnetic field,and indicating that the four fundamental forces in the universe can be unified.Finally,through our spatial helical motion model,we computed the specific values of the four fundamental forces at the moment of strong nuclear force separation.The results reveal that they are in complete agreement with the theoretical calculation values or experimental values in modern physics and quantum mechanics,thereby providing an interesting hint for the unified field theories.展开更多
针对电动化底盘动力转向系统(electric power steering,EPS)的多工况特征和协调不同工况下转向性能的要求,建立了EPS系统动力学模型和汽车三自由度转向模型,建立了EPS系统动态行为描述。设计了EPS系统的切换控制结构,针对助力工况、回...针对电动化底盘动力转向系统(electric power steering,EPS)的多工况特征和协调不同工况下转向性能的要求,建立了EPS系统动力学模型和汽车三自由度转向模型,建立了EPS系统动态行为描述。设计了EPS系统的切换控制结构,针对助力工况、回正工况和阻尼工况分别设计了柔性PID控制算法、模糊PID控制算法和Bang-Bang-PID控制算法,在不同的工况下采用相应的控制算法实时切换和协调控制。设计了1/4试验台架,进行了输入/输出特性试验、输入转矩/电动机电流特性试验和助力特性试验。结果表明:输入/输出特性的左右对称度>90%;输入转矩/电动机电流特性的左右对称度>90%,回程迟滞∈[0.2,0.8],非灵敏区∈[0,2],最大电流∈[30,35];原地转向时的转向轻便性提高了69.6%,5km/h时的转向轻便性提高了56.2%,随着车速的增加,汽车EPS系统的助力效能降低。展开更多
基金Supported by the China Geological Survey(Resources No.[2002]004)the National Natural Science Foundation of China(No.30371112)+1 种基金the Liaoning Science and Technology Foundation(Nos.002119,20022100)the Special Program for Key Basic Research of Ministry of Science and Technology,China(No.2014FY210700)
文摘The seasonal variations in biomass, abundance, and species composition of plankton in relation to hydrography were studied in the saline Bange Lake, northern Tibet, China. Sampling was carried out between one to three times per month from May 2001 to July 2002. Salinity ranged from 14 to 146. The air and water temperature exhibited a clear seasonal pattern, and mean annual temperatures were approximately 4.8℃ and 7.3℃, respectively. The lowest water temperature occurred in winter from December to March at-2℃ and the highest in June and July at 17.7℃. Forty-one phytoplankton taxa, 21 zooplankton, and 5 benthic or facultative zooplankton were identifi ed. The predominant phytoplankton species were Gloeothece linearis, Oscillatoria tenuis, Gloeocapsa punctata, Ctenocladus circinnatus, Dunaliella salina, and Spirulina major. The predominant zooplankton species included H olophrya actra, Brachionus plicatilis, Daphniopsis tibetana, Cletocamptus dertersi, and A rctodiaptomus salinus. The mean annual total phytoplankton density and biomass for the entire lake were 4.52×10^7 cells/L and 1.60 mg/L, respectively. The annual mean zooplankton abundance was 52, 162, 322, and 57, 144 ind./L, in the three sublakes. The annual mean total zooplankton biomass in Lakes 1–3 was 1.23, 9.98, and 2.13 mg/L, respectively. The annual mean tychoplankton abundances in Bg1, 2, and 3 were 47, 67, and 654 ind./L. The annual mean tychoplankton biomass was 2.36, 0.16, and 2.03 mg/L, respectively. The zooplankton biomass（including tychoplankton） in the lake was 9.11 mg/L. The total number of plankton species in the salt lake was signifi cantly negatively correlated with salinity.
文摘We put forward an enlightening view on repulsive force between antimatter:Antimatter repels each other,and the repulsive force is proportional to the product of their masses and inversely proportional to the square of the distance between them;There is no gravitational or anti-gravitational interaction between antimatter and positive matter.As their applications,we explain the Big Bang process in a new light.
基金Sponsored by CAS,the Chinese Ministry of Science and Technology and the National Natural Science Foundation of China,the project is anticipated to break through on the frontiers of fundamental physics,astrophysics and cosmology.
文摘In July,the Ali CMB Polariza〓〓tion Telescope(AliCPT)of〓〓ficially released high-quality maps of 150 GHz radiation from the Moon and Jupiter.The quality of these images not only validates the exceptional performance of the core instrument of AliCPT-1 but also signifies the successful completion of its first-stage con〓〓struction.
文摘A team of researchers from the Beijing Normal University,the Institute of High Energy Physics(IHEP)under the Chinese Academy of Sciences(CAS),and the National Astronomical Observatories,CAS(NAOC),reported in Nature Astronomy on January 23,2025 their discovery of an X-ray flash about 12.5 billion lightyears away.The signals burst out only 1.2 billion years after the Big Bang,when our 13.8-billion-year-old universe was still in its infancy,and a science satellite swiftly recorded them.
文摘INFOCUS|Listening to Echoes of Big Bang According to Inflation theory,a violent expansion in the wake of the Big Bang that stretched the spacetime from an extremely condense point to a cosmological scale,could have estab lished the initial conditions that determined the subsequent evolution of our universe,sowing the seeds for the universe’s large-scale structure,like galaxy clusters.This very inflation could have also triggered the first ripples in our cosmos,the primordial gravitational waves(PGWs).Therefore,listening to such echoes of the Big Bang,we might better understand the early cosmos and its subsequent evolution.
文摘Based on the mass-energy equation of special relativity and the assumption of the helical motion of light speed in cosmic space,we have theoretically demonstrated the true implications of Planck’s physical quantities:Planck length and time represent the step size and period of the helical motion of light speed in the earliest cosmic space following the Big Bang;Planck energy constitutes the minimum energy unit associated with this spatial helical motion;Planck mass is the mass derived from this minimum energy unit.In accordance with the expression of Planck time,we have derived the relationship formula between gravitational acceleration and the speed of light,thereby uncovering an inevitable intrinsic connection between the gravitational field and the electromagnetic field,and indicating that the four fundamental forces in the universe can be unified.Finally,through our spatial helical motion model,we computed the specific values of the four fundamental forces at the moment of strong nuclear force separation.The results reveal that they are in complete agreement with the theoretical calculation values or experimental values in modern physics and quantum mechanics,thereby providing an interesting hint for the unified field theories.
文摘针对电动化底盘动力转向系统(electric power steering,EPS)的多工况特征和协调不同工况下转向性能的要求,建立了EPS系统动力学模型和汽车三自由度转向模型,建立了EPS系统动态行为描述。设计了EPS系统的切换控制结构,针对助力工况、回正工况和阻尼工况分别设计了柔性PID控制算法、模糊PID控制算法和Bang-Bang-PID控制算法,在不同的工况下采用相应的控制算法实时切换和协调控制。设计了1/4试验台架,进行了输入/输出特性试验、输入转矩/电动机电流特性试验和助力特性试验。结果表明:输入/输出特性的左右对称度>90%;输入转矩/电动机电流特性的左右对称度>90%,回程迟滞∈[0.2,0.8],非灵敏区∈[0,2],最大电流∈[30,35];原地转向时的转向轻便性提高了69.6%,5km/h时的转向轻便性提高了56.2%,随着车速的增加,汽车EPS系统的助力效能降低。
