青海湖区大型底栖动物群落结构与空间分布格局

为了解青海湖大型底栖动物的群落结构特征、空间分布格局及关键驱动力,于2011—2012年分4次对青海湖区主体湖、3个子湖和5条入湖河流进行了系统调查。共采集到底栖动物28个分类单元,隶属于3门5纲15科,主体湖区、咸水和淡水子湖及入湖河流分布有9、5、9和15种;它们的密度分别为455.8、1562.7、741.3和331.2 ind./m2;生物量为1.18、3.70、2.75和4.53 g/m2。优势度分析显示,喜盐摇蚊为主体湖区绝对优势种(占总密度的83.32%)。Surfer模拟显示,主体湖区东南部沿岸带的密度和生物量最高,湖心区最低;高峰值主要出现在布哈河、菜挤河等大型河流入湖的河口附近。CCA分析表明:青海湖区大型底栖动物的分布主要受水体pH、水深、总氮和盐度等环境因子的驱动

Challenges facing soil science: a view from the outside

为了解青海湖大型底栖动物的群落结构特征、空间分布格局及关键驱动力,于2011—2012年分4次对青海湖区主体湖、3个子湖和5条入湖河流进行了系统调查。共采集到底栖动物28个分类单元,隶属于3门5纲15科,主体湖区、咸水和淡水子湖及入湖河流分布有9、5、9和15种;它们的密度分别为455.8、1562.7、741.3和331.2 ind./m2;生物量为1.18、3.70、2.75和4.53 g/m2。优势度分析显示,喜盐摇蚊为主体湖区绝对优势种(占总密度的83.32%)。Surfer模拟显示,主体湖区东南部沿岸带的密度和生物量最高,湖心区最低;高峰值主要出现在布哈河、菜挤河等大型河流入湖的河口附近。CCA分析表明:青海湖区大型底栖动物的分布主要受水体pH、水深、总氮和盐度等环境因子的驱动

Microstructural and Interfacial Characterization of Ti-V Diffusion Bonding Zones

Ti and V were bonded together and subjected to high-temperature treatment at 1000 or 1100 degrees C for 16 h to study the microstructural evolution and interfacial behavior of Ti-V diffusion interfaces. The samples were prepared by electro-polishing and analyzed using scanning electron microscopy, electron probe microanalysis, electron back-scattered diffraction, and nano-indentation. The results indicated that Ti-V diffusion bonding interfaces comprises a martensite Ti zone, a body-center-cubic Ti (beta-Ti) zone, and a V-based alloy zone. They are divided by two composition interfaces with V contents of similar to 13.5% and similar to 46%. The original interface between the pure Ti and the V alloy substrate falls within the beta-Ti zone. The observation of acicular-martensite rather than lath-martensite is due to the distortion caused by the beta-to-alpha phase transformation in the adjacent pure Ti. The recrystallization of beta-Ti is distributed along the interface direction. The hardness varies across the Ti-V interface bonding zones with the maximum value of 7.9 GPa

Additively manufactured aluminium nested composite hybrid rocket fuel grains with breathable blades

Hybrid rocket engines suffer from the restricted mechanical properties and low regression rates of current polymeric fuel grains. We propose a three-dimensional printed aluminium (Al) nested composite fuel grain with millimetre-scale lattice pores (referred to as Al-L). In this study, breathable Al blades with micrometer-scale interconnected pores (Al-B) and blades combining millimetre-scale and micrometer-scale pores (Al-B & L) are designed. The formation mechanisms, characteristics, and effects of the breathable blades are analysed in simulations, micro-computed tomography, and cyclic compression tests. The mechanical properties of the composite fuel grains are investigated numerically and in compression tests. Al-B has the highest Young's modulus at more than 15 times that of a paraffin-based fuel grain and Al-B & L has the highest yield stress at 4 times that of the paraffin-based fuel grain. Referring to combustion properties, the regression rates of the Al-B and Al-B & L grains are respectively 63.3% and 58.2% greater than the regression rate of the paraffin-based fuel grain

成層圏における放射線量の測定と無線通信による画像のリアルタイム転送∼ ANCO-project ∼

レポート番号: isas23-sbs-05

Measurement of integrated luminosity of data collected at 3.773 GeV by BESIII from 2021 to 2024

We present a measurement of the integrated luminosity e+e- of collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm = 3.773 GeV. The integrated luminosities of the datasets taken from December 2021 to June 2022, from November 2022 to June 2023, and from October 2023 to February 2024 were determined to be 4.995±0.019 fb-1, 8.157±0.031 fb-1, and 4.191±0.016 fb-1, respectively, by analyzing large angle Bhabha scattering events. The uncertainties are dominated by systematic effects, and the statistical uncertainties are negligible. Our results provide essential input for future analyses and precision measurements

Determination of the number of ψ(3686) events taken at BESIII

The number of ψ(3686) events collected by the BESIII detector during the 2021 run period is determined to be (2259.3±11.1)×106 by counting inclusive ψ(3686) hadronic events. The uncertainty is systematic and the statistical uncertainty is negligible. Meanwhile, the numbers of ψ(3686) events collected during the 2009 and 2012 run periods are updated to be (107.7±0.6)×106 and (345.4±2.6)×106, respectively. Both numbers are consistent with the previous measurements within one standard deviation. The total number of ψ(3686) events in the three data samples is (2712.4±14.3)×10^