多联式空调机组的应用

分析了多联式空调机组的系统匹配、室内外机配比、室内外机之间的管长和高差对制冷量和制热量的影响，给出了确定室内外机容量的方法。     

水源热泵空调系统在地下建筑中应用的研究

分析了水源热泵，水源－空气源热泵空调系统的热力特性，认为地下建筑中采用水源热泵，水源－空气源热泵空调系统比常规空调系统热效率高，且有助于减少能耗。     

高C3S水泥与萘系减水剂的适应性分析

实验分析了高C4S水泥与萘系减水剂产生适应性问题的原因,高c3s水泥在提高水泥胶凝性的同时由于具有较高的易磨性,使其在粉磨过程中形成较多的细颗粒,其0～2．36um的颗粒所占比例明显高于其它同级水泥,从而对萘系减水剂产生过多的吸附,早期水化速率较高、消耗更多的水量而造成减水率降低和流动性损失较快,其最有效的解决方法是采用缓凝剂。     

Energy-Efficient Large-Scale Antenna Systems with Hybrid Digital-Analog Beamforming Structure

A large-scale antenna system(LSAS) with digital beamforming is expected to significantly increase energy efficiency(EE) and spectral efficiency(SE) in a wireless communication system. However, there are many challenging issues related to calibration, energy consumption, and cost in implementing a digital beamforming structure in an LSAS. In a practical LSAS deployment, hybrid digital-analog beamforming structures with active antennas can be used. In this paper, we investigate the optimal antenna configuration in an N × M beamforming structure, where N is the number of transceivers, M is the number of active antennas per transceiver, where analog beamforming is introduced for individual transceivers and digital beamforming is introduced across all N transceivers. We analyze the green point, which is the point of maximum EE on the EE-SE curve, and show that the log-scale EE scales linearly with SE along a slope of-lg2/N. We investigate the effect of M on EE for a given SE value in the case of fixed NM and independent N and M. In both cases, there is a unique optimal M that results in optimal EE. In the case of independent N and M, there is no optimal(N, M) combination for optimizing EE. The results of numerical simulations are provided, and these results support our analysis.     

聚焦城市降温关键问题的可持续发展解决方案 ——世界银行与广州的"清凉城市"试点实践

全球人口城市化率在超过50％后持续上升和全球气候变化是当前世界各地城市发展面临的两大趋势.随着城市人口和开发建设的高度集聚,城市热环境过载问题日益突显,对城市带来复杂且持续的影响.这一问题的解决与联合国2030年可持续发展目标的17个领域均直接相关,可作为统筹推进城市可持续发展的重要抓手.本文结合世界银行2020年在广州市启动的全球首个可持续降温试点项目阶段成果,展示并总结以"清凉城市"为主题的城市可持续转型新模式:助力中国城市应对气候变化,贡献实现碳中和路径,面向可持续发展综合目标,聚焦关键问题,通过国际合作和知识共享,以系统化思维构建集成化的解决方案,并促进方案高效实施.     

Geomagnetic polarity transitions recorded in the Miocene lavas of the Wuyu basin,Tibet

Geomagnetic polarity transitions were the most important phenomena in the study of the geomagnetic field evolution and the earth's deep interior dynamics.The Miocene postcollisional ultrapotassic-potassic rocks are widely distributed in the Lhasa Block of southern Tibet.Paleomagnetic studies on the Wuyu Formation indicated that these volcanic rocks recorded the C5Bn.2n-C5Bn.1r and C5ACr-C5ACn geomagnetic polarity transitions.The virtual geomagnetic poles(VGPs) of these two polarity transitions were located ...     

Enrichment mechanisms of rare earth elements in marine hydrogenic ferromanganese crusts

A series of selective extraction experiments were conducted on marine hydrogenic ferromanganese crusts from the seamount near the Line Island to investigate the distribution of rare earth elements(REEs) and the mechanisms of combination between REEs and the hydrogenic ferromanganese crusts.The enrichment of REEs in hydrogenic ferromanganese crusts is attributed mainly to the mineral or oxide/hydroxide of the crust rather than the growth environment.The REEs are present mainly in amorphous ferric oxide/hydro...     

Exploring the deep biosphere

Over the past two decades, scientific drilling into sediments and rocks in the ocean and the continent has revealed the presence of physiologically and phylogenetically complex microbial life in the deep subsurface. Microorganisms, most of which have no cultured or known relatives in the surface biosphere, have been discovered in sediments and rock at depth as deep as 1 km below the seafloor and more than 3 km deep in the continent. The deep biosphere probably represents the most voluminous part of the glob...     

Evolution of kaolinite subgroup minerals and mixed-layer illite/smectite in the Paleogene Damintun Depression in Liaohe Basin of China and its implication for paleotemperature

The oil-rich Damintun Depression is located in the Liaohe Basin, Northeast China, and was formed during the Paleogene. The major oil-producing strata in the depression are mudstone and shale. To explore the burial diagenetic history of the basin and the formation thresholds of hydrocarbons, the characters of the kaolinite subgroup minerals and mixed-layer illite/smectite in the mudstone and the shale are studied by using X-ray diffraction, electron probe, scanning electron microscope, and Fourier infrared s...     

Two types of changes in apparent resistivity in earthquake prediction

Two types of changes in apparent resistivity (AR) have been linked to earthquake occurrences. This paper studies the changes and their causes, in detail with the ultimate purpose of developing and assessing a method of earthquake (EQ) prediction. The AR changes of the first type (CFT) are considered to be precursors related to earthquakes (EQs); these appear mostly in the medium-term period before EQs and in the short-term period preceding EQs. The changes of the second type (CST) are characterized by a tur...