分类： 物理学 >> 核物理学 提交时间： 2023-11-15
Ke Liu
Huan Zhou
Qin Xu
Huating Kong
Kunhao Zhang
Weiwei Wang
Minjun Li
Zhijun Wang
Qiangyan Pan
Xingya Wang
Feng Yu
Qisheng Wang
摘要： Macromolecular crystallography beamline BL17U1 at the Shanghai Synchrotron Radiation Facility hasbeenrelocated, upgraded, and given a newID (BL02U1). It now deliversX-rays intheenergyrangeof616 keV, withafocusedbeamof11.6m 4.8 m andphotonfluxgreater than 10^12phs/s. Thehighcredibilityandstabilityofthebeamandgoodtimingsynchronizationof the equipmentsignificantly improvetheexperimentalefficiency. SinceJune2021, whenitofficially openedtousers, over4200 hofbeamtimehavebeenprovidedto over200 researchgroupstocollectdataatthebeamline. Its goodperformanceandstableoperationhave led to the resolution of several structuresbasedondatacollectedatthebeamline.
分类： 生物学 >> 植物学 >> 植物生态学和植物地理学 提交时间： 2016-05-04
Eric K. Anderson
Ezra Aberle
Chengci Chen
Josh Egenolf
Keith Harmoney
Vijaya Gopal Kakani
Robert Kallenbach
Madhu Khanna
Weiwei Wang
DoKyoung Lee
摘要： Perennial grass mixtures planted on Conservation Reserve Program (CRP) land are a potential source of dedicated bioenergy feedstock. Long-term nitrogen (N) and harvest management are critical factors for maximizing biomass yield while maintaining the longevity of grass stands. A six-year farm-scale study was conducted to understand the impact of weather variability on biomass yield, determine optimal N fertilization and harvest timing management practices for sustainable biomass production, and estimate economic viability at six CRP sites in the United States. Precipitation during the growing season was a critical factor for annual biomass production across all regions, and annual biomass production was severely reduced when growing season precipitation was below 50% of average. The N rate of 112kgha1 produced the highest biomass yield at each location. Harvest timing resulting in the highest biomass yield was site-specific and was a factor of predominant grass type, seasonal precipitation, and the number of harvests taken per year. The use of N fertilizer for yield enhancement unambiguously increased the cost of biomass regardless of the harvest timing for all six sites. The breakeven price of biomass at the farmgate ranged from $37 to $311Mg1 depending on the rate of N application, timing of harvesting, and location when foregone opportunity costs were not considered. Breakeven prices ranged from $69 to $526Mg1 when the loss of CRP land rental payments was included as an opportunity cost. Annual cost of the CRP to the federal government could be reduced by over 8% in the states included in this study; however, this would require the biomass price to be much higher than in the case where the landowner receives the CRP land rent. This field research demonstrated the importance of long-term, farm-scale research for accurate estimation of biomass feedstock production and economic viability from perennial grasslands.
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