Olivine-norite rock detected by the lunar rover Yutu-2 likely crystallized from the SPA-impact melt pool

Chang’E-4 landed in the South Pole-Aitken (SPA) basin, providing a unique chance to probe the composition of the lunar interior. Its landing site is located on ejecta strips in Von Kármán crater that possibly originate from the neighboring Finsen crater. A surface rock and the lunar regolith at 10 sites along the rover Yutu-2 track were measured by the onboard Visible and Near-Infrared Imaging Spectrometer in the first three lunar days of mission operations. In situ spectra of the regolith have peak band positions at 1 and 2 μm, similar to the spectral data of Finsen ejecta from the Moon Mineralogy Mapper, which confirms that the regolith''s composition of the landing area is mostly similar to that of Finsen ejecta. The rock spectrum shows similar band peak positions, but stronger absorptions, suggesting relatively fresh exposure. The rock may consist of 38.1 ± 5.4% low-Ca pyroxene, 13.9 ± 5.1% olivine and 48.0 ± 3.1% plagioclase, referred to as olivine-norite. The plagioclase-abundant and olivine-poor modal composition of the rock is inconsistent with the origin of the mantle, but representative of the lunar lower crust. Alternatively, the rock crystallized from the impact-derived melt pool formed by the SPA-impact event via mixing the lunar crust and mantle materials. This scenario is consistent with fast-cooling thermal conditions of a shallow melt pool, indicated by the fine to medium-sized texture (<3 mm) of the rock and the SPA-impact melting model [Icarus 2012; 220: 730–43].     

Large-scale academic achievement testing of deaf and hard-of-hearing students: past, present, and future

The first large-scale, nationwide academic achievement testing program using Stanford Achievement Test (Stanford) for deaf and hard-of-hearing children in the United States started in 1969. Over the past three decades, the Stanford has served as a benchmark in the field of deaf education for assessing student academic achievement. However, the validity and reliability of using the Stanford for this special student population still require extensive scrutiny. Recent shifts in educational policy environment, which require that schools enable all children to achieve proficiency through accountability testing, warrants a close examination of the adequacy and relevance of the current large-scale testing of deaf and hard-of-hearing students. This study has three objectives: (a) it will summarize the historical data over the last three decades to indicate trends in academic achievement for this special population, (b) it will analyze the current federal laws and regulations related to educational testing and special education, thereby identifying gaps between policy and practice in the field, especially identifying the limitations of current testing programs in assessing what deaf and hard-of-hearing students know, and (c) it will offer some insights and suggestions for future testing programs for deaf and hard-of-hearing students.     

几种蒸散模型在玉米农田蒸散量计算中的应用比较

模拟蒸散的物理过程,计算农田蒸散量是进行生态系统水资源评价和管理的重要手段,同时也是气象部门进行土壤湿度预报的首要条件.本研究以玉米农田为研究对象,基于涡度相关法观测的蒸散实测资料,比较分析了基于常规气象数据的蒸散模型(Hargreaves法、Priestlev-Taylor法、FAO-Penman-Monteith法)和基于气象梯度数据的蒸散模型(波文比法、梯度法、生态系统过程模型模拟)的模拟精度.结果表明:①Hargreaves法、Priestley-Taylor法和FAO-Penman-Monteith法日蒸散的模拟结果较为一致,总体上高估20%～26%,其中Priestley-Taylor法模拟结果最优;②生态系统过程模型模拟的农田日蒸散精度较高,但模型中涉及的物理过程和参数较多,在实际应用中难于获取;③波文比法在波文比小于0.4且仪器精度较高时可以得到较准确的估算值.研究同时还指出,仪器的安装高度及高差设计对梯度法估算蒸散十分重要.     

我国冰雪运动产业政策演进特征及展望

运用文献资料、专家访谈、文本分析等方法,分析我国冰雪运动产业政策演进特征,并提出展望。冰雪运动产业政策经历了初创与曲折期、起步期、探索期、黄金期4个演进阶段,呈现出政策目标定位逐渐清晰化、政策主体逐渐多元化、政策工具类型更具均衡性、政策执行监管机制逐步健全的特征。未来我国冰雪运动产业政策制定应细化政策目标,强化目标适切性;加大跨部门协同合作,明确权责主体;丰富政策工具,提升决策效果;加快构建政策执行监管体系,调控执行效果。     

关于军队院校研究生教育树立和落实科学发展观的思考

以信息技术为核心的新军事变革对我军现代化建设和军事斗争准备提出了前所未有的严峻挑战。建设信息化军队、打赢信息化战争,既是我军新时期现代化建设的战略目标,也是应对新军事变革挑战的重要举措。我们要在机械化建设任务尚未完成的情况下,建设信息化军队,实现军队建设的跨越式发展,必须紧紧依靠高层次军事指挥人才和军事技术人才。军队院校研究生教育作为军队高层次人才培养的主要途径,必须适应军队现代化建设的新形势, 牢固树立和认真落实科学发展观,采取切实有效的措施,谋求研究生教育的科学发展,为国防和军队现代化建设提供人才和智力支撑。     

高职院校图书馆内涵建设的几点思考——由“三馆”免费开放引发的启示

高职院校图书馆内涵建设一直受到各职能部门的关注,虽然有所发展,但不尽人意。这次＂三馆＂免费向社会公众开放,对高职院校图书馆内涵建设无疑是一个重大启示：高职院校图书馆内涵建设应立足长远发展,除馆员素质有待提高外,服务方式、模式的转变及资源库的建设等应引起各高职院校的重视。     

敦煌壁画中的胡床家具(一)

通过对胡床家具图像和相关文献的梳理,说明胡床传入中国的时间并非晚到佛教传入的东汉灵帝时代,而是在章帝、和帝时期,比通常所认定的时间早近百年.胡床的传人是经过漫长岁月由古埃及、中东、西亚等地,经多个民族之手辗转传播而来.它的传人对于中华文化的发展,起到了很大的促进作用.     

The legacy of Nikola Tesla The AC system that he helped to usher in

Alternating Current (AC) is used all over the world today. In India we use AC at 50 Hz (cycles per second) and in USA and Canada at 60 Hz. During the latter part of the 19th century, even during the early part of the 20th century, Direct Current or DC was widely used. Had we continued with DC, electricity would not have been as widely available as it is today and its use would have been cumbersome, costly and severely restricted. We owe it mainly to the Serbian genius Nikola Tesla that electricity has reached almost every nook and corner of most continents.     

论政府职能的服务本质

新一轮行政体制改革的主旨是加强政府的社会管理职能和公共服务职能。其政府职能的本质就是服务,服务精神应成为21世纪政府行政的灵魂。     

客家话的三个标准

客家话和赣语应该划分为两个大方言区。看一种汉语方言是不是客家话，可以有三个标准：一是客家人自我意识的标准；二是词汇上的标准；三是语音的标准。主要是看古次浊声母上声字今是否读阴平，这可以用“野尾有暖软冷”六个字作为典型例字来检验。