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先进的航天发动机试验

固体火箭技术 1981年第2期 46-55页

作者： r.A.Ellis r.n.hammond P.Donguy 王德升美国联合工艺公司美国联合工艺公司法国欧洲动力公司

本文报导一种航天发动机的高空模拟点火试验。这种发动机综合利用了几种先进技术:90%固体燃料的端羟基聚丁二烯/铝粉/过氯酸铵/奥克托金推进剂;在凯夫拉壳体内的头端满装药;无支撑的整体喉部和收敛段入口;特轻的喷管和用充气膨胀的作动... 详细信息

本文报导一种航天发动机的高空模拟点火试验。这种发动机综合利用了几种先进技术:90%固体燃料的端羟基聚丁二烯/铝粉/过氯酸铵/奥克托金推进剂;在凯夫拉壳体内的头端满装药;无支撑的整体喉部和收敛段入口;特轻的喷管和用充气膨胀的作动筒展开的可延伸出口锥。这次试验结束了法国欧洲动力公司和美国联合工艺公司化学系统分部之间为期两年的分工协作的研究和试制工作。所达到的比冲值被认为是复合推进剂在样机发动机中的一个最高记录。

关键词：绝热层动力公司化学系统发动机作动筒隔热层推进剂装药喷管点火试验发动机试验绝热壳体纤维缠绕壳体航天飞行

natural regeneration in logging gaps of different sizes in Subri river Forest reserve(Ghana)

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Journal of Forestry research 2022年第4期33卷 1157-1174页

作者： Maame Esi hammond radek Pokorný Simon Abugre Augustine Gyedu Department of Silviculture Faculty of Forestry and Wood TechnologyMendel University in BrnoZemědělská361300 BrnoCzech Republic Department of Forest Science School of Natural ResourcesUniversity of Energy and Natural ResourcesP.O.Box 214SunyaniGhana Forest Services Division(FSD) P.M.BKumasiGhana

Subri river Forest reserve(Sr)is the most extensive forest area in Ghana with an accompanying rich floral *** the years,logging from both legally prescribed and illegal operations remain the predominant forest disturbance in *** creation following logging is crucial in determining tree species composition and ***,the study evaluated the composition and diversity of naturally regenerated tree species in logging gaps of different sizes and,again examined the roles of these tree species in fulfilling the economic and ecological agenda of sustainable forest management after logging in *** gaps were randomly selected:4 each were grouped into small size(≤200 m^(2)),medium size(201–300 m^(2)),and large size(≥300 m^(2)).Data were gathered from 1 m^(2) circular area at gap centres and repeatedly inside 1 m width strip along 20 m individual n-S-E-W *** diversity differed significantly between gap *** diversity indices were measured in large size *** sizes shared similar *** were significant differences among various height groupings of tree species across all three gap *** preferred medium to large size gaps,while shadetolerant tree species preferred small size gaps for their *** and Lower risk near Threatened tree species under Conservation Status and,Premium and Commercial tree species under Utilisation Status preferred small size gaps for their proliferation and ***,we recommend the single tree-based selective logging for ensuring creations of small to medium size(200–300 m^(2))gaps through adjustments to the logging permit process,revision of Allocation Quota Permit,strict adherence to the 40-year polycyclic selection system,along with more dedicated enforcement and *** along these protocols would tremendously facilitate natural regeneration of different suites of timber species resulting in the improvement of the overall biodiversity conservat

关键词： Conservation status Gap size Diversity Logging natural regeneration Subri river Forest reserve Tree species Utilisation status

Improved Interpretive Accuracy of Sugar Content on Beverage Labels Following an Educational Intervention for Children

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Journal of Health Science 2017年第4期5卷 198-205页

作者： Myrtle McCulloch Priscilla (Ofori) hammond Jill Chanley School of nursing and Health Studies Georgetown University Washington DC 20057 USA Better Living for Texans Texas A &M AgriLife Extension Service Bryan 77803 USA The Campaign for Tobacco-Free Kids Washington DC 20005 USA

To address childhood obesity, it is important to help children make better choices with regards to intake of sugary drinks and snacks. The purpose of this study was to evaluate the validity of a novel educational intervention designed to convert grams of sugar into teaspoons on labeled beverages. A convenience sample of children （n = 21） at a charter elementary school in Washington, D. C was studied. A pre-test required an estimation of teaspoons of sugar on labels, followed by a practice demonstration and song. A post-test was given requiring estimation of teaspoons of sugar in on the same labels. Two weeks later, a retention test as well as qualitative questions assessed participant learning and information usage. Test scores revealed increased accuracy from pre-test （26.2%） to post-test （79.8%）. Estimations were more accurate after the demonstration, as evidenced by the decreased range in average variation of responses （＋25.6 tsp to ＋1.8 tsp）. Two-week recall maintained accuracy （66.7%）, with an average variance of ＋3.8 teaspoons. Qualitative responses revealed participants had learned and used the conversion concepts. These results suggest that the educational intervention was effective. Qualitative data suggest behavior change, increased awareness, and the potential for change extending to caregivers.

关键词： children obesity sugar-sweetened beverages education

Composition Operators on a Banach Space of Analytic Functions

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Acta Mathematica Sinica,English Series 1998年第2期14卷 201-208页

作者： Cao Guangfu (Department of Mathematics,Sichuan University,Chengdu 610064,China)n.Elias (6611 Tauglewood Court 3B,hammond,In46323)P.Ghatage (Department of Mathematics,Cleveland State University,Cleveland,OH44115)Yu Dahai (Department of Mathematics,Sichuan University,Chengdu 610064,China) Department of Mathematics Sichuan University Department of Mathematics Cleveland State University

In this paper,we study composition operators on a Banach space of analytic functions, denoted by X,which includes the Bloch *** space arises naturally as the dual space of analytic functions in the Bergman space L_a^1(D)which admit an atomic *** charac- terize the functions which induce compact composition operators and those which induce Fredholm operatorson this *** also investigate when a composition operator has a closed range.

关键词： Bergman space Composition operator Compact operator Fredholm operator

Effectiveness of quality physical education in improving students' manipulative skill competency

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Journal of Sport and Health Science 2016年第2期5卷 231-238页

作者： Weiyun Chen Weimo Zhu Steve Mason Austin hammond-Bennett Andrew Colombo-Dougovito School of Kinesiology University of Michigan Kinesiology and Community Health University of Illinois Department of Kinesiology University of Virginia

Purpose： This study aimed to examine the extent to which the quality physical education teaching （QPET） practices contributed to improving 4th- and 5th-grade students＇ manipulative skill competency. Methods： Participants were 9 elementary physical education （PE） teachers and their 4th- and 5th-grade students （n = 2709 3420）. The students＇ skill competency was assessed with 3 manipulative skills using PE metrics assessment rubrics. The PE teachers＇ levels of QPET were assessed by coding 63 videotaped lessons using the assessing quality teaching rubrics （AQTr）, which consisted of 4 essential dimensions including task design, task presentation, class management, and instructional guidance. Codes were confirmed through inter-rater reliability （82.4%, 84.5%, and 94%）. Data were analyzed through descriptive statistics, multiple r2 regression models, and independent sample t tests. results： This study indicated that the 4 essential dimensions of QPET were all significant contributors to students＇ manipulative skill competency. These predictors were significantly higher for boys than for girls in soccer and striking skills, while they were significantly higher for girls than for boys in throwing skill competency. Of the 4 essential dimensions of QPET, task presentation played the most significant role in contributing to all 3 skill competencies for both boys and girls. Further, students who experienced high QPET were significantly more skillfully competent than those students who did not have this experience. Conclusion： It was concluded that the QPET practices played a significantly critical role in contributing to students＇ manipulative skill competency.

关键词： Assessment of quality teaching Essential dimensions of teaching Manipulative skill competency Skill assessment

发作后血氨水平作为惊厥性癫痫发作的生物标志物:一项前瞻性研究

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癫痫杂志 2017年第4期3卷 348-353页

作者： Albadareen r Gronseth G Landazuri P He J hammond n Uysal U 吴梦倩慕洁

有报道指出全面性惊厥性癫痫发作(Generalized convulsive seizures,GCS)后出现短暂性高血氨症(Transient hyperammonemia,THA),没有足够的证据证实与癫痫的关系。文章的目的是确定发作后THA是否可以区分不同类型的发作,如使用视频脑电... 详细信息

有报道指出全面性惊厥性癫痫发作(Generalized convulsive seizures,GCS)后出现短暂性高血氨症(Transient hyperammonemia,THA),没有足够的证据证实与癫痫的关系。文章的目的是确定发作后THA是否可以区分不同类型的发作,如使用视频脑电图(VEEG)监测确认脑电变化。在前瞻性队列中,筛选了所有进入癫痫监测单元并同意接受研究的成年患者(>18岁)。血氨的基础值以及在发作(所有患者)的60 min内、发作后24 h(只要有可能)的血氨水平均被检测。根据VEEG,将患者进行分组,分别为GCS、心因性惊厥性非痫性发作(Psychogenic nonepileptic seizures with convulsions,PnES-C)或局灶性癫痫发作(Focal seizures,FS)。使用描述性统计和参数/非参数方法分析数据。纳入患者78例,13例为GCS、8例为FS、9例为PnES-C。这些组在性别(P=0.04)和血氨基础值(P=0.02)方面是不同的,但年龄无差异。三组之间发作后血氨水平较血氨基础值的变化差异有统计学意义(P=0.004)。区分GCS与其他组差异的发作后血氨水平rOC曲线下面积为0.88[95%CI(0.69,0.96)],表明检测血氨水平是一种很好的用来区分GCS与其他发作的试验。血氨水平≥80μmol/L可以准确为80%的患者分类(灵敏度53.9%,特异性100%)。VEEG监测为THA与GCS癫痫发作之间的关联提供了客观证据,并为今后关于确定发作后血氨水平作为GCS的廉价诊断试验作用的研究奠定了基础。

关键词：发作后高氨血症血氨惊厥性癫痫发作非痫性发作灵敏度和特异性

Stability and Electronic Properties of Metal-n4 and Metal-n2 Complexes

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Journal of Physical Science and Application 2012年第6期2卷 200-204页

作者： Shanese Jasper Asya hammond Sharonda Phelps Za'Queta Eddins Douglas L. Strout Department of Physical Sciences Alabama State University Montgomery AL 36101 USA

nitrogen molecules nx have been the subject of much recent research because of their potential as high-energy materials. Many nitrogen molecules dissociate with very low barriers, including molecules such as acyclic n4 that are essentially unbound. A number of studies have reported the ability of heteroatoms to stabilize complex nitrogen molecules. In the present study, the energetic and electronic properties of scandium（Ⅰ） and titanium（Ⅱ） complexes with n2 and n4 are calculated and discussed. Dissociation energies and singlet-triplet energies are determined by theoretical calculations using second-order perturbation theory （MP2） in conjunction with the Dunning basis sets.

关键词： nitrogen scandium titanium high-energy materials computational chemistry.

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全球并购交易大爆发

商业周刊（中文版） 2021年第20期 20-21页

作者： Ed hammond 王非(译) 不详

今年是并购交易大爆发的一年。有美国电话电报公司(AT&T)媒体业务与Discovery的合并计划,有对铁路公司Kansas City Souther n的巨额竞购,还有Square同意收购澳大利亚先买后付公司Afterpay的交易。全球交易规模已经超过了2007年创下的4.... 详细信息

今年是并购交易大爆发的一年。有美国电话电报公司(AT&T)媒体业务与Discovery的合并计划,有对铁路公司Kansas City Souther n的巨额竞购,还有Square同意收购澳大利亚先买后付公司Afterpay的交易。全球交易规模已经超过了2007年创下的4.1万亿美元纪录高位。到2021年底,全年总交易规模可能轻松站上5万亿美元大关。

关键词：交易规模全球交易并购交易澳大利亚媒体业务收购

root symbioses as belowground C pumps:a mitigation strategy against rising CO_(2)levels

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Circular Agricultural Systems 2021年第1期1卷 62-64页

作者： Peter E.Mortimer James hammond Kevin D.Hyde Heng Gui Jianchu Xu Center for Mountain Futures Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China International Livestock research Institute(ILrI) PO Box 30709Nairobi 00100Kenya Centre of Excellence in Fungal research Mae Fah Luang UniversityChiang Rai 57100Thailand CIFOr-ICrAF China Program World Agroforestry CenterKunming 650201China

Mycorrhizal and n-fixing root symbioses evolved at two points in the past when global CO_(2)was highest,consistent with the high demand these symbioses place on host *** hosting both mycorrhiza and n-fixing bacteria are able to fix more atmospheric CO_(2)and grow at faster rates than non-symbiotic plants,or plants with only *** argue that on the basis of this improved C capture,n-fixing trees act as C-pumps,sequestering C and locking it in biomass,thus,if properly managed,can contribute significantly towards the mitigation of rising CO_(2)levels.

关键词： root (2) properly