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由咸鸭蛋引出的探究
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作者 崔胜春 《数理天地(初中版)》 2008年第10期42-42,共1页
题"端午节"时,王聪同学将几个吃完的成鸭蛋蛋壳按不同方式放置在桌面上拍打,发现有的蛋壳"脆弱",有的蛋壳"坚硬".他想蛋壳能够承受压力的大小与什么因素有关呢?于是找来了一张大的纸板模拟蛋壳进行探究.... 题"端午节"时,王聪同学将几个吃完的成鸭蛋蛋壳按不同方式放置在桌面上拍打,发现有的蛋壳"脆弱",有的蛋壳"坚硬".他想蛋壳能够承受压力的大小与什么因素有关呢?于是找来了一张大的纸板模拟蛋壳进行探究.作出以下猜想: 展开更多
关键词 纸板 猜想 加重物 控制变量法 探究 形状 木块 大小 验证 实验方案
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Preparation of micro-nanostructure on titanium implants and its bioactivity 被引量:12
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作者 张蕊 万熠 +2 位作者 艾兴 王滕 门博 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第4期1019-1024,共6页
Surface modification of medical implants was considered as an effective method to improve the cellular behaviors and the integration of tissue onto materials. The micro-nanostructured surface on the titanium alloy was... Surface modification of medical implants was considered as an effective method to improve the cellular behaviors and the integration of tissue onto materials. The micro-nanostructured surface on the titanium alloy was prepared by laser treatment and multiple acid etching. The surface morphologies of different titanium alloy substrates were characterized by scanning electron microscopy (SEM). The effects of micro-nanostructured surfaces on the cellular responses were investigated in vitro by observing hydroxyapatite formation, cell morphology and cell adhesion. The results indicate that the micro-sized structure promoted the adhesion and proliferation of cultured osteoblasts. Furthermore, the micro-nanostructured surface was more conducive to cell adhension stretching compared with the micro-structured surface. All results suggest that the micro-nanostructured surface improved the biocompatibility and integration of tissue onto titanium alloy implants. 展开更多
关键词 titanium alloy MICRO-NANOSTRUCTURE laser treatment multiple acid etching bioactivity
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辣椒蜜饯的制作
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《中国农垦》 北大核心 1995年第3期28-28,共1页
辣椒蜜饯的制作一、选料。选用伏天采收的灯笼状、牛角形大辣椒作原料为佳,要求柄蒂完好、色泽鲜红、肉质硬实、无虫眼、大小均匀。二、制坯。将原料用清水洗净,用刀顺体斜划一道3厘米长的小口,将籽取净,蒂保持完好,尔后将辣椒浸... 辣椒蜜饯的制作一、选料。选用伏天采收的灯笼状、牛角形大辣椒作原料为佳,要求柄蒂完好、色泽鲜红、肉质硬实、无虫眼、大小均匀。二、制坯。将原料用清水洗净,用刀顺体斜划一道3厘米长的小口,将籽取净,蒂保持完好,尔后将辣椒浸入4%的石灰水缸内,并用蔑席覆于水... 展开更多
关键词 辣椒 糖衣 鲜辣椒 质量要求 加重物 糖渍 煮制 清漂 石灰水 原料
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放手让学生去试——谈《浮与沉》一课难点的突破
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作者 冯连生 《湖北教育(科学课)》 1995年第2期11-11,共1页
第二册中的第二课《浮与沉》如何使学生理解:“只有给上浮的物体增加足够的重量,才能由浮变沉。”我采用了充分让学生去实验、去发现的教法,取得子较好的效果。 一、动脑筋想办法。首先我让学生想:怎么办才能使大槽中的塑料瓶由浮在水... 第二册中的第二课《浮与沉》如何使学生理解:“只有给上浮的物体增加足够的重量,才能由浮变沉。”我采用了充分让学生去实验、去发现的教法,取得子较好的效果。 一、动脑筋想办法。首先我让学生想:怎么办才能使大槽中的塑料瓶由浮在水面变为沉到水底?当时,学生想出了三种方法:①在瓶内加水②在瓶内加铁块或沙子等重物;③在瓶颈处挂上重物。显然,学生考虑到了只有添加重物小瓶才能下沉这一层,而没有考虑到要“ 展开更多
关键词 难点 加重物 物体 大槽 塑料瓶 完全下沉 再实验 沙子 动脑 教法
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高楼失火自救新招
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《消防月刊》 1994年第4期26-26,共1页
高楼,特别是高楼中上部失火后,受灾的住户居民如何自救,近年来一直是国际灾难学界的热门话题。 “休氏跳楼法” 世界灾难学者曾提出不少“自救”技巧,其中,休斯在1991年提出的人们意想不到的“软家具加重物”的廖窍,获得了专家们赞扬。
关键词 软家具 高楼 模拟实验 加重物 杆棒 伤害程度 席梦思 热门话题 联合体 休斯
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机引圆盘耙故障原因及排除方法
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作者 丁启先 《山东农机化》 1997年第6期17-17,共1页
机引圆盘耙在工作中,常见的故障原因及排除方法是: 1.土(代土)破碎不充分。①耙组的偏角太小,应适当调大耙组的偏角;②轴承润滑不良,产生滑行,应拆卸并清洗轴承,安装后加注润滑脂;③耙组的重量轻,应在配重箱上加重物。 2.耙后地面不平... 机引圆盘耙在工作中,常见的故障原因及排除方法是: 1.土(代土)破碎不充分。①耙组的偏角太小,应适当调大耙组的偏角;②轴承润滑不良,产生滑行,应拆卸并清洗轴承,安装后加注润滑脂;③耙组的重量轻,应在配重箱上加重物。 2.耙后地面不平。①耙架没有调平。 展开更多
关键词 机引圆盘耙 耙组 排除方法 故障原因 配重箱 耙架 加重物 轴承润滑 润滑脂 汽车改装
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Optimization of Multiplex PCR and Multiplex Gel Electrophoresis in Sunflower SSR Analysis Using Infrared Fluorescence and Tailed Primers 被引量:3
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作者 张潞生 Vanessa BECQUET +1 位作者 李绍华 David ZHANG 《Acta Botanica Sinica》 CSCD 2003年第11期1312-1318,共7页
In an effort to simplify the procedure and to reduce the cost of fluorescence SSR analysis, the conditions of the multiplex PCR and the multiplex gel electrophoresis were optimized in the genetic analysis of sunflower... In an effort to simplify the procedure and to reduce the cost of fluorescence SSR analysis, the conditions of the multiplex PCR and the multiplex gel electrophoresis were optimized in the genetic analysis of sunflower (Helianthus annuus L.) inbred lines. Results indicated that factors for a successful multiplex PCR assay were related to the cycling touchdown annealing temperature, the balance of primer concentration at the various loci, the concentration of PCR buffer and the Taq DNA polymerase. Based on the optimization, a tailed primer strategy was outlined, and the effective ways were proposed to overcome the troubleshootings commonly encountered in the multiplex PCR and the multiplex gel electrophoresis. 展开更多
关键词 simple sequence repeat (SSR) tailed primer multiplex PCR multiplex gel electrophoresis SUNFLOWER
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行车通廊汽车荷重等效均布荷载及其效应的估算
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作者 苏天 薛刚 《内蒙古科技大学学报》 CAS 2016年第1期90-93,共4页
为解决工业厂房行车通廊静载试验中重物加载量过大而不便操作的问题,利用汽车荷重等效均布荷载的原理,将汽车重量转化为局部的均布荷载,以汽车代替重物进行加载,得到了载重量与堆载步间的对应关系.有限元分析表明,当选取双后轴载重车进... 为解决工业厂房行车通廊静载试验中重物加载量过大而不便操作的问题,利用汽车荷重等效均布荷载的原理,将汽车重量转化为局部的均布荷载,以汽车代替重物进行加载,得到了载重量与堆载步间的对应关系.有限元分析表明,当选取双后轴载重车进行加载时,汽车前轮荷载对楼板内力影响较小,计算时可忽略. 展开更多
关键词 静载试验 重物 汽车荷重
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Advanced characterization for industrial catalysis applications
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作者 Shelly Kelly Wharton Sinkler +4 位作者 Lijun Xu Sergio Sanchez Cem Akatay Haiyan Wang John Qianjun Chen 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第11期1637-1654,共18页
The interplay between analytical technique and industrial practice has been central in the development of catalytic materials for processing petroleum. This article presents reviews of key aspects of two of the most i... The interplay between analytical technique and industrial practice has been central in the development of catalytic materials for processing petroleum. This article presents reviews of key aspects of two of the most important classes of catalytic materials: noble-metal Pt nanoparticles (NPs) on alumina, which are the basis of catalytic reforming;and layered sulfides of Mo and W, which catalyze hydrogenation and hetero-atom removal in hydroprocessing. The state of understanding of Pt cluster growth and resulting structures, as developed using X-ray absorption spectroscopy and STEM, is reviewed. Influences of both Pt reduction temperature in hydrogen gas, and oxidizing pretreatment conditions prior to Pt reduction, are considered. Recent work by the present authors on Pt NP structure evolution is presented in the context of the previous work. A review is subsequently presented of layered sulfide based NPs, summarizing contributions from a range of analytical techniques. Work on active site structures of sulfide NPs is reviewed, focusing particularly on the critical interactions of active edge sites with sulfur and hydrogen in chemisorption, physisorption, and spillover interactions. New temperature programmed reduction (TPR) results are presented for supported and unsupported sulfide NPs. Structural changes in TPR of alumina-supported MoS2 are investigated using extended X-ray absorption fine structure and density functional theory modeling, and are determined to arise from removal of identifiable edge-site sulfur species. 展开更多
关键词 Catalysis fundamental PLATINUM Metal sulfides Catalytic reforming HYDROPROCESSING
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The ecosystem of Lake Kenon:past and present(Transbaikal Territory,Russia)
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作者 Alexey P.KUKLIN Gazhit Ts.TSYBEKMITOVA +2 位作者 Evgenia P.GORLACHEVA Balzhit B.BAZAROVA Alexey V.AFONIN 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2016年第3期507-516,共10页
Present-day conditions of the Lake Kenon ecosystem are determined by a combination of natural and anthropogenic factors. We have estimated the effects of a complex of factors on the condition of the abiotic environmen... Present-day conditions of the Lake Kenon ecosystem are determined by a combination of natural and anthropogenic factors. We have estimated the effects of a complex of factors on the condition of the abiotic environment and on specific biological components in the lake ecosystem. Change in biogenic load has caused an increase in the role of phytoplankton in the general balance of organic matter during the high-water period. Charophytes are the main dominants of bottom vegetation. Anthropogenic load has caused a decrease in both fish species and fish capacity. The lake application as a water reservoir-cooler has influenced the average annual water mineralization (from 420 mg/L to 530.0 mg/L with a maximum 654 mg/L in 1993) and fluctuations in its hydrochemical composition. The present composition of the lake is sulfate-hydrocarbonate-chloride calcium-sodic-magnesium in character. S(Y44 content is twice as much as the maximum permissible concentration in fishery waters. Water drainage from an ash disposal area to the lake has caused an increase in chemical-element concentrations including the heavy metals. Hg concentration in Perca fluviatilis muscles is 0.5 9g/g dry wt. Thus, understanding directions in the ecosystem of the water reservoir-cooler under changing hydrological conditions will let us forecast the consequences of new combined heat and power plant operation. 展开更多
关键词 water reservoir-cooler of combined heat and power plant (CHP) HYDROCHEMISTRY ICHTHYOFAUNA BIODIVERSITY the chemical elements
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Effects of Species and Low Dose Nitrogen Addition on Litter Decomposition of Three Dominant Grasses in Hulun Buir Meadow Steppe 被引量:11
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作者 张彩虹 李胜功 +2 位作者 张雷明 辛晓平 刘杏认 《Journal of Resources and Ecology》 CSCD 2013年第1期20-26,共7页
Atmospheric nitrogen (N) deposition caused by anthropogenic activities may alter litter decomposition and species composition, and then affect N cycling and carbon (C) sequestration in an ecosystem. Using the litt... Atmospheric nitrogen (N) deposition caused by anthropogenic activities may alter litter decomposition and species composition, and then affect N cycling and carbon (C) sequestration in an ecosystem. Using the litterbag method, we studied the effects of N addition (CK: no N addition; low-N: 1 g N m-2 y-l; high-N: 2 g N m-2 y-l) on changes in mass remaining of shoot litter decomposition of three grasses (Stipa baicalensis, Carex pediformis and Leymus chinensis) over 28 months in the Hulun Buir meadow steppe of Inner Mongolia. The results showed that the addition of high and low N had no significant effect on the decomposition of single-species litter, but low N addition slightly inhibited the decomposition of litter mixtures. In addition, litter decomposition was strongly species dependent. Our results suggest that species type is likely the main determinant of litter decomposition, and low N deposition in natural ecosystems does not influence single-species litter decomposition. 展开更多
关键词 GRASSLAND mixed litter N addition remaining mass
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此题问法欠妥!
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作者 陈隽 陈祥书 《物理教师》 1996年第12期27-27,共1页
现行九年义务教育三年制初级中学试用课本《物理·第一册》(上海科学技术出版社)第123页上有这样一道题:
关键词 九年义务教育 悬浮水 加重物 江苏海安 初级中学 科学技术出版社 三年制 轮胎 物体 分析物
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Synergistic improvement of perovskite film quality for efficient solar cells via multiple chloride salt additives 被引量:6
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作者 Pengyang Wang Qi Jiang +5 位作者 Yang Zhao Yong Chen Zema Chu Xingwang Zhang Yuqin Zhou Jingbi You 《Science Bulletin》 SCIE EI CSCD 2018年第11期726-731,共6页
Perovskite crystal film quality is critical for obtaining efficient perovskite solar cells. Anti-solvent processing was used for fast crystallization of perovskite precursor film, which can form dense perovskite film.... Perovskite crystal film quality is critical for obtaining efficient perovskite solar cells. Anti-solvent processing was used for fast crystallization of perovskite precursor film, which can form dense perovskite film. However, the crystals from this method are usually small due to the fast crystal growth process, which could lead to grain boundary recombination. Here, element chloride is introduced to enhance the perovskite layer crystallinity via slowing down the perovskite crystallization process by simultaneous introduction of methylammounium chloride (MACI) and cesium chloride (CsCl) into precursor solution. As a result, we achieve high quality of pin-hole free perovskite film with large crystal size. A power conversion efficiency of 21.55% with free of hysteresis of the device is obtained, which is among the highest efficiency of planar structure perovskite solar cells. 展开更多
关键词 Metal halide perovskite Solar cells Crystallization Power conversion efficiency
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