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间歇性动态压力促进兔胫骨近端骺板梯度增殖分化的实验研究
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作者 李建军 杨东翔 +3 位作者 元香南 孔战 陈旭 赵群 《山东医药》 CAS 北大核心 2011年第20期46-47,I0002,I0003,共4页
目的观察兔骺板在周期性压应力生物反应器中受到不同时间的间歇性动态压力对其增殖分化的影响。方法取2周龄的兔胫骨近端骺板,置于动态压力生物反应器内培养5d,接受不同时间的间歇性动态压力刺激。A组为无压力刺激组,B~E组分别为每天... 目的观察兔骺板在周期性压应力生物反应器中受到不同时间的间歇性动态压力对其增殖分化的影响。方法取2周龄的兔胫骨近端骺板,置于动态压力生物反应器内培养5d,接受不同时间的间歇性动态压力刺激。A组为无压力刺激组,B~E组分别为每天间歇动态压力1.5、3、6和12h。免疫组织化学染色检测骺板标本中CollagenⅡ、CollagenⅩ、BMP-6、PTHrp、Sox-9和HIF-1的表达和分布。结果与A组比较,B、C、D和E组增殖层明显增厚,且C组增殖层增厚程度明显大于B、D和E组。CollagenⅡ和Sox-9主要在增殖层表达,CollagenⅩ和BMP-6主要在肥大层表达,PTHrp主要在肥大前区表达,HIF-1在全层均有表达,呈现梯度变化特点,在肥大前区表达最强。结论骺板在间歇性动态压力刺激下,分别针对增殖层及肥大层产生不同的梯度压应力,能够促进其梯度增殖分化。HIF-1可能是骺板在力学环境下产生梯度增殖的重要影响因素。 展开更多
关键词 骺板 间歇性动态压力 生物反应器 梯度增殖分化
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小学数学灵动课堂教学中活动单的设计依据与特色
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作者 赖娜 《教学管理与教育研究》 2023年第3期72-74,共3页
为了适应当前社会发展要求,寻找一种以学生为主体的教学模式显得尤为重要。在此背景下学校开展“以学定导,多元互动”的灵动课堂实践改革,让以往严肃的课堂灵动起来。从“活动单导学”为载体的数学灵动课堂教学实践中摸索出了一些活动... 为了适应当前社会发展要求,寻找一种以学生为主体的教学模式显得尤为重要。在此背景下学校开展“以学定导,多元互动”的灵动课堂实践改革,让以往严肃的课堂灵动起来。从“活动单导学”为载体的数学灵动课堂教学实践中摸索出了一些活动单的设计依据与要求“精”“新”铺垫,让新知顺理迁移;梯度分化任务,让自主学习得心应手;引发难点争议,交流辨析出真知;分层检测,拾级而上促进核心素养提升等。 展开更多
关键词 精心铺垫 梯度分化 引发争议 检测提升
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Profile of Absolute Light Utilization Efficiency Within Leaves of Euonymus japonicus 被引量:2
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作者 樊大勇 韩涛 +2 位作者 李竟 王强 高荣孚 《Acta Botanica Sinica》 CSCD 2003年第2期169-176,共8页
Absolute light utilization efficiency across leaf section of Euonymus japonicus T. was calculated based on the measurements of photoacoustic technique (PA technique) and microscopic fiber optic probe. This new method ... Absolute light utilization efficiency across leaf section of Euonymus japonicus T. was calculated based on the measurements of photoacoustic technique (PA technique) and microscopic fiber optic probe. This new method was based on the principal of depth analysis by PA technique and the differential analysis of light gradients across leaf section by micro-optical probe technique. The depth analysis was shown by a sample of PA scan light absorption spectra. Results showed that the tissue layers between palisade tissue and spongy tissue used the smallest proportion of incident light energy for photochemical reactions (about 0.026% incident light energy of 660 nm light), while in tissue layer more close to the adaxial surface of leaf or the abaxial surface of leaf, the efficiency of utilization of light energy tended to be improved, e. g. 0.092% for tissue layers close to adaxial surface; 0.036% for tissue layers close to abaxial surface. The results that different leaf tissue layers utilized different proportion of incident light energy for photochemical reaction directly prove the hypothesis put forward by Han and Vogelmann. 展开更多
关键词 depth analysis by PA technique light gradients across leaf section photochemical loss light absorption profile
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Gradient Analysis of Urbanization Pattern Based on Class-level Landscape Metrics for Shanghai Region 被引量:1
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作者 黄震 张利权 陈亮 《Journal of Donghua University(English Edition)》 EI CAS 2005年第5期90-95,共6页
The spatial pattern of urbanization in the Shanghai metropolitan area is quantified with GIS-based land use data set and gradient analysis of landscape metrics. A number of landscape metrics were computed along a 64 I... The spatial pattern of urbanization in the Shanghai metropolitan area is quantified with GIS-based land use data set and gradient analysis of landscape metrics. A number of landscape metrics were computed along a 64 Ion long and 6 km wide west-east transect and another 66 km long and 6 km wide south-north transect. The results of transect analysis with class-level metrics showed that the spatial pattern of urbanization could be reliably quantified using landscape metrics with a gradient analysis approach, and the location of the urbanization center could be identified precisely and consistently with multiple indices of the landscape metrics used in this study. Different land use types exhibited distinctive, but not necessarily unique, spatial signatures that were dependent on specific landscape metrics. These results seemed to characterize the urban core of the Shanghai metropolitan area rather accurately and precisely.. Agriculture patches were abundant and less fragmented; the urban land use types were extensive, having many small patches and highly fragmented. 展开更多
关键词 URBANIZATION gradient analysis landscape pattern class-level metrics
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Proton-gradient-transfer acid complexes and their catalytic performance for the synthesis of geranyl acetate
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作者 陈永乐 丁诗雅 +3 位作者 郑文涛 张艺扬 吴有庭 胡兴邦 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2016年第12期2114-2121,共8页
Special proton-gradient-transfer acid complexes (PGTACs) in which the bonded protons are not equivalent and have gradients in transfer ability, acidity, and reactivity were reported. The acidity gradient of the prot... Special proton-gradient-transfer acid complexes (PGTACs) in which the bonded protons are not equivalent and have gradients in transfer ability, acidity, and reactivity were reported. The acidity gradient of the protons gave the PGTACs excellent catalytic activity and selectivity in the esterifica- tion of terpenols. These PGTACs are "reaction-induced self-separation catalysts" and can be easily reused. The kinetics with PGTACs as catalyst in the esterification of geraniol were also studied for use in engineering design. 展开更多
关键词 Geranyl acetatel Esterification Kinetics Proton gradient transfer Reaction-induced self-separation catalyst
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A NONMONOTONE CONJUGATE GRADIENT ALGORITHM FOR UNCONSTRAINED OPTIMIZATION 被引量:28
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《Journal of Systems Science & Complexity》 SCIE EI CSCD 2002年第2期139-145,共7页
Abstract. Conjugate gradient methods are very important methods for unconstrainedoptimization, especially for large scale problems. In this paper, we propose a new conjugategradient method, in which the technique of n... Abstract. Conjugate gradient methods are very important methods for unconstrainedoptimization, especially for large scale problems. In this paper, we propose a new conjugategradient method, in which the technique of nonmonotone line search is used. Under mildassumptions, we prove the global convergence of the method. Some numerical results arealso presented. 展开更多
关键词 Unconstrained optimization conjugate gradient nonmonotone line search global convergence.
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A Novel Magnetic Separation Oxygen-enriched Method and the Influence of Temperature and Magnetic Field on Enrichment 被引量:1
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作者 Li WANG Jun CAI Ping WU Lige TONG Shufeng SUN 《Journal of Thermal Science》 SCIE EI CAS CSCD 2007年第1期79-83,共5页
A novel oxygen-enriched method is presented. Using two opposite magnetic poles of two magnets with certain distance forms a magnetic space having a field intensity gradient near its borders. When air injected into the... A novel oxygen-enriched method is presented. Using two opposite magnetic poles of two magnets with certain distance forms a magnetic space having a field intensity gradient near its borders. When air injected into the magnetic space outflows from the magnetic space via its borders, oxygen molecules in air will experience the interception effect of the gradient magnetic field, but nitrogen molecules will outflow without hindrance. Thereby the continuous oxygen enrichment is realized. The results show that the maximum increment of oxygen concentration reaches 0.49% at 298 K when the maximum product of magnetic flux density and field intensity gradient is 563T^2/m. The enrichment level is significantly influenced by the gas temperature and the magnetic field. The maximum increment of oxygen concentration drops to 0.16% when the gas temperature rises to 343 K, and drops to 0.09% when the maximum product of magnetic flux density and gradient is reduced to 101 T^2/m from 563 T^2/m. 展开更多
关键词 magnetic separation oxygen enrichment oxygen separation gradient magnetic field magnetizing force
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Polystyrene-based blend nanorods with gradient composition distribution 被引量:2
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作者 WU Hui SU ZhaoHui +1 位作者 TERAYAMA Yuki TAKAHARA Atsushi 《Science China Chemistry》 SCIE EI CAS 2012年第5期726-734,共9页
The polystyrene-based polymer blends, partially miscible poly(bisphenol A carbonate)/polystyrene (PC/PS) and completely miscible poly(2,6-dimethylphenylene oxide)/polystyrene (PPO/PS), in nanorods with gradient compos... The polystyrene-based polymer blends, partially miscible poly(bisphenol A carbonate)/polystyrene (PC/PS) and completely miscible poly(2,6-dimethylphenylene oxide)/polystyrene (PPO/PS), in nanorods with gradient composition distribution were discussed. The polymer blend nanorods were prepared by infiltrating the polymer blends into nanopores of anodic aluminum oxide (AAO) templates via capillary action. Their morphology was investigated by micro-Fourier transform infrared spectroscopy (micro-FTIR) and nano-thermal analysis (nano-TA) with spatial resolution. The composition gradient of polymer blends in the nanopores is governed by the difference of viscosity and miscibility between the two polymers in the blends and the pore diameter. The capillary wetting of porous AAO templates by polymer blends offers a unique method to fabricate functional nanostructured materials with gradient composition distribution for the potential application to nanodevices. 展开更多
关键词 NANORODS gradient composition distribution polymer blends anodic aluminum oxide micro-FTIR nano-TA
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