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基于Wnt/β-catenin通路探讨拔毒生肌散对糖尿病大鼠皮肤溃疡愈合的促进作用 被引量:6
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作者 王双勋 李大勇 《中华中医药学刊》 CAS 北大核心 2023年第2期115-119,I0018,I0019,共7页
目的探讨拔毒生肌散通过调控Wnt/β-连环蛋白(β-catenin)通路对糖尿病大鼠皮肤溃疡愈合的促进作用。方法随机将60只Wistar雄性大鼠分为正常对照组和糖尿病组。采用腹腔注射链脲佐菌素结合喂食高脂高糖饲料方法制备糖尿病模型。28 d后,... 目的探讨拔毒生肌散通过调控Wnt/β-连环蛋白(β-catenin)通路对糖尿病大鼠皮肤溃疡愈合的促进作用。方法随机将60只Wistar雄性大鼠分为正常对照组和糖尿病组。采用腹腔注射链脲佐菌素结合喂食高脂高糖饲料方法制备糖尿病模型。28 d后,对比正常对照组和糖尿病组大鼠的体质量和血糖,然后制备背部皮肤溃疡模型。造模成功的糖尿病大鼠分为模型组、拔毒生肌散组、一效膏组、清创胶组。各组用药14 d。在第7、14天,采用Image-pro plus 6.0软件测量各组大鼠创面愈合率,采用苏木素-伊红(HE)染色法检测肉芽组织病理变化,酶联免疫吸附测定(ELISA)法检测肉芽组织晚期糖基化终末产物(advanced glycation end products,AGEs)、晚期糖基化终末产物受体(receptor for advanced glycation end-products,RAGE)、Wnt1、β-catenin、糖原合成酶激-3β(glycogen synthase exciter-3β,GSK-3β)蛋白含量,逆转录-聚合酶链反应(RT-PCR)法检测肉芽组织RAGE、Wnt、β-catenin、GSK-3βmRNA表达水平。结果与正常对照组比较,糖尿病组大鼠的体质量下降(P<0.01),血糖升高(P<0.01)。与正常对照组比较,模型组第7、14天创面愈合率均较低(P<0.01);肉芽组织中炎症细胞较多,成纤维细胞、胶原纤维和毛细血管数量较少;肉芽组织Wnt1、β-catenin mRNA表达水平较低(P<0.01),AGEs蛋白、RAGE、GSK-3β蛋白和mRNA含量较高(P<0.01)。与模型组比较,拔毒生肌散组第7、14天创面愈合率较高(P<0.01);肉芽组织AGEs蛋白、RAGE、GSK-3β蛋白和mRNA含量较低(P<0.05,P<0.01),Wnt1、β-catenin mRNA表达水平较高(P<0.01)。结论拔毒生肌散通过调节Wnt/β-catenin通路促进糖尿病大鼠皮肤溃疡的愈合。AGEs的沉积导致Wnt/β-catenin通路的抑制。 展开更多
关键词 毒生肌散 糖尿病皮肤溃疡 愈合 晚期糖基化终末产物 WNT/Β-CATENIN通路
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Effect of wire diameter compression ratio on drawing deformation of micro copper wire
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作者 Tao HUANG Han-jiang WU +3 位作者 Ke-xing SONG Yan-min ZHANG Yan-jun ZHOU Shao-lin LI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第8期2605-2618,共14页
A crystal plasticity finite element model was developed for the drawing deformation of pure copper micro wire,based on rate-dependent crystal plasticity theory.The impact of wire diameter compression ratio on the micr... A crystal plasticity finite element model was developed for the drawing deformation of pure copper micro wire,based on rate-dependent crystal plasticity theory.The impact of wire diameter compression ratio on the micro-mechanical deformation behavior during the wire drawing process was investigated.Results indicate that the internal deformation and slip of the drawn wire are unevenly distributed,forming distinct slip and non-slip zones.Additionally,horizontal strain concentration bands develop within the drawn wire.As the wire diameter compression ratio increases,the strength of the slip systems and the extent of slip zones inside the deformation zone also increase.However,the fluctuating stress state,induced by contact pressure and frictional stress,results in a rough and uneven wire surface and diminishes the stability of the drawing process. 展开更多
关键词 micro copper wire drawing deformation crystal plasticity finite element slip mode
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Physicochemical composition and climate response of surface sediments at different altitudes in Motuo on the southern slope of the Himalayas
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作者 XIE Mengping SONG Yougui +2 位作者 LAN Minwen ZHANG Mingyu HAN Yixiao 《地球环境学报》 CSCD 2024年第4期624-640,共17页
Background,aim,and scope Certain physicochemical indexes of topsoil are closely related to climatic factors including temperature,and precipitation.Understanding the relationship between modern topsoil properties and ... Background,aim,and scope Certain physicochemical indexes of topsoil are closely related to climatic factors including temperature,and precipitation.Understanding the relationship between modern topsoil properties and climatic factors is essential for quantitative paleoclimate reconstruction.Motuo located in the eastern Himalayas,exhibits a significant elevation gradient of over 7000 m from Nnamjagbarwa Peak(7782 m a.s.l.)to the Baxika(150 m a.s.l.).This region features a complete vertical zonation of vegetation,from alpine meadow to tropical forest,presenting an ideal place to investigate the relationships among vegetation,soil and climate conditions across altitudinal gradients.This study aims to explore the vertical variations in the physicochemical composition of topsoil and its relationship with temperature and precipitation.Materials and methods Twenty-seven topsoil samples were collected at 100 m intervals from 800 m to 3600 m a.s.l.along the southern slope of the Himalayas.Grain size,magnetic susceptibility and geochemical elements were measured to discuss the vertical variation characteristics of topsoil composition and their correlation with climatic factors.Results(1)The grain size of topsoil at different altitudes in Motuo is mainly composed of sand accounting for an averaged 53.2%,followed by silt and clay.(2)In the mixed forest zone,frequency dependent magnetic susceptibility(χfd%)shows a clear relationship with altitude,and clay is positively correlated with both altitude and climatic factors.(3)The oxides of topsoil in this area mainly consist of SiO_(2),Al_(2)O_(3) and Fe_(2)O_(3),followed by MgO,CaO,Na_(2)O and K_(2)O,with slight variations in the primary components at different altitudes.The sensitivity of elements to climate varies across different altitudes and vegetation zone,likely due to the region’s complex topography and vegetation.(4)Physical and biological weathering dominates in the broad-leaved forest zone of Motuo,while chemical weathering is more prominent in the coniferous forest zone,with the mixed forest zone falling in between.Discussion The formation of topsoil across the three vegetation zones is influenced by various factors,including parent material,vegetation,and climate.In the broad-leaved forest zone,physical weathering(precipitation,root wedging etc.)and pedogenesis dominate,resulting in finer grain size.The χ_(fd)% increases with altitude likely due to the high temperature and abundant precipitation in this zone,which facilitate the transformation of strong magnetic miners into weaker ones,particularly when the soil is oversaturated.Zirconium(Zr),primarily found in zircon,is depleted at lower altitudes by strong current erosion.Barium(Ba)is similarly reduced at low altitudes in this zone.In mixed forest zone,clay content is the lowest,indicating weaker physical weathering conditions than broad-leaved forest zone.The coarser grain size may result from the combined effects of topography and vegetation coverage.Magnetic susceptibility and organic matter show a positive correlation with altitude.Zr concentration is higher than that in the broad-leaved forest zone,likely resulting from decreased precipitation.In the coniferous zone,the clay content shows considerable fluctuations,with grain size generally becoming finer as altitude increases.This trend may be explained by intensified soil disintegration from seasonal freeze-thaw cycles.The χ_(fd)% values lack a clear trend or pattern,possibly due to soil erosion causing the migration of magnetic minerals or insufficient iron precipitation,which reduces the concentration of magnetic minerals in the soil.Additionally,a positive correlation is observed between altitude and organic matter content,with higher altitudes associated with greater organic matter accumulation.This may be attributed to lower microbial activity in colder conditions,which slows the decomposition and transformation of organic matter.Conclusions The variations in grain size,magnetic susceptibility,and geochemical elements differ across altitudes and vegetation zones,closely connected to the complex interplay of terrain,vegetation,and climate in Motuo.In the mixed forest,altitude has a significant impact onχfd%,and the clay component is particularly sensitive to changes in altitude,mean annual temperature,and precipitation.Zr shows a strong correlation with altitude and climate factors,making it a valuable indicator for assessing changes in atmospheric precipitation within specific altitude ranges.Recommendations and perspectives This study enhances our understanding of the relationships between the physicochemical properties of topsoil and climate conditions,offering valuable insights for paleoclimate reconstruction in Motuo. 展开更多
关键词 southern slope of the Himalayas MOTUO TOPSOIL altitude difference vegetation zone physicochemical indexes
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“柞棫斯拔,松柏斯兑”的“斯”字索解
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作者 查清兰 殷云霞 《兰台世界》 2020年第5期151-153,共3页
"帝省其山,柞棫斯拔,松柏斯兑"出自《诗经·大雅·皇矣》。关于这几句的解释,古注主要落实了"省""兑"等字的解释,并从整体分析句义,而对于关键词语"斯""拔"都没有单独解释... "帝省其山,柞棫斯拔,松柏斯兑"出自《诗经·大雅·皇矣》。关于这几句的解释,古注主要落实了"省""兑"等字的解释,并从整体分析句义,而对于关键词语"斯""拔"都没有单独解释。今人基于古注,对《诗经》中的"斯"字解释纷纭。结合诗歌的具体语境,借助其他的文献用例对今人的常见注释进行了分析,认为此处的"斯"应为结构助词,置于主语和谓语之间,起协调诗歌音节的作用。 展开更多
关键词 《诗经》 索解
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Influence of drawing process parameters on forming of micro copper tube with straight grooves 被引量:4
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作者 汤勇 欧栋生 +2 位作者 万珍平 陆龙生 练彬 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第10期2264-2269,共6页
Using high-speed oil-filled spinning method,high quality micro copper tube with straight grooves(MCTSG) with an outer diameter of 6 mm was obtained.Then,MCTSG with an outer diameter of 3-6 mm was fabricated successf... Using high-speed oil-filled spinning method,high quality micro copper tube with straight grooves(MCTSG) with an outer diameter of 6 mm was obtained.Then,MCTSG with an outer diameter of 3-6 mm was fabricated successfully by multi-pass drawing processing method.The influence of drawing parameters on the forming of micro straight grooves was investigated based on the forming mechanism.The results show that the values of groove depth and width decrease,while the wall thickness increases as the drawing diameter decreases.At the same time,the groove depth and width increase,while the wall thickness decreases as the die angle increases.The drawing force increases as the reduction increases.Excessive copper tube reduction may results in groove folding and segmental teeth.The drawing force decreases firstly and then increases with the increases in die angle.When the die angle α is 16°,the drawing force is the smallest,indicating 16° is the optimal angle. 展开更多
关键词 micro-groove DRAWING drawing parameter drawing force heat pipe
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Texture evolution and its simulation of cold drawing copper wires produced by continuous casting 被引量:9
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作者 陈建 严文 +2 位作者 李巍 苗健 范新会 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第1期152-158,共7页
The texture evolution of cold drawing copper wires produced by continuous casting was measured by X-ray diffractometry and electron back-scatter diffractometry,and was simulated using Taylor model.The results show tha... The texture evolution of cold drawing copper wires produced by continuous casting was measured by X-ray diffractometry and electron back-scatter diffractometry,and was simulated using Taylor model.The results show that in the drawn poly-crystal copper wires produced by traditional continuous casting,111 and 100 duplex fiber texture forms,and with increasing strain,the intensities of 111 and 100 increase.In the drawn single-crystal copper wires produced by Ohno continuous casting,100 rotates to 111,and there is inhomogeneous distribution of fiber texture along radial direction of the wires,which is caused by the distribution of shear deformation.Compared with 100,111 fiber texture is more stable in the drawn copper wires.Comparison of the experimental results with the simulated results shows that the simulation by Taylor model can analyze the texture evolution of drawn copper wires. 展开更多
关键词 cold drawing copper wires TEXTURE Taylor model
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The trend of tree line on the northern slope of Changbai Mountain 被引量:8
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作者 张扬建 代力民 潘洁 《Journal of Forestry Research》 SCIE CAS CSCD 2001年第2期97-100,146,共4页
In order to decipher phenomenon of tree line changing with climate variety, the trend of tree line on the northern slope of Changbai Mountain was studied. Based on the meteorological data of Changbai Mountain, the Jan... In order to decipher phenomenon of tree line changing with climate variety, the trend of tree line on the northern slope of Changbai Mountain was studied. Based on the meteorological data of Changbai Mountain, the January temperature (the limiting effect for tree line) and annual mean temperature were mainly investigated. In the ecotone between Betula ermanii and alpine tundra, the number and diameter at ground level of Betula ermanii in the plots were measured. According to the correlation between diameter at ground level (DGL) and age, the diameter at ground level can represent age directly. The results showed that the distribution age of Betula ermanii was in the trend of decreasing with elevation rising. In resent years, the annual mean temperature near Changbai Mountain is rising, which has led to the tree line ascending. 展开更多
关键词 Tree line TEMPERATURE ELEVATION Meteorological data
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Effect of electropulsing on deformation behavior of Ti-6Al-4V alloy during cold drawing 被引量:10
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作者 周岩 陈国清 +1 位作者 付雪松 周文龙 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第4期1012-1021,共10页
Electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) were used to investigate effect of electropulsing on microstructure and texture evolution of Ti-6Al-4V during cold drawing. Rese... Electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) were used to investigate effect of electropulsing on microstructure and texture evolution of Ti-6Al-4V during cold drawing. Research results demonstrate that the electropulsing treatment (EPT) can enhance the deformability of the grains with unfavorable orientations, which makes the compatibility of deformation among grains much better. A comparison in texture evolution between conventional cold drawing and EPT cold drawing indicates that the EPT promotes prismatic 〈a〉 slip moving, restricts pyramidal 〈c+a〉 slip occurring and accommodates the deformation with c-component by grain boundary sliding. The fraction decrease of low-angle grain boundaries for samples deformed with EPT reveals that the application of electropulsing restricts the formation of the incidental dislocation boundaries and the geometrically necessary boundaries. 展开更多
关键词 Ti-6Al-4V alloy ELECTROPULSING cold drawing texture evolution
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Study on complexity of plant communities at different altitudes on the Northern Slope of Changbai Mountain 被引量:4
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作者 郝占庆 于德永 +1 位作者 邓红兵 姜萍 《Journal of Forestry Research》 SCIE CAS CSCD 2002年第1期17-20,82,共4页
By the method of gradient pattern analysis, twenty plots were set at altitudes of 700-2600 m with an interval of 100 m on the northern slope of the Changbai Mountain. The dissimilarity of respective sub-plots in the s... By the method of gradient pattern analysis, twenty plots were set at altitudes of 700-2600 m with an interval of 100 m on the northern slope of the Changbai Mountain. The dissimilarity of respective sub-plots in the same community was measured and the complexity of plant communities at different altitudes was analyzed. The result from binary data of tree species in canopy tree indicated that the sub-plots in the communities, except subalpine Betula ermanii forest, showed comparatively high dissimilarity in species composition. Especially, the dissimilarity index (0.7) of broadleaved/Korean pine forest at low altitudes was obviously higher than other communities. The differences are not obvious between communities referring to dark coniferous forest. Comparatively, the dissimilarity in sub-plots of the communities at altitude of 1400 m was slightly higher than that of other communities, which reflected the complexity of tree species compositions of transitory-type communities. For subalpine Betula ermanii forest, tree species composition was simple and showed a high similarity between sub-plots. The results derived from binary data of shrub showed that the dissimilarity index of shrub species in broadleaved/Korean pine forest at low altitudes was higher than that in other communities, but the divergence tendency wasn抰 so obvious as that of arbor species. The dissimilarity derived from binary data of herb and all plant species at different altitudes showed greatly close tendency, and the differences in herb and all plant species between sub-plots were the greatest for the communities of broad-leaved-Korean pine forest and alpine tundra zone.. 展开更多
关键词 Changbai Mountain COMPLEXITY Plant community Altitude gradient
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Starch RVA Profile Properties for Cold Tolerant and Sensitive Cultivars of Japonica Rice at Different Altitudes 被引量:5
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作者 朱振华 金基永 +6 位作者 袁平荣 赵国珍 苏振喜 世荣 邹茜 杨世准 戴陆园 《Agricultural Science & Technology》 CAS 2011年第12期1831-1836,共6页
[Objective] By investigating of change rule rice starch RVA profile properties and the influence of cold tolerance on rice quality,the aim was to provide scientific references to the breeding of new cold-tolerant japo... [Objective] By investigating of change rule rice starch RVA profile properties and the influence of cold tolerance on rice quality,the aim was to provide scientific references to the breeding of new cold-tolerant japonica rice varieties with high quality in the Yunnan plateau.[Method] Four cold-tolerant and five cold-sensitive japonica rice cultivars were grown at three locations with different altitudes in Yunnan plateau to investigate rice starch RVA profile characteristics.[Result] The results showed that with increasing altitude,the setback viscosity in cold-sensitive cultivars increased significantly,while the peak viscosity and breakdown viscosity decreased significantly.However,the peak viscosity and breakdown viscosity in cold-tolerant cultivars initially decreased and then gradually increased with rising altitude,whereas the setback viscosity initially increased and then decreased.[Conclusion] The starch RVA parameters of cold-tolerant cultivars were less sensitive to different environments than those of cold-sensitive cultivars.Cooking and eating quality of cold-tolerant cultivars had relatively stable trends with rising altitude,whereas cooking and eating quality of cold-sensitive cultivars had a trend toward inferior. 展开更多
关键词 Japonica rice Cold tolerance Rice quality Starch viscosity ALTITUDE
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Distributional patterns of species diversity of main plant communities along altitudinal gradient in secondary forest region,Guandi Mountain,China 被引量:7
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作者 高俊峰 张芸香 《Journal of Forestry Research》 SCIE CAS CSCD 2006年第2期111-115,共5页
Fourteen plots were chosen along with the altitude of 1600-2600 m in Guandi Mountain, Shanxi Province, China to investigate all the trees in the plots, and the species diversity indexes were calculated for analyzing t... Fourteen plots were chosen along with the altitude of 1600-2600 m in Guandi Mountain, Shanxi Province, China to investigate all the trees in the plots, and the species diversity indexes were calculated for analyzing the effects of altitudinal gradient on plant species diversity. The results showed that the order of dominant species from low altitude to high altitude is as Quercus liaotungensis Koidz, Pinus tabulaeformis, Betula platyphylla, B. albo-sinensis, Picea wilsonii, P. Meyeri and Larix principis-rupprechtii. With altitude increasing, the average height and DBH of the arbor firstly increase and then decrease, the maximal height and DBH of the arbor present the unimodal variable trend, the maximal height of coniferous and broad-leaved trees firstly increases and then decreases, the maximal DBH of broad-leaf trees has no clear fluctuation, and the maximal DBH of the needle-leaf trees decreases gradually. Moreover, in middle altitudinal communities (the altitude of 1900-2200 m), the maximal height and DBH of the needle-leaf trees are larger than these of broad-leaf trees. Both Shannon-wiener index and Margalef index of the communities present the unimodal variable trend, with a peak in the mid-altitude. Plant species diversity in the mid-altitude (1900-2200 m) is higher than that of the low altitude (1600-1900 m) and the high altitude (2200-2600 m). In addition, the unimodal variable trend of α species diversity is clearly correlated with the altitudinal gradient. The change of plant species diversity is significantly correlated with the altitudinal gradient, and also related to the community structure, the community composition, the feature of species and the human disturbance. 展开更多
关键词 Species diversity Altitudinal gradient COMMUNITY Guandii Mountain
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The changes of co-possession of plant species between communities with altitudes on northern slope of Changbai Mountain 被引量:3
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作者 邓红兵 郝占庆 王庆礼 《Journal of Forestry Research》 SCIE CAS CSCD 2001年第2期89-92,146,共4页
Twenty plots were investigated on northern slope of Changbai Mountain at an attitude interval of 100 m (from 700 to 2600 m). The species co-possession between plant communities at different altitudes was analyzed by J... Twenty plots were investigated on northern slope of Changbai Mountain at an attitude interval of 100 m (from 700 to 2600 m). The species co-possession between plant communities at different altitudes was analyzed by Jaccard index. The analytical results showed that the co-possession calculated according to species in different layers or all species between adjacent communities was higher than that between disjunct communities. The co-possessions between adjacent communities calculated by species in different layers had comparability and dissimilarity. If the two adjacent communities belong to different types of vegetation, then their co-possession was lower. The peak values and valley values of species co-possession between communities along elevation gradient just matched vegetation gradient patterns, and species subrogation of shrubs had more obvious rule on northern slope of Changbai Mountain. Co-possessions between communities with same altitude difference were much similar, and it decreased as the increase of elevation difference, which showed that species compositions in different layers of the communities were highly related. 展开更多
关键词 Changbai Mountain Co-possession Plant community Altitude gradient
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Application of ultra-smooth composite diamond film coated WC-Co drawing dies under water-lubricating conditions 被引量:5
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作者 沈彬 孙方宏 +2 位作者 张志明 沈荷生 郭松寿 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第1期161-169,共9页
A specific revised HFCVD apparatus and a novel process combining HFCVD and polishing technique were presented to deposit the micro-and nano-crystalline multilayered ultra-smooth diamond(USCD) film on the interior-ho... A specific revised HFCVD apparatus and a novel process combining HFCVD and polishing technique were presented to deposit the micro-and nano-crystalline multilayered ultra-smooth diamond(USCD) film on the interior-hole surface of WC-Co drawing dies with aperture ranging from d1.0 mm to 60 mm.Characterization results indicate that the surface roughness values(Ra) in the entry zone,drawing zone and bearing zone of as-fabricated USCD coated drawing die were measured as low as 25.7,23.3 and 25.5 nm,respectively.Furthermore,the friction properties of USCD films were examined in both dry sliding and water-lubricating conditions,and the results show that the USCD film presents much superior friction properties.Its friction coefficients against ball-bearing steel,copper and silicon nitride balls(d4 mm),is always lower than that of microcrystalline diamond(MCD) or WC-Co sample,regardless of the lubricating condition.Meanwhile,it still presents competitive wear resistance with the MCD films.Finally,the working lifetime and performance of as-fabricated USCD coated drawing dies were examined under producing low-carbon steel pipes in dry-sliding and water-lubricating conditions.Under the water-lubricating drawing condition,its production significantly increases by about 20 times compared with the conventional WC-Co drawing dies. 展开更多
关键词 CVD diamond coated drawing die ultra-smooth composite diamond(USCD) film friction properties water-lubricating drawing dry sliding water lubrication
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Study on Influencing Factors of Farmland Soil Heavy Metals in Central Yunnan Province 被引量:2
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作者 余小芬 陈军 +3 位作者 彭荣珍 邱学礼 付斌 倪明 《Agricultural Science & Technology》 CAS 2013年第4期645-650,共6页
[Objective] This study aimed to explore the relationship between contents of heavy metals with soil type, altitude distribution as well as physical and chemical properties. [Method] Based on determination of contents ... [Objective] This study aimed to explore the relationship between contents of heavy metals with soil type, altitude distribution as well as physical and chemical properties. [Method] Based on determination of contents of soil heavy metals and soil physical and chemical properties from agricultural land in Central Yunnan Province, the relationship between soil heavy metals with soil type, altitude distribu- tion and soil physical and chemical properties were analyzed. [Result] The average contents of all heavy metals in farmland of Central Yunnan didn't extend their limits of Grade II in the National Soil Environmental Quality Standard (GB15618-1995). and the heavy metals content in red soil was higher than that in other types. Soil Cd content changes slightly with the altitude, while contents of other heavy metals were greatly affected by altitude. There were extremely significant positive correlation between heavy metals and clay particle content, that is, soil with heavier texture has more heavy metals. There was positive correlation between pH and each heavy metal content; there were positive correlation between Mn with Pb, Cd, Hg and Hg; exchangeable Ca and Mg contents in soil show negative correlations with most heavy metals. [Conclusion] This study has provided scientific bases for the heavy metal management in Central Yunnan area. 展开更多
关键词 Soil type Altitude distribution Physical and chemical properties Heavy metals
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Study on the Changes of Non-structural Carbohydrates and Nitrogen Contents of Quercus aquifolioides Scrub along Different Elevation Gradient 被引量:2
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作者 黄亚洲 吴杰 +3 位作者 孟玉山 吕俊 王三根 朱万泽 《Agricultural Science & Technology》 CAS 2011年第4期576-580,共5页
[Objective] The aim was to compare the content changes between the non-structural carbohydrates(NSC)and the total nitrogen in various growing seasons,and to explore the response relationship between altitude and the... [Objective] The aim was to compare the content changes between the non-structural carbohydrates(NSC)and the total nitrogen in various growing seasons,and to explore the response relationship between altitude and the contents.[Method] Taking Quercus aquifolioides scrub which widely distributed in Zheduoshan in the west of Sichuan as the experimental objects,the changes between NSC and the toal nitrogen in various growing seasons at different altitude were studied.[Result] The results showed that the content of NSC in Quercus aquifolioides underground increased with the lift of elevation in the dormancy,but decreased in the early germination,growing period and growth stage.The content of NSC in the ground tissue changed non-linearly with increasing elevation.In addition,the total nitrogen of Quercus aquifolioides organizations was decreasing with increasing elevation in the dormant period,which did not change significantly in the other periods.This result implied that the content of NSC in Quercus aquifolioides underground was more sensitive to temperature.[Conclusion] The experiment laid basis for the exploration of the physical and ecological mechanism of underground plants adaptability to highland environment,their response to global climate changes and adjustment to high altitude ecological system. 展开更多
关键词 Quercus aquifolioides Total nitrogen NON-STRUCTURAL Carbohydrates ELEVATION
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Effects of Enhanced Ultraviolet Radiation-B on Maize in Arid Regions of Middle-high Elevation 被引量:13
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作者 张磊 王连喜 +2 位作者 李福生 车晶晶 杜宏娟 《Agricultural Science & Technology》 CAS 2009年第1期11-14,73,共5页
[Objective] The experiment aimed to explore the influence of enhanced ultraviolet radiation-B on maize in arid regions of middle-high elevation for correct assessing the influence of enhanced ultraviolet radiation-B o... [Objective] The experiment aimed to explore the influence of enhanced ultraviolet radiation-B on maize in arid regions of middle-high elevation for correct assessing the influence of enhanced ultraviolet radiation-B on maize and providing scientific reference to make proper countermeasures. [ Method] The location test in field and lift lamp of UV-B were used to observe the changes of maize height, leaf area and number of green leaves under influences of different UV-B radiation. [ Result] In arid regions of middle-high elevation, enhanced ultraviolet radiation-B could dwarf maize plant, decrease leaf area, decline number of green leaves and yield. The reason of decreasing leaf area was that enhanced ultraviolet radiation-B shortened leaf length and leaf width while the reason of declining yield was that yield components were all negatively influ- enced and with the increase of ultraviolet radiation-B, the yield declined dramatically. [ Concluslonl The result of this experiment would be good for maize production in arid regions of middle-high elevation. 展开更多
关键词 UV-B Middle-high elevation Arid area MAIZE
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Influences of fillet radius and draft angle on local loading process of titanium alloy T-shaped components 被引量:1
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作者 张大伟 杨合 +1 位作者 孙志超 樊晓光 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第12期2693-2704,共12页
In order to study influences of geometric parameters on the T-shaped components local loading process, a new mathematical model considering the fillet radius and draft angle was established by using the slab method. T... In order to study influences of geometric parameters on the T-shaped components local loading process, a new mathematical model considering the fillet radius and draft angle was established by using the slab method. The results obtained by the mathematical model agree with the data form experiment and numerical simulation, and the results are closer to the experimental and simulation results. The influence of draft angle may be neglected under the forming conditions used. The influence of fillet radius is notable, especially in the case that the ratio of fillet radius to rib width is less than 0.75. 展开更多
关键词 fillet radius draft angle T-shaped component local loading slab method
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Study on Species Diversity of Alpine Vegetation with Different Altitudes in Daban Mountain 被引量:1
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作者 周芸芸 赵敏杰 +2 位作者 李熙萌 马帅 冯金朝 《Agricultural Science & Technology》 CAS 2011年第3期313-316,332,共5页
[Objective] The aim of this study is to investigate species diversity of alpine vegetation in different altitudes of Daban mountain. [Method] Plant communities were surveyed in three different altitudes (3 025 m,3 40... [Objective] The aim of this study is to investigate species diversity of alpine vegetation in different altitudes of Daban mountain. [Method] Plant communities were surveyed in three different altitudes (3 025 m,3 405 m,3 813 m) of Daban mountain,the eastern Qilian,and the richness or diversity index of vegetation in three different altitudes was comparatively analyzed. [Result] The species richness decreased with the gradual increase of altitude,and species diversity of plant communities was relatively lower in medium altitude. Furthermore,community similarity also decreased with the increase of altitude,and β diversity of communities had a significant change. [Conclusion] Environmental factor change caused by different altitudes and human disturbance are important reasons for the change of species distribution pattern in different altitudes. 展开更多
关键词 Daban Mountain Alpine vegetation Altitude gradient Species diversity
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Research on the Correlation between Meteorological Factors and Flue-cured Tobacco Chemical Components in Different Altitudes of Lincang Region 被引量:1
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作者 王娜 赵正雄 +2 位作者 白羽祥 李世琛 陈泽 《Agricultural Science & Technology》 CAS 2015年第3期593-599,共7页
In this study, the relationship between major meteorological factors and tobacco chemical components in different altitudes of Yongde County, Lincang Region of Yunnan Province was studied using correlation analysis an... In this study, the relationship between major meteorological factors and tobacco chemical components in different altitudes of Yongde County, Lincang Region of Yunnan Province was studied using correlation analysis and path analysis methods.The results showed that there was a difference on meteorological factors in different altitudes, causing different impacts on chemical components of flue-cured tobacco; contents of nicotine and total nitrogen decreased with the rising of altitude, conversely, total sugar and reducing sugar contents increased with the rising trend of altitude, and the differences on the contents of potassium (K) and chlorine(CI), and the ratio of K to CI in different altitudes were not significant, at the altitude of 1 250-1 450 m, each chemical component indicator was better. The correlation between main meteorological factors and conventional chemical components of tobacco leaves was as follows: contents of reducing sugar and total sugar increased with the increase of rainfall and relative humidity, and decreased with the increase of sunshine duration; nicotine content increased with the increase of accumulated temperature and sunshine duration; total nitrogen (N) content increased with the increase of daily mean temperature and accumulated temperature; sugar-alkali ratio increased with the increase of rainfall. Path analysis showed that the direct effect of sunshine duration on reducing sugar and total sugar of tobacco leaves was faint, but the indirect effect was obvious; meanwhile, the direct and indirect effects of it on nicotine and total N were the greatest. 展开更多
关键词 ALTITUDE Meteorological factors . Chemical components Correlation anal- ysis Path analysis
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PULTRUSION OF POLYBENZOXAZINE RESIN MATRIX Z-PIN
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作者 张向阳 李勇 +4 位作者 肖军 王宏远 胡晶晶 郑莹莹 刘博 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2012年第3期237-244,共8页
The pultrusion of the polybenzoxazine resin matrix Z-pin is studied, because the Z-pin technology is an efficient reinforcement method for composites. Based on the curing characteristics acquired by differential scann... The pultrusion of the polybenzoxazine resin matrix Z-pin is studied, because the Z-pin technology is an efficient reinforcement method for composites. Based on the curing characteristics acquired by differential scanning calorimeter(DSC) analysis, the suitable mould temperature for pultrusion is researched with the visual inspection and the Z-pin short beam shear test. The pull-out test is designed to evaluate the post oven temperature that can affect the combination between Z-pins and laminates. And then, the appropriate temperature for the post oven is obtained. Finally, micro photos are used to inspect the defects in Z-pins. The results show that when the resin is heated to 70°C, Z-pin pultrusion demands for viscosity are satisfied, and the shelf-life is about 4 h. With the mould temperature increasing to 140°C, the Z-pin short beam shear strength rises correspondingly and the cross section profile is the best. When the post oven temperature declines, the combination between Z-pins and laminates becomes stronger. However, pores appear in Z-pins unless the oven temperature increases to 200°C. Therefore, the optimum post oven temperature should be set at 200°C. 展开更多
关键词 Z-PIN POLYBENZOXAZINE PULTRUSION short beam shear test pull-out test
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