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Effects of Vegetation Cover and Rainfall Intensity on Sediment-Bound Nutrient Loss,Size Composition and Volume Fractal Dimension of Sediment Particles

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Pedosphere 2011年第5期21卷 676-684页

作者： zhang guan-hua LIU Guo-Bin WANG Guo-Liang WANG Yu-Xia College of Resource and Environment Northwest A&F University Yangling 712100 (China) Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water Resources Yangling 712100 (China)

Vegetation and rainfall are two important factors affecting soil erosion and thus resulting in nutrient loss in the Chinese Loess Plateau.A field experiment was conducted to investigate the effects of rainfall intensities(60,100 and 140 mm h-1) and vegetation(Caragana korshinskii) coverages(0%,30% and 80%) on soil loss,nutrient loss,and the composition and volume fractal dimension of eroded sediment particles under simulated rainfall *** results showed that vegetation cover,rainfall intensity and their interaction all had significant effects on sediment transport and the sedimentbound nutrient *** rainfall intensity and lower coverage led to higher sediment and nutrient *** linear relationships were observed between soil loss and nutrient *** treatments showed more significant effects on the enrichment ratio(ER) of nitrogen(ERN) than organic matter(EROM) and phosphorus(ERP).Compared with the original surface soil,the eroded sediment contained more fine *** the same coverage,the clay content significantly decreased with increasing rainfall *** ER of sediment-bound nutrients was positively correlated with that of clay,suggesting that the clay fraction was preferentially eroded and soil nutrients were mainly adsorbed onto or contained within this *** were increments in the fractal dimension of the sediment particles compared to that of the original surface ***,the fractal dimension was positively correlated with clay,silt,and sediment-bound OM,N,and P contents,whereas it was negatively correlated with sand *** study demonstrated that fractal dimension analysis can be used to characterize differences in particle-size distribution and nutrient loss associated with soil erosion.

关键词： fractal features Loess Plateau particle-size distribution runoff nutrients simulated rainfall

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Effects of moss-dominated biocrusts on soil detachment by overland flow in the Three Gorges Reservoir Area of China

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Journal of Mountain Science 2020年第10期17卷 2418-2431页

作者： zhang guan-hua DING Wen-feng PU Jian LI Jian-ming QIAN Feng SUN Bao-yang Soil and Water Conservation Department Changjiang River Scientific Research InstituteWuhan430010China Research Center on Mountain Torrent&Geologic Disaster Prevention of Ministry of Water Resources Wuhan430010China

Biological soil crusts(biocrusts)are important landscape components that exist in various climates and *** roles of biocrusts in numerous soil processes have been predominantly recognized in many dryland regions ***,little is known about their effects on soil detachment process by overland flow,especially in humid *** study quantified the effects of moss-dominated biocrusts on soil detachment capacity(Dc)and soil erosion resistance to flowing water in the Three Gorges Reservoir Area which holds a subtropical humid *** factors driving soil detachment variation and their influencing mechanism were analyzed and *** designed five levels of coverage treatments(1%–20%,20%–40%,40%–60%,60%–80%,and 80%–100%)and a nearby bare land as control in a mossdominated *** soil samples were taken and subjected to water flow scouring in a hydraulic flume under six shear stresses ranging from 4.89 to 17.99 *** results indicated that mean Dc of mosscovered soil varied from 0.008 to 0.081 kg m^-2 s^-1,which was 1.9 to 21.0 times lower than that of bare soil(0.160 kg m^-2 s^-1).Rill erodibility(Kr)of mosscovered soil ranged from 0.0095 to 0.0009 s m^-1,which was 2 to 20 times lower than that of bare soil(0.0187 s m^-1).Both relative soil detachment rate and Kr showed an exponential decay with increasing moss coverage,whereas the critical shear stress(τc)for different moss coverage levels did not differ *** coverage,soil cohesion,and sand content were key factors affecting Dc,while moss coverage and soil bulk density were key factors affecting Kr.A power function of flow shear stress,soil cohesion,and moss coverage fitted well to estimate Dc(NSE=0.947).Our findings implied that biocrusts prevented soil detachment directly by their physical cover and indirectly by soil properties *** could be rehabilitated as a promising soil conservation measure during ecological recovery to enhance so

关键词： Soil detachment Soil erosion resistance Rill erodibility Biological soil crusts Yangtze River

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Apportioning above-and below-ground effects of moss biocrusts on soil detachment by overland flow in a subtropical climate

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Journal of Mountain Science 2021年第10期18卷 2646-2655页

作者： zhang guan-hua YI Liang DING Wen-feng LEI Xu WANG Yi-ran SUN Bao-yang LI Jian-ming Soil and Water Conservation Department Changjiang River Scientific Research InstituteWuhan 430010China Research Center on Mountain Torrent&Geologic Disaster Prevention of Ministry of Water Resources Wuhan 430010China Central-Southern Safety&Environment Technology Institute Co. LtdWuhan 430071China

Biocrusts affect soil detachment through above-ground(top crust’s surface covering)and below-ground(sub-crust’s binding and bonding,B&B)effects,which might vary with biocrust development or ***,these effects in humid climates are still *** study was conducted to apportion and quantify the surface covering and B&B effects of moss biocrusts with five coverage levels(1%–20%,20%–40%,40%–60%,60%–80%,and 80%–100%)on soil detachment by overland flow in a subtropical humid *** treatments with one being intact moss crusts and one removing the aboveground moss tissues were designed for each coverage level,and bare soil was used as the *** results indicated that soil detachment capacity(Dc)and rill erodibility(Kr)decreased with biocrust *** removing the above-ground moss tissues,the impeding effect of biocrusts on soil detachment weakened,but still increasing soil erosion resistance relative to bare *** intact crust,Dc was reduced by 50%–95%compared with bare soil,wherein 36%–55%and 14%–40%were attributed to the surface covering and B&B,*** top crust contributed more than sub-crust to the soil detachment reduction,which were related to but not linear with biocrust *** biocrust coverage reached mid-to-higher level(40%–100%),both top crust and sub-crust steadily contributed to soil detachment reduction with 60%and 40%,*** findings advance a better understanding of the influencing mechanism of biocrusts on soil erosion in humid climates and highlight the importance of saving biocrusts as ecosystem functions.

关键词： Soil detachment Rill erodibility Effect apportionment Contribution rate Three Gorges

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Assay of mitochondrial functions by resazurin in vitro

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Acta Pharmacologica Sinica 2004年第3期25卷 131-135页

作者： Hai-xia zhang,guan-hua DU2,Jun-tian zhang Institute of Materia Medica,Peking Union Medical College & Chinese Academy of Medical Sciences,Beijing100050,China Institute of Materia Medica Peking Union Medical College & Chinese Academy of Medical Sciences 北京 100050

AIM: To study the mechanism of resazurin as indicator of mitochondrial function and to develop a rapid and sensitive assay for measuring metabolic activity of isolated mitochondria from rat liver in vitro. METHODS: The screening was carried out on 96-well microtitre plates by monitoring fluorescence intensity of resazurin reduced by mitochondria. Experimental conditions were optimized and influences of several inhibitors on mitochondrial func- tion were observed. RESULTS: Fluorescence intensity increased in a linear manner when the mitochondrial protein concentration from 5 to 50 μg protein per well was incubated with resazurin (5 μmol/L) during 230 min period at 37 oC. Edetic acid could promote the reduction of resazurin in mitochondria. The fluorescence intensity decreased greatly after pretreatment with NaN3, antimycin A, carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP), and oligomycin compared with the control. However, the typical complex I inhibitor, rotenone enhanced the fluorescence intensity without mitochondria. CONCLUSION: Using resazurin to determine mitochondrial func- tion is sensitive, inexpensive and could be easily automated for high throughput screening.

关键词： resazurin drug screening mitochondria

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Molecular dynamics simulations of helium transport through inorganic mineral nanopores

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Science China Earth Sciences 2025年第1期68卷 237-252页

作者： Dandan SONG Ping guan Chi zhang Jiahao REN School of Earth and Space Sciences Peking University

Helium transport through nanoscale inorganic mineral pores and pore throats is essential for its overall migration. To elucidate helium's transport dynamics within nanopores, we employed equilibrium and non-equilibrium molecular dynamics simulations to investigate helium's static self-diffusion and pressure-driven flow in quartz slit-shaped nanopores. We also introduced water and various gases, including hydrogen, methane, ethane, nitrogen, and carbon dioxide, into the nanopores to assess their influence on helium transport. Our findings indicate minimal helium adsorption on quartz pore surfaces. Under conditions where the pore size is less than 5 nm and the pressure under 10 MPa, environmental factors markedly influence helium diffusion. Large pore sizes, high temperatures, and low gas pressures enhance helium desorption and facilitate faster diffusion. We observed a positive correlation between helium flow velocity and factors such as pore size, pressure gradient, and surface smoothness of the pores. Notably, the presence of pore water and carrier gases in quartz nanopores, which diffuse more slowly than helium, tends to reduce helium surface adsorption and slow its diffusion. Among the carrier gases studied, nitrogen showed similar adsorption capacity, diffusivity, and stability to helium, while carbon dioxide displayed the highest adsorption capacity and the slowest diffusion rate, markedly differing from helium. Based on the simulation results, we concluded that water and carrier gases primarily function as transport mediums in helium migration, moving together with helium. Nitrogen, which shares similar properties with helium, effectively assists in this co-migration process. Conversely, carbon dioxide, due to its high adsorption capacity and slow diffusion, tends to be lost during co-migration. As a result, gas reservoirs with high nitrogen levels and low carbon dioxide levels are more likely to have higher helium concentrations. Additionally, the smaller por

关键词： Helium transport Slit nanopores Molecular dynamics simulations Diffusion Flow carriers

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砼连续箱梁人行天桥振动特性测试与分析

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振动与冲击 2009年第2期28卷 102-106页

作者：张冠华葛耀君同济大学土木工程防灾国家重点实验室上海200092 辽宁省交通勘测设计院沈阳110005

以某座普通钢筋砼连续箱梁人行天桥为工程背景,通过对其振动特性进行大量实测试验,利用有限元理论对结构整体进行计算,深入分析其大幅度竖向、侧向振动的成因,结合实测数据探讨现行人行桥振动舒适度评价方法所存在的不足之处,评价天桥... 详细信息

以某座普通钢筋砼连续箱梁人行天桥为工程背景,通过对其振动特性进行大量实测试验,利用有限元理论对结构整体进行计算,深入分析其大幅度竖向、侧向振动的成因,结合实测数据探讨现行人行桥振动舒适度评价方法所存在的不足之处,评价天桥的舒适程度,为该桥的质量检测与评价提供依据,并提出了人行天桥振动舒适性评价建议。这为今后对该类桥梁的设计、维修加固具有实际参考价值。

关键词：人行天桥固有频率人致振动振动测试共振

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双循环新发展格局下两岸融合发展形势与走向

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亚太经济 2021年第2期 133-142页

作者：张冠华中国社会科学院台湾研究所北京100005

近年来,中美贸易摩擦、新冠肺炎疫情、两岸关系紧张等因素叠加,已冲击两岸经济关系传统发展格局,两岸供应链出现局部重构,部分台商调整两岸及全球投资布局,两岸高科技产业交流与合作受到制约,对深化两岸融合发展形成新的挑战。同时,大... 详细信息

近年来,中美贸易摩擦、新冠肺炎疫情、两岸关系紧张等因素叠加,已冲击两岸经济关系传统发展格局,两岸供应链出现局部重构,部分台商调整两岸及全球投资布局,两岸高科技产业交流与合作受到制约,对深化两岸融合发展形成新的挑战。同时,大陆新经济快速发展、确立双循环新发展格局以及签署RCEP等,对增强两岸经济关系发展的创新驱动、改变大陆台商“飞地”式经营模式、深化两岸产业合作等提供了新的重要机遇。两岸经济关系中传统格局的重构、新发展格局的塑造,有助于推动两岸融合发展进入新阶段。

关键词：双循环新发展格局供应链两岸融合发展

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全球经济变局下两岸供应链重构走向探讨

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亚太经济 2023年第5期 143-152页

作者：张冠华中国社会科学院台湾研究所北京100008

在国际地缘政治紧张、中美贸易摩擦、两岸关系严峻复杂等重大因素的叠加影响下,传统两岸经贸关系发展方式正面临新挑战,两岸供应链加快调整和局部重构,进而对两岸贸易与投资格局产生重要影响。同时,内地构建双循环新发展格局、新一轮产... 详细信息

在国际地缘政治紧张、中美贸易摩擦、两岸关系严峻复杂等重大因素的叠加影响下,传统两岸经贸关系发展方式正面临新挑战,两岸供应链加快调整和局部重构,进而对两岸贸易与投资格局产生重要影响。同时,内地构建双循环新发展格局、新一轮产业技术革命等,也为两岸经贸关系转型升级提供重大机遇,两岸经济难以脱钩。对此,应善于因势利导、化危为机,通过深化两岸融合发展,加快促进两岸供应链合作转型升级,推动两岸经贸关系高质量发展。

关键词：世界经济两岸经贸供应链重构方向

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流线型闭口箱梁断面风荷载空间相关性试验研究

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振动与冲击 2012年第2期31卷 76-80,114页

作者：张冠华赵林葛耀君同济大学土木工程防灾国家重点实验室上海200092 辽宁省交通规划设计院沈阳110005

对典型流线型闭口箱梁断面的风荷载效应进行同步测压风洞试验,比较了来流平均风速、湍流度、风攻角、展向间距等不同参数条件下风荷载在空间分布状况,对风速及其荷载效应的空间相关性进行深入研究,从时、频域两个方面来尝试分析现象及原... 详细信息

对典型流线型闭口箱梁断面的风荷载效应进行同步测压风洞试验,比较了来流平均风速、湍流度、风攻角、展向间距等不同参数条件下风荷载在空间分布状况,对风速及其荷载效应的空间相关性进行深入研究,从时、频域两个方面来尝试分析现象及原因,探讨影响因素,证实升力、扭矩的展向相关性远大于风速、阻力的相关性,并发现升力与扭矩的相关性规律相似,风速与阻力相关性规律相似;验证了传统随机抖振动气动力理论所存在的不足。

关键词：气动力荷载空间相关性相干函数相关系数湍流

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中国民间故事中的生态寓意

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郑州大学学报（哲学社会科学版） 2006年第2期39卷 160-163页

作者：张冠华郑州大学文学院河南郑州450001

中国民间故事在赞扬劳动人民优秀品质的表层意义下,还有着丰富的生态寓意:人与天地、与大自然的血肉相连;人类与万物的伙伴关系;尊重动物,将人道与天道统一起来等等。对此揭示,有助于展示民间故事的广阔阐释空间,并丰富当今的生态观念。

关键词：中国民间故事生态寓意天人合一大地伦理生态道德

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