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度:生态包装的重要标尺
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作者 刘文良 金正萍 《包装学报》 2010年第1期57-60,共4页
发展生态包装,是我国包装工业的必然选择,是建设"两型社会"的必然要求。"量"度、"质"度和"法"度是生态包装的重要标尺。拒绝过量化媚俗包装,辩证看待绿色材质,熟悉与遵循"绿色"法规... 发展生态包装,是我国包装工业的必然选择,是建设"两型社会"的必然要求。"量"度、"质"度和"法"度是生态包装的重要标尺。拒绝过量化媚俗包装,辩证看待绿色材质,熟悉与遵循"绿色"法规,是正确看待和发展生态包装应该把握的3个基本维度。 展开更多
关键词 生态包装 “量”度 “质”度 “法”度
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Constitution identification model in traditional Chinese medicine based on multiple features
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作者 XU Anying WANG Tianshu +7 位作者 YANG Tao HAN Xiao ZHANG Xiaoyu WANG Ziyan ZHANG Qi LI Xiao SHANG Hongcai HU Kongfa 《Digital Chinese Medicine》 CAS CSCD 2024年第2期108-119,共12页
Objective To construct a precise model for identifying traditional Chinese medicine(TCM)constitutions;thereby offering optimized guidance for clinical diagnosis and treatment plan-ning;and ultimately enhancing medical... Objective To construct a precise model for identifying traditional Chinese medicine(TCM)constitutions;thereby offering optimized guidance for clinical diagnosis and treatment plan-ning;and ultimately enhancing medical efficiency and treatment outcomes.Methods First;TCM full-body inspection data acquisition equipment was employed to col-lect full-body standing images of healthy people;from which the constitutions were labelled and defined in accordance with the Constitution in Chinese Medicine Questionnaire(CCMQ);and a dataset encompassing labelled constitutions was constructed.Second;heat-suppres-sion valve(HSV)color space and improved local binary patterns(LBP)algorithm were lever-aged for the extraction of features such as facial complexion and body shape.In addition;a dual-branch deep network was employed to collect deep features from the full-body standing images.Last;the random forest(RF)algorithm was utilized to learn the extracted multifea-tures;which were subsequently employed to establish a TCM constitution identification mod-el.Accuracy;precision;and F1 score were the three measures selected to assess the perfor-mance of the model.Results It was found that the accuracy;precision;and F1 score of the proposed model based on multifeatures for identifying TCM constitutions were 0.842;0.868;and 0.790;respectively.In comparison with the identification models that encompass a single feature;either a single facial complexion feature;a body shape feature;or deep features;the accuracy of the model that incorporating all the aforementioned features was elevated by 0.105;0.105;and 0.079;the precision increased by 0.164;0.164;and 0.211;and the F1 score rose by 0.071;0.071;and 0.084;respectively.Conclusion The research findings affirmed the viability of the proposed model;which incor-porated multifeatures;including the facial complexion feature;the body shape feature;and the deep feature.In addition;by employing the proposed model;the objectification and intel-ligence of identifying constitutions in TCM practices could be optimized. 展开更多
关键词 Traditional Chinese medicine(TCM) Constitution identification Deep feature Facial complexion feature Body shape feature Multiple features
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Artificial intelligence models based on non-contrast chest CT for measuring bone mineral density
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作者 DUAN Wei YANG Guoqing +6 位作者 LI Yang SHI Feng YANG Lian XIONG Xin CHEN Bei LI Yong FU Quanshui 《中国医学影像技术》 CSCD 北大核心 2024年第8期1231-1235,共5页
Objective To observe the value of artificial intelligence(AI)models based on non-contrast chest CT for measuring bone mineral density(BMD).Methods Totally 380 subjects who underwent both non-contrast chest CT and quan... Objective To observe the value of artificial intelligence(AI)models based on non-contrast chest CT for measuring bone mineral density(BMD).Methods Totally 380 subjects who underwent both non-contrast chest CT and quantitative CT(QCT)BMD examination were retrospectively enrolled and divided into training set(n=304)and test set(n=76)at a ratio of 8∶2.The mean BMD of L1—L3 vertebrae were measured based on QCT.Spongy bones of T5—T10 vertebrae were segmented as ROI,radiomics(Rad)features were extracted,and machine learning(ML),Rad and deep learning(DL)models were constructed for classification of osteoporosis(OP)and evaluating BMD,respectively.Receiver operating characteristic curves were drawn,and area under the curves(AUC)were calculated to evaluate the efficacy of each model for classification of OP.Bland-Altman analysis and Pearson correlation analysis were performed to explore the consistency and correlation of each model with QCT for measuring BMD.Results Among ML and Rad models,ML Bagging-OP and Rad Bagging-OP had the best performances for classification of OP.In test set,AUC of ML Bagging-OP,Rad Bagging-OP and DL OP for classification of OP was 0.943,0.944 and 0.947,respectively,with no significant difference(all P>0.05).BMD obtained with all the above models had good consistency with those measured with QCT(most of the differences were within the range of Ax-G±1.96 s),which were highly positively correlated(r=0.910—0.974,all P<0.001).Conclusion AI models based on non-contrast chest CT had high efficacy for classification of OP,and good consistency of BMD measurements were found between AI models and QCT. 展开更多
关键词 OSTEOPOROSIS bone density tomography X-ray computed artificial intelligence
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Scoring and Consequential Validity Evidence of Computer-and Paper-Based Writing Tests in Times of Change
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作者 María GUAPACHA-CHAMORRO Orlando CHAVES-VARÓN 《Chinese Journal of Applied Linguistics》 2024年第3期450-480,525,共32页
Little is known about how the assessment modality,i.e.,computer-based(CB)and paper-based(PB)tests,affects language teachers’scorings,perceptions,and preferences and,therefore,the validity and fairness of classroom wr... Little is known about how the assessment modality,i.e.,computer-based(CB)and paper-based(PB)tests,affects language teachers’scorings,perceptions,and preferences and,therefore,the validity and fairness of classroom writing assessments.The present mixed-methods study used Shaw and Weir’s(2007)sociocognitive writing test validation framework to examine the scoring and consequential validity evidence of CB and PB writing tests in EFL classroom assessment in higher education.Original handwritten and word-processed texts of 38 EFL university students were transcribed to their opposite format and assessed by three language lecturers(N=456 texts,152 per teacher)to examine the scoring validity of CB and PB tests.The teachers’perceptions of text quality and preferences for assessment modality accounted for the consequential validity evidence of both tests.Findings revealed that the assessment modality impacted teachers’scorings,perceptions,and preferences.The teachers awarded higher scores to original and transcribed handwritten texts,particularly text organization and language use.The teachers’perceptions of text quality differed from their ratings,and physical,psychological,and experiential characteristics influenced their preferences for assessment modality.The results have implications for the validity and fairness of CB and PB writing tests and teachers’assessment practices. 展开更多
关键词 scoring validity consequential validity CB and PB writing tests classroom assessment
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Density functional theory study of influence of impurity on electronic properties and reactivity of pyrite 被引量:8
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作者 李玉琼 陈建华 +1 位作者 陈晔 郭进 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第8期1887-1895,共9页
The electronic property of pyrite supercell containing As,Se,Te,Co or Ni hetero atoms were calculated using density functional theory(DFT),and the reactivities of pyrite with oxygen and xanthate were discussed by fr... The electronic property of pyrite supercell containing As,Se,Te,Co or Ni hetero atoms were calculated using density functional theory(DFT),and the reactivities of pyrite with oxygen and xanthate were discussed by frontier orbital methods.The cell volume expands due to the presence of impurity.Co and Ni mainly affect the bands near Fermi levels,while As mainly affects the shallow and deep valence bands,and Se and Te mainly affect the deep valence bands.Electronic density analysis suggests that there exists a strong covalent interaction between hetero atom and its surrounding atoms.By frontier orbital calculation,it is suggested that As,Co and Ni have greater influence on the HOMO and LUMO of pyrite than Se and Te.In addition,pyrite containing As,Co or Ni is easier to oxidize by oxygen than pyrite containing Se or Te,and pyrite containing Co or Ni has greater interaction with collector.These are in agreement with the observed pyrite practice. 展开更多
关键词 PYRITE IMPURITY density functional theory electronic properties REACTIVITY
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Effects of Temperature on Determination of Protein Concentration with Coomassie Brilliant Blue Method 被引量:4
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作者 赵卓 孙文斌 +1 位作者 嵇雅茹 郝锡联 《Agricultural Science & Technology》 CAS 2015年第2期209-213,共5页
[Objective] This study aimed to investigate the effects of temperature on determination of protein concentration with Coomassie Brilliant Blue method,thus proving advice and guidance for accurate determination of prot... [Objective] This study aimed to investigate the effects of temperature on determination of protein concentration with Coomassie Brilliant Blue method,thus proving advice and guidance for accurate determination of protein concentration.[Method] With Coomassie Brilliant Blue method,the concentrations of different bovine serum albumin samples were determined under different temperatures and incubation time.[Result] According to the standard curve,when the determination range of protein concentration was 0-100 mg/ml,the determined protein concentration was relatively stable after incubation at 20 ℃ for 20-30 min.Furthermore,the determination result of higher protein concentration with Coomassie Brilliant Blue method was less affected by various factors.[Conclusion] In determination of protein concentration with Coomassie Brilliant Blue method,temperature,sample concentration and incubation time were important factors affecting the accuracy of experimental results. 展开更多
关键词 Coomassie Brilliant Blue method PROTEIN TEMPERATURE CONCENTRATION Incubation time
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Relationship between Al(OH)_3 solubility and particle size in synthetic Bayer liquors 被引量:5
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作者 李小斌 阎丽 +5 位作者 赵东峰 周秋生 刘桂华 彭志宏 杨帅帅 齐天贵 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第5期1472-1479,共8页
Surface tension of sodium aluminate solution and the contact angle between Al(OH)3 particles and aluminate solution were measured, then the dependence of Al(OH)3 solubility on its particle size was calculated and ... Surface tension of sodium aluminate solution and the contact angle between Al(OH)3 particles and aluminate solution were measured, then the dependence of Al(OH)3 solubility on its particle size was calculated and thus the variation of the critical nucleus sizes was determined based on the Ostwald ripening formula. The results show that the Al(OH)3 solubility in sodium aluminate solution decreases with the increment of particle size, and the critical nucleus sizes increase with the rise of alkali concentration, caustic ratio and precipitation temperature. The results also imply that the presence of small particles in seeded precipitation system is an important factor to limit the depth of precipitation. 展开更多
关键词 Bayer liquor Al(OH)3 interfacial property SOLUBILITY critical nucleus size
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Seismic wave propagation in Kelvin visco-elastic VTI media 被引量:3
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作者 芦俊 王赟 《Applied Geophysics》 SCIE CSCD 2010年第4期357-364,400,共9页
In this article,under the assumption of weak anisotropy and weak attenuation, we present approximate solutions of anisotropic complex velocities and quality-factors for Kelvin visco-elastic transverse isotropy(KEL-VT... In this article,under the assumption of weak anisotropy and weak attenuation, we present approximate solutions of anisotropic complex velocities and quality-factors for Kelvin visco-elastic transverse isotropy(KEL-VTI) media,based on the complex physical parameter matrix.Also,combined with the KEL-VTI media model,the propagation characteristics of the qP-,qS V-,and qSH-wave phases and energies are discussed.Further, we build a typical KEL-VTI media model of the Huainan coal mine to model the wave propagation.The numerical simulation results show that the PP- and PSV-wave theoretical wave-fields are close to the wave-fields of three-component P- and converted-waves acquired in the work area.This result proves that the KEL-VTI media model gives a good approximation to this typical coalfield seismic-geologic conditions and is helpful to the study of attenuation compensation of multi-component seismic data. 展开更多
关键词 KEL-VTI media complex velocity quality-factor ANISOTROPY
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Cultivation Density of Toona ciliate 被引量:6
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作者 吴际友 黄明军 +5 位作者 陈明皋 程勇 廖德志 李艳 刘球 王旭军 《Agricultural Science & Technology》 CAS 2014年第10期1730-1732,共3页
ln order to discuss the optimum seedling density of Toona ciliate, different seedling densities were studied. The results showed that seeding height and basal diameter decreased and quality of the seedlings declined w... ln order to discuss the optimum seedling density of Toona ciliate, different seedling densities were studied. The results showed that seeding height and basal diameter decreased and quality of the seedlings declined with the increase of seedling density. The reasonable density of seedlings is key to cultivate high-quality seedlings and achieve the best seedling efficiency. The optimum density was 30 plants/m2 for the first class seedlings of biennial seedlings, and the optimum density of l and ll seedlings for production afforestation was 40 plants/m2. 展开更多
关键词 Toona ciliate Cultivation density Seedling quality
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Study on the scales of heterogeneous geologic bodies in random media 被引量:2
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作者 李灿苹 刘学伟 《Applied Geophysics》 SCIE CSCD 2011年第4期363-369,373,共8页
In order to study the scale characteristics of heterogeneities in complex media, a random medium is constructed using a statistical method and by changing model parameters (autocorrelation lengths a and b), the scal... In order to study the scale characteristics of heterogeneities in complex media, a random medium is constructed using a statistical method and by changing model parameters (autocorrelation lengths a and b), the scales of heterogeneous geologic bodies in the horizontal and the vertical Cartesian directions may be varied in the medium. The autocorrelation lengths a and b represent the mean scale of heterogeneous geologic bodies in the horizontal and vertical Cartesian directions in the randQm medium, respectively. Based on this model, the relationship between model autocorrelation lengths and heterogeneous geologic body scales is studied by horizontal velocity variation and standard deviation. The horizontal velocity variation research shows that velocities are in random perturbation. The heterogeneous geologic body scale increases with increasing autocorrelation length. The recursion equation for the relationship between autocorrelation lengths and heterogeneous geologic body scales is determined from the velocity standard deviation research and the actual heterogeneous geologic body scale magnitude can be estimated by the equation. 展开更多
关键词 random medium autocorrelation length velocity standard deviation heterogeneous geologic body scale
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A first-principle calculation of structural,mechanical and electronic properties of titanium borides 被引量:3
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作者 闫海燕 魏群 +1 位作者 常少梅 郭平 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第7期1627-1633,共7页
The first-principle calculations are performed to investigate the structural,mechanical and electronic properties of titanium borides (Ti2B,TiB and TiB2).Those calculated lattice parameters are in good agreement wit... The first-principle calculations are performed to investigate the structural,mechanical and electronic properties of titanium borides (Ti2B,TiB and TiB2).Those calculated lattice parameters are in good agreement with the experimental data and previous theoretical values.All these borides are found to be mechanically stable at ambient pressure.Compared with parent metal Ti (120 GPa),the larger bulk modulus of these borides increase successively with the increase of the boron content in three borides,which may be due to direction bonding introduced by the boron atoms in the lattice and the strong covalent Ti-B bonds.Additionally,TiB can be regarded as a candidate of incompressible and hard material besides TiB2.Furthermore,the elastic anisotropy and Debye temperatures are also discussed by investigating the elastic constants and moduli.Electronic density of states and atomic Mulliken charges analysis show that chemical bonding in these titanium borides is a complex mixture of covalent,ionic,and metallic characters. 展开更多
关键词 titanium borides first-principle calculations mechanical properties density of states Mulliken atomic population analysis
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Carbon pool structure and carbon density of soil in Pinus koraiensis plantation ecosystem 被引量:4
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作者 丁壮 张彦东 《Journal of Forestry Research》 SCIE CAS CSCD 2010年第2期177-182,I0005,共7页
The organic carbon contents,carbon density and carbon storage of the soil in the Pinus koraiensis plantation ecosystem were investigated in Maoershan experimental forest farm,Shangzhi County,Heilongjiang,on the west s... The organic carbon contents,carbon density and carbon storage of the soil in the Pinus koraiensis plantation ecosystem were investigated in Maoershan experimental forest farm,Shangzhi County,Heilongjiang,on the west slope of the Zhangguangcai Mountains in northeastern China for providing data to evaluation of the carbon balance in forest ecosystem of northeastern China.These soil carbon indicators were measured in three forest types,pure P.koraiensis plantation,P.koraiensis and Betula platyphylla mixed forest,and the P.koraiensis and Quercus mongolica mixed forest.The soil carbon pool consisted of four compartments,namely L layer,F layer,H layer and B layer.With variance analysis,we found that both organic carbon content and carbon density of the soil were significantly affected by forest types,soil compartments and slope positions.The highest soil carbon density(278.63 Mg·ha^-1).was observed in the mixed forest of P.koraiensis and Q.mongolica.The B layer had the highest carbon density(212.28 Mg·ha^-1) among all the soil compartments.In terms of slope position,the highest soil carbon density(394.18 Mg·ha^-1) presented in the low slope.Besides,soil carbon content and carbon density had a marked change with the organic matter content and vertical depth of the soil in each compartment.The results of this study implied that in the temperate humid region,the mixed ecosystem of regional Pinus koraiensis plantations and natural forest had relatively high carbon storage capability. 展开更多
关键词 soil carbon pool soil carbon density soil carbon content Pinus koraiensis plantation ecosystem mixed forest
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Evaluation of Productivity and Light Quality in Two High Density Dwarf Rootstock Apple Orchards in Central China 被引量:2
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作者 高登涛 郭景南 +2 位作者 魏志峰 范庆锦 杨朝选 《Agricultural Science & Technology》 CAS 2012年第9期1848-1853,2011,共7页
[Ohjective] The aim of the study is to investigate the productivity and light quality in two high density M26 dwarf rootstock apple orchards in central China so as to provide some management guidance for close plantin... [Ohjective] The aim of the study is to investigate the productivity and light quality in two high density M26 dwarf rootstock apple orchards in central China so as to provide some management guidance for close planting of dwarf rootstock apples.[Method] The technical parameters of individual trees and group parameters as shoot number and composition and canopy coverage were determined, and the light quality in the canopy, fruit production and quality were investigated. [Result] Slender spindle (SS) orchard has 54 thousands shoots per 667 m^2. Coverage rate is 76%. Leaf area index is 1.9. The ratio of long, medium and spur shoots is 1:1:8. Fruit yield is 3 263 kg/667 m^2 with 85% first grade fruit. Light interception in the canopy is 58% while the ratio of canopy with good light is 65%. Modified slender spindle (MSS) orchard has 93 thousands shoots per 667 m^2 and the coverage is 77%. Leaf area index is 3.3. The ratio cf long, medium and spur shoots is 1:2:7. Fruit yield is 3 931 kg/667 m^2 with 85% first grade fruit. The light interception in the canopy is 73% while the ratio of canopy with good light is 35%. [Conclusion] Apple orchard with M26 dwarf rootstock trained as SS and MSS tree form in medium planting density may be useful to the management of the similar orchards in Central China. 展开更多
关键词 Apple trees on dwarf rootstocks High density planting Tree form Pro-ductivity Light quality
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Research and Development of Cemented Carbide Multifacet Drill for Drilling High Strength Steel 被引量:1
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作者 庞思勤 于启勋 姬广振 《Journal of Beijing Institute of Technology》 EI CAS 1999年第1期72-76,共5页
Aim To research on a solid cemented carbide multi facet drill for drilling high strength steel. Methods Assimilating some features of multi facet drill edge structures, through systematic drilling experiments, a n... Aim To research on a solid cemented carbide multi facet drill for drilling high strength steel. Methods Assimilating some features of multi facet drill edge structures, through systematic drilling experiments, a new type of solid cemented carbide drill was developed and the drill geometry was optimized. Results With the new type drill,the drilling force decreases by 10%-20%, the drilling productivity (drilled holes per hour) increases by 2-3 times, and the drilling precision and surface finish increase by one level. Conclusion The new type drill possesses excellent drilling performance. 展开更多
关键词 DRILLING multi facet drill cemented carbide high strength steel
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An Analytical Model of Drain Current for Ultra-Thin Body and Double-Gate Schottky Source/Drain MOSFETs Accounting for Quantum Effects 被引量:2
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作者 栾苏珍 刘红侠 +3 位作者 贾仁需 蔡乃琼 王瑾 匡潜玮 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2008年第5期869-874,共6页
A compact drain current including the variation of barrier heights and carrier quantization in ultrathin-body and double-gate Schottky barrier MOSFETs (UTBDG SBFETs) is developed. In this model, Schrodinger's equat... A compact drain current including the variation of barrier heights and carrier quantization in ultrathin-body and double-gate Schottky barrier MOSFETs (UTBDG SBFETs) is developed. In this model, Schrodinger's equation is solved using the triangular potential well approximation. The carrier density thus obtained is included in the space charge density to obtain quantum carrier confinement effects in the modeling of thin-body devices. Due to the quantum effects, the first subband is higher than the conduction band edge, which is equivalent to the band gap widening. Thus, the barrier heights at the source and drain increase and the carrier concentration decreases as the drain current decreases. The drawback of the existing models,which cannot present an accurate prediction of the drain current because they mainly consider the effects of Schottky barrier lowering (SBL) due to image forces,is eliminated. Our research results suggest that for small nonnegative Schottky barrier (SB) heights,even for zero barrier height, the tunneling current also plays a role in the total on-state currents. Verification of the present model was carried out by the device numerical simulator-Silvaco and showed good agreement. 展开更多
关键词 Schottky barrier quantum effects the effective mass electron density
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Influence of Gradient on Stability of Soil Slope Containing Roots 被引量:1
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作者 朱海丽 李燕婷 宋路 《Agricultural Science & Technology》 CAS 2015年第10期2350-2353,共4页
Abundant herbaceous and shrub roots play an important role in preventing water and soil erosion and increasing shallow slope stability. In order to make a quantitative analysis on the contribution of root system to sl... Abundant herbaceous and shrub roots play an important role in preventing water and soil erosion and increasing shallow slope stability. In order to make a quantitative analysis on the contribution of root system to slope stability under dif- ferent slope gradient, an unconsolidated and undrained triaxial compression test was conducted to measure the shear strengths of soil and root-soil composite in the two slopes in eastern Qinghai Province. In addition, under the protection of plant roots, the effect of gradient on stability of soil slope was investigated by limit equilibrium method. The results showed that the stability coefficient of soil slope planted with two kinds of brush was decreased with the increase in slope gradient, and the sta- bility coefficient increment of soil slope containing Atriplex canescens roots was higher than that containing Caragana korshinskii roots. When the slope gradient ranged from 25° to 50°, the stability coefficient of soil slope planted with Atriplex canescens or Caragana korshinskii ranged from 0.80 to 1.38. However, when the slope gradient exceeded 55°, the increment of stability coefficient of soil slope became small. 展开更多
关键词 Soil slope Slope gradient Shear strength Stability coefficient Root system
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Modeling Photovoltaic Performances of BTBPD-PC61BM System via Density Functional Theory Calculations
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作者 赵蔡斌 唐志华 +3 位作者 郭小华 葛红光 马剑琪 王文亮 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2017年第3期268-276,I0001,共10页
Designing and fabricating high-performance photovoltaic devices have remained a major challenge in organic solar cell technologies. In this work, the photovoltaic performances of BTBPD-PC61BM system were theoretically... Designing and fabricating high-performance photovoltaic devices have remained a major challenge in organic solar cell technologies. In this work, the photovoltaic performances of BTBPD-PC61BM system were theoretically investigated by means of density functional theory calculations coupled with the Marcus charge transfer model in order to seek novel photovoltaic systems. Moreover, the hole-transfer properties of BTBPD thin-film were also studied by an amorphous cell with 100 BTBPD molecules. Results revealed that the BTBPD- PC61BM system possessed a middle-sized open-circuit voltage of 0.70 V, large short-circuit current density of 16.874 mA/cm2, large fill factor of 0.846, and high power conversion effi- ciency of 10%. With the Marcus model, the charge-dissociation rate constant was predicted to be as fast as 3.079×10^13 s^-1 in the BTBPD-PC61BM interface, which was as 3-5 orders of magnitude large as the decay (radiative and non-radiative) rate constant (108-10^10 s^-1), indicating very high charge-dissociation efficiency (-100%) in the BTBPD-PC61BM system. Furthermore, by the molecular dynamics simulation, the hole mobility for BTBPD thin-film was predicted to be as high as 3.970× 10^-3 cm^2V^-1s^-1, which can be attributed to its tight packing in solid state. 展开更多
关键词 BTBPD PC61BM Photovoltaie performances Density functional theory
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Effects of Loading Methods on the Color,Phenolic and Antioxidant Properties of Cured Tobacco Leaves
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作者 傅茂润 赵双 +12 位作者 侯连涛 曲清莉 代红飞 董梅 苏建东 刘广玉 杨举田 王梅勋 田雷 杨永花 谭效磊 徐硕 宗浩 《Agricultural Science & Technology》 CAS 2014年第7期1196-1199,共4页
[Objective] To investigate the effects of different loading methods on tobacco leaf quality.[Method] With tobacco comb,tobacco clamp,and tobacco basket,color,phenolic compounds and their antioxidant capacity of flue-c... [Objective] To investigate the effects of different loading methods on tobacco leaf quality.[Method] With tobacco comb,tobacco clamp,and tobacco basket,color,phenolic compounds and their antioxidant capacity of flue-cured tobacco leaves were studied.[Result] The results showed that L*,a* and b* values of tobacco leaves packaged by tobacco clamp and comb were higher than those of tobacco basket and no significant differences were found beween values of a* and b*,however,between L* and h values,remarkable differences existed among three loading methods.Total phenolic content and chlorogenic acid content of tobacco leaves loaded by tobacco comb kept the highest,followed by smoke clamp and tobacco basket (P<0.05).On the other hand,rutin content showed little differences among treatments.The order of the antioxidant properties,such as DPPH free radical scavenging activity and reducing powder,of tobacco leaves by different loading methods was tobacco comb > tobacco clamp > loose basket and a positive relationship was found of antioxiang property with total phenolic content and chlorogenic acid content.[Conclusion] In view of tobacco leaves quality and antioxidant property,loading method with tobacco comb proved to be a better choice. 展开更多
关键词 PHENOLIC Color parameters Antioxidant capacity loading method Tobacco leaves
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High Pressure Structural Instability and Thermal Properties of Rutile TiO2 from First-principles
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作者 胡翠娥 曾召益 +3 位作者 孔春阳 崔玉亭 张林 蔡灵仓 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2014年第1期69-74,I0004,共7页
We report a first-principles calculation to investigate the structural instability of rutile TiO2. The high pressure structural parameters are well reproduced. The calculated phonon disper-sion curves agree with exper... We report a first-principles calculation to investigate the structural instability of rutile TiO2. The high pressure structural parameters are well reproduced. The calculated phonon disper-sion curves agree with experiments at zero pressure. Under compression, we capture a large softening around Γ point, which indicates the structural instability. From the high pressure elastic constants, we find that the rutile TiO2 is unstable when the applied pressure is larger than 17.7 GPa. Within the quasi-harmonic approximation, the thermal equation of state, thermal expansion oefficient, bulk modulus, and entropy are well reproduced. The thermal properties confirm the available experimental data and are extended to a wider pressure and temperature range. 展开更多
关键词 TiO2 Phonon dispersion THERMODYNAMICS Density functional theory
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Variation in litter decomposition-temperature relationships between coniferous and broadleaf forests in Huangshan Mountain, China 被引量:6
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作者 何兴兵 宋福强 +6 位作者 张鹏 林永慧 田兴军 任利利 陈成 李晓娜 谭海霞 《Journal of Forestry Research》 SCIE CAS CSCD 2007年第4期291-297,共7页
A study was conducted to identify the differences in the decompositions of leaf litter, lignin and carbohydrate between coniferous forest and broadleaf forest at 20℃ and 30℃ in Huangshan Mountain, Anhui Province, Ch... A study was conducted to identify the differences in the decompositions of leaf litter, lignin and carbohydrate between coniferous forest and broadleaf forest at 20℃ and 30℃ in Huangshan Mountain, Anhui Province, China. Results showed that at 20℃ mass loss of leaf litter driven by microbial decomposers was higher in broadleaf forest than that in coniferous forest, whereas the difference in mass loss of leaf litter was not significant at 30℃. The temperature increase did not affect the mass loss of leaf litter for coniferous forest treatment, but significantly reduced the decomposition rate for broadleaf forest treatment. The functional decomposers of microorganism in broadleaf forest produced a higher lignin decomposition rate at 20℃, compared to that in coniferous forest, but the difference in lignin decomposition was not found between two forest types at 30℃. Improved temperature increased the lignin decomposition for both broadleaf and coniferous forest. Additionally, the functional group of microorganism from broadleaf forest showed marginally higher carbohydrate loss than that from coniferous forest at both temperatures. Temperature increase reduced the carbohydrate decomposition for broadleaf forest, while only a little reduce was found for coniferous forest. Remarkable differences occurred in responses between most enzymes (Phenoloxidase, peroxidase, !5-glucosidase and endocellulase) and decomposition rate of leaf litter to forest type and temperature, although there exist strong relationships between measured enzyme activities and decomposition rate in most cases. The reason is that more than one enzyme contribute to the mass loss of leaf litter and organic chemical components. In conclusion, at a community scale the coniferous and broadleaf forests differed in their temperature-decomposition relationships. 展开更多
关键词 Castanopsis eyrei Mass loss LIGNIN CARBOHYDRATE Temperature Decomposition ENZYME Leaf litter
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