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81.
82.
城市绿化植物由于其滞尘能力能够有效改善城市大气环境,滞尘能力的主要影响因素是其表面特性和润湿性。植物叶片表面的润湿性和偏振反射特性都与表面粗糙度相关,因此以粗糙度为结点,探究植物表面润湿性与偏振反射光谱的关系,利用偏振反射特性对植物叶片润湿性进行快速无损监测。以长春市常见的八种绿色植物叶片为研究对象,利用Kruss DSA 100液滴形状分析系统测量其表面接触角,利用多角度光谱测量装置测量其在不同探测天顶角上的偏振反射光谱,探讨了润湿性能在400~1 000 nm波段对植物叶片不同探测天顶角上偏振度的影响。通过相关分析确定八种植物叶片的特征波段,并在特征波段对偏振度随探测天顶角的变化程度与润湿性的关系之间进行定量分析。结果表明,在特征波段(700±10) nm处,偏振度随着探测天顶角的变化程度θ0与接触角距离100°的偏差值θ具有很强的相关性,可决系数R2为0.82,说明偏振度随探测天顶角的变化程度θ0可以反映植物叶片的润湿性,可以利用偏振反射特性对植物叶片润湿性进行分析,研究成果将对今后城市绿化物种的选择提供可行性建议。 相似文献
83.
It is conjectured that the Pauli exclusion principle alone may be responsible for a particular geometric arrangement of confined systems of identical fermions even when there is no interaction between them. These geometric structures, called Pauli crystals, are predicted for a two‐dimensional (2D) system of free fermions under harmonic confinement. In this work, the possibility of this outcome is pursued and a theoretical model is considered that may capture both qualitatively and quantitatively, the key features of the abovementioned setup. The results for and 6 particles show that the minimum energy configuration corresponds to and is in good quantitative agreement with the reported values of Pauli crystals seen in single‐shot imaging data obtained via the configuration density technique. Numerical results for larger systems of and 30 particles show that the crystalline configurations observed are not the same as the classical Wigner crystal structures that emerge should the confined charged particles interact with a Coulomb potential. An important question floated is whether such crystalline structures do really exist in a quantum system or whether they are artifacts of the methods used to analyze them. 相似文献
84.
Su Juan WANG Yue Hu PEI* Hui Ming HUA Department of Natural Products Chemistry Shenyang Pharmaceutical University Shenyang 《中国化学快报》2001,(6)
Betula platyphylla Suk., whose bark and juice are used as anti-inflammatory and cough relieving agent1, is widespread in China. Previous investigations of this plant have led to the isolation of various compounds2,3. We herein report structural elucidation of a new caffeoylquiniclactone, named neochlorgeniclatone (1) isolated from the leaves of Betula platyphylla Suk..Compound 1 was obtained as white powder (EtOAc). The EI-MS gave ion fragments at m/z 336 [M]+, 163 [caffeoyl]+, which indi… 相似文献
85.
Yuran Wang Sen Lian Xiangli Dong Caixia Wang Baohua Li Pingliang Li 《Biomedical chromatography : BMC》2019,33(2)
As one of the main fungicides for the apple leaf disease control, thiophanate‐methyl (TM) mainly exerts its fungicidal activity in the form of its metabolite carbendazim (MBC), whose dissipation kinetics is very distinct from that of its parent but has been paid little attention. The aim of this work was to investigate the dissipation kinetics of TM and its active metabolite MBC in apple leaves using a modified QuEChERS–UPLC–MS/MS method. The results showed that TM and MBC could be quickly extracted by this modified QuEChERS procedure with recoveries of 81.7–96.5%. The method linearity was in the range of 0.01–50.0 mg kg?1 with the quantification limit of 0.01 mg kg?1. Then this method was applied to the analysis of fungicide dissipation kinetics in apple leaves. The results showed that the dissipation kinetics of TM for the test in 3 months can be described by a first‐order kinetics model with a DT50 (dissipation half‐life) range of 5.23–6.03 days and the kinetics for MBC can be described by a first‐order absorption–dissipation model with the Tmax (time needed to reach peak concentration) range of 4.78–7.09 days. These models can scientifically describe the behavior of TM and MBC in apple leaves, which provides necessary data for scientific application. 相似文献
86.
Shuo Liu Xin Li Xifeng Yang Linhui Zhou Xiangfeng Liang Ruchen Qiu Yun Fa 《Journal of separation science》2022,45(2):623-630
A method for the simultaneous determination of six monosaccharides by pre-column derivatization with 1-phenyl-3-methyl-5-pyrazolone and capillary electrophoresis was developed in this work. The derivatization (i.e., reaction temperature, capillary electrophoresis duration, and extraction number) and separation (i.e., pH and buffer concentration) conditions for capillary electrophoresis were optimized. Results showed that the limits of detection under optimal conditions were in the range of 0.036–0.35 mg/L with a mean correlation coefficient >0.99. The recoveries were in the range of 87.3–108.49%, and the relative standard deviations of intra- and inter-day variations were in the ranges of 2.2–3.8 and 3.2–5.0%, respectively. The method was successfully applied to the analysis of six free monosaccharides in three types of Ginkgo biloba leaves. 相似文献
87.
For a complex semisimple Lie group and a real form we define a Poisson structure on the variety of Borel subgroups of with the property that all -orbits in as well as all Bruhat cells (for a suitable choice of a Borel subgroup of ) are Poisson submanifolds. In particular, we show that every non-empty intersection of a -orbit and a Bruhat cell is a regular Poisson manifold, and we compute the dimension of its symplectic leaves.
88.
Japón-Luján R Luque-Rodríguez JM Luque de Castro MD 《Analytical and bioanalytical chemistry》2006,385(4):753-759
Microwave assistance is proposed for the first time in order to accelerate the extraction of biophenols from olive leaves. Under optimal working conditions, obtained using a multivariate methodology, complete extraction of the target analytes was achieved in 8 min. The extracts required no clean-up nor concentration prior to injection into a chromatograph–photodiode array detector assembly for individual separation–quantification. The optimal extractant (an 80:20 ethanol–water mixture) was also used in the development of a stirring-based extraction method which required around 24 h for complete extraction of the target compounds. These mixtures can be used as replacements for toxic extractants, with a view to exploiting olive leaves in order to obtain biophenols for human use. 相似文献
89.
Lambert J Lampen P von Bohlen A Hergenröder R 《Analytical and bioanalytical chemistry》2006,384(1):231-236
A three-dimensional nuclear magnetic resonance imaging (MRI) technique for non-invasive mapping of iron in the apoplastic
fluid of plant compartments was developed. The new technique was applied to a leaf of red stem dogwood (Cornus stolonifera). The results are compared with MRI measurements of iron distributions in two dimensions and with total reflection X-ray fluorescence
results. 相似文献
90.
高效液相色谱/大气压化学电离质谱分析银杏叶中聚戊烯醇化合物 总被引:5,自引:0,他引:5
采用高效液相色谱,大气压化学电离质谱法(HPLC/APCIMS)分析银杏叶中聚戊烯醇化合物。在ODS-3柱上,以异丙醇-甲醇-正己烷-水(50:25:15:2,V/V)为流动相分离银杏叶中不同碳链长度的聚戊烯醇,通过质谱分析对每种聚戊烯醇化合物进行定性鉴定,外标法定量分析各聚戊烯醇含量。经HPLC/APCIMS分析,银杏叶中含有C75-C105聚戊烯醇,其中主要为C85、C90和C95聚戊烯醇。该方法简便,快速。 相似文献