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81.
Angelica pubescens and Angelica sinensis belong to the Umbelliferae family and both are used as traditional Chinese medicines. In the present study, headspace solid-phase microextraction (HS-SPME) with gas chromatography-mass spectrometry (GC-MS) was used for the analysis of the volatile constituents present in their roots. Eighty-seven compounds in Angelica pubescens and thirty-six compounds in Angelica sinensis were identified by GC-MS. Their relative contents were calculated by the peak area ratio. HS-SPME was compared to steam distillation (SD) by analyzing the volatile constituents of Angelica sinensis root. A good agreement between results obtained with both techniques was found. As a conclusion, HS-SPME is a powerful tool for determining the volatile constituents present in the TCMs.  相似文献   
82.
乙醇-盐-水-5-Br-PADAP体系萃取分离测定钯   总被引:3,自引:0,他引:3  
研究了在硫酸铵存在下 ,5 Br PADAP乙醇体系中Pd(Ⅱ )、Rh(Ⅲ )、Pt(Ⅳ )的萃取行为及乙醇溶液的分相条件 ,讨论了影响萃取率的各种因素 ,试验表明 ,室温下 ,一定 pH范围内 ,该体系中的Pd(Ⅱ )几乎可完全被乙醇相萃取 ,而Rh(Ⅲ )、Pt(Ⅳ )不被萃取或萃取率很低 ,从而可实现Pd(Ⅱ )、Rh(Ⅲ )、Pt(Ⅳ )混合离子的定量分离 ,同时建立了Pd(Ⅱ )的测定方法。乙醇相中Pd(Ⅱ ) 5 Br PADAP配合物表观摩尔吸光系数为 1.18× 10 5L·mol- 1·cm- 1,钯量在 0~ 9.6 0 μg/10ml范围内符合比耳定律 ,检出限为 0 .0 90 μg/10ml。用该法分离混合样和测定两种活性碳钯催化剂中钯 ,结果满意  相似文献   
83.
84.
Summary Electronic stopping power of 19F in Ni, Pd and Gd was measured and compared to Mstar and SRIM calculation as well as experimental results published in literature. It turns out that the present electronic stopping power agrees reasonably well with them.  相似文献   
85.
本文报道了一套适用于液相体系的高灵敏度脉冲激光光声量热装置的建立。用此仪器对香豆素激光染料C428, C47和C120的无辐射过程进行了研究, 测得它们在无水乙醇中的无辐射跃迁量子产额分别为0.50, 0.47和0.38。  相似文献   
86.
ω-Tetrahydropyran-2-ylsulfanylalkylmagnesium chlorides are prepared as Grignard reagents containing protected mercaptoalkyl chains, which are useful for the direct introduction of ω-mercaptoalkyl chains to electrophiles. In order to prove the usefulness of these reagents, they were reacted with buckminsterfullerene (C60) to give 1-(ω-mercaptoalkyl)-1,2-dihydrobuck minsterfullerenes after the deprotection of THP group with TFA.  相似文献   
87.
丹麦生物质发电的现状和研究发展趋势   总被引:9,自引:7,他引:9  
丹麦是世界上利用秸秆生物质燃烧发电技术开发、运行最好的国家,其经验值得中国借鉴。根据作者在丹麦对生物质燃烧发电的研究经历,系统地介绍了丹麦在秸秆生物质发电的经验、遇到的问题及相应的研究和今后的发展方向。  相似文献   
88.
89.
The structural variations of silica gels heated at different temperatures have been firstly studied using Nd(3+) as a probe by photoacoustic spectroscopy (PAS), together with IR spectroscopy and thermal analysis. With increasing temperature, the f-f transitions of Nd(3+) show a red shift and the PA intensities increase. The PA branching vector of the transitions from ground state to 4G(5/2)+(2)G(7/2), which are hypersensitive transitions, increase and the others decrease or change little. These indicate that the covalency of the bond that Nd(3+) forms increases and the symmetry around Nd(3+) decreases, which reflects the structural variations of silica gels.  相似文献   
90.
Reaction of transition metal formate M(HCOO)(2).2H2O (M = Mn, Co, Ni) with 4,4'-bpy (4,4-bipyridine) has led to four new compounds with the formula M(HCOO)2(4,4'-bpy).nH2O (M = Mn, Co (1.Mn, 2.Co), n = 0; M = Co, Ni (3.Co, 4.Ni), n = 5). Compounds 1.Mn and 2.Co are isomorphous and crystallized in the tetragonal crystal system with the chiral space group P4(1)2(1)2. They are of three-dimensional diamondoid structure connected by anti-anti formate with 4,4'-bpy in the cavities of the framework reinforcing the intermetallic connections; the diamond-like net was observed also in their azide analogue (Mn(N3)2(4,4'-bpy)). Compounds 3.Co and 4.Ni are isomorphous also but crystallized in the monoclinic crystal system with the space group Cc. Both structures are uninterpenetrated 3D "CdSO4" type with big channels, constructed by anti-anti formate and 4,4'-bpy. This type of net was not observed in their azide analogue. Residing in the channels, water molecules form a new type of 1D tape constructed by vertex-sharing cyclic pentamers. Magnetic measurements were performed on all of these four compounds. 1.Mn and 2.Co are weak ferromagnets with the critical temperature Tc = 5.3 and 7.4 K, respectively. 3.Co is an antiferromagnet with Neel temperature TN = 3.0 K, and 4.Ni is a weak ferromagnet below 20 K. Hysteresis loop can be observed for 2.Co and 4.Ni at 1.8 K. As an analogue of azide, formate can be used to construct molecular architectures, which structurally and magnetically have great similarities to and also differences from those of azide. This offers a promising method for the design of new molecular architectures with formate.  相似文献   
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