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41.
L. Hou H. Schmidt B. Hoffmann M. Mennig 《Journal of Sol-Gel Science and Technology》1997,8(1-3):927-929
Organic-inorganic hybrid materials synthesized via sol-gel processing are excellent solid matrices for photochromic dyes like
spirooxazine, and the photochromic performance can be further enhanced by introducing suitable additives. This work describes
the effects of additives on the photochromic intensity (ΔA
0), decolouration rate (k) and photostability of spirooxazine in sol-gel derived organic-inorganic hybrid matrices. They include fluoroalkylsilane
(FAS), bisphenolA (BPA) and methyl-imidazole (MI). FAS enhances both ΔA
0 and photostability, but has little effect onk. The higher the content of BPA, the higher the ΔA
0 and the higher the photostability, but the lower thek. The effect of MI on ΔA
0 andk is not so considerable as that of BPA and is a little complicated, while significant improvement in photostability is achieved
by the addition of MI at an optimum concentration with the presence of BPA at a higher content. 相似文献
42.
Photochromic ormosil coatings containing Ag(Cl1–x
Br
x
) microcrystals were formed on a glass substrate via the sol-gel process. Methyltrimethoxysilane and 3-glycidoxypropyltrimethoxysilane were used as starting materials of the ormosil matrices. 3-chloropropyltrimethoxysilane and bromophenyltrimethoxysilane were added as halogen sources and silver colloidal dispersion was introduced into the precursor sol. The coated glass became transparent and photosensitive after Ag(Cl1–x
Br
x
) microcrystals were precipitated in the coatings above 300°C. Insertion of a SiO2 buffer layer between the substrate and photochromic layer was effective in preventing Ag+ migration into the substrate. Photochromic performances were improved by the substitution of Cl with Br and the incorporation of a minute amount of Cu. 相似文献
43.
本文报道了在固体基底表面上用PE方法连续自组装沉积PW12和1,10-DAD分子,构建了PW12/1,10-DAD自组装多层膜.紫外-可见吸收、X射线衍射等分析结果表明此多层膜有好的超晶格结构,层间距为3.19nm.与真空蒸镀WO3薄膜相比,PW12/1,10-DAD自组装多层膜表现出更好的光致变色特性. 相似文献
44.
S. M. Dolotov V. S. Miroshnikov T. A. Chibisova Sin Su-Lan O. V. Venidiktova T. M. Valova A. A. Dunaev Yu. P. Strokach V. A. Barachevsky V. F. Traven’ 《Russian Chemical Bulletin》2007,56(5):904-909
The photochromic properties and aggregation processes of merocyanine forms of indoline spiropyrans of the coumarin series
in the block and film poly(methyl methacrylate) (PMMA) were studied and compared by spectral and kinetic methods. Photochromism
of the synthesized compounds depends on their structure. The efficient formation of J-aggregates was observed for indoline
spiropyrans of the coumarin series based on 8-formyl-7-hydroxy-4-methylcoumarin and 3-formyl-4-hydroxycoumarin.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 870–875, May, 2007. 相似文献
45.
Safoklov B. B. Luk"yanov B. S. Bulanov A. O. Metelitsa A. V. Minkin V. I. Tkachev V. V. Aldoshin S. M. 《Russian Chemical Bulletin》2002,51(3):462-466
Spiropyran of the chromene series, viz., 8"-formyl-3,6"-dimethyl-4-oxospiro(3,4-dihydro-2H-1,3-benzoxazine-2,2"-[2H]chromene), was synthesized. In the solid phase, this compound exhibits photochromic properties. These properties were examined and the crystal structure of the compound was established by X-ray diffraction analysis. The compound is a convenient starting reagent for the synthesis of new spiropyrans containing functional groups at position 8". 相似文献
46.
Luigi Angiolini Tiziana Benelli Loris Giorgini Francesco Mauriello Elisabetta Salatelli 《Macromolecular Symposia》2006,234(1):68-75
The synthesis by radical homopolymerization of a novel optically active methacrylic polymer containing a side-chain chiral moiety linked to a photochromic bisazoaromatic chromophore has been carried out starting from the related monomer (S)-3-methacryloyloxy-1-[4′-phenylazo-(4-azobenzene)]-pyrrolidine [(S)- MPAAP ]. The polymeric derivate has been fully characterized and its spectroscopic properties compared to those of the monomer and of the corresponding homopolymer bearing only one azoaromatic chromophore in the side chain. The optical activity displayed by the bisazo polymer is discussed in terms of extent of chiral conformation assumed by the macromolecules as a consequence of dipole-dipole interactions between the bisazoaromatic chromophores. 相似文献
47.
光致变色分子经掺杂或键合作用嵌在液晶聚合物中可形成光致变色液晶聚合物,在线性偏振光或非偏振光的照射下,此物质中光致变色分子的构型变化会引起整个液晶分子的二维或三维光致再取向的形成,本文综述了光致变色液晶聚合物的光致再取向的近期研究进展. 相似文献
48.
报道了新化合物含108个丁氧基偶氮基元端基的三代(D3)碳硅烷光致变色液晶树状物在各溶液中的反-顺光异构化(光致变色)反应速率常数kp, 光化学回复异构化正/逆反应速率常数kt和kc, 热回复异构化反应速率常数kH, 光化学回复异构化反应平衡常数kt/kc, 活化能E, 异构化转换率及热回复异构化反应中的反-顺异构体组分比. D3的光致变色反应速率常数为10-1 s-1, 而含偶氮基元的光致变色液晶聚硅氧烷的光致变色反应速率常数为10-8 s-1, 因此, D3的光响应速度比后者快107倍. 相似文献
49.
Photochromic Dithienylethene‐Containing Triarylborane Derivatives: Facile Approach to Modulate Photochromic Properties with Multi‐addressable Functions
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Dr. Chun‐Ting Poon Dr. Wai Han Lam Dr. Hok‐Lai Wong Prof. Dr. Vivian Wing‐Wah Yam 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(5):2182-2192
A series of dithienylethene‐containing triarylboranes has been designed, synthesized, and characterized. The electrochemistry, photophysics, and photochromic behavior have also been studied. The photophysical and photochromic properties could be facilely tuned in this system by varying the thiophene spacers (thiophene, thienothiophene, and bithiophene) between the dithienylethene and the dimesitylboron (BMes2) or the position of the BMes2 substitution in the thiophene spacers. The absorption of closed form has been found to be more sensitive towards the structural modification upon incorporation of the BMes2 unit. Moreover, multi‐addressable photochromic reactivity is obtained upon addition of Lewis base (F?), which is due to the formation of boron–Lewis base adduct. The dependence of the photophysical and photochromic properties on the thiophene spacers and the position of the BMes2 substitution has been further supported by computational studies. 相似文献
50.
Hong-Yang Zhu Prof.Dr. Quan-Song Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(53):e202201360
The first reversible photoisomerization between a borepin and a borirane was reported in the photo-induced reactions of B(npy)Ar2 (npy=2-(naphthalen-1-yl) pyridine, Ar=phenyl or electron rich aryl; S. Wang, et al. Angew. Chem. Int. Ed. 2019 , 58, 6683–6687). In this work, the detailed mechanisms of the unprecedented reversible photoisomerization between the borepin (compound a ) and the borirane (compound b ) of B(npy)Ph2 in the first excited singlet (S1) state and the ground (S0) state were studied by carrying out calculations with the complete active space self-consistent field (CASSCF) and its second-order perturbation (CASPT2) methods combined with time-dependent density functional theory (TD-DFT). The calculation results show that photoexcitation of a -S0 at 365 nm and b -S0 at 450 nm populate their S1 state with evident charge transfer characteristics. The photoisomerization is triggered in the S1 state and ends in the S0 state, at which the intersection points in a (S1/S0)x intersection seam participate in and promote phenyl migration and ring-closure processes. Furthermore, we reveal that the not large energy difference (less than 0.6 eV) and similar conjugation properties of π electrons between a -S0 and b -S0 are responsible for their unique photo-reversible reactivity, compared with those of the isomers of the thermally reversible compound B(ppy)Mes2. Our results contribute to an understanding of the excited-state reactivity of organoboron compounds and will be useful to support the design of new boron-based photo-responsive materials. 相似文献