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31.
32.
X. H. Jiao P. Guillon L. Bermudes 《International Journal of Infrared and Millimeter Waves》1989,10(4):519-528
This paper proposes a new type of high permittivity whispering gallery mode cylindrical dielectric resonators with a geometry which is very suitable for use in microstrip type integrated circuits. These oversized resonators, together with high Q factors and ease of fabrication, are potentially interesting for millimeter wave integrated filters and oscillators. In this paper, we report an experimental investigation of such resonators carried out in Ka band (26.5–40 GHz). Measured results including resonant frequencies and loaded quality factors will be presented. Application to millimeter wave filters will also be demonstrated. 相似文献
33.
ZnCuCoAlNO3型四元水滑石及其多氧阴离子柱撑物的合成与催化氧化性能 总被引:4,自引:0,他引:4
Anionic clay, ZnCuCoAlNO3 and its polyoxometalate intercalates were synthesized, and were characterized by XRD, IR, 31PMAS NMR, DTA and elemental analysis. The pillared products are found to be effective catalysts for oxidation of cyclohexene with molecular oxygen under mild reaction conditions 相似文献
34.
综述了1β-Methyl Carbapenem中间体的合成方法,重点强调了如何构筑1位β构型的甲基。参考文献37篇。 相似文献
35.
X. -H. Deng S. -F. Jiao Y. Yan C. Wang G. -F. Wang B. Fang 《Russian Journal of Electrochemistry》2006,42(8):873-877
Aminylferrocene is successfully immobilized on nanosized gold colloid particles associated with a 1,4-benzenedimethanethiol
monolayer on a gold electrode surface and characterized by cyclic voltammograms and electrochemical impedance spectroscopy.
In a pH 7.0 phosphate buffer solution, the formal potential (E
0’) of Fc is 0.432 V (SCE), and the apparent surface electron-transfer rate constant is 0.89 s−. The immobilized Fc gives an excellent electrocatalytic response to the terbutaline oxidation. The catalytic-current response
of differential pulse voltammograms increases linearly with the terbutaline concentration from 1.75 × 10−7 to 5.62 × 10−4 mol/l. The detection limit is 2.30 × 10−8 mol/l. The determination of terbutaline in a tablet dosage is satisfactory. The method is simple, quick, and sensitive.
Published in Russian in Elektrokhimiya, 2006, Vol. 42, No. 8, pp. 969–974.
The text was submitted by the authors in English. 相似文献
36.
37.
原子转移自由基聚合原位合成温敏性微球 总被引:1,自引:0,他引:1
以过硫酸钾为引发剂、丙酮-水[V(丙酮)∶V(水)=4∶6]的混合溶剂为反应介质, 在少量二乙烯苯存在的条件下使苯乙烯(St)和对氯甲基苯乙烯(CMSt)进行无皂乳液共聚反应, 得到了粒径大小均匀的交联型聚苯乙烯(PSt)微球, 由X射线光电子能谱对表面组分测定发现: CMSt上的氯原子在聚合过程中富集于交联微球的表面. 以此交联型PSt微球为原子转移自由基聚合(ATRP)的引发剂, 在22 ℃下引发N-异丙基丙烯酰胺(NIPAAm)进行原位ATRP反应, 得到了表面原子转移自由基聚合接枝的交联聚苯乙烯(PNIPAAm-g-PSt)温敏性微球. 借助傅立叶变换红外光谱、差示扫描量热仪、扫描电子显微镜及激光光散射仪等对PNIPAAm-g-PSt的结构、相转变温度、形态及不同温度下的粒径变化进行了测定, 结果表明NIPAAm单体成功地原位ATRP接枝在交联PSt微球的表面, 接枝微球的球形更规整, 在水中的相转变温度约为32 ℃, 具有明显的温度敏感性. 相似文献
38.
39.
担载液相催化剂的研究——Ⅳ.催化剂的原位红外光谱表征 总被引:1,自引:0,他引:1
本文利用原位红外光谱方法对铑基担载液相催化剂(SLPC)在接近于实际反应条件下进行了表征。结果表明,新鲜催化剂上,铑膦络合物主要以二聚物的形式存在,如Rh_2(CO)_2(PPh_3)_4而在合成气或反应气氛中,催化剂铑膦络合物以单核络合物HRh(CO)_2(PPh_3)_2的形式存在。文中还对SLPC在CO,H_2,C_2-H_4,空气和HCl中处理时铑络合物种的变化进行了原位观察。实验结果表明,SLPC上活性铑络合物与对应的均相过程完全一致,进一步证实了SLPC催化在微观上就是一个均相催化过程。 相似文献
40.
Cui X Delgado R Carapuça HM Drew MG Félix V 《Dalton transactions (Cambridge, England : 2003)》2005,(20):3297-3306
A tetraazamacrocycle containing ferrocene moieties has been synthesized and characterized. The tetraprotonated form of this compound was evaluated as a receptor (R) for anion recognition of several substrates (S), Cl(-), PF(6)(-), HSO(4)(-), H(2)PO(4)(-) and carboxylates, such as p-nitrobenzoate (p-nbz(-)), phthalate (ph(2-)), isophthalate (iph(2-)) and dipicolinate (dipic(2-)). (1)H NMR titrations in CD(3)OD indicated that this receptor is not suitable for recognizing HSO(4)(-) and H(2)PO(4)(-), but weakly binds p-nbz(-), and strongly interacts with ph(2-), dipic(2-), and iph(2-) anions forming 1 : 2 assembled species. The largest beta(2) binding constant was determined for ph(2-), followed by dipic(2-) and finally iph(2-). The effect of the anionic substrates on the electron-transfer process of the ferrocene units of R was evaluated using cyclic voltammetry (CV) and square wave voltammetry (SWV) in methanol solution and 0.1 mol dm(-3)(CH(3))(4)NCl as the supporting electrolyte. Titrations of the receptor were undertaken by addition of anion solutions in their tetrabutylammonium or tetramethylammonium forms. The protonated ligand exhibits a reversible voltammogram, which shifts cathodically in the presence of the substrates. The data revealed kinetic constraints in the formation of the receptor/substrate entity for dipic(2-), ph(2-) and iph(2-) anions, but not for p-nbz(-). In spite of the slow kinetics of assembled species formation with the ph(2-) substrate, this anion provides the largest redox-response when the supramolecular entity is formed, followed by dipic(2-), iph(2-) and finally p-nbz(-) anions. This trend is in agreement with the (1)H NMR results and the values of the binding constants. Single crystal X-ray structures of the receptor with PF(6)(-), ph(2-), iph(2-) and p-nbz(-) were carried out and showed that supermolecules with a RS(2) stoichiometry are formed with the first three anions, but RS(4) with p-nbz(-). In all cases the binding occurs outside the macrocyclic cavity via N-H...O=C hydrogen bonds for carboxylate anions and N-H...F hydrogen bonds for the PF(6)(-) anion, which is in agreement with the solution results. The macrocyclic framework adopts different conformations in order to interact with each substrate having Fe...Fe intramolecular distances ranging from 10.125(14) to 12.783(15)A. 相似文献