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Yang CH Li SW Chi Y Cheng YM Yeh YS Chou PT Lee GH Wang CH Shu CF 《Inorganic chemistry》2005,44(22):7770-7780
A series of heteroleptic Ir(III) metal complexes 1-3 bearing two N-phenyl-substituted pyrazoles and one 2-pyridyl pyrazole (or triazole) ligands were synthesized and characterized to attain highly efficient, room-temperature blue phosphorescence. The N-phenylpyrazole ligands, dfpzH = 1-(2,4-difluorophenyl)pyrazole, fpzH = 1-(4-fluorophenyl)pyrazole, dfmpzH = 1-(2,4-difluorophenyl)-3,5-dimethylpyrazole, and fmpzH = 1-(4-fluorophenyl)-3,5-dimethylpyrazole, show a similar reaction pattern with respect to the typical cyclometalated (C(wedge)N) chelate, which utilizes its ortho-substituted phenyl segment to link with the central Ir(III) atom, while the second 2-pyridylpyrazole (or triazole) ligand, namely, fppzH = 3-(trifluoromethyl)-5-(2-pyridyl)pyrazole, fptzH = 3-(trifluoromethyl)-5-(2-pyridyl)triazole, and hptzH = 3-(heptafluoropropyl)-5-(2-pyridyl)triazole, undergoes typical anionic (N--N) chelation to complete the octahedral framework. X-ray structural analyses on complexes [(dfpz)(2)Ir(fppz)] (1a) and [(fmpz)(2)Ir(hptz)] (3d) were established to confirm their molecular structures. Increases of the pipi energy gaps of the Ir(III) metal complexes were systematically achieved with two tuning strategies. One involves the substitution for one or two fluorine atoms at the N-phenyl segment or the introduction of two electron-releasing methyl substituents at the pyrazole segment of the H(C--N) ligands. Alternatively, we have applied the more electron-accepting triazolate in place of the pyrazolate segment for the third (N--N)H ligand. Our results, on the basis of steady-state, relaxation dynamics, and theoretical approaches, lead to a conclusion that, for complexes 1-3, the weakening of iridium metal-ligand bonding strength in the T(1) state plays a crucial role for the fast radiationless deactivation. For the case of [(fmpz)(2)Ir(hptz)] (3d), a thermal deactivation barrier of 4.8 kcal/mol was further deduced via temperature-dependent studies. The results provide a theoretical basis for future design and synthesis of the corresponding analogues suited to blue phosphorescent emitters. 相似文献
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Shih-Wen Liao Chu-Chin Hsieh Kuo-Yi Li Shu-Yao Tsai Jo-Ming Tseng Jin-Shuh Li Chun-Ping Lin 《Journal of Thermal Analysis and Calorimetry》2014,116(1):205-214
This is a novel idea: replacing highly dangerous and complex testing of solid thermally reactive materials through smart technology. We investigated the prediction of the storage lifetime and the thermal impact of thermally reactive material by different thermal analysis models: differential scanning calorimetry (DSC) for non-isothermal tests versus DSC isothermal tests. Two kinds of kinetic models were compared for evaluating appropriate kinetic parameters of thermal decomposition, and then the thermal hazard parameters were estimated by cartridge package simulation, which could result in reliable thermal hazard properties of a thermal reactive material’s thermal decomposition. We also determined the unsafe characteristics of a thermally reactive material stored in a depot under lifetime, so as to prevent runaway reactions that induce incidents by heat attack during storage. We were interested in an effective and smart analysis technology to reduce energy consumption of the dangerous testing. There are also calls for a smart testing technology which is the achieved object here for reducing energy consumption and avoiding runaway reaction disaster of thermally reactive materials. 相似文献
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Shih-Wen Chiu Hsiang-Chiu Wu Ting-I Chou Hsin Chen Kea-Tiong Tang 《Analytical and bioanalytical chemistry》2014,406(16):3985-3994
This article introduces a power-efficient, miniature electronic nose (e-nose) system. The e-nose system primarily comprises two self-developed chips, a multiple-walled carbon nanotube (MWNT)–polymer based microsensor array, and a low-power signal-processing chip. The microsensor array was fabricated on a silicon wafer by using standard photolithography technology. The microsensor array comprised eight interdigitated electrodes surrounded by SU-8 “walls,” which restrained the material–solvent liquid in a defined area of 650?×?760 μm2. To achieve a reliable sensor-manufacturing process, we used a two-layer deposition method, coating the MWNTs and polymer film as the first and second layers, respectively. The low-power signal-processing chip included array data acquisition circuits and a signal-processing core. The MWNT–polymer microsensor array can directly connect with array data acquisition circuits, which comprise sensor interface circuitry and an analog-to-digital converter; the signal-processing core consists of memory and a microprocessor. The core executes the program, classifying the odor data received from the array data acquisition circuits. The low-power signal-processing chip was designed and fabricated using the Taiwan Semiconductor Manufacturing Company 0.18-μm 1P6M standard complementary metal oxide semiconductor process. The chip consumes only 1.05 mW of power at supply voltages of 1 and 1.8 V for the array data acquisition circuits and the signal-processing core, respectively. The miniature e-nose system, which used a microsensor array, a low-power signal-processing chip, and an embedded k-nearest-neighbor-based pattern recognition algorithm, was developed as a prototype that successfully recognized the complex odors of tincture, sorghum wine, sake, whisky, and vodka. Figure
The miniature e-nose device prototype 相似文献
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In this work, we consider the positive solutions to the singular problem $$ \left\{\begin{array}{ll} -\Delta u = am(x)u-f(u) - \dfrac{c}{u^{\alpha}} & {\rm in}\;\Omega,\\ u=0 & {\rm on}\; \partial\Omega, \end{array} \right. $$ where 0?<?α?<?1,a?>?0 and c?>?0 are constants, Ω is a bounded domain with smooth boundary $\partial\Omega$ , Δ is a Laplacian operator, and $f:[0,\infty] \longrightarrow{\mathbb R}$ is a continuous function. The weight functions m(x) satisfies m(x)?∈?C(Ω) and m(x)?>?m 0?>?0 for x?∈?Ω and also ||m||?∞??=?l?<?∞. We assume that there exist A?>?0, M?>?0, p?>?1 such that alu???M?≤?f(u)?≤?Au p for all u?∈?[0,?∞?). We prove the existence of a positive solution via the method of sub-supersolutions when $m_{0}a>\frac{2\lambda_{1} }{1+\alpha}$ and c is small. Here λ 1 is the first eigenvalue of operator ??Δ with Dirichlet boundary conditions. 相似文献
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This research seeks to increase our understanding on the laminar-turbulent transition under an external body force. Direct numerical simulation by the spectral method with a weak formulation is used to solve the transient 3-D Navier-Stokes equations. Initial disturbances consist of the finite-amplitude 2-D Tollmien-Schlichting wave and two 3-D oblique waves. Competitions among different modes were computed during transition for different Richardson numbers. It is found that the body force can modify the transition mechanism of flows between two vertical plates. The body force was found to hasten the formation of three-dimensional flow. A non-laminar flow induced by the body force may present when the background flow is still laminar. 相似文献
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This paper deals with the analytic Feynman integral of functionals on a Wiener space. First the authors establish the existence of the analytic Feynman integrals of functionals in a Banach algebra S_α. The authors then obtain a formula for the first variation of integrals. Finally, various analytic Feynman integration formulas involving the first variation are established. 相似文献
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