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11.
A procedure for preparation of clear and stable indium cyanide electrolytes, containing indium salt, d(+)-Glucose and KCN is proposed. NMR investigations revealed that the formation of a complicated indium complex in which the
products of the disintegration of d(+)-Glucose in the KCN-solution are closely situated to the indium ion ensures the clearness of the electrolyte. The effect
of nitrate, chloride and sulphate ions on the electrochemical processes of indium and silver–indium alloy electrodeposition
is studied by cyclic voltammetry. During alloy electrodeposition under galvanostatic conditions unique spatio–temporal structures
are observed on the cathodic surface. 相似文献
12.
D. König W. H. Weber B. D. Poindexter J. R. McBride G. W. Graham K. Otto 《Catalysis Letters》1994,29(3-4):329-338
Ellipsometry is used to follow the growth of a PdO layer on the surface of a thick Pd-film catalyst during methane oxidation at 500°C. The oxide layer that develops under rich conditions (excess CH4) is quite porous and roughens with time. Little CO is formed during this period, but the CO2 formation rate increases until spontaneous oscillations develop, which correlate with changes in the ellipsometric data. These changes indicate that the porous oxide rapidly converts to a metal-rich state, which has decreased catalytic activity, and then slowly reoxidizes. 相似文献
13.
Constrained spectral non-negative matrix factorization(NMF)analysis of perturbed oscillatory process control loop variable data is performed for the isolation of multiple plant-wide oscillatory sources.The technique is described and demonstrated by analyzing data from both simulated and real plant data of a chemical process plant. Results show that the proposed approach can map multiple oscillatory sources onto the most appropriate control loops,and has superior performance in terms of reconstruction accuracy and intuitive understanding compared with spectral independent component analysis(ICA). 相似文献
14.
The effects of ultrasonic oscillations and die materials on die pressure, productivity of extrusion, melt viscosity of metallocene‐catalyzed linear low density polyethylene (mLLDPE), as well as their mechanism were studied in a special ultrasonic oscillations extrusion system developed in our lab. Die materials used in our experiment included steel, brass, and polytetrafluoroethylene (PTFE). The experimental results showed that ultrasonic oscillations as well as die materials have great influence on the rheological and processing behavior of mLLDPE. Ultrasonic oscillations can greatly increase the productivity of mLLDPE melt extruded through different dies, and can decrease the die pressure and the melt viscosity of mLLDPE. Compared with steel or brass die, mLLDPE melt extruded through PTFE die is more sensitive to ultrasonic oscillations. A possible mechanism for the improved processability of mLLDPE is proposed in this article. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1873–1878, 2003 相似文献
15.
ON THE CHEMICAL OSCILLATIONS IN DIFFERENTIAL REACTORS: A CASE STUDY OF AMMONIA OXIDATION ON PLATINUM
Trying to identify the mechanism(s) responsible for isothermal oscillatory behavior of heterogeneous catalytic reaction systems, many investigators have assumed low conversions with respect to the limiting reactant(s) so that the bulk phase concentrations of the reactants may be considered constant. In this study, it is shown that even in a differential catalytic CSTR, in which conversion of the reactants may be less than %, the changes of the gas phase concentrations of the reacting.species may play a key role in the overall dynamic behavior of a reaction system; for instance, they may drive the oscillations observed. The reduction of nitric oxide by ammonia on polycrystalline platinum is discussed in detail within this context. Several other oxidation reactions are also discussed 相似文献
16.
In this paper an experimental and theoretical investigation of the forced vibration of a partially immersed fiber has been carried out. An optical method utilizing a forward light scattering pattern has been used to detect a small (<1.0 μm) vibration amplitude of the fiber. The physical and mathematical model of the partially immersed fiber vibration has been put forward. Based on an analytical solution of the model, natural frequencies of the partially immersed fiber vibration have been found; they are consecutive positive roots of the transcendental equation. An “effective” speed of the wave propagation over the fiber has been introduced, which allows one to find the physical meaning of normal modes of the partially immersed fiber vibration. Theoretical predictions agree well with experimental data. The sensor exhibits an excellent sensitivity and could be used for measuring physical properties of fluids and liquid level. 相似文献
17.
风电并网所引起的次/超同步振荡研究多集中于小信号模型分析,较少考虑遭受大扰动后限幅等非线性影响。基于单边限幅的描述函数与广义Nyquist判据,对正阻尼直驱式永磁同步发电机(PMSG)限幅环节间歇饱和引起的切换型次/超同步振荡进行分析。首先给出并网PMSG状态空间简化模型并分析其小干扰稳定性;其次发现一种大扰动后并网PMSG因不对称单边d轴电流限幅间歇饱和引起的新型切换型振荡现象;再次结合并网PMSG网侧变流器的频域模型以及单边限幅的描述函数,给出含限幅环节的PMSG系统近似分析模型;最后结合广义Nyquist判据,近似分析不同限幅值和参数下的振荡频率,并解释该种振荡频率随限幅上限降低而增加的现象。 相似文献
18.
19.
This communique presents forced second-order consensus protocols with communication time-delays for the network of agents with double integrator dynamics and gives a measure of the robustness of the protocols to the communication time-delays. By employing a frequency domain method, it is proven that the forced consensus is achieved asymptotically for appropriate time-delay if the network is connected. Particularly, the maximum fixed time-delay that can be tolerated by the network is found. The forced consensus protocols are distributed in the sense that each agent only needs information from its neighboring agents, which reduces the complexity of connections between agents significantly. Numerical simulation results are provided to demonstrate the effectiveness and the sharpness of the theoretical results. 相似文献
20.