Oscillations and multiscale dynamics in a closed chemical reaction system: Second law of thermodynamics and temporal complexity

2008 ◽  
Vol 129 (15) ◽  
pp. 154505 ◽  
Author(s):  
Yongfeng Li ◽  
Hong Qian ◽  
Yingfei Yi
Keyword(s):  
Chemical Reaction ◽  
Reaction System ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Temporal Complexity ◽  
Multiscale Dynamics ◽  
Chemical Reaction System

Fabrication of Semiconductor Nano-particles in the Protein Cage of Apoferritin

2005 ◽  
Vol 873 ◽  
Author(s):  
Kenji Iwahori ◽  
Keiko Yoshizawa ◽  
Masahiro Muraoka ◽  
Ichiro Yamashita
Keyword(s):  
Chemical Reaction ◽  
Reaction System ◽  
Nano Particles ◽  
Internal Cavity ◽  
Reaction Parameters ◽  
Synthesis System ◽  
X Ray ◽  
Protein Cage ◽  
High Resolution Tem ◽  
Chemical Reaction System

AbstractWe specially designed a slow chemical reaction system to synthesize the zinc selenide nanoparticles (ZnSe NPs), in the cavity of the cage-shaped protein, apoferritin. The newly designed chemical synthesis system for ZnSe NPs makes the chemical reaction of compound semiconductor element ions dramatically slow, resulting in that ZnSe NPs can be synthesized in the internal cavity of the apoferritin. The ZnSe NPs synthesized by the optimized reaction parameters are efficiently produced in the aqueous solution. The UVVis spectrum analysis of synthesized ZnSe-ferritin suggests that the formation of ZnSe nuclei in the apoferritin cavity takes about 6 hours by using our slow chemical reaction system. The synthesized ZnSe NPs were characterized by high resolution TEM, X-ray powder diffraction (XRD) and Energy Dispersive Spectrometory (EDS) and it was revealed that the synthesized NPs are a collection of cubic ZnSe crystals.

Models and Explanations: Understanding Chemical Reaction Mechanisms

2000 ◽  
Author(s):  
Barry K. Carpenter
Keyword(s):  
Internal Rotation ◽  
Chemical Reaction ◽  
Reaction Mechanisms ◽  
Second Law Of Thermodynamics ◽  
The Other ◽  
Second Law ◽  
Original Design ◽  
Mechanical Analogy ◽  
Boston College ◽  
Chemical Reaction Mechanisms

In 1997, Ross Kelly and his coworkers at Boston College reported their results from an experiment with an intriguing premise (Kelly et al., 1997; see also Kelly et al., 1998). They had synthesized the molecule shown in figure 12.1. It was designed to be a “molecular ratchet,” so named because it appeared that it should undergo internal rotation about the A—B bond more readily in one direction than the other. The reason for thinking this might occur was that the benzophenanthrene moiety—the “pawl” of the ratchet—was anticipated to be helical. Thus, in some sense, this might be an inverse ratchet where the asymmetry dictating the sense of rotation would reside in the pawl rather than in the “teeth” on the “wheel” (the triptycene unit) as it does in a normal mechanical ratchet. Kelly and coworkers designed an elegant experiment to determine whether their molecular ratchet was functioning as anticipated, and they were (presumably) disappointed to find that it was not—internal rotation about the A—B bond occurred at equal rates in each direction. In 1998 Davis pointed out that occurrence of the desired behavior of the molecular ratchet would have constituted a violation of the second law of thermodynamics (Davis, 1998). With hindsight, I think most chemists would agree that Davis’s critique is unassailable, although the appeal of the mechanical analogy was so strong that I imagine those same chemists would also understand if Kelly et al. had overlooked the thermodynamic consequences of their proposal in the original design of the experiment. But now comes the interesting question: Suppose Kelly et al. had been fully aware that their experiment, if successful, would undermine the second law of thermodynamics, should they have conducted it anyway? Davis, in his critique writes: . . .Some would argue that this experiment was misconceived. To challenge the Second Law may be seen as scientific heresy (a nice irony, considering the Jesuit origins of Boston College), and the theoretical arguments against molecular ratchets and trapdoors are well developed. . . .

Buffer capacity in multiple chemical reaction systems involving solid phases

2006 ◽  
Vol 84 (8) ◽  
pp. 1036-1044 ◽  
Author(s):  
Ilie Fishtik ◽  
Igor Povar
Keyword(s):  
Chemical Reaction ◽  
Buffer Capacity ◽  
Reaction System ◽  
Chemical Species ◽  
Abundant Species ◽  
Stoichiometric Coefficient ◽  
Reaction Systems ◽  
Chemical Reaction Systems ◽  
Chemical Reaction System ◽  
Multiple Chemical

The buffer capacity of a chemical species in a multiple chemical reaction system is discussed in terms of a special class of stoichiometrically unique reactions referred to as response reactions (RERs). More specifically, it is shown that the buffer capacity may be partitioned into a sum of contributions associated with RERs. This finding provides a deeper understanding of the factors that determine the buffer capacity. In particular, the main contributions to the buffer capacity come from the RERs involving the most abundant species. Concomitantly, the RERs approach provides a simple stoichiometric algorithm for the derivation and analysis of the buffer capacity that may be easily implemented into a computer software.Key words: buffer capacity, response reaction, heterogeneous system, stoichiometric coefficient.

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