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131.
The modern world has made all things interrelated, the relations are continuous and contiguous around the globe, affected by nuances and diversity... The question is man and his environment, an event of local as well as of global order. 1 Le Corbusier was very interested in the ideas of the Jesuit priest and distinguished palaeontologist Pere Pierre Teilhard de Chardin. 'Do you know this man and his research (Palaeontology, the human condition, the future)?' wrote the architect to his friend and collaborator Andreas Speiser on 22 December, 1954.2 In this letter (Fig. 1) he relates that he spent the whole journey back from India reading the priest's works. 'I was very favourably impressed by him' he wrote, 'I must get in touch with him before long.' Le Corbusier includes in the letter a list of papers by Teilhard, which he must have believed to be of particular interest. The 'etc' at the end of this list is of interest, indicating the extent of the architect's reading of this profoundly religious man. Le Corbusier asterisked the first essay, linking it with the word ' avenir ' or future and also the word ' definitives ,' definitive answers, a word which he then crossed out with one line, leaving it clearly legible. It is as though he believed that Teilhard had the answers that he was so desperately looking for, but years of disappointment, secrecy and disillusionment had made him wary. Being first on the list, the essay La Planetisation Humaine , 'The Planetisation of Mankind' is probably the most important in terms of Le Corbusier's reading of Teilhard.3 In this paper I will focus on the essay in an attempt to deduce just why Le Corbusier was so impressed by the works of this radical priest. In doing so, I hope to shed some light on Le Corbusier's spiritual agenda for architecture, an aspect of his work which still remains remarkably obscure. In particular I will focus on the concept of community expressed in the Unite block in Marseilles (1952). It should be mentioned that Le Corbusier does make other references to Teilhard, for example in an interesting stream of consciousness in one of his sketchbooks of 1960.4 Incidents such as this indicate that the priest's ideas were a continuing source of inspiration for the architect.  相似文献   
132.
Although the main features of the protein folding problem are coming into clearer focus, the microscopic viewpoint of nucleic acid folding mechanisms is only just beginning to be addressed. Experiments, theory, and simulations are pointing to complex thermodynamic and kinetic mechanisms. As is the case for proteins, molecular dynamics (MD) simulations continue to be indispensable tools for providing a molecular basis for nucleic acid folding mechanisms. In this review, we provide an overview of biomolecular folding mechanisms focusing on nucleic acids. We outline the important interactions that are likely to be the main determinants of nucleic acid folding energy landscapes. We discuss recent MD simulation studies of empirical force field and Go-type MD simulations of RNA and DNA folding mechanisms to outline recent successes and the theoretical and computational challenges that lie ahead.  相似文献   
133.
With the increased interest in thermoset resin nanocomposites, it is important to understand the effects of the material on nanoscale characteristics. In this study, a curing reaction of an epoxy resin, which contained 0.25, 0.50, or 1.00 wt % of multiwalled carbon nanotubes (MWCNTs), at different heating rates was monitored by differential scanning calorimetry; cure kinetics were also evaluated to establish a relationship between crosslinking (network formation) and mechanical properties. MWCNT concentrations above 0.25 wt % favored crosslinking formation and decreased the activation energy (Ea) in the curing reaction. Examination of the kinetic mechanism suggests that the MWCNT locally restricted the spatial volume and favored the formation of nodular morphology in the resin, especially for high MWCNT concentrations. The MWCNT exhibited some entanglement in the matrix, which hindered a more pronounced effect on the mechanical properties. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39857.  相似文献   
134.
It is well known that acidity, pH, of a solution accelerates the hydrolysis of soluble amides. Here we describe the unexpected result that weak small organic acids at low concentrations hydrolyze a polyamide at rates approximately twice that of a water HCl solution of the same pH. The effect of three small organic acids in dilute solutions, acetic, propanoic, and butanoic was studied. It is observed that the effect on the hydrolysis rate increases as the organic acid gets weaker. Butanoic, the weakest acid, has the strongest effect on increasing the hydrolysis rate. Measurements on the concentration of these acids in the polyamide reveal that there is a selective desire for these weak organic acids to diffuse into the polyamide. The concentration of these acids in the polyamide is found to be several multiples of the concentration in the water environment. And the acid concentration is highest for butanoic. The hydrolysis rate is shown to be governed by solubility, not pH of the water environment. The longer hydrocarbon tail on the carboxylic group increases its compatibility with the polyamide's monomer structure. Results are reported on the hydrolysis of polyamide-11 polymerized from aminoundecanoic acid, both neat and a commercial plasticized composition, placed in water at 100 °C and 120 °C under anaerobic conditions in high pressure glass tubes.  相似文献   
135.
Ion implantation has the advantage of being a unidirectional doping technique. Unlike gaseous diffusion, this characteristic highlights strong possibilities to simplify solar cell process flows. The use of ion implantation doping for n‐type PERT bifacial solar cells is a promising process, but mainly if it goes with a unique co‐annealing step to activate both dopants and to grow a SiO2 passivation layer. To develop this process and our SONIA cells, we studied the impact of the annealing temperature and that of the passivation layers on the electrical quality of the implanted B‐emitter and P‐BSF. A high annealing temperature (above 1000 °C) was necessary to fully activate the boron atoms and to anneal the implantation damages. Low J0BSF (BSF contribution to the saturation current density) of 180 fA/cm2 was reached at this high temperature with the best SiO2 passivation layer. An average efficiency of 19.7% was reached using this simplified process flow (“co‐anneal process”) on large area (239 cm2) Cz solar cells. The efficiency was limited by a low FF, probably due to contaminations by metallization pastes. Improved performances were achieved in the case of a “separated anneals” process where the P‐BSF is activated at a lower temperature range. An average efficiency of 20.2% was obtained in this case, with a 20.3% certified cell. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
136.
Measurements of the electrical conductivities of three types of polysilanes were carried out over a range of dc fields and temperatures. These polymers are varied in substituents and structures with formulas of [C6H5SiCH3]n, [(C6H5SiCH3)70(CH3SiH)30]n, and [(C6H5SiCH3)50(C6H5SiH)30(CH3Si)20]n. Undoped polysilanes behaved as insulators since their conductivities were observed in the range of 10−10 to 10−13 S cm−1, while SbF5-doped polysilanes of all kinds behaved as semiconductors with conductivities in the range of 10−2 to 10−4 S cm−1. No significant difference in conductivities was observed among three SbF5-doped polysilanes although these polymers are very different in chemical properties. These experimental results suggest that electrical conductivities of polysilanes are associated with the Si Si main-chain backbone rather than with the side groups. It is evident that the dopant is able to diffuse throughout the bulk of the polymer and the conductivity of the doped polymer is a function of the dopant concentration from the result of in situ monitoring of the resistance of the silane homopolymer during SbF5 doping at room temperature. The conductivities of polysilanes appeared to be temperature-dependent. The activation energy for the conduction of SbF5-doped silane copolymer was found to change at its glass transition temperature. © 1996 John Wiley & Sons, Inc.  相似文献   
137.
防患于未然:水坝潜在溃决模式探究与分析   总被引:1,自引:0,他引:1  
本文简介三种常见水坝的一些具有代表性的潜在溃决模式和导致这些模式发生的根本原因(即所谓的风险因素和可能的理由),俗云:“不经一事,不长一智”,冀望从过去的溃坝案例中吸取宝贵的教训,以正视每一个可能影响水坝安全的问题。本文略述近期发展的蓄水坝潜在溃决模式分析方法的步骤,借着制度面的革新,透过团队合作方式,以确认、判断可能存在的潜在溃决模式及其发生的相对可能性,采取必要的补救措施。  相似文献   
138.
Mitochondrial bioenergetics reprogramming is an essential response of cells to stress. Platelets, an accessible source of mitochondria, have a crucial role in cancer development; however, the platelet mitochondrial function has not been studied in urothelial carcinoma (UC) patients. A total of 15 patients with UC and 15 healthy controls were included in the study. Parameters of platelet mitochondrial respiration were evaluated using the high-resolution respirometry method, and the selected antioxidant levels were determined by HPLC. In addition, oxidative stress was evaluated by the thiobarbituric acid reactive substances (TBARS) concentration in plasma. We demonstrated deficient platelet mitochondrial respiratory chain functions, oxidative phosphorylation (OXPHOS), and electron transfer (ET) capacity with complex I (CI)-linked substrates, and reduced the endogenous platelet coenzyme Q10 (CoQ10) concentration in UC patients. The activity of citrate synthase was decreased in UC patients vs. controls (p = 0.0191). γ-tocopherol, α-tocopherol in platelets, and β-carotene in plasma were significantly lower in UC patients (p = 0.0019; p = 0.02; p = 0.0387, respectively), whereas the plasma concentration of TBARS was increased (p = 0.0022) vs. controls. The changes in platelet mitochondrial bioenergetics are consistent with cell metabolism reprogramming in UC patients. We suppose that increased oxidative stress, decreased OXPHOS, and a reduced platelet endogenous CoQ10 level can contribute to the reprogramming of platelet mitochondrial OXPHOS toward the activation of glycolysis. The impaired mitochondrial function can contribute to increased oxidative stress by triggering the reverse electron transport from the CoQ10 cycle (Q-junction) to CI.  相似文献   
139.
140.
There is an urgent need to better understand the mechanisms involved in scar formation in the brain. It is well known that astrocytes are critically engaged in this process. Here, we analyze incipient scar formation one week after a discrete ischemic insult to the cerebral cortex. We show that the infarct border zone is characterized by pronounced changes in the organization and subcellular localization of the major astrocytic protein AQP4. Specifically, there is a loss of AQP4 from astrocytic endfoot membranes that anchor astrocytes to pericapillary basal laminae and a disassembly of the supramolecular AQP4 complexes that normally abound in these membranes. This disassembly may be mechanistically coupled to a downregulation of the newly discovered AQP4 isoform AQP4ex. AQP4 has adhesive properties and is assumed to facilitate astrocyte mobility by permitting rapid volume changes at the leading edges of migrating astrocytes. Thus, the present findings provide new insight in the molecular basis of incipient scar formation.  相似文献   
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