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31.
Thin film CdS/Cu2S heterojunction solar cells were fabricated on gold grid plated glass substrates by first depositing Cu2S by elemental evaporation of copper and sulphur and then evaporating CdS. The Cu2S layer and the grid contacts were thus sandwiched between the glass substrate and the CdS layer and were prevented from coming in contact with air and humidity. Open-circuit voltages of 450–470 mV and short-circuit current densities of 14–16 mA cm-2 were found. The cell efficiencies were between 4.8% and 5%. The degradation of the cells was minimized and the cells were found to be stable. 相似文献
32.
33.
A continuously variable transmission (CVT) is an emerging automotive transmission technology that offers a continuum of gear
ratios between desired limits. A chain CVT is a friction-limited drive as its performance and torque capacity rely significantly
on the friction characteristic of the contact patch between the chain and the pulley. Moreover, such a CVT is susceptible
to clearance formation due to assembly defects or extensive continual operation of the system, which further degrades its
performance and leads to early wear and failure of the system. The present research focuses on developing models to understand
the influence of clearance and different friction characteristics on the dynamic performance of a chain CVT drive. A detailed
planar multibody model of a chain CVT is developed in order to accurately capture the dynamics characterized by the discrete
structure of the chain, which causes polygonal excitations in the system. A suitable model for clearance between the chain
links is embedded into this multibody model of the chain CVT. Friction between the chain link and the pulley sheaves is modeled
using different mathematical models which account for different loading scenarios. The mathematical models, the computational
scheme, and the results corresponding to different loading scenarios are discussed. The results discuss the influence of friction
characteristics and clearance parameters on the dynamic performance, the axial force requirements, and the torque transmitting
capacity of a chain CVT drive. 相似文献
34.
Mingjun Liu Miroslav Petro Jean M. J. Fréchet S. A. Haque Hsien-Chang Wang 《Polymer Bulletin》1999,43(1):51-58
Summary
Poly(propylene imine) dendrimers with amino chain ends have been used for the preparation of hydrophobic star polymers with
hydrophilic dendritic cores. The unsaturated end groups of polyisobutylene (PIB) were transformed into reactive anhydride
end groups by an “ene” reaction with maleic anhydride, and the resulting functionalized PIB was then reacted with dendrimers
to afford dendrimer-PIB star copolymers.
Received: 20 May 1999/Accepted: 17 June 1999 相似文献
35.
Mammalian mitochondria synthesize polypeptides crucial for energy generation using ribosomes with a number of unique features. These ribosomes are very protein rich and have very truncated ribosomal RNAs. The bulk of the mammalian mitochondrial ribosome is composed of proteins, only about half of which are homologs of ribosomal proteins found in other translational systems. A number of distinctive features are found in these ribosomes. Among these is a gate-like structure that allows entrance of the primarily leaderless mRNAs that characterize this system. The exit tunnel of the large subunit is also quite unusual and includes a site in which the nascent peptide is visible to solvent prior to the normal exit site. Further, this region of the mitochondrial ribosome is dominated by ribosomal proteins rather than rRNA and is involved in the interaction of the ribosome with the inner membrane where all of the translation products are ultimately located. The proteins of the mitochondrial ribosome appear to play a number of important roles in the cell in addition to their function in protein biosynthesis, including roles in apoptosis and in cell cycle control. 相似文献
36.
Md. Forhad Mina Md. Akramul Haque Md. Khairul Hassan Bhuiyan Md. Abdul Gafur Yukihiro Tamba Tsutomu Asano 《应用聚合物科学杂志》2010,118(1):312-319
Nanocomposites of isotactic polypropylene (iPP) and multiwalled carbon nanotubes (MWCNTs) with various contents of MWCNTs were fabricated by double molding techniques. X‐ray diffraction measurements reveal a development of α‐crystal with lamellar stacks having a long period of 150 Å in the neat iPP that increases to 165 Å in 2 wt % MWCNTs‐loaded composites, indicating that MWCNTs enhance crystallization of iPP as a nucleating factor. Mechanical properties, such as tensile strength, flexural strength, Young's modulus, tangent modulus, and microhardness are found to increase with increasing MWCNTs content. Thermal analyses represent an increase of crystallization and melting temperatures and a decrease of thermal stability of the composites with increasing MWCNTs. Changes in structural, mechanical, and thermal properties of the composites due to the addition of MWCNTs are elaborately discussed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
37.
38.
Hyo Joong Lee Henry C. LeventisSaif A. Haque Tomas TorresMichael Grätzel Md. Khaja Nazeeruddin 《Journal of power sources》2011,196(1):596-599
In pursuit of panchromatic sensitizers for mesoporous TiO2-based solid-state solar cells, a near-IR absorbing zinc phthalocyanine dye (coded TT1) was firstly adsorbed over relatively thin (∼1 μm) TiO2 mesoporous films and then a visible-light absorbing polymer [regioregular poly(3-hexylthiophene), P3HT] was incorporated into the mesopores as both a second sensitizer and a solid hole conductor. After optimizing some experimental parameters, these hybrid solid-state cells exhibited a clear panchromatic response, and an overall conversion efficiency of around 1% at full sun intensity. 相似文献
39.
Md. Nazrul Islam Md. Rezaur Rahman Md. Mominul Haque Md. Monimul Huque 《Composites Part A》2010,41(2):192-198
The physico-mechanical properties of coir reinforced polypropylene (PP) composites been investigated. In order to attain improved mechanical properties of the composites coir was chemically treated with o-hydroxybenzene diazonium salt. Both raw and treated coir samples were utilized for the fabrication of the composites. The mechanical properties of the composites prepared from chemically treated coir are found to be much better compared to those of untreated ones. Tensile strengths of the composites of both raw and chemically treated coir-PP composites showed a decreasing trend with increasing filler content. However, the values for the chemically treated coir-PP composites at all mixing ratios are found to be higher than that of neat PP. The surface morphologies of the fractured surfaces of the composites were recorded using scanning electron microscopy (SEM) to gain information about the fiber–matrix interfacial adhesion in the composites. 相似文献
40.
AbstractWhite etching cracking (WEC) is a subsurface bearing failure mechanism influenced by a number of factors, including lubricant composition. Certain metal-containing lubricants have been reported to promote WEC-induced failure; however, the exact mechanisms linking lubricant effects on WEC propensity are still not fully understood. An interesting field that has not been elucidated is the influence of additive concentration and tribofilm growth on WEC initiation, propagation, and failure. The investigations conducted in this work involved two series of oil formulations: one with additives that give rise to WEC (WEC oils) in different combinations and concentrations and another with additives that do not cause WEC (non-WEC oils). A mini traction machine (MTM) in combination with a spacer layer imaging machine (SLIM) was employed to study the growth of tribofilms and their influence on friction response. Insights from the MTM-SLIM study allowed for better interpretation of FE8 bearing tests. When using oils that contribute to WEC formation, the tribofilm-induced WEC mechanism was confirmed, with cracks initiating as early as after 20 h of FE8 testing. Metal-containing additives were found to favor the formation of WECs by generating a high-friction tribofilm and increasing the water content in the lubricant. Furthermore, the source of subsurface H associated with WEC failure is investigated using heavy water (D2O)-saturated oil. A mechanism of water dissociation induced in tribofilm growth (incubation period) is proposed in this article. 相似文献