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81.
Phuong D. Ngo Yung C. Shin 《The International Journal of Advanced Manufacturing Technology》2013,66(9-12):1641-1655
Machining contour error plays important roles in product quality. This paper presents an implementation of multilevel fuzzy controller in controlling contour errors while maintaining the desired feed rate of milling processes. The orthogonal global task frame was used to transform the tool positions from the Cartesian coordinate system to the curvilinear coordinate system. Contour error and tracking lag error calculated from the curvilinear coordinate system were used by the multilevel fuzzy controller to drive the machining axis on the Mazak VQC-15/40 vertical machining center. The contour error of the machined work piece measured by the coordinate measuring machine showed that the contour error were significantly reduced and the feed rate were regulated at the desired speed. 相似文献
82.
Dan Phuong Nguyen Chan-Woo Park Young-Min Lee Keesam Shin Hee-Kyu Choi Woo-Hyun Chung Chan-Gyu Lee 《Metals and Materials International》2008,14(1):111-115
The effect of thickness on interdiffusion in Fe/Pt multilayer thin films was studied using rapid thermal annealing. [Fe(1
nm)/Pt(1 nm)]20 and [Fe(3 nm)/Pt(3 nm)]10 multilayers were prepared via DC magnetron sputtering and subsequently annealed at temperatures of 523 K to 603 K in an argon
atmosphere in an infrared lamp furnace for a very short time. X-ray diffraction yielded the interdiffusion coefficients from
the slopes of the satellite peak versus annealing time. The temperature dependence of interdiffusion in the range of 523 K
to 603 K can be described by D(t)=3.42×10−15 exp(−0.83 eV/kBT) (m2/s) for [Fe(1 nm)/Pt(1 nm)]20 and D(t) =7.85×10−16 exp(−0.62 eV/kBT) (m2/s) for [Fe(3 nm)/Pt(3 nm)]10. The activation energy Q=0.83 eV for [Fe(1 nm)/Pt(1 nm)]20 is higher than that of Q=0.62 eV for [Fe(3 nm)/Pt(3 nm)]10. This phenomenon suggests that the atoms in the thicker film can move more easily in the interface and the lattice, which
results in lower activation energy and higher diffusivity. 相似文献
83.
MicroRNAs (miRNAs) are a group of endogenous non-coding RNAs that regulate gene expression. Alteration in miRNA expression results in changes in the profile of genes involving a range of biological processes, contributing to numerous human disorders. With high stability in human fluids, miRNAs in the circulation are considered as promising biomarkers for diagnosis, as well as prognosis of disease. In addition, the translation of miRNA-based therapy from a research setting to clinical application has huge potential. The aim of the current review is to: (i) discuss how miRNAs traffic intracellularly and extracellularly; (ii) emphasize the role of circulating miRNAs as attractive potential biomarkers for diagnosis and prognosis; (iii) describe how circulating microRNA can be measured, emphasizing technical problems that may influence their relative levels; (iv) highlight some of the circulating miRNA panels available for clinical use; (v) discuss how miRNAs could be utilized as novel therapeutics, and finally (v) update those miRNA-based therapeutics clinical trials that could potentially lead to a breakthrough in the treatment of different human pathologies. 相似文献
84.
The molecular structure and rheological properties of high-amylose water caltrop (Trapa bispinosa Roxb.) starch cultivated in Vietnam were investigated. The water caltrop starch had 47.1% amylose and its molecular weight (Mw) was (4.77±0.27)×106 g/mol, whereas the Mw was (2.07±0.10)×107 g/mol for amylopectin. The average chain length of amylopectin was DPn=19.0 and the proportions of A, B1, B2, and B3 chains were 28.2, 50.3, 13.1, and 8.5%, respectively. The DSC thermogram of the water caltrop starch was broadly endothermic, with 2 distinct endothermic peaks at 73.6 and 80.7°C. Gel formation of water caltrop starch occurred rapidly, with an extremely high storage modulus up to approximately 1,200 Pa. High-amylose water caltrop starch paste had an extremely high final viscosity compared to that of other cereal starches. These rheological behaviors may have been due to the extremely high amylose content. 相似文献
85.
Solving inverse problems usually calls for adapted priors such as the definition of a well chosen representation of possible solutions. One family of approaches relies on learning redundant dictionaries for sparse representation. In image processing, dictionary learning is applied to sets of patches. Many methods work with a dictionary with a number of atoms that is fixed in advance. Moreover optimization methods often call for the prior knowledge of the noise level to tune regularization parameters. We propose a Bayesian non parametric approach that is able to learn a dictionary of adapted size. The use of an Indian Buffet Process prior permits to learn an adequate number of atoms. The noise level is also accurately estimated so that nearly no parameter tuning is needed. We illustrate the relevance of the resulting dictionaries on numerical experiments. 相似文献
86.
Wireless Personal Communications - In the current information era, data mining has been extensively applied in many fields to discover the huge knowledge. It is desirable to design a system to... 相似文献
87.
You-Hsin Chen Thi Ngoc Lan Thao Ngo Kung-Yuh Chiang 《International Journal of Hydrogen Energy》2021,46(27):14083-14095
This research provides a perspective on sludge-to-energy using sewage sludge (SS) and industrial wastewater sludge (IS) co-gasification in a pilot-scale fluidized bed gasifier with temperature controlled at (600–800 °C) using IS addition ratio (0%–60%), and steam-to-biomass ratio (S/B) (0–1.0). The experimental results show that the increase in thermal reaction activity occurred in concordance with the increase in the IS addition. The explanation for such phenomena is that relatively high catalytic Fe/Mn content in industrial wastewater sludge could lower the activation energy. Hydrogen production was increased from 9.1% to 11.94% with an increase in industrial wastewater sludge ratios from 0% to 60%. The produced gas heating value ranged from 4.84 MJ/Nm3 to 5.11 MJ/Nm3, which was coupled with the cold gas efficiency (CGE) ranging from 33.91% to 36.15%. Enhanced hydrogen production in sewage sludge and industrial wastewater sludge co-gasification is investigated in this study. 相似文献
88.
Jigme Dorji Iona M. MacLeod Amanda J. Chamberlain Christy J. Vander Jagt Phuong N. Ho Majid Khansefid Brett A. Mason Claire P. Prowse-Wilkins Leah C. Marett William J. Wales Benjamin G. Cocks Jennie E. Pryce Hans D. Daetwyler 《Journal of dairy science》2021,104(1):575-587
Feed efficiency and energy balance are important traits underpinning profitability and environmental sustainability in animal production. They are complex traits, and our understanding of their underlying biology is currently limited. One measure of feed efficiency is residual feed intake (RFI), which is the difference between actual and predicted intake. Variation in RFI among individuals is attributable to the metabolic efficiency of energy utilization. High RFI (H_RFI) animals require more energy per unit of weight gain or milk produced compared with low RFI (L_RFI) animals. Energy balance (EB) is a closely related trait calculated very similarly to RFI. Cellular energy metabolism in mitochondria involves mitochondrial protein (MiP) encoded by both nuclear (NuMiP) and mitochondrial (MtMiP) genomes. We hypothesized that MiP genes are differentially expressed (DE) between H_RFI and L_RFI animal groups and similarly between negative and positive EB groups. Our study aimed to characterize MiP gene expression in white blood cells of H_RFI and L_RFI cows using RNA sequencing to identify genes and biological pathways associated with feed efficiency in dairy cattle. We used the top and bottom 14 cows ranked for RFI and EB out of 109 animals as H_RFI and L_RFI, and positive and negative EB groups, respectively. The gene expression counts across all nuclear and mitochondrial genes for animals in each group were used for differential gene expression analyses, weighted gene correlation network analysis, functional enrichment, and identification of hub genes. Out of 244 DE genes between RFI groups, 38 were MiP genes. The DE genes were enriched for the oxidative phosphorylation (OXPHOS) and ribosome pathways. The DE MiP genes were underexpressed in L_RFI (and negative EB) compared with the H_RFI (and positive EB) groups, suggestive of reduced mitochondrial activity in the L_RFI group. None of the MtMiP genes were among the DE MiP genes between the groups, which suggests a non-rate limiting role of MtMiP genes in feed efficiency and warrants further investigation. The role of MiP, particularly the NuMiP and OXPHOS pathways in RFI, was also supported by our gene correlation network analysis and the hub gene identification. We validated the findings in an independent data set. Overall, our study suggested that differences in feed efficiency in dairy cows may be linked to differences in cellular energy demand. This study broadens our knowledge of the biology of feed efficiency in dairy cattle. 相似文献
89.
90.
Alexa S. Kuenstler Yuzhen Chen Phuong Bui Hyunki Kim Antonio DeSimone Lihua Jin Ryan C. Hayward 《Advanced materials (Deerfield Beach, Fla.)》2020,32(17):2000609
Liquid crystal elastomers (LCEs) are an attractive platform for dynamic shape-morphing due to their ability to rapidly undergo large deformations. While recent work has focused on patterning the director orientation field to achieve desired target shapes, this strategy cannot be generalized to material systems where high-resolution surface alignment is impractical. Instead of programming the local orientation of anisotropic deformation, an alternative strategy for prescribed shape-morphing by programming the magnitude of stretch ratio in a thin LCE sheet with constant director orientation is developed here. By spatially patterning the concentration of gold nanoparticles, uniform illumination leads to gradients in photothermal heat generation and therefore spatially nonuniform deformation profiles that drive out-of-plane buckling of planar films into predictable 3D shapes. Experimentally realized shapes are shown to agree closely with both finite element simulations and geometric predictions for systems with unidirectional variation in deformation magnitude. Finally, the possibility to achieve complex oscillatory motion driven by uniform illumination of a free-standing patterned sheet is demonstrated. 相似文献