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991.
L. C. Hastie S. L. Cooksley F. Scougall M. R. Young P. J. Boon M. J. Gaywood 《河流研究与利用》2004,20(8):1001-1013
The spatial distribution and associated physical habitat of endangered freshwater pearl mussels (Margaritifera margaritifera) in a 145 km stretch of the River Spey, northeast Scotland, were investigated. The overall size of the Spey M. margaritifera population was estimated to be in the order of 10 million. Mussel distributions were compared with River Corridor Survey (RCS) macrohabitat data and found to be positively associated with coarse riverbed substrata, ‘fast‐flowing’ waters, riparian woodland, and river bends; and negatively associated with shingle bars, flood barriers, ‘slow‐flowing’ waters, eroding cliffs and aquatic macrophytes. Significant positive relationships between mussel density and channel slope, width and bank height, were also observed. Binary logistic regression models (based on four to six features) were used to predict the presence/absence of mussels or the occurrence of ‘optimal’ mussel habitat (i.e. mussel density >1 m?2) at any given site. Overall predictive success rates of 79% and 78% were achieved, respectively. Discriminant function models (based on five variables) were also used, with predictive success rates of 78% and 88%, respectively. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
992.
993.
Hyoung‐Woo Kim Hongju Kim Soonman Kwon Joon‐Young Choi 《IEEJ Transactions on Electrical and Electronic Engineering》2016,11(5):633-639
A robust backstepping controller with nonlinear damping is designed for the grid‐side converter (GSC) of a grid‐connected doubly fed induction generator (DFIG) in wind energy conversion systems (WECSs). The designed controller achieves the exponential ultimate boundedness of both the DC‐link voltage and GSC current errors with an arbitrarily fast decay rate and an arbitrarily small bound in the presence of both model uncertainties and time‐varying external disturbances. A desirable feature that distinguishes the proposed controller from other existing controllers is that the control input of GSC is constructed only by the static feedback of the measurable states. As a result, the control input becomes smooth and easy to implement without requiring differentiation or switching operations. The exponential boundedness and performance of the designed controller are demonstrated by simulation using a 1.5‐MW DFIG‐based WECS model built in MATLAB/SimPowerSystems and compared with a standard proportional‐integral controller. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
994.
Seok Hoan Jeong Yong Joo Kim Kyung Ho Kong Tae Hee Cho Young Kyun Kim Hyun Kyu Lim Won Tae Kim Do Hyang Kim 《Metals and Materials International》2018,24(2):391-399
The effect of pre-aging treatment before extrusion has been investigated in Mg–9.0Al–1.0Zn–1MM–0.7CaO–0.3Mn alloy. The as-cast microstructure consists of α-Mg dendrite with secondary solidification phase particles, (Mg, Al)2Ca, β-Mg17Al12 and Al11RE3 at the inter-dendritic region. After extrusion, β-Mg17Al12 precipitates are present, but higher density and more homogeneous distribution in pre-aged alloy. In addition, μm-scale banded bulk β-Mg17Al12 particles are generated during extrusion. Al11RE3 particles are broken into small particles, and are aligned along the extrusion direction. (Mg, Al)2Ca particles are only slightly elongated along the extrusion direction, providing stronger particle stimulated nucleation (PSN) effect by severe deformation during extrusion. The mechanical properties can be significantly enhanced by introducing pre-aging treatment, i.e. β-Mg17Al12 precipitates provide grain refining and strengthening effects and (Mg, Al)2Ca particles provide PSN effect. 相似文献
995.
Young Jun Kwak Hye Ryoung Park Myoung Youp Song 《Metals and Materials International》2018,24(2):423-432
Zn(BH4)2 made in our former investigation and Ni were mixed with MgH2 to promote the hydrogen absorption and release features of Mg. A 96 w/o MgH2 + 2 w/o Ni + 2 w/o Zn(BH4)2 sample [named MgH2–4NZ] was prepared by milling in a planetary ball mill in a hydrogen atmosphere. The proportion of the additive was small (4 w/o) in order to increase hydrogen absorbing and releasing rates without majorly sacrificing the hydrogen-storage capacity. The hydrogen absorption and release features of the MgH2–4NZ were inspected in detail and compared with those of 99 w/o MgH2 + 1 w/o Zn(BH4)2 [named MgH2–1Z] and 95 w/o MgH2 + 2.5 w/o Ni + 2.5 w/o Zn(BH4)2 [named MgH2–5NZ] samples. The activation of the MgH2–4NZ was not required. The MgH2–4NZ had a useful hydrogen-storage capacity (the quantity of hydrogen absorbed after 60 min) of about 5.5 w/o at the first cycle. At the first cycle, the MgH2–4NZ absorbed 3.84 w/o hydrogen after 5 min and 5.47 w/o hydrogen after 60 min at 593 K in 12 bar hydrogen. The MgH2–4NZ had a higher releasing rate, larger amounts of hydrogen absorbed and released after 60 min, and a better cycling capability than the MgH2–1Z. Staying of Ni (as Mg2Ni) and a larger amount of Zn among particles is believed to have led to the better cycling capability of the MgH2–4NZ. 相似文献
996.
Hee Jeong Yoo Kyung Kim In Hyang Kim Seong-Hwan Rho Jong-Eun Park Ki Young Lee Soon Ae Kim Byung Yoon Choi Namshin Kim 《International journal of molecular sciences》2015,16(3):5697-5713
Rubinstein-Taybi syndrome (RSTS) is a rare condition with a prevalence of 1 in 125,000–720,000 births and characterized by clinical features that include facial, dental, and limb dysmorphology and growth retardation. Most cases of RSTS occur sporadically and are caused by de novo mutations. Cytogenetic or molecular abnormalities are detected in only 55% of RSTS cases. Previous genetic studies have yielded inconsistent results due to the variety of methods used for genetic analysis. The purpose of this study was to use whole exome sequencing (WES) to evaluate the genetic causes of RSTS in a young girl presenting with an Autism phenotype. We used the Autism diagnostic observation schedule (ADOS) and Autism diagnostic interview revised (ADI-R) to confirm her diagnosis of Autism. In addition, various questionnaires were used to evaluate other psychiatric features. We used WES to analyze the DNA sequences of the patient and her parents and to search for de novo variants. The patient showed all the typical features of Autism, WES revealed a de novo frameshift mutation in CREBBP and de novo sequence variants in TNC and IGFALS genes. Mutations in the CREBBP gene have been extensively reported in RSTS patients, while potential missense mutations in TNC and IGFALS genes have not previously been associated with RSTS. The TNC and IGFALS genes are involved in central nervous system development and growth. It is possible for patients with RSTS to have additional de novo variants that could account for previously unexplained phenotypes. 相似文献
997.
Cheol Park Won Sup Lee Se-Il Go Arulkumar Nagappan Min Ho Han Su Hyun Hong Gon Sup Kim Gi Young Kim Taeg Kyu Kwon Chung Ho Ryu Sung Chul Shin Yung Hyun Choi 《International journal of molecular sciences》2015,16(1):645-659
Evidence suggests that phytochemicals can safely modulate cancer cell biology and induce apoptosis. Here, we investigated the anti-cancer activity of morin, a flavone originally isolated from members of the Moraceae family in human leukemic cells, focusing on apoptosis. An anti-cancer effect of morin was screened with several human leukemic cell lines. U937 cells were most sensitive to morin, where it induced caspase-dependent apoptosis in a dose-dependent manner. It also induced loss of MMP (ΔΨm) along with cytochrome c release, down-regulated Bcl-2 protein, and up-regulated BAX proteins. The apoptotic activity of morin was significantly attenuated by Bcl-2 augmentation. In conclusion, morin induced caspase-dependent apoptosis through an intrinsic pathway by upregulating BAD proteins. In addition, Bcl-2 protein expression is also important in morin-induced apoptosis of U937 cells. This study provides evidence that morin might have anticancer properties in human leukemic cells. 相似文献
998.
Do‐Hyun Kim Chang‐Hwan Lee Young K. Ju Sang‐Dae Kim 《The Structural Design of Tall and Special Buildings》2015,24(4):243-256
In this study, a subassemblage test was performed using buckling‐restrained braces with an H‐shaped core element, which have been proven in a previous uniaxial component test to have good performance. The loading protocol prescribed the quasi‐static cyclic pattern with stepwise incremental displacement amplitude. Two different end connections (bolted connection and pin connection) and two different buckling‐restrained mechanisms (concrete‐filled tube and hollow steel tube) were examined as the test parameters. The performance of the specimen was evaluated by comparing the test results with the recommended provisions for buckling‐restrained braces. The test results showed that the compression strength capacity of buckling‐restrained brace (BRB) with in‐filled concrete increased by about 10% compared with BRB without in‐filled concrete. According to test result at same story drift of 2Dbm, structural performance of pin connection specimen without bolt slippage is superior to bolted connection specimen. Also, bolted connection specimens showed similar performance for total energy dissipation and cumulative plastic ductility, regardless of the connection types and the existence of concrete filling. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
999.
P. Huczkowski D. J. Young T. Olszewski A. Chyrkin W. J. Quadakkers 《Oxidation of Metals》2018,89(5-6):651-681
During oxyfuel combustion metallic heat exchangers are subjected to service environments which substantially differ from those prevailing during the conventional air firing process. In the present study the behaviour of three selected construction materials (P92, super S304HCu and alloy 617) during exposure in simulated oxyfuel gas with and without addition of SO2 at temperatures between 550 and 700 °C has been investigated. The alloy microstructure and the corrosion products formed during exposures up to 1000 h were studied by SEM/EDX and correlated with gravimetric data collected during the discontinuous exposures. It was found that the behaviour of the martensitic steel was hardly affected by the presence of SO2; however, in the case of the austenitic steel S304HCu the SO2 suppressed internal oxidation occurring at 650 °C in the SO2-free gas, thus promoting formation of a protective chromium-rich oxide. In the case of the nickel base alloy 617 the SO2 addition increased the corrosion rates at 550 and 650 °C due to replacement of the external chromia scale by a multiphase scale with sulphur-containing surface nodules. At 700 °C the alloy formed a chromia base surface scale and SO2 addition suppressed the formation of volatile Cr species. The results are explained using classical oxidation theory related to conditions for external scale formation in combination with thermodynamic considerations of phase stability as well as relative rates of adsorption of various gas species. 相似文献
1000.
The reduction behaviour of wustite-type iron oxide scale on a low-carbon, low-silicon steel by dissolved carbon in the steel at 650–900 °C under pure nitrogen was studied. It was found that dissoved carbon in the steel examined was able to react with the wustite scale on the surface, leading to reduction of this scale. It was also found that the scale reduction rate was the most rapid within 750–800 °C, followed by that at 700 °C and then at 850 °C, whereas the rates were essentially zero at 650 and 900 °C. Decarburization occurred to the steel as a result of scale reduction, and the degree of decarburization at 750–800 °C was also the most severe. The rate of scale–carbon reaction was primarily controlled by carbon diffusion through the decarburization layer as the calculated carbon permeability, defined as the product of carbon diffusivity and the carbon concentration difference across the decarburization layer, also reached its maximum within 750–800 °C. Scale reduction led to the formation of pores at the scale–steel interface as a result of volume shrinkage when wustite was reduced to iron, but the porosity volume was smaller than calculated at 800–850 °C, which could have an inhibiting effect on the scale–carbon reaction. The calculated volume of CO + CO2 gases generated as a result of scale–carbon reactions was about 100 times the calculated porosity volume. It was believed that the wustite scale was permeable to CO and/or CO2, allowing the much larger volume of CO and CO2 gases to escape through the scale layer. 相似文献