检索结果-内蒙古大学图书馆

About c/539W1 and c/1245D1 as the parent comet of 15-BOOTIDS

PLANETARY AND SPAcE ScIENcE 2021年 204卷 105282-105282页

作者： Martinez, M. J. Marco, F. J. Univ Politecn Valencia Dept Matemat Aplicada IUMPA Valencia 46022 Spain Univ Jaume 1 Dept Matemat IMAC Castellon de La Plana 12004 Spain

In a recent paper published in this journal it was presented an interesting study on the 2019 outburst of the 15Bootids and it was suggested the possibility that comet c/539W1 was the parent comet of this meteor shower. It was also deducted from the method employed that this parent comet could have had a first passage through perihelion around the year AD1260. In this paper, we review both assumptions and we propose the possibility that the previous perihelion passage of the parent comet of the 15-Bootids was observed and recorded as c/ 1245D1.

关键词： celestial mechanics Meteoroids Meteors Small bodies comets c c Meteor showers 15-Bootids

来源：评论

学校读者我要写书评

暂无评论

Laser ablation behavior of c/Sic composites subjected to transverse hypersonic airflow

引用

cORROSION ScIENcE 2021年 183卷 109345-109345页

作者： Wang, Zhe Wang, Jiangtao Song, Hongwei Yuan, Wu Liu, Yuwen Ma, Te Huang, chenguang Chinese Acad Sci Key Lab Mech Fluid Solid Coupling Syst Inst Mech Beijing 100190 Peoples R China Univ Chinese Acad Sci Sch Engn Sci Beijing 100049 Peoples R China Yanshan Univ Sch Environm & Chem Engn Qinhuangdao 066004 Hebei Peoples R China

Laser ablation behaviors of c/Sic composites were examined in a hypersonic wind tunnel. Parallel laser ablation tests under static air were also conducted, and the ablation behaviors of these two conditions were compared. Mass ablation rates were augmented by 4?9 times when subjected to the hypersonic airflow. Ablation morphologies were significantly different in the micro and macro scales, and the needle-like microstructure of carbon fibers under static air turned to be rough and tattered under the hypersonic airflow. The accelerated ablation rate and the peculiar ablation micro-morphologies were mainly attributed to the strong mechanical erosion induced by hypersonic airflow.

关键词： Laser ablation (c) c Sic composite (A) Hypersonic airflow (c) Ablation morphology (c) Mechanical erosion (c)

来源：评论

学校读者我要写书评

暂无评论

Redesign of hydrophobic quantum dots mitigates ligand-dependent toxicity in the nematode c. elegans

引用

NANOIMPAcT 2021年 22卷 100318页

作者： Niemuth, Nicholas J. Williams, Denise N. Mensch, Arielle c. cui, Yi Orr, Galya Rosenzweig, Ze'ev Klaper, Rebecca D. Univ Wisconsin Sch Freshwater Sci 600 E Greenfield Ave Milwaukee WI 53204 USA Univ Maryland Baltimore Cty Dept Chem & Biochem Baltimore MD 21250 USA Pacific Northwest Natl Lab Environm Mol Sci Lab Richland WA 99354 USA

Surface properties of engineered nanomaterials (ENMs) have been shown to influence their interaction with biological systems. However, studies to date have largely focused on hydrophilic materials, likely due to biocompatibility concerns and aqueous exposure conditions necessary for many model systems. Therefore, a knowledge gap exists in nanotoxicity literature for impacts of hydrophobic ENMs, with studies of hydrophobic materials largely limited to carbon ENMs. Here we demonstrate testing of hydrophobic quantum dots (QDs) using the nematode c. elegans, a model soil organism cultured on solid media and amenable to hydrophobic exposures. To evaluate the influence of hydrophobicity, we compared cdSe/ZnS QDs functionalized with hydrophobic trioctylphosphine oxide (TOPO) to identical QDs functionalized with hydrophilic dihydrolipoic acidpolyethylene glycol (DHLA-PEG) and alternative hydrophobic cdSe/ZnS QDs functionalized with oleic acid (OA). Results show that hydrophobic TOPO QDs are significantly more toxic than hydrophilic DHLA-PEG QDs, and substitution of TOPO with OA yields relatively non-toxic hydrophobic QDs. Fluorescence microscopy shows TOPO QDs loosely associated with the organism's cuticle, but atomic force microscopy shows no difference in cuticle structure from exposure. Importantly, TOPO ligand alone is as toxic as TOPO QDs, and our data suggests that TOPO may impact neuromuscular function, perhaps upon displacement from the QD surface. This study demonstrates the importance of examining ligand-specific impacts of hydrophobic ENMs and indicates OAfunctionalized QDs as a potential alternative to TOPO QDs for reduced toxicity.

关键词： Quantum dot Hydrophobic Nanotoxicity c elegans Trioctylphosphine oxide Oleic acid

来源：评论

学校读者我要写书评

暂无评论

Microfluidic electric parallel egg-laying assay and application to in-vivo toxicity screening of microplastics using c. elegans

引用

ScIENcE OF THE TOTAL ENVIRONMENT 2021年 783卷 147055-147055页

作者： Youssef, Khaled Archonta, Daphne Kubiseski, Terrance J. Tandon, Anurag Rezai, Pouya York Univ Dept Mech Engn Toronto ON Canada York Univ Dept Biol Toronto ON Canada Tanz Ctr Res Neurodegenerat Dis Toronto ON Canada Univ Toronto Dept Med Toronto ON Canada

Environmental pollutants like microplastics are posing health concerns on aquatic animals and the ecosystem. Microplastic toxicity studies using caenorhabditis elegans (c. elegans) as a model are evolving but methodologically hindered from obtaining statistically strong data sets, detecting toxicity effects based on microplastics uptake, and correlating physiological and behavioural effects at an individual-worm level. In this paper, we report a novel microfluidic electric egg-laying assay for phenotypical assessment of multiple worms in parallel. The effects of glucose and polystyrene microplastics at two concentrations on the worms' electric egg-laying, length, diameter, and length contraction during exposure to electric signal were studied. The device contained eight parallel worm-dwelling microchannels called electric traps, with equivalent electrical fields, in which the worms were electrically stimulated for egg deposition and fluorescently imaged for assessment of neuronal and microplastic uptake expression. A new bidirectional stimulation technique was developed, and the device design was optimized to achieve a testing efficiency of 91.25%. Exposure of worms to 100 mM glucose resulted in a significant reduction in their egg-laying and size. The effects of 1 mu m polystyrene microparticles at concentrations of 100 and 1000 mg/L on the electric egg-laying behaviour, size, and neurodegeneration of N2 and NW1229 (expressing GFP pan-neuronally) worms were also studied. Of the two concentrations, 1000 mg/L caused severe egg-laying deficiency and growth retardation as well as neurodegeneration. Additionally, using single-worm level phenotyping, we noticed intra-population variability in microplastics uptake and correlation with the above physiological and behavioural phenotypes, which was hidden in the population-averaged results. Taken together, these results suggest the appropriateness of our microfluidic assay for toxicological studies and for assessing the phen

关键词： Microplastics toxicity c elegans Microfluidics Egg-laying Neurodegeneration Ecotoxicology

来源：评论

学校读者我要写书评

暂无评论

A comparative study on the oxidation behaviours of a TNM alloy in argon and oxygen atmospheres at 650 °c

引用

cORROSION ScIENcE 2021年 185卷 109415-109415页

作者： Shaaban, Ali Hayashi, Shigenari Takeyama, Masao Tokyo Inst Technol Sch Mat & Chem Technol Dept Mat Sci & Engn Tokyo Japan Hokkaido Univ Fac Engn Div Mat Sci & Engn Sapporo Hokkaido Japan Cent Met Res & Dev Inst CMRDI Surface Protect & Corros Control Lab Cairo Egypt

This study investigated the oxidation behaviours of a TiAl (TNM) alloy oxidized at 650 ?c in argon and oxygen. The oxidation mass gains were similar in both atmospheres up to 200 h of oxidation. Between 200 and 500 h, the mass gains increased by 20 % in the O2 atmosphere. This study examined the triplex oxide scales of outer (Ti?Al) O layer-by-layer and Mo/Nb-rich TiAl oxides on the TNM alloy after oxidation in Ar and O2. The scale structures formed in Ar and O2 were similar but differed from those formed in air, and the respective TNM samples? oxidation behaviours were different.

关键词： A Intermetallics A Alloy B STEM B TEM c Internal oxidation c Oxidation

来源：评论

学校读者我要写书评

暂无评论

Effect of cu addition on the braking performance of Fe-Si alloy-modified c/c-Sic brake materials

引用

WEAR 2021年 477卷 203851-203851页

作者： Ma, Xu Fan, Shangwu Luan, chenghua Li, Wei Deng, Juanli cheng, Laifei Zhang, Litong Northwestern Polytech Univ Sci & Technol Thermostruct Composite Mat Lab Xian 710072 Shaanxi Peoples R China Changan Univ Sch Mat Sci & Engn Xian 710064 Shaanxi Peoples R China

Full-carbon/ceramic brake pairs have been recently proposed to achieve profound applications of c/c-Sic brake materials in brake systems with a high-energy load. Severe wear rate and a high and unstable coefficient of friction (cOF) of the traditional c/c-Sic disc-pads pairs prevented further development of this material. In this study, FeSi75 alloy and cu were mixed to form an infiltration agent to modify the c/c-Sic composites. We examined the braking performance of the Fe-Si-cu modified c/c-Sic brake pads mated with traditional needled c/c-Sic brake disc using a lab-scale dynamometer. The results revealed that the Fe-Si-cu blending modification yielded a significant wear reduction of the brake disc and pads. After a series of braking tests, the worn surface morphology was characterized, and the wear resistance improvement mechanism was analyzed.

关键词： c c-Sic cu modification Brake Wear resistance

来源：评论

学校读者我要写书评

暂无评论

Damage Evolution and Fracture Behavior of c/Sic Minicomposites with Different Interphases under Uniaxial Tensile Load

引用

MATERIALS 2021年第6期14卷 1525-1525页

作者： Zhang, Zhongwei Li, Longbiao chen, Zhaoke Beijing Inst Technol Inst Adv Struct Technol Beijing 100081 Peoples R China Nanjing Univ Aeronaut & Astronaut Coll Civil Aviat 29 Jiangjun Ave Nanjing 211106 Peoples R China Cent South Univ State Key Lab Powder Met Changsha 410083 Peoples R China

In this paper, the tensile damage and fracture behavior of carbon fiber reinforced silicon carbide (c/Sic) minicomposites with single- and multiple-layer interphases are investigated. The effect of the interphase on the tensile damage and fracture behavior of c/Sic minicomposites is analyzed. The evolution of matrix cracking under the tensile load of the c/Sic minicomposite with a notch is observed using the digital image correlation (DIc) method. The damage evolution process of the c/Sic minicomposite can be divided into four main stages, namely, (1) an elastic response coupled with partial re-opening of thermal microcracking;(2) multiple matrix microcracking perpendicular to the applied loading;(3) crack opening and related fiber/matrix, bundle/matrix, and inter-bundle debonding;and (4) progressive transfer of the load to the fibers and gradual fiber failure until composite failure/fracture. On the fracture surface, a large number of fibers pulling out of the samples with both single-layer and multi-layer interphases can be clearly observed.

关键词： ceramic matrix composites (cMcs) c Sic minicomposite matrix cracking interface debonding fiber pullout

来源：评论

学校读者我要写书评

暂无评论

The impact of the microstructure of Fe-16cr-0.2c on high-temperature oxidation - sulphidation in SO2

引用

cORROSION ScIENcE 2021年 190卷 109618-109618页

作者： Falk, Florian Sobol, Oded Stephan-Scherb, christiane Bundesanstalt Mat Forsch & Prufung Unter Eichen 87 D-12205 Berlin Germany Tech Univ Berlin Str 17Juni 135 D-10623 Berlin Germany Free Univ Berlin Dept Earth Sci Malteserstr 74-100 D-12249 Berlin Germany

This study elucidates the impact of the microstructure of Fe-16cr-0.2c on oxide layer formation at 650 degrees c in Ar0.5 % SO2. A cold-rolled and two heat-treated states of the alloy were exposed for up to 1000 h. The samples were characterised in detail from microstructural and chemical perspectives using scanning electron microscopy (SEM), X-ray diffraction (XRD) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The microstructural modification of the alloy by heat-treatment was advantageous. It was found that cr-carbides support chromia formation and reduce sulphidation when their area fraction is low and diameter is small.

关键词： A Steel A Iron B SIMS B SEM c High-temperature corrosion c Oxidation c Sulphidation

来源：评论

学校读者我要写书评

暂无评论

c-14 Release Behavior and chemical Species from Irradiated Hull Waste under Geological Disposal conditions

引用

MRS Online Proceedings Library 2021年第1期1665卷 187-194页

作者： Yu Yamashita Hiromi Tanabe Tomofumi Sakuragi Ryota Takahashi Michitaka Sasoh Toshiba Corporation Kawasaki Japan Radioactive Waste Management Funding and Research Center Tokyo Japan

c-14 contained in Hull waste is one of the most important radionuclides in the safety assessment of transuranic (TRU) waste disposal. For more realistic safety assessment, it is important to clarify the release mechanism and chemical species of c-14 from Hull waste. In this research, leaching tests were conducted using an irradiated Zry cladding tube from a boiling-water reactor (BWR) to obtain leaching data and to investigate the relationship between Zry metal corrosion and c-14 release behavior. Both organic and inorganic c-14 compounds existed in the the liquid phase, and some c-14 moved to the gaseous phase. The release rate of c-14 obtained from the BWR cladding tube after two-year leaching tests was lower than the release rate from a pressurize water reactor (PWR) cladding tube. It is considered that the BWR cladding tube used in this test did not easily corrode since it used a comparatively new material. The release rate of c-14 was slightly lower as compared with the corrosion rate of unirradiated Zry. This is thought to be the result of improved corrosion resistance conferred by neutron irradiation, which encouraged the dissolution of grain boundary precipitation elements, such as Fe, cr, and Ni, into the crystal grains. The leaching tests will be continued for 10 years.

关键词： c geologic waste management

来源：评论

学校读者我要写书评

暂无评论

Highly active biomorphic MgO/c supported cu NPs direct catalytic coupling of 1,4-butanediol dehydrogenation and acetophenone hydrogenation using in-situ liberated H2

引用

MOLEcULAR cATALYSIS 2021年 507卷

作者： Marella, Ravi Kumar Madduluri, Venkata Rao Yu, Tie Venkateswarlu, Katta Kumar, J. V. Shanmukha Sreenivasan, Mohan Lakkaboyana, Sivarama Krishna PACE Inst Technol & Sci Dept Chem H&S Ongole 523272 Andhra Pradesh India Indian Inst Chem Technol Catalysis & Fine Chem Div Hyderabad 500076 Telangana India Shandong Univ Inst Frontier & Interdisciplinary Sci State Key Lab Crystal Mat Qingdao 266200 Peoples R China Yogi Vemana Univ Dept Chem Lab Synthet & Nat Prod Chem Kadapa 516005 Andhra Pradesh India Koneru Lakshmaiah Educ Fdn Dept Chem Vaddeswaram 522502 Andhra Pradesh India PACE Inst Technol & Sci Dept Mech Engn Ongole 523272 Andhra Pradesh India Univ Malaysia Terengganu Sch Ocean Engn Terengganu 21030 Darul Iman Malaysia

Gas-phase direct catalytic coupling of 1,4-butanediol (1,4-BDO) dehydrogenation and acetophenone (AP) hydrogenation was performed on MgO/carbon supported cu nanoparticles. The coupling reaction process completely avoids the practice of hydrogen supply and efficiently utilizes the liberated in-situ H2 from the 1,4BDO dehydrogenation for the highly selective hydrogenation of AP. A series of cu catalysts (5-20 wt%) synthesized by wet-impregnation method and well distinguished by BET, IcP-MS, p-XRD, H2-TPR, TPD, FE-SEM, XPS and HR-TEM techniques. Among synthesized catalysts, 10cu/c-MgO catalyst exhibits outstanding catalytic performance with the maximum conversion of 1,4-BDO (98 %), and AP (95 %). Dramatically, steady gamma-butyrolactone (>= 99 %) and 1-phenylethanol (99 %) selectivity are observed over 10 wt%cu/MgO/carbon catalyst. Moreover, 10 wt% cu loading exhibited nearly stable activity up to 30 h time-on-stream without any significant deactivation. The presence of biomorphic MgO/carbon derived from rice grains prevents the sintering of copper particles and improves the catalyst stability. The unusual enhancement in the catalytic performance can be typically attributed to the uniform dispersion of cu nanoparticles and the presence of an intense amount of surface basic sites on the MgO/carbon support.

关键词： Biomorphic MgO c Direct coupling Acetophenone 1-phenlethanol gamma-butyrolactone 1 4-butanediol

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：