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Photo-Induced Spin Dynamics in Nanoelectronic Devices

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Chinese Physics Letters 2012年第10期29卷 248-252页

作者： Mina D.Asham Walid A.Zein adel h.phillips Faculty of Engineering Benha UniversityBenhaEgypt Faculty of Engineering Ain-Shams UniversityCairoEgypt

The present research is devoted to the investigation of electron spin transmission through a nanoelectronic *** device is modeled as nonmagnetic semiconductor quantum dot coupled to two diluted magnetic semiconductor *** spin transport characteristics through such a device are investigated under the effect of an ac-field of a wide range of *** present result shows a periodic oscillation of the conductance for both the cases of parallel and antiparallel spin *** oscillations are due to *** for spin polarization and giant magneto-resistance show the coherency *** present research might be useful for developing single spin-based quantum bits(qubits)required for quantum information processing and quantum spin-telecommunication.

关键词： property quantum electronic

Carbon nanotube-based nanoelectromechanical resonatoras mass biosensor

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Chinese Physics B 2020年第7期29卷 583-587页

作者： Ahmed MElseddawy adel hphillips Ahmed S Bayoumi Faculty of Graduate Studies University of WindsorWindsorOntarioCanada Faculty of Engineering Ain-Shams UniversityCairoEgypt Faculty of Engineering Kafr-Elsheikh UnversityKafr-ElsheikhEgypt

The use of single walled carbon nanotube-based nanoelectromechanical system(NEMS)resonator to sense the biomolecules'mass is investigated under the influence of an external ac-field.A single walled carbon nanotube(SWCNT)cantilever has been proposed and studied if the mass is attached at the tip or various intermediate *** shift of the resonant frequency and the quality factor have been investigated and show high sensitivity to the attached mass of biomolecule and its *** proposed SWCNT-based NEMS resonator is a good candidate for sensing and tracing biomolecules'mass as concentration of acetone in human exhale,resulting in a painless,correct,and simple diabetics'diagnosis.

关键词： single walled carbon nanotube nanoelectromechanical system resonator ac-field biomolecule

Nanofabricated high turn-density spiral coils for on-chip electromagneto-optical conversion

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Microsystems & Nanoengineering 2024年第2期10卷 181-192页

作者： Ilhan Bok Alireza Ashtiani Yash Gokhale Jack phillips Tianxiang Zhu Aviad hai Department of Biomedical Engineering University of Wisconsin–MadisonMadisonWIUSA Department of Electrical and Computer Engineering University of Wisconsin–MadisonMadisonWIUSA Wisconsin Institute for Translational Neuroengineering(WITNe) University of Wisconsin–MadisonMadisonWIUSA

Circuit-integrated electromagnets are fundamental building blocks for on-chip signal transduction,modulation,and tunability,with specific applications in environmental and biomedical micromagnetometry.A primary challenge for improving performance is pushing quality limitations while minimizing size and fabrication complexity and retaining spatial *** efforts have exploited highly involved three-dimensional synthesis,advanced insulation,and exotic material ***,we present a rapid nanofabrication process that employs electron beam dose control for high-turn-density diamond-embedded flat spiral coils;these coils achieve efficient on-chip electromagnetic-to-optical signal *** fabrication process relies on fast 12.3 s direct writing on standard poly(methyl methacrylate)as a basis for the metal lift-off *** with 70 micrometer overall diameters and 49–470 nm interturn spacings with corresponding inductances of 12.3–12.8 nh are *** utilize optical micromagnetometry to demonstrate that magnetic field generation at the center of the structure effectively correlates with finite element modeling *** designs based on our process can be integrated with photolithography to broadly enable optical magnetic sensing and spin-based computation.

关键词： utilize retaining high

Synthesis,Structures,and Chiroptical Properties of NBN-Doped helicenes with Boron Atoms in the Inner Rims

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Precision Chemistry 2024年第1期2卷 28-39页

作者： Weiwen Zhuang Yujian Liu Ziqi Deng Yu Guo Philip C.Y.Chow David Lee phillips Wei Jiang Zhaohui Wang Junzhi Liu State Key Laboratory of Synthetic Chemistry HKU-CAS Joint Laboratory on New Materials and Department of ChemistryThe University of Hong KongPokfulamHong KongChina Key Laboratory of Organic Optoelectronics and Molecular Engineering Department of ChemistryTsinghua UniversityBeijing 100084China Department of Mechanical Engineering The University of Hong KongPokfulamHong KongChina

The precise synthesis of helicenes with topologically defined length and specific heteroatomic perturbation in the screw-like conjugated skeletons plays an emerging role in the manipulation of chiral ***,selective,and programmable routes to helicenes or heterohelicenes are highly desirable yet challenging for structure-chiroptical property relationship ***,we report the synthesis and characterization of NBN-doped helicenes with boron atoms in the inner rims,enabled by the highly regioselective one-pot borylation of rationally designed precursors with,namely,fold-in or pan-out *** incorporation of nonbonded boron and nitrogen atoms resulted in narrow-band emission and improved optical properties for the single-stranded carbon *** addition,numbers and arrangement modes of fused six-membered rings have distinct effects on configurational stability and chiroptical properties,revealing that BN-[6]h with strong circular dichroism is a promising candidate for chiral *** combination of experimental and theoretical studies on these helical structures might provide insights into the design of helically chiral small-molecule-based sensors or emitters.

关键词： Nitrogen-boron helicenes Borylation Chiroptical properties Narrow-band emission

Thermodynamics Properties of Mesoscopic Quantum Nanowire Devices

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Chinese Physics Letters 2007年第5期24卷 1339-1341页

作者： Attia A. AwadAlla adel h. phillips Department of Physics Faculty of Science Beni-Suef University Beni-Suef Egypt Department of Physics and Department of Mathematics Faculty of Engineering Ain Shams University Egypt

We investigate the thermodynamics properties of mesoscopic quantum nanowire devices, such as the effect of electron-phonon relaxation time, Peltier coefficient, carrier concentration, frequency of this field, and channel width. The influence of time-varying fields on the transport through such device has been taken into consideration. This device is modelled as nanowires connecting to two reservoirs. The two-dimensional electron gas in a GaAs- AlGaAs heterojunction has a Fermi wave length which is a hundred times larger than that in a metal. The results show the oscillatory behaviour of dependence of the thermo power on frequency of the induced field. These results agree with the existing experiments and may be important for electronic nanodevices.

关键词： ThERMOPOWER TRANSPORT

Thermal 9hot Noise through Boundary Roughness of Carbon Nanotube Quantum Dots

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Chinese Physics Letters 2011年第1期28卷 186-189页

作者： Attia A. Awadalla adel h. phillips Department of Physics Faculty of Science Beni-Suef University Beni-Suef Egypt Department of Engineering Physics and Mathematics Faculty of Engineering Ain Shams University Cairo Egypt

Thermal shot noise, thermal voltage and thermo power are studied through a carbon nanotube quantum dot coupled to two leads with random roughness of amplitude on each of the two boundaries, under the effect of microwave field, and magnetic field. The expressions for the thermal shot noise and thermal energy are deduced when the barrier strength and contact area are taken into consideration. A model for such mesoscopic devices is proposed as a carbon nanotube quantum dot coupled to two leads with random roughness of amplitude on each of the two boundaries. The results show oscillatory behaviors of the dependence of the thermal shot noise on the studied parameters. The thermopower oscillates with the variation of the contact area, and the peak heights decrease linearly with the contact area and increases with temperature. This trend of behavior is due to the interplay of the induced microwave photons and the tunneling rate through the side bands. This research is important for using a model as a high-frequency shot noise detector and the thermopower is sensitive to the energy dependence of the conductance.

关键词： Noise Energy Carbon Lead Carbonates Carbonation Models Boundaries Fields

Uranium sequestration in sediment at an iron-rich contaminated site at Oak Ridge, Tennessee *** followed by reoxidation

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Journal of Environmental Sciences 2019年第11期31卷 156-167页

作者： Peng-Song Li Wei-Min Wu Debra h.phillips David B.Watson Shelly Kelly Bing Li Tonia Mehlhorn Kenneth Lowe Jennifer Earles hu-Chun Tao Tong Zhang Craig S.Criddle Department of Civil and Environmental Engineering William & Cloy Codiga Resource Recovery Center Center for Sustainable Development & Global Competitiveness Stanford University Stanford CA 94305-4020 USA Key Laboratory for heavy Metal Pollution Control and Reutilization School of Environment and Energy Peking University Shenzhen Graduate School Shenzhen 518055 China Institute of New Energy Technology Tsinghua University Beijing 100084 China School of Natural and Built Environment Queen's University Belfast Belfast BT9 5AG Northern Ireland UK Environmental Sciences Division Oak Ridge National Laboratory Oak Ridge P.O.Box 2008 TN 37831 USA EXAFS Analysis Bolingbrook IL 60440 USA Department of Civil Engineering The University of Hong Kong Hong Kong China

This study evaluated uranium sequestration performance in iron-rich (30 g/kg) sediment via bioreduction followed by *** tests (1383 days) at Oak Ridge,Tennessee demonstrated that uranium contents in sediments increased after bioreduced sediments were re-exposed to nitrate and oxygen in contaminated *** of contaminated sediments (1200 mg/kg U) with ethanol in microcosm reduced aqueous U from 0.37 to 0.023 mg/*** of the bioreduced sediment were reoxidized with O2,h2O2,and NaNO3,respectively,over 285 days,resulting in aqueous U of 0.024,1.58 and 14.4 mg/L at ph 6.30,6.63 and 7.62,*** source-and the three reoxidized sediments showed different desorption and adsorption behaviors of U,but all fit a Freundlich *** adsorption capacities increased sharply at ph 4.5 to 5.5,plateaued at ph 5.5 to 7.0,then decreased sharply as ph increased from 7.0 to *** O2-reoxidized sediment retained a lower desorption efficiency at ph over *** NO3--reoxidized sediment exhibited higher adsorption capacity at ph 5.5 to *** ph-dependent adsorption onto Fe(Ⅲ) oxides and formation of U coated particles and precipitates resulted in U sequestration,and bioreduction followed by reoxidation can enhance the U sequestration in sediment.

关键词： Sediments Uranium Sequestration Bioreduction Reoxidation

The formation of orthogonal joint systems and cuboidal blocks:New insights gained from flat-lying limestone beds in the region of havre-Saint-Pierre(Quebec,Canada)

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第12期15卷 3079-3093页

作者： Shaocheng Ji Yvéric Rousseau Denis Marcotte Noah John phillips Département des Génies Civil Géologique et des MinesÉcole Polytechnique de MontréalMontréalQuébecH3C 3A7Canada Department of Geology Lakehead UniversityThunder BayOntarioP7B 5E1Canada

Vertical orthogonal joints are a common feature in shallow crustal *** are several competing theories for their formation despite the *** examined the exceptional exposures of orthogonal joints in flat-lying Ordovician limestone beds from the havre-Saint-Pierre Region in Quebec,Canada(north shore of Saint-Lawrence River)to test conceptual models of joint formation in a natural *** the region,the spacing of cross-joints is consistently larger than the spacing of systematic joints by a factor of 1.5 *** joint-spacing-to-bed-thickness ratios(s/t)are much larger in these beds(s/t=4.3 for systematic joints,and 6.4 for cross-joints)than those in higher strained strata along the south shore of the Saint-Lawrence River(s/t=1),highlighting the effect of tectonic strain in decreasing fracture spacing and block *** high values of s/t indicate that cross-joint formation was unlikely caused by a switch from compression to tension once a critical s/t ratio for systematic joints was reached(as hypothesized in previous studies).We proposed a new model for the formation of orthogonal joint systems where the principal stress axes locally switch during the formation of systematic *** presence of ladder-shaped orthogonal joints suggests a state of effective stress withσ_(1)^(∗)≫0>σ_(2)^(∗)>σ_(3)^(∗)and whereσ_(2)^(∗)-σ_(3)^(∗)is within the range of fracture strength variability at the time of *** research provides a new mechanical model for the formation of orthogonal joint systems and cuboidal blocks.

关键词： Plato's cuboids Orthogonal joints Fracture spacing Limestone Layered rock mechanics Appalachian geology

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远东的水质污染(上)

交通环保 1991年第5期13卷 52-56页

作者： DavidJ .h.phillips Shinsuke Tanade 鲍建国

本文概述了远东地区所面临的水质污染(重点是沿海水污染)问题。由于社会——经济因素的缘故,该地区的发展中国家和发达国家所面临的污染问题的类型有所不同。在发展中国家,适当的污水处理和排放仍然是一个特殊问题,许多国家工业和和农... 详细信息

本文概述了远东地区所面临的水质污染(重点是沿海水污染)问题。由于社会——经济因素的缘故,该地区的发展中国家和发达国家所面临的污染问题的类型有所不同。在发展中国家,适当的污水处理和排放仍然是一个特殊问题,许多国家工业和和农业废水对海洋资源影响明显。

关键词：水质污染沿海水污染藻花内陆水体工业污水有机废物远东地区有机物负荷发展中国家微生物污染