다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology.

Spintronics, or spin electronics, involves the study of active control and manipulation of spin degrees of freedom in solid-state systems. This article reviews the current status of this subject, including both recent advances and well-established results. The primary focus is on the basic physical principles underlying the generation of carrier spin polarization, spin dynamics, and spin-polarized transport in semiconductors and metals. Spin transport differs from charge transport in that spin is a nonconserved quantity in solids due to spin-orbit and hyperfine coupling. The authors discuss in detail spin decoherence mechanisms in metals and semiconductors. Various theories of spin injection and spin-polarized transport are applied to hybrid structures relevant to spin-based devices and fundamental studies of materials properties. Experimental work is reviewed with the emphasis on projected applications, in which external electric and magnetic fields and illumination by light will be used to control spin and charge dynamics to create new functionalities not feasible or ineffective with conventional electronics.

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Spintronics: Fundamentals and applications

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Self-assembled monolayers of thiolates on metals as a form of nanotechnology.

We report the experimental discovery of intrinsic ferromagnetism in Cr 2 Ge 2 Te 6 atomic layers by scanning magneto-optic Kerr microscopy. In this 2D van der Waals ferromagnet, unprecedented control of transition temperature is realized via small magnetic fields.

Discovery of intrinsic ferromagnetism in two-dimensional van der Waals crystals

We polarize nuclear spins in a GaAs double quantum dot by controlling two-electron spin states near the anticrossing of the singlet (S) and mS �� 1 triplet (T� ) using pulsed gates. An initialized S state is

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Dynamic Nuclear Polarization with Single Electron Spins

Double quantum dots (DQDs), sometimes referred to as ``artificial molecules'', are highly controllable quantum systems that serve as building blocks for spin-based quantum computation. A fast, high-fidelity charge sensor is needed for determining the number of electrons trapped in the DQD, and for spin-state readout. Here the authors integrate a Josephson parametric amplifier into the readout chain, improving the signal to noise ratio by a factor of 2000 and enabling live tuning of the DQD potential well, without the slow, painstaking adjustment of voltages on several electrodes.

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Fast Charge Sensing of a Cavity-Coupled Double Quantum Dot Using a Josephson Parametric Amplifier

We report on electron spin resonance measurements of phosphorus donors localized in a 200  μm^{2} area below the inductive wire of a lumped element superconducting resonator. By combining quantum limited parametric amplification with a low impedance microwave resonator design, we are able to detect around 2×10^{4} spins with a signal-to-noise ratio of 1 in a single shot. The 150 Hz coupling strength between the resonator field and individual spins is significantly larger than the 1-10 Hz coupling rates obtained with typical coplanar waveguide resonator designs. Because of the larger coupling rate, we find that spin relaxation is dominated by radiative decay into the resonator and dependent upon the spin-resonator detuning, as predicted by Purcell.

Electron Spin Resonance at the Level of 1 0 4 Spins Using Low Impedance Superconducting Resonators

Driving a direct current through a double quantum dot in a semiconducting nanowire coupled to an optical cavity results in the emission of photons.

Photon emission from a cavity-coupled double quantum dot.

Electrons confined in Si quantum dots possess orbital, spin, and valley degrees of freedom (DOF). We perform Landau-Zener-St\"uckelberg-Majorana (LZSM) interferometry on a Si double quantum dot that is strongly coupled to a microwave cavity to probe the valley DOF. The resulting LZSM interference pattern is asymmetric as a function of level detuning and persists for drive periods that are much longer than typical charge decoherence times. By correlating the LZSM interference pattern with charge-noise measurements, we show that valley-orbit hybridization provides some protection from the deleterious effects of charge noise. Our work opens the possibility of harnessing the valley DOF to engineer charge-noise-insensitive qubits in Si.

Jason R. Petta

Papers

Dynamic Nuclear Polarization with Single Electron Spins

Fast Charge Sensing of a Cavity-Coupled Double Quantum Dot Using a Josephson Parametric Amplifier

Electron Spin Resonance at the Level of 1 0 4 Spins Using Low Impedance Superconducting Resonators

Photon emission from a cavity-coupled double quantum dot.

Landau-Zener interferometry of valley-orbit states in Si/SiGe double quantum dots