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排序方式: 共有346条查询结果,搜索用时 31 毫秒
251.
252.
Xander F. van Kooten Lorenzo F. T. Petrini Aditya Kashyap Lena Voith von Voithenberg Moran Bercovici Govind V. Kaigala 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(43):15403-15406
We have developed a method for spatially resolved genetic analysis of formalin‐fixed paraffin‐embedded (FFPE) cell block and tissue sections. This method involves local sampling using hydrodynamic flow confinement of a lysis buffer, followed by electrokinetic purification of nucleic acids from the sampled lysate. We characterized the method by locally sampling an array of points with a circa 200 μm diameter footprint, enabling the detection of single KRAS and BRAF point mutations in small populations of RKO and MCF‐7 FFPE cell blocks. To illustrate the utility of this approach for genetic analysis, we demonstrate spatially resolved genotyping of FFPE sections of human breast invasive ductal carcinoma. 相似文献
253.
The effective viscosity of a dilute emulsion of spherical drops containing a soluble surfactant is calculated under a linear creeping flow. It is assumed that convection of surfactant is small relative to diffusion, and thus the Peclet number, Pe, is small. We calculate the effective viscosity of the emulsion to \(\mathcal {O}(Pe\phi \mu )\), where ? is the small volume fraction of the dispersed drops and μ is the viscosity of the surfactant-free suspending fluid. This \(\mathcal {O}(Pe\phi \mu )\) contribution is a sensitive function of the bulk and interfacial surfactant transport. Specifically, soluble surfactant molecules diffuse from the bulk to the interface and then adsorb to the interface. The ratio of the time scale for bulk diffusion to the time scale for adsorption to the interface is quantified by a Damkohler number, Da. The adsorption of surfactant to the interface may cause a significant decrease in the bulk concentration, which is known as depletion. The impact of depletion is characterized by two parameters: h, which is a dimensionless depletion depth; and k, which is the ratio of the desorption time scale to the adsorption time scale. We analytically determine how the \(\mathcal {O}(Pe\phi \mu )\) contribution to the effective viscosity depends on h, k, and Da. Surprisingly, for certain regimes in the h ? k ? Da parameter space, we predict the effective viscosity of the emulsion to be greater than Einstein’s result for the viscosity of a suspension of rigid spheres. Large Marangoni stresses driven by convective transport of soluble surfactant molecules are responsible for this result. 相似文献
254.
Chien‐Pin Chou Aditya Wibawa Sakti Yoshifumi Nishimura Hiromi Nakai 《Chemical record (New York, N.Y.)》2019,19(4):746-757
The density‐functional tight‐binding (DFTB) method is one of the useful quantum chemical methods, which provides a good balance between accuracy and computational efficiency. In this account, we reviewed the basis of the DFTB method, the linear‐scaling divide‐and‐conquer (DC) technique, as well as the parameterization process. We also provide some refinement, modifications, and extension of the existing parameters that can be applicable for lithium‐ion battery systems. The diffusion constants of common electrolyte molecules and LiTFSA salt in solution have been estimated using DC‐DFTB molecular dynamics simulation with our new parameters. The resulting diffusion constants have good agreement to the experimental diffusion constants. 相似文献
255.
Shiraiwa S Ide S Itoh S Mitarai O Naito O Ozeki T Sakamoto Y Suzuki T Takase Y Tanaka S Taniguchi T Aramasu M Fujita T Fukuda T Gao X Gryaznevich M Hanada K Jotaki E Kamada Y Maekawa T Miura Y Nakamura K Nishi T Tanaka H Ushigusa K;JT- Team 《Physical review letters》2004,92(3):035001
A new operational scenario of advanced tokamak formation was demonstrated in the JT-60U tokamak. This was accomplished by electron cyclotron and lower hybrid waves, neutral beam injection, and the loop voltage supplied by the vertical field and shaping coils. The Ohmic heating (OH) solenoid was not used but a small inboard coil (part of the shaping coil), providing less than 20% of total poloidal flux, was used. The plasma thus obtained had both internal and edge transport barriers, with an energy confinement time of 1.6 times H-mode scaling, a poloidal beta of 3.6, and a normalized beta of 1.6, and a large bootstrap current fraction (>90%). This result opens up a possibility to reduce, and eventually eliminate, the OH solenoid from a tokamak reactor, which will greatly improve its economic competitiveness. 相似文献
256.
Kirk A Wilson HR Counsell GF Akers R Arends E Cowley SC Dowling J Lloyd B Price M Walsh M;MAST Team 《Physical review letters》2004,92(24):245002
This Letter provides information on the spatial and temporal structure of periodic eruptions observed in magnetically confined laboratory fusion plasmas, called edge-localized modes (ELMs), and highlights similarities with solar eruptions. Taken together, the observations presented in this Letter provide strong evidence for ELMs being associated with a filamentlike structure. These filaments are extended along a field line, are generated on a 100 micros time scale, erupt from the outboard side, and connect back into the plasma. Such structures are predicted by a theoretical model based on the "ballooning" instability, developed for both solar and tokamak applications. 相似文献
257.
Greenfield CM Burrell KH DeBoo JC Doyle EJ Stallard BW Synakowski EJ Fenzi C Gohil P Groebner RJ Lao LL Makowski MA McKee GR Moyer RA Rettig CL Rhodes TL Pinsker RI Staebler GM West WP;DIII-D Team 《Physical review letters》2001,86(20):4544-4547
A new sustained high-performance regime, combining discrete edge and core transport barriers, has been discovered in the DIII-D tokamak. Edge localized modes (ELMs) are replaced by a steady oscillation that increases edge particle transport, thereby allowing particle control with no ELM-induced pulsed divertor heat load. The core barrier resembles those usually seen with a low (L) mode edge, without the degradation often associated with ELMs. The barriers are separated by a narrow region of high transport associated with a zero crossing in the E x B shearing rate. 相似文献
258.
Hobirk J Wolf RC Gruber O Gude A Günter S Kurzan B Maraschek M McCarthy PJ Meister H Peeters AG Pereverzev GV Stober J Treutterer W;ASDEX Upgrade Team 《Physical review letters》2001,87(8):085002
In the ASDEX Upgrade tokamak, high poloidal beta up to beta(pol) = 3 at the Greenwald density with H-mode confinement has been reached. Because of the high beta, the plasma current is driven almost fully noninductively, consisting of 51% bootstrap and 43% neutral beam driven current. To reach these conditions the discharge is operated at low plasma current ( I(P) = 400 kA) and high neutral beam heating power ( P(NBI) = 10 MW). The discharge combines an edge (H mode) and internal transport barrier at high densities without confinement-limiting MHD activities. The extrapolation to higher plasma currents may offer a promising way for an advanced scenario based fusion reactor. 相似文献
259.
Ryter F Leuterer F Pereverzev G Fahrbach HU Stober J Suttrop W;ASDEX Upgrade Team 《Physical review letters》2001,86(11):2325-2328
Energy transport by the electrons in a tokamak is examined in steady-state and power modulation experiments using electron cyclotron heating. The results are consistent with the assumption that temperature profiles are limited by a critical gradient length, leading to "stiff" profiles. The modulation experiments show that the stiffness factor increases with temperature. They strongly suggest that turbulence driven by the electron temperature gradient may be a dominant mechanism of electron transport. Although possibly not universal, these results are valid under various plasma conditions. 相似文献
260.
Leonid G. Eliseev Alexander V. Melnikov Ludmila I. Krupnik HIBP Team 《Czechoslovak Journal of Physics》2000,50(12):1413-1420
Heavy Ion Beam Probe diagnostics was used to study plasma potential and density in the regimes with improvement in confinement
on the T-10 tokamak. Time-spatial potential distribution was analyzed during the formation of transport barriers. The time
evolution of the potential profile shows simultaneous formation of the internal negative potential well and external layer
with strong Er, during the simultaneous formation of the internal and external transport barriers. The time history of the
plasma potential in the inner region (0.6<ρ<1) shows its clear correlation with theD
α intensity.
Presented at the Workshop on the Role of Electric Fields in Plasma Confinement and Exhaust, Budapest, 18–19 June, 2000.
This work was supported by Russian Basic Research Foundation, Grant No. 99-02-18457. 相似文献