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Modeling and simulating of reservoir operation using the artificial neural network, support vector regression, deep learning algorithm
Reservoirs and dams are vital human-built infrastructures that play essential roles in flood control, hydroelectric power generation, water supply, navigation, and other functions. The realization of those functions requires efficient reservoir operation, and the effective controls on the outflow from a reservoir or dam. Over the last decade, artificial intelligence (AI) techniques have become increasingly popular in the field of streamflow forecasts, reservoir operation planning and scheduling approaches. In this study, three AI models, namely, the backpropagation (BP) neural network, support vector regression (SVR) technique, and long short-term memory (LSTM) model, are employed to simulate reservoir operation at monthly, daily, and hourly time scales, using approximately 30 years of historical reservoir operation records. This study aims to summarize the influence of the parameter settings on model performance and to explore the applicability of the LSTM model to reservoir operation simulation. The results show the following: (1) for the BP neural network and LSTM model, the effects of the number of maximum iterations on model performance should be prioritized; for the SVR model, the simulation performance is directly related to the selection of the kernel function, and sigmoid and RBF kernel functions should be prioritized; (2) the BP neural network and SVR are suitable for the model to learn the operation rules of a reservoir from a small amount of data; and (3) the LSTM model is able to effectively reduce the time consumption and memory storage required by other AI models, and demonstrate good capability in simulating low-flow conditions and the outflow curve for the peak operation period
Active optical clock based on four-level quantum system
Active optical clock, a new conception of atomic clock, has been proposed
recently. In this report, we propose a scheme of active optical clock based on
four-level quantum system. The final accuracy and stability of two-level
quantum system are limited by second-order Doppler shift of thermal atomic
beam. To three-level quantum system, they are mainly limited by light shift of
pumping laser field. These limitations can be avoided effectively by applying
the scheme proposed here. Rubidium atom four-level quantum system, as a typical
example, is discussed in this paper. The population inversion between
and states can be built up at a time scale of s.
With the mechanism of active optical clock, in which the cavity mode linewidth
is much wider than that of the laser gain profile, it can output a laser with
quantum-limited linewidth narrower than 1 Hz in theory. An experimental
configuration is designed to realize this active optical clock.Comment: 5 page
The 7-channel FIR HCN Interferometer on J-TEXT Tokamak
A seven-channel far-infrared hydrogen cyanide (HCN) laser interferometer has
been established aiming to provide the line integrated plasma density for the
J-TEXT experimental scenarios. A continuous wave glow discharge HCN laser
designed with a cavity length 3.4 m is used as the laser source with a
wavelength of 337 {\mu}m and an output power up to 100 mW. The system is
configured as a Mach-Zehnder type interferometer. Phase modulation is achieved
by a rotating grating, with a modulation frequency of 10 kHz which corresponds
to the temporal resolution of 0.1 ms. The beat signal is detected by TGS
detector. The phase shift induced by the plasma is derived by the comparator
with a phase sensitivity of 0.06 fringe. The experimental results measured by
the J-TEXT interferometer are presented in details. In addition, the inversed
electron density profile done by a conventional approach is also given. The
kinematic viscosity of dimethyl silicone and vibration control is key issues
for the system performance. The laser power stability under different kinematic
viscosity of silicone oil is presented. A visible improvement of measured
result on vibration reduction is shown in the paper.Comment: conference (15th-International Symposium on Laser-Aided Plasma
Diagnostics
GaSb quantum rings in GaAs/AlxGa1−xAs quantum wells
We report the results of continuous and time-resolved photoluminescence measurements on type-II GaSb quantum rings embedded within GaAs/AlxGa1-xAs quantum wells. A range of samples were grown with different well widths, compensation-doping concentrations within the wells, and number of quantum-ring layers. We find that each of these variants have no discernible effect on the radiative recombination, except for the very narrowest (5 nm) quantum well. In contrast, singleparticle numerical simulations of the sample predict changes in photoluminescence energy of up to 200 meV. This remarkable difference is explained by the strong Coulomb binding of electrons to rings that are multiply charged with holes. The resilience of the emission to compensation doping indicates that multiple hole occupancy of the quantum rings is required for efficient carrier recombination, regardless of whether these holes come from doping or excitation
Mapping QTLs for mineral element contents in brown and milled rice using an Oryza sativa × O. rufipogon backcross inbred line population
Biofortifying food crops with essential minerals would help to alleviate mineral deficiencies in humans. Detection of quantitative trait loci (QTLs) for mineral nutrient contents in rice was conducted using backcross inbred lines derived from an interspecific cross of Oryza sativa × O. rufipogon. The population was grown in Hangzhou and Lingshui, with the contents of Mg, Zn, Fe, Mn, Cu and Se in brown rice measured in both trials and that in milled rice tested in Hangzhou only. A total of 24 QTLs for mineral element contents were identified, including two for both the brown and milled rice, 17 for brown rice only, and five for milled rice only. All the seven QTLs detected for the mineral contents in milled rice and 13 of the 19 QTLs for the contents in brown rice had the enhancing alleles derived from O. rufipogon. Fifteen QTLs were clustered in seven chromosomal regions, indicating that common genetic-physiological mechanisms were involved for different mineral nutrients and the beneficial alleles could be utilized to improve grain nutritional quality by markerassisted selection
Numerical simulation of water waves interacting with elastic ice floes
摘要:本文围绕弹性冰群与波浪相互作用问题,建立了基于 OpenFOAM 开源软件的数值
计算模型,实现了流体与弹性浮冰耦合运动的双向迭代求解,并以规则波与两片弹性浮冰
的相互作用为例,分析了浮冰间距和浮冰刚度等参数对二维波浪传播特性的影响。研究发
现,在所考虑的参数范围内,刚度越大、间距越小的两块浮冰,对应的波浪反射系数越小、
透射系数越大,并且波浪反射系数的减小幅度大于透射系数的增加幅度。
关键词:OpenFOAM;流固耦合;浮冰;波物作用;水弹
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