12,557 research outputs found
On the role of initial and boundary conditions in numerical simulations of accretion flows
We study the effects of initial and boundary conditions, taking
two-dimensional hydrodynamical numerical simulations of hot accretion flow as
an example. The initial conditions considered include a rotating torus, a
solution expanded from the one-dimensional global solution of hot accretion
flows, injected gas with various angular momentum distributions, and the gas
from a large-scale numerical simulation. Special attention is paid to the
radial profiles of the mass accretion rate and density. Both can be described
by a power-law function, and . We find
that if the angular momentum is not very low, the value of is not sensitive
to the initial condition and lies within a narrow range, 0.47\la s \la 0.55.
However, the value of is more sensitive to the initial condition and lies
in the range 0.48\la p \la 0.8. The diversity of the density profile is
because different initial conditions give different radial profiles of radial
velocity due to the different angular momentum of the initial conditions. When
the angular momentum of the accretion flow is very low, the inflow rate is
constant with radius. Taking the torus model as an example, we have also
investigated the effects of inner and outer boundary conditions by considering
the widely adopted "outflow" boundary condition and the "mass flux
conservation" condition. We find that the results are not sensitive to these
two boundary conditions.Comment: 10 pages, 15 figures, accepted by MNRA
Robust Tickets Can Transfer Better: Drawing More Transferable Subnetworks in Transfer Learning
Transfer learning leverages feature representations of deep neural networks
(DNNs) pretrained on source tasks with rich data to empower effective
finetuning on downstream tasks. However, the pretrained models are often
prohibitively large for delivering generalizable representations, which limits
their deployment on edge devices with constrained resources. To close this gap,
we propose a new transfer learning pipeline, which leverages our finding that
robust tickets can transfer better, i.e., subnetworks drawn with properly
induced adversarial robustness can win better transferability over vanilla
lottery ticket subnetworks. Extensive experiments and ablation studies validate
that our proposed transfer learning pipeline can achieve enhanced
accuracy-sparsity trade-offs across both diverse downstream tasks and sparsity
patterns, further enriching the lottery ticket hypothesis.Comment: Accepted by DAC 202
Factors influencing Collaborative Communication in Virtual Teams
Collaborative communication has properties different from face to face communication. For instance team can generate ideas, manage information that are beyond the skills of any single team member. In this paper we examine factors that can influence collaborative communication in virtual teams. To study this we used a survey method across various organizations in China. We collected data to get responses from managers and experts engaged in collaborative efforts for product design developments in virtual environments. We conducted factor analysis and used the mean value of factors to test our hypothesis. We found that in the Chinese context, the significant factors were: constructs of team collaboration; information technology support and training; clear descriptions of team objectives and of tasks to be accomplished. Our results show that collaborative communication in collaborative virtual team environment is guided both by the global competition as well as indigenous and institutional pressures. Managers view decision making as a business issue in a globally competitive environment
Tetraaquabis[2-(2,4-dichlorophenoxy)acetato]nickel(II)
In the title complex, [Ni(C8H5Cl2O3)2(H2O)4], the NiII atom (site symmetry ) adopts a slightly distorted NiO6 octahedral coordination. An intramolecular O—H⋯O hydrogen bond helps to establish the conformation. In the crystal, further O—H⋯O hydrogen bonds link the molecules
Novel Microfiber Sensor and Its Biosensing Application for Detection of hCG Based on a Singlemode-Tapered Hollow Core-Singlemode Fiber Structure
A novel microfiber sensor is proposed and demonstrated based on a singlemode-tapered hollow core -singlemode (STHS) fiber structure. Experimentally a STHS with taper waist diameter of 26.5 μm has been fabricated and RI sensitivity of 816, 1601.86, and 4775.5 nm/RIU has been achieved with RI ranges from 1.3335 to 1.3395 , from 1.369 to 1.378, and from 1.409 to 1.4175 respectively, which agrees very well with simulated RI sensitivity of 885, 1517, and 4540 nm/RIU at RI ranges from 1.3335 to 1.337, from 1.37 to 1.374, and from 1.41 to 1.414 . The taper waist diameter has impact on both temperature and strain sensitivity of the sensor structure: (1) the smaller the waist diameter, the higher the temperature sensitivity, and experimentally 26.82 pm/°C has been achieved with a taper waist diameter of 21.4 μm; (2) as waist diameter decrease, strain sensitivity increase and 7.62 pm/με has been achieved with a taper diameter of 20.3 μm. The developed sensor was then functionalized for human chorionic gonadotropin (hCG) detection as an example for biosensing application. Experimentally for hCG concentration of 5 mIU/ml, the sensor has 0.5 nm wavelength shift, equivalent to limit of detection (LOD) of 0.6 mIU/ml by defining 3 times of the wavelength variation (0.06 nm) as measurement limit. The biosensor demonstrated relatively good reproducibility and specificity, which has potential for real medical diagnostics and other applications
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