52,407 research outputs found
Applicability of Phase-Function Normalization Techniques for Radiation Transfer Computation
No full textThe applicability of recently-developed four phase-function (PF) normalization techniques for modeling radiation transfer in strongly anisotropic scattering media is intensively examined using the discrete-ordinate method. The three simple techniques via normalization of only the forward- and/or backward-scattering directions were shown to reduce normalization complexity whilst retaining diffuse radiation computation accuracy for Henyey-Greenstein (HG) PFs. For Legendre PFs, however, such simple techniques are found to result in unphysical negative PF value at one or few correction direction in some cases. Additionally, negative PF values can occur for these simple techniques for ballistic radiation transfer for both HG and Legendre PF types. If negative-intensity correction is applied, however, radiative heat transfer calculation can still converge regardless of the appearance of negative PF values. The relatively complex Hunter and Guo 2012 technique, in which normalization is realized through a correction matrix covering all discrete directions, is shown to be applicable for diffuse and ballistic radiation for both PF types.Peer reviewed
Processing of figure and background motion in the visual system of the fly
No full textReichardt W, Egelhaaf M, Guo A-K. Processing of figure and background motion in the visual system of the fly. Biological Cybernetics. 1989;61(5):327-345
On the Semilinear Elliptic Equation w-1/2 y . w+ w-w- =0 in Rn
No full textGuo, Jong-Shenq. (1989). On the Semilinear Elliptic Equation w-1/2 y . w+ w-w- =0 in Rn. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/5002
High thermal conductance across c-BN/diamond interface
No full textHigh thermal conductivity electronic components with low interfacial thermal resistance are of technological importance and fundamental interest of research. Diamond, a superhard material with ultrahigh thermal conductivity at room temperature, is desirable for microelectronics thermal management. Cubic polymorph of boron nitride (c-BN) is a promising material due to wide bandgap and diamond like structure and properties. To understand the nature in thermal transport of diamond, c-BN and the most commonly used silicon (Si) semiconductor, ab initio phonon Boltzmann transport equations are employed to investigate lattice vibrational properties of these three materials. At 300 K, the predicted thermal conductivity of Si, diamond and c-BN reached 142, 2112, and 736 W/(m·K), respectively. What's more, heat transport phenomena across the interfaces of Si/diamond, c-BN/diamond and Si/c-BN are unfolded. In comparison, the interfacial thermal conductance of c-BN/diamond is ten-fold of Si/diamond; besides, the thermal conductance across Si/c-BN interface is 20.2% larger than that of Si/diamond at 300 K and 18.9% larger at 340 K. These findings provide us new vision and potential solution to heat dissipation of high-local-power density devices, shedding light on future thermal management of c-BN and diamond related electronics.Peer reviewe
On injectors of Finite Soluble Groups
No full textGuo, W. On injectors of Finite Soluble Groups / Wenbin Guo, N. T. Vorob’ev // Communications in Algebra. – 2008. – Vol. 36, № 9. – P. 3200–3208.In this article, we give the description of the f)-injectors of a finite soluble group, for a Hartley class f).The authors are grateful for the helpful suggestions of the referee. Research of the first author is supported by a NNSF grant of China(#10771180)
Guo, R., Wang, J.M., Zhang, W., He, D., Yu, J. & Yang, D.M. (2022) Pteris pseudoamoena (Pteridaceae), a new species from Guangxi, China and Vietnam. Phytotaxa 550 (3): 215-223.
No full textGuo, R., Wang, J.M., Zhang, W., He, D., Yu, J., Yang, D.M. (2022): Guo, R., Wang, J.M., Zhang, W., He, D., Yu, J. & Yang, D.M. (2022) Pteris pseudoamoena (Pteridaceae), a new species from Guangxi, China and Vietnam. Phytotaxa 550 (3): 215-223. Phytotaxa 552 (4): 277-277, DOI: https://doi.org/10.11646/phytotaxa.552.4.6, URL: http://dx.doi.org/10.11646/phytotaxa.552.4.
Enhancement of hot spot cooling by capped diamond layer deposition for multifinger AlGaN/GaN HEMTs
No full textThe impact of a capped diamond layer for enhanced cooling of multi-finger AlGaN/GaN high-electron-mobility-transistors (HEMTs) has been investigated under steady-state operating condition. By depositing a capped diamond thin film onto the HEMTs, the temperature distribution around the hot spots tends to be more uniform and the junction temperature can be suppressed significantly. The capped diamond serves as a highly effective heat spreader and its thermal spreading ability depends on the structural design patterns and working conditions. Some key parameters affecting the thermal performance of the capped diamond have been examined, including the heat dissipation power density, gate pitch distance, embedding depth of the heat source, thermal boundary resistance, substrate material as well as the cap thickness. For the twelve-finger model with 20 µm gate pitch distance and gate power density 6 W/mm, a 20 µm layer of capped diamond could reduce the junction temperature by 12.1% for GaN-on-Diamond HEMTs and by 25.3% for GaN-on- SiC HEMTs, respectively. Even with a 1 µm capped diamond layer, the reduction would be 7.6% and 9.9%, respectively. The temperature reduction for GaN-on-Si is more significant.Peer reviewe
Flow and heat transfer inside a new diversion-type gas heating device
No full textThe present paper characterizes ethylene glycol flow and heat transfer inside a new diversion-type gas heating device. A 2-D natural convection heat transfer model was built and solved by the finite volume method with unstructured body-fitted grids. The numerical model was first validated through temperature comparison with experimental measurements in a conventional device structure. Then analyses and comparisons of the flow fields and temperature distributions with use of different guide plate structures were carried out. The numerical results show that using the guide plate structures can form better organized flow patterns that augment heat transfer. The heat required for heating up the gas passing through the heating device can be reduced by 3% via installing two guide plates.Peer reviewed
Molecular Dynamics Study of Wettability and Pitch Effects on Maximum Critical Heat Flux in Evaporation and Pool Boiling Heat Transfer
No full textMolecular dynamics (MD) simulations were employed to investigate the effects of wettability (contact angle) and pitch on nanoscale evaporation and pool boiling heat transfer of a liquid argon thin film on a horizontal copper substrate topped with cubic nano-pillars. The liquid-solid potential was incrementally altered in order to vary the contact angle between hydrophilic (~0°) and hydrophobic (~127°), and the pitch (distance between nano-pillars) was varied between 21.7Å and 106.6Å to observe the resultant effect on boiling heat transfer enhancement. For each contact angle the superheat was gradually increased to initiate nucleate boiling and eventually pass the critical heat flux (CHF) into the film boiling regime. The CHF increases significantly with pitch (up to 57%), and tends to increase substantially with decreasing contact angle. A maximum overall heat flux of 1.59x108 W/m2 occurs at the largest pitch investigated (106.6Å), and as the contact angle increases the superheat required to reach the CHF condition also increases. Finally, in certain cases of small pitch and large contact angle, the liquid film was seen to transition to a Cassie-Baxter state, which greatly hindered heat transfer.Peer reviewe
- …
