Representing the Heat-to-Moisture Transport Efficiency in Stable Conditions: An Extension of Two Different Approaches

Guo Xiaofeng,Yang Kun,Yang Wei,Zhao Long,Li Shenghai,Ding Baohong 한국기상학회 2020 Asia-Pacific Journal of Atmospheric Sciences Vol.56 No.4

Using eddy-covariance turbulence measurements over a Tibetan glacier, we present a description of scalar turbulence characteristics in the stable boundary layer. Interesting behaviours are demonstrated in terms of temperature–humidity de-correlation and dissimilarity. That is, a lack of perfect correlation occurs between the two scalars (i.e., correlation coefficients <1 in magnitude); overall, sensible heat is more efficiently transported than water vapour over snow and ice surfaces. Such behaviours provide evidence of departures from the idealized expectation of Monin–Obukhov similarity theory—all scalars assume a perfect level of linear correlation and an equal efficiency level of vertical transport. Results presented herein are noteworthy in that observations over uniform glaciated surfaces involve negligible effects of either a canopy-induced roughness sublayer or heterogeneity in the temperature–humidity source/sink distributions. Moreover, we address two different approaches to representing the heat-to-moisture transport efficiency in stable conditions. A new approach is extended through application of the quadrant analysis technique, thereby representing it as a function of atmospheric stability. Caution is further advised in the use of this approach, when temperature–humidity turbulence becomes markedly de-correlated. A second approach, as previously applied for estimating forest evaporation fluxes in unstable conditions, is extended to a stable boundary layer over snow and ice surfaces.

Triple-Mode Bi2WO6/Pg-C3N4@rGO Core-Shell Synergistic Effect with Enhanced Light-induced Photocatalytic Activity

Xiaofeng Guo,Hongbo Wang,Liying Wang,Defen Zeng,Qian Xiang,Ba Chai 대한화학회 2019 Bulletin of the Korean Chemical Society Vol.40 No.3

Synthesizing composites is one of the most effective ways to reduce the recombination probability of electron?hole pairs and to improve photocatalytic activity. In this study, our research group first combined reduced graphene oxide (rGO) with porous graphitic carbon nitride (pg-C3N4) to form pg-C3N4@rGO core-shell, and then loaded bismuth tungstate (Bi2WO6) onto the pg-C3N4@rGO to acquire a ternary composite catalyst. The results of the experiment show that, the ternary photocatalyst exhibited better phototalytic performance than pure pg-C3N4 and Bi2WO6. When the weight radio of pg-C3N4@rGO and Bi2WO6 was 100:8, the ternary photocatalyst showed the best photocatalytic performance. Its photocatalytic kinetic constant reached 68 ? 10?4 min?1, which was 13.6 times that of pg-C3N4 and 7.6 times that of Bi2WO6. The photocatalytic performance was boosted by the heterojunction structure of the ternary composite, which can effectively separate electron?hole pairs rapidly, and thereby increased quantum yield, thus improving the photocatalytic performance.

Integrated aero-structural optimization design of pre-bend wind turbine blades

Xiaofeng Guo,Xiaoli Fu,Huichao Shang,Jin Chen 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.11

In the optimization design of a pre-bend wind turbine blade, there is a coupling relationship between blade aerodynamic shape and structural layup. The evaluation index of a wind turbine blade not only shows on conventional ones, such as Annual energy production (AEP), cost, and quality, but also includes the size of the loads on the hub or tower. Hence, the design of pre-bend wind turbine blades is a true multi-objective engineering task. To make the integrative optimization design of the pre-bend blade, new methods for the blade’s pre-bend profile design and structural analysis for the blade sections were presented, under dangerous working conditions, and considering the fundamental control characteristics of the wind turbine, an integrated aerodynamic-structural design technique for pre-bend blades was developed based on the Multi-objective particle swarm optimization algorithm (MOPSO). By using the optimization method, a three-dimensional Pareto-optimal set, which can satisfy different matching requirements from overall design of a wind turbine, was obtained. The most suitable solution was chosen from the Pareto-optimal set and compared with the original 1.5 MW blade. The results show that the optimized blade have better performance in every aspect, which verifies the feasibility of this new method for the design of pre-bend wind turbine blades.

Natural frequency analysis of joined conical-cylindrical-conical shells made of graphene platelet reinforced composite resting on Winkler elastic foundation

Xiangling Wang,Xiaofeng Guo,Masoud Babaei,Rasoul Fili,Hossein Farahani Techno-Press 2023 Advances in nano research Vol.15 No.4

Natural frequency behavior of graphene platelets reinforced composite (GPL-RC) joined truncated conical-cylindrical- conical shells resting on Winkler-type elastic foundation is presented in this paper for the first time. The rule of mixture and the modified Halpin-Tsai approach are applied to achieve the mechanical properties of the structure. Four different graphene platelets patterns are considered along the thickness of the structure such as GPLA, GPLO, GPLX, GPLUD. Finite element procedure according to Rayleigh-Ritz formulation has been used to solve 2D-axisymmetric elasticity equations. Application of 2D axisymmetric elasticity theory allows thickness stretching unlike simple shell theories, and this gives more accurate results, especially for thick shells. An efficient parametric investigation is also presented to show the effects of various geometric variables, three different boundary conditions, stiffness of elastic foundation, dispersion pattern and weight fraction of GPLs nanofillers on the natural frequencies of the joined shell. Results show that GPLO and BC3 provide the most rigidity that cause the most natural frequencies among different BCs and GPL patterns. Also, by increasing the weigh fraction of nanofillers, the natural frequencies will increase up to 200%.

Leader-Following Finite-Time Consensus in Second-order Multi-Agent Networks with Nonlinear Dynamics

Huaqing Li,Xiaofeng Liao,Guo Chen 제어·로봇·시스템학회 2013 International Journal of Control, Automation, and Vol.11 No.2

Robust finite-time consensus problems in leader-following multi-agent directed networks with second-order nonlinear dynamics are considered in this paper. By using matrix theory, algebraic graph theory and finite-time control scheme, a class of continuous distributed control algorithms are designed in a quite unified way for each follower agent to reach consensus in a finite time. A numerical example is also employed to illustrate the effectiveness and correctness of our theoretical results.

Effects of solvent extraction on the microstructure of bituminous coal-based graphite

Wang Lipeng,Yao Zongxu,Guo Zhimin,Shen Xiaofeng,Li Zhiang,Zhou Zhengqi,Wang Yuling,Yang Jian-Guo 한국탄소학회 2022 Carbon Letters Vol.32 No.3

Coal-based graphite has become the main material of emerging industries. The microstructure of coal-based graphite plays an important role in its applications in many fields. In this paper, the effect of carbon disulfide/N-methyl-2-pyrrolidone solvent mixture extraction on the microstructure of bituminous coal-based graphite was systematically studied through preliminary extraction coupled with high-temperature graphitization. The graphitization degree g (75.65%) of the coal residue-based graphite was significantly higher than that of the raw coal-based graphite. The crystallite size La of the coal residue-based graphite was reduced by 47.06% compared with the raw coal-based graphite. The ID/ IG value of the coal residue-based graphite is smaller than that of the raw coal-based graphite. The specific surface area (16.72 m2/g) and total pore volume (0.0567 m3/g) of the coal residue-based graphite are increased in varying degrees compared with the raw coal-based graphite. This study found a carbon source that can be used to prepare coal-based graphite with high graphitization degree. The results are expected to provide a theoretical basis for further clean and efficient utilization of the coal residue resources.

Development of ML-based Ultra-Sensitive Ceramic Sensor for Stress Visualization

Tao. Cai,Songtao Guo,Di Peng,Xiaofeng Zhao,Weizhe Wang,Yingzheng Liu,Kyung Chun Kim,Ping Xiao 한국가시화정보학회 2019 한국가시화정보학회 학술발표대회 논문집 Vol.2019 No.12

Correction to: Effects of solvent extraction on the microstructure of bituminous coal‑based graphite

Lipeng Wang,Zongxu Yao,Zhimin Guo,Xiaofeng Shen,Zhiang Li,Zhengqi Zhou,Yuling Wang,Jian‑Guo Yang 한국탄소학회 2022 Carbon Letters Vol.32 No.3

Macrophage migration inhibitory factor mediates peripheral nerve injury-induced hypersensitivity by curbing dopaminergic descending inhibition

Xian Wang,Shaolei Ma,Haibo Wu,Xiaofeng Shen,Shiqin Xu,Xirong Guo,Maria L Bolick,Shizheng Wu,Fuzhou Wang 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

Our previous works disclosed the contributing role of macrophage migration inhibitory factor (MIF) and dopaminergic inhibition by lysine dimethyltransferase G9a/Glp complex in peripheral nerve injury-induced hypersensitivity. We herein propose that the proinflammatory cytokine MIF participates in the regulation of neuropathic hypersensitivity by interacting with and suppressing the descending dopaminergic system. The lumbar spinal cord (L-SC) and ventral tegmental area (VTA) are two major locations with significant upregulation of MIF after chronic constriction injury (CCI) of the sciatic nerve, and they display time-dependent changes, along with a behavioral trajectory. Correspondingly, dopamine (DA) content shows the reverse characteristic change to MIF with a time-dependent curve in post-surgical behavior. The levels of both MIF and DA are reversed by the MIF tautomerase inhibitor ISO-1, and a negative relationship exists between MIF and DA. The reversed role of ISO-1 also affects tyrosine hydroxylase expression. Furthermore, CCI induces Th promoter CpG site methylation in the L-SC and VTA areas, and this effect could be abated by ISO-1 administration. G9a/SUV39H1 and H3K9me2/H3K9me3 enrichment within the Th promoter region following CCI in the L-SC and VTA was also decreased by ISO-1. In cultured dopaminergic neurons, rMIF enhanced the recruitment of G9a and SUV39H1, followed by an increase in H3K9me2/H3K9me3. These molecular changes correspondingly exhibited alterations in Th promoter CpG site methylation and pain behaviors. In summary, MIF functions as a braking factor in curbing dopaminergic descending inhibition in peripheral nerve injury-induced hypersensitivity by mediating Th gene methylation through G9a/SUV39H1-associated H3K9 methylation.

Predictors and Dynamic Nomogram to Determine the Individual Risk of Malignant Brain Edema After Endovascular Thrombectomy in Acute Ischemic Stroke

Qian-mei Jiang,Shuai Yu,Xiaofeng Dong,Huai-shun Wang,Jie Hou,Zhi-chao Huang,Zhi-liang Guo,Shou-jiang You,Guo-dong Xiao 대한신경과학회 2022 Journal of Clinical Neurology Vol.18 No.3

Background and Purpose This study aimed to construct an optimal dynamic nomogram for predicting malignant brain edema (MBE) in acute ischemic stroke (AIS) patients after endovascular thrombectomy (ET). Methods We enrolled AIS patients after ET from May 2017 to April 2021. MBE was defined as a midline shift of >5 mm at the septum pellucidum or pineal gland based on follow-up computed tomography within 5 days after ET. Multivariate logistic regression and LASSO (least absolute shrinkage and selection operator) regression were used to construct the nomogram. The area under the receiver operating characteristic curve (AUC) and decisioncurve analysis were used to compare our nomogram with two previous risk models for predicting brain edema after ET. Results MBE developed in 72 (21.9%) of the 329 eligible patients. Our dynamic web-based nomogram (https://successful.shinyapps.io/DynNomapp/) consisted of five parameters: basal cistern effacement, postoperative National Institutes of Health Stroke Scale (NIHSS) score, brain atrophy, hypoattenuation area, and stroke etiology. The nomogram showed good discrimination ability, with a C-index (Harrell’s concordance index) of 0.925 (95% confidence interval=0.890–0.961), and good calibration (Hosmer-Lemeshow test, p=0.386). All variables had variance inflation factors of <1.5 and tolerances of >0.7, suggesting no significant collinearity among them. The AUC of our nomogram (0.925) was superior to those of Xiang-liang Chen and colleagues (0.843) and Ming-yang Du and colleagues (0.728). Conclusions Our web-based dynamic nomogram reliably predicted the risk of MBE in AIS patients after ET, and hence is worthy of further evaluation.