Linear stability analysis of Rayleigh-Bénard convection of cold water near its density maximum in a vertically heated annular container

Xiao-Ran Ma,Li Zhang,You-Rong Li 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.4

In order to understand the onset of Rayleigh-Bénard convection of cold water near its density maximum in a vertical annular container heated from below and cooled from above, the instability of the static diffusive state was investigated by linear stability analysis. Two kinds of thermal boundary conditions, perfect insulating and conducting sidewalls, were used. The aspect ratio and radius ratio of the annular container varied from 0.5 to 4.5 and 0.1 to 0.8, respectively. Results indicate that the critical Rayleigh number and the critical wave number increase with the increase of density inversion parameter. There are some new flow modes with large azimuthal wave number near the convection onset for cold water with density maximum, which are not observed in Rayleigh-Bénard convection of the Boussinesq fluids. The stratified flow phenomenon in cold water with density maximum is certified. The larger the density inversion parameter is, the more obvious the stratified flow phenomenon becomes. With the increase of the aspect ratio, the critical Rayleigh number decreases, but the critical wave number increases. However, with the increase of the radius ratio, both the critical Rayleigh number and the critical wave number increase continuously. Furthermore, the effect of thermal boundary conditions at the sidewalls on the convection stability is also validated.

Bacterial and Fungal Diversity in the Starter Production Process of Fen Liquor, a Traditional Chinese Liquor

Xiao-Ran Li,En-Bo Ma,Liang-Zhen Yan,Han Meng,Xiao-Wei Du,Zhe-Xue Quan 한국미생물학회 2013 The journal of microbiology Vol.51 No.4

Fermented foods and beverages are important parts of human diet. Fen liquor, a Chinese liquor is a fermented beverage that uses a traditional fermentation process. Starters are the main microbial source and also provide nutrients for microorganisms during fermentation. In this study, starters of Fen liquor were produced through a complex traditional fermentation process. To investigate the community structure and the composition of microorganisms in the starter production process, bacterial 16S rRNA and fungal internal transcribed spacer (ITS) regions were sequenced using clone libraries and pyrosequencing, respectively. There was much higher diversity among the bacteria than among the fungi in the starter production process. Bacteria on the surface of the starters belonged mostly to the Lactobacillaceae family,while members of the Bacillacae family were dominant in the interior of the samples that lacked access to air and water. In the fungi population, diversity was high only in the raw material. In all other samples, nearly all of the fungal sequences were from Pichia kudriavzevii, a member of the Saccharomycetaceae family. Nearly all samples showed similar fungal community structures, indicating that there was little change in the fungal community. To the best of our knowledge, this is the first report to reveal the whole process of the starter production of Chinese traditional liquor. The findings obtained in this study provide new insights into understanding the composition of the microbial community during the traditional Chinese liquor starter production process and information about the production process control and monitoring.

A Study of Physiological Activities for Cosmeceutical Ingredient from Fermented Aroniamelanocarpa Extract

Jeong Ran Kang,Dong-Soon Oh,Xiao Xiao Huang,Jong-Hwa Kim,Kap-Hoon Han 중소기업융합학회 2020 융합정보논문지 Vol.10 No.1

아로니아는 특유의 신맛과 떫은 맛 때문에 생과보다는 가공용으로 개발할 필요성이 대두되고 있다. 유산균 을 이용한 아로니아분말 발효추출물에 대한 항산화 활성 및 세포독성을 검정한 결과 총 폴리페놀 함량의 경우 발효전 32.15 μg/mg, 발효 후 43.08 μg/mg으로 증가하였고, 플라보노이드 함량은 발효전 0.47 μg/mg, 0.44 μg/mg 으로 조금 높거나 유사하게 나타내었다. DPPH radical 억제 활성은 발효전 77.5% 에서 89.1%로 발효전 보다 조금더 높은 활성을 나타냈으며, Nitric oxide (NO) 측정은 농도 의존적인 억제효능이 나타났다. 이상의 결과로부터 아로니아분말을 발효할 경우 일부 항산화 활성을 기반으로한 활용가능성과 향후 식물성 천연 추출물 과 발효 화장품 소재로서의 이용가능성을 확인할 수 있었다. Due to the unique sourness and sweet taste of Aronia, it is necessary to develop it for processing rather than raw. The antioxidant activity and cytotoxin about the aronia powder fermentation extract using lactobacillus are verified. In the case of total polyphenol content, the content of non-fermented extract was 32.15 μg/mg fermentation extract, 43.08 μg/mg after fermentation, and the flavonoid content was 0.47 μg/mg in non-fermented extract and 0.44 μg/mg in fermented extract, which was similar to that of non-fermented extract. In the DPPH radical inhibition assay, 77.5% of the non-fermented extract and 89.1% of the fermented extract showed better activity than the non-fermented extract. Nitric oxide (NO) measurement showed a concentration-dependent inhibitory effect. From the above results, it was confirmed that the fermentation of Aronia powder could be utilized based on some antioxidant activities and the possibility of using it as a vegetable extract and fermented cosmetic material in the future.

Changes of Plasma Tumor Necrosis Factor α and C-Reactive Protein Levels in Patients with Hypertension Accompanied by Impaired Glucose Tolerance and their Clinical Significance

Xiao, Qiang,Wang, Lan-Ping,Ran, Zhang-Shen,Zhang, Xin-Huan Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.8

Background: Chronic inflammation could affect the occurrence and development of malignant tumors. To explore the levels of tumor necrosis factor ${\alpha}$ (TNF-${\alpha}$) and C-reactive protein (CRP) in patients accompanied by impaired glucose tolerance (IGT) and their clinical significance. Materials and Methods: A total of 210 patients hospitalized in Affiliated Hospital of Taishan Medical University from Jun., 2013 to Dec., 2014 were selected, in which 92 cases were accompanied by IGT. Meanwhile, 80 randomly-selected healthy people by physical examination were as the control. The levels of routine biochemical indexes, plasma TNF-${\alpha}$ and CRP in all subjects were measured. Results: Both systolic and diastolic pressures in hypertension group and hypertension plus IGT group were significantly higher than in control group (p<0.01), but there was no statistical significance between these two groups (p>0.05). The levels of fasting plasma glucose (FPG) and blood glucose 2 h after taking glucose in hypertension plus IGT group were markedly higher than other groups (p<0.01). Homeostasis model assessment-insulin resistance (HOMA-IR), TNF-${\alpha}$ and CRP contents were on the progressive increase in control, hypertension and hypertension plus IGT groups, but significant differences were presented among each group (P<0.01). Hypertension accompanied by IGT had a significantly-positive association with CRP, TNF-${\alpha}$, FPG and blood glucose 2h after taking glucose. Conclusions: The levels of plasma TNF-${\alpha}$ and CPR in patients with hypertension accompanied by IGT increase significantly, indicating that inflammatory reaction in these patient increases, thus suggesting that these patients should be focused regarding cancer prevention.

Analysis of Chloride Ingress into Cracked Concrete

Run-Sheng Lin(임윤생),Xiao-Yong Wang(왕소용) 한국콘크리트학회 2017 한국콘크리트학회 학술대회 논문집 Vol.29 No.1

Global and Local Moth-flame Optimization Algorithm for UAV Formation Path Planning Under Multi-constraints

Xiao-Jing Wu,Lei Xu,Ran Zhen,Xue-Li Wu 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.3

To improve the global and local search ability of moth-flame optimization algorithm, three optimization strategies are proposed in this paper, namely chaos-based moth initialization, adaptive weighted position update strategy and population diversity improvement strategy. In moth initialization process, chaos-based Logistic map is adopted to improve population diversity. Then, a nonlinear weighting factor is introduced into the spiral function to adaptively balance the global and local search ability. Besides, new moth is generated by population diversity improvement strategy, which improves diversity and optimality of the population. Finally, simulation tests of unmanned aerial vehicle (UAV) formation under multi-constraints are carried out and comparison results show that the proposed global and local moth-flame optimization algorithm has the superiority in rapidity and optimality in UAV path planning problem compared with the latest path planning algorithms.

Influence of different fatigue loads and coating thicknesses on service performance of RC beam specimens with epoxy-coated reinforcement

Xiao-Hui Wang,Yang Gao,Run-Dong Gao,Jing Wang,Xi-La Liu 사단법인 한국계산역학회 2017 Computers and Concrete, An International Journal Vol.19 No.3

Epoxy-coated reinforcing bars are widely used to protect the corrosion of the reinforcing bars in the RC elements under their in-service environments and external loads. In most field surveys, it was reported that the corrosion resistance of the epoxy-coated reinforcing bars is typically better than the uncoated bars. However, from the experimental tests conducted in the labs, it was reported that, under the same loads, the RC elements with epoxy-coated reinforcing bars had wider cracks than the elements reinforced with the ordinary bars. Although this conclusion may be true considering the bond reduction of the reinforcing bar due to the epoxy coating, the maximum service loads used in the experimental research may be a main reason. To answer these two phenomena, service performance of 15 RC beam specimens with uncoated and epoxy-coated reinforcements under different fatigue loads was experimentally studied. Influences of different coating thicknesses of the reinforcing bars, the fatigue load range and load upper limit as well as fatigue load cycles on the mechanical performance of RC test specimens are discussed. It is concluded that, for the test specimens subjected to the comparatively lower load range and load upper limit, adverse effect on the service performance of test specimens with thicker epoxy-coated reinforcing bars is negligible. With the increments of the coating thickness and the in-service loading level, i.e., fatigue load range, load upper limit and fatigue cycles, the adverse factor resulting from the thicker coating becomes noticeable.

Reliability assessment method based on the meta-action unit for complex mechanical system

Xiao Zhu,Yan Ran,Xinglong Li 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.3

In this paper, a functionality unit named as meta-action unit (MAU) is proposed to correlate the system function with the part actions and assess reliability of mechanical system. Firstly, the function of system is decomposed into multiple MAUs by function-movementaction (FMA). Then, the lifetime of MAU is fitted by Weibull distribution, and its parameters are estimated by support vector regression (SVR). In addition, taking the distributions of MAU as marginal distributions, the lifetime distribution of mechanical system is constructed by copula function to assess system reliability, and its parameters are estimated using the maximum likelihood estimator (MLE). Further, the reliability assessment accuracy based on MAU is compared with that from traditional method based on mechanical part failure modes. Finally, the reliability assessment of the indexing turntable (IT) is performed as an example to illustrate the feasibility and reasonability of the proposed method.

Inhibitory effects of osteoprotegerin on osteoclast formation and function under serum-free conditions

Ying-Xiao Fu,Jian-Hong Gu,Yi-Ran Zhang,Xi-Shuai Tong,Hong-Yan Zhao,Yan Yuan,Xue-Zhong Liu,Jian-Chun Bian,Zong-Ping Liu 대한수의학회 2013 Journal of Veterinary Science Vol.14 No.4

The purpose of this study was to determine whether osteoprotegerin (OPG) could affect osteoclat differentiation and activation under serum-free conditions. Both duck embryo bone marrow cells and RAW264.7 cells were incubated with macrophage colony stimulatory factor (M-CSF) and receptor activator for nuclear factor κB ligand (RANKL) in serum-free medium to promote osteoclastogenesis. During cultivation, 0,10, 20, 50, and 100 ng/mL OPG were added to various groups of cells. Osteoclast differentiation and activation were monitored via tartrate-resistant acid phosphatase (TRAP) staining,filamentous-actin rings analysis, and a bone resorption assay. Furthermore, the expression osteoclast-related genes, such as TRAP and receptor activator for nuclear factor κB (RANK),that was influenced by OPG in RAW264.7 cells was examined using real-time polymerase chain reaction. In summary,findings from the present study suggested that M-CSF with RANKL can promote osteoclast differentiation and activation,and enhance the expression of TRAP and RANK mRNA in osteoclasts. In contrast, OPG inhibited these activities under serum-free conditions.

Grenville-age orogenic event along the northeastern margin of the Quanji massif, NW China: constraints from ~1.1 Ga migmatite

Zhouxuan Xiao,Licheng Ma,Wan Jiang,Ran Wang,Yuyan Yao,Jie Cai,Jingyu Lin,Lu Li 한국지질과학협의회 2020 Geosciences Journal Vol.24 No.3

Detailed petrologic, geochemical and geochronological investigation on migmatites provide key information on the tectonic-magmatic history of the Quanji Massif, NW China. The studied migmatites are mainly composed of granitic gneisses, with lenticular refractory residua spread along its foliation. Zircon U-Pb ages of 1129.2 ± 7.4 Ma (1σ, MSWD = 0.34, N = 31) and 1135.1 ± 9.5 Ma (1σ, MSWD = 0.05, N = 22) were determined for the granitic gneiss and refractory residue, respectively. Garnet grains from the refractory residue show no distinctive intra-crystalline zonation, and are rich in Fe and Mg, but poor in Ca and Mn, akin to those from metapelite. Samples from the granitic gneisses have high contents of SiO2 (from 67.92% to 69.89%), K2O (from 3.94% to 5.00%) and A/CNK (1.11–1.17), with LREE enrichment and distinctly negative Eu anomalies (Eu/Eu* = 0.49–0.53) in the chondrite-normalized REE patterns, and significantly negative Nb, Ta, Ti and Sr anomalies in the primitive mantle-normalized spider diagrams. Granitic gneisses samples have consistent Nd isotope compositions with negative εNd(t) values ranging from –1.06 to –6.04, and TDM model ages ranging from 1.83 to 2.23 Ga. These geochemical features suggest that the granitic rocks belong to the S-type granites, which were predominately derived from a late Paleoproterozoic crustal source. The granitic gneiss was probably formed by partial melting of the sediments which had been suffered graunlite-facies metamorphism. The components with low melting points (e.g., felsic minerals) might replace the sediments to form migmatites and migmatitic granites, and thus preserved the refractory residua. Therefore, the late Mesoproterozoic orogenic event is the coeval response of the global Grenvillian orogeny, indicating an important crustal remelting episode in the Quanji Massif.