High Temperature Oxidation Resistance of NiCoCrAl High Entropy Alloy Coating on the TiAl Alloy

Yuanyuan Sun,Qiang Miao,Wenping Liang,Kai Zang,Yuting Wu,Haiyang Yu,Mengjuan Yin,Xiguang Gao,Yindong Song 대한금속·재료학회 2024 METALS AND MATERIALS International Vol.30 No.1

The high entropy alloy coating is considered as one of the most promising methods to improve the high-temperature oxidationresistance of titanium aluminum alloys due to its fine mechanical property and thermal stability. However, the high entropyalloy coating prepared so far has poor coating quality, and low coating forming efficiency and there are certain requirementsfor the substrate alloys. To this end, a NiCoCrAl high entropy alloy coating was developed using the double glow plasmaalloying technique on the TiAl alloy. The morphology, phase structure, and high temperature oxidation resistance of thecoating were comprehensively studied. The results indicate that a uniform and dense coating with a single solid solution offace-centered cube phase formed on the alloy surface. Furthermore, isothermal oxidation test was performed, and the oxidationfailure process of the TiAl substrate and the NiCoCrAl-coated sample with different oxidation times was analyzed. It isfound that the coating efficiently prevented the TiAl alloy from degeneration for up to 100 h at 900 °C.

Superwetting TiO2-decorated single-walled carbon nanotube composite membrane for highly efficient oil-in-water emulsion separation

Yahong Sun,Ruiguang Zhao,Quanyong Wang,Yuanyuan Zheng,Gongrang Li,Dejun Sun,Tao Wu,Yujiang Li 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.11

With the advantages of one-dimensional hollow structure, high porosity and prominent mechanical strength, single-walled carbon nanotubes (SWCNTs) have been extensively utilized to improve conventional filtration membranes for oil/water separation. Their intrinsic hydrophobicity, however, adversely affects the anti-fouling performance of the SWCNT membrane. Herein, a super-hydrophilic and underwater super-oleophobic hierarchical modified membrane with enhanced permeability and anti-fouling property was fabricated using the vacuum-assisted filtration technique by synergistically assembling SWCNTs and titanium dioxide (TiO2) nanoparticles on a cellulose acetate membrane. Highly dispersed SWCNTs were obtained by carboxylating treatment of agglomerate SWCNTs. The controlled stacking of SWCNTs fibers and a controllable amount of TiO2 rendered a modified membrane with high porosity and hierarchical structure, leading to an ultrahigh water flux up to 4,777.07 L·m2·h1, and excellent separation performance with efficiency greater than 99.47%. Most importantly, the membrane exhibited excellent anti-fouling ability during ten cycles with the aid of the super-wetting property of TiO2 nanoparticles. The results indicated that coating TiO2 nanoparticles on SWCNTs modified the surface topography of the obtained SWCNT/TiO2 membrane, which improved hydrophilicity, permeability and anti-fouling property, manifesting attractive potential applications in oil/water separation.

Experimental Analysis of Vertical Deformation and Bearing Characteristics of Bridge Piles in High and Steep Slopes

Yuanyuan Wang,Ronggui Deng,Tao Guo,Yi Sun,Bo Huang,Qinke Wang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.3

More and more rigid frame bridges with high piers and large spans are built in the high and steep slope areas of deep valleys in southwest China. The slow deformation of the slope in the geological sense often causes the problems of piles, which in turn causes damage of the upper bridges. The vertical bearing characteristics of bridge piles in slope still need to be conducted because of the peculiarity of slope topography. The vertical deformation and bearing characteristics of piles in the slope area were experimentally studied by considering different influencing factors and the fitting formula for the ultimate bearing capacity of the piles under vertical load is obtained. The results show that the vertical deformation and ultimate bearing capacity (defined by vertical limit settlement deformation of 0.013 times the pile diameter) of the pile are closely related to its position in the slope. The pile in the middle of the slope has the lowest vertical ultimate bearing capacity. Moreover, the side frictional resistance transfer depth of the pile in continuous slope is greater than that of the pile in unilateral slope. Additionally, the slope angle has a significant influence on the vertical bearing performance of piles. The delayed settlement of the pile top decreases approximately 40% at most and the vertical ultimate bearing capacity of the pile increases 48.6% at most as the slope angle decreases by 15°. Meanwhile, the side friction resistance of the pile increases with the decrease of slope angle. The bending moment applied to the pile top reduces the vertical ultimate bearing capacity of the pile and increases the axial force of the pile body. The results can provide data support for pile design and instability judgment with similar geological conditions.

Simplified Analytical Model for Investigating the Output Power of Solar Array on Stratospheric Airship

Yuanyuan Zhang,Jun Li,Mingyun Lv,Dongjie Tan,Weiyu Zhu,Kangwen Sun 한국항공우주학회 2016 International Journal of Aeronautical and Space Sc Vol.17 No.3

Solar energy is the ideal power choice for long-endurance stratospheric airships. The output performance of solar array on stratospheric airship is affected by several major factors: flying latitude, flight date, airship’s attitude and the temperature of solar cell, but the research on the effect of these factors on output performance is rare. This paper establishes a new simplified analytical model with thermal effects to analyze the output performance of the solar array. This model consisting of the geometric model of stratospheric airship, solar radiation model and incident solar radiation model is developed using MATLAB computer program. Based on this model, the effects of the major factors on the output performance of the solar array are investigated expediently and easily. In the course of the research, the output power of solar array is calculated for five airship’s latitudes of 0°, 15°, 30°, 45° and 60°, four special dates and different attitudes of five pitch angles and four yaw angles. The effect of these factors on output performance is discussed in detail. The results are helpful for solving the energy problem of the long endurance airship and planning the airline.

An Enzymolysis-Assisted Agrobacterium tumefaciens-Mediated Transformation Method for the Yeast-Like Cells of Tremella fuciformis

( Yuanyuan Wang ),( Danyun Xu ),( Xueyan Sun ),( Lisheng Zheng ),( Liguo Chen ),( Aimin Ma ) 한국균학회 2019 Mycobiology Vol.47 No.1

Agrobacterium tumefaciens-mediated transformation (ATMT), as a simple and versatile method, achieves successful transformation in the yeast-like cells (YLCs) of Tremella fuciformis with lower efficiency. Establishment of a more efficient transformation system of YLCs is important for functional genomics research and biotechnological application. In this study, an enzymolysis-assisted ATMT method was developed. The degradation degree of YLCs depends on the concentration and digestion time of Lywallzyme. Lower concentration (_0.1%) of Lywallzyme was capable of formation of limited wounds on the surface of YLCs and has less influence on their growth. In addition, there is no significant difference of YLCs growth among groups treated with 0.1% Lywallzyme for different time. The binary vector pGEH under the control of T. fuciformis glyceraldehyde-3-phosphate dehydrogenase gene (gpd) promoter was utilized to transform the enzymolytic wounded YLCs with different concentrations and digestion time. The results of PCR, Southern blot, quantitative real-time PCR (qRT-PCR) and fluorescence microscopy revealed that the T-DNA was integrated into the YLCs genome, suggesting an efficient enzymolysis-assisted ATMT method of YLCs was established. The highest transformation frequency reached 1200 transformants per 10⁶ YLCs by 0.05% (w/v) Lywallzyme digestion for 15 min, and the transformants were genetically stable. Compared with the mechanical wounding methods, enzymolytic wounding is thought to be a tender, safer and more effective method.

Model diagnostics of parametric Tobit model based on cumulative residuals

Sun Zhihua,Guo Yuanyuan,Xie Tianfa,Wang Miaomiao 한국통계학회 2021 Journal of the Korean Statistical Society Vol.50 No.1

In this paper, we investigate the adequate check of the parametric Tobit model. A Cramér–Von Mises type test statistic is constructed, and its asymptotic properties under the null and alternative hypotheses are rigorously studied. The method is efective for the adequacy check of parametric regression models with a scalar or multivariate covariate. Furthermore, it avoids the nonparametric smoothing of the regression function and the choice of the smoothing parameter. Simulation studies are conducted to compare the performance of the proposed test procedure and the existing methods in the literature. A real data set of income is analyzed by applying the proposed method.

Why does SLIPS inhibit P.aeruginosa initial adhesion in static condition?

Yuanyuan Shen,Yihan Sun,Peng Wang,Dun Zhang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.124 No.-

Slippery liquid-infused porous surfaces (SLIPSs) have distinguished themselves in inhibiting bacteriaattachment and biofilm development in static conditions. However, underlying antifouling mechanisms,especially from gene level in bioinformatics, is still lacking. In this work, we investigated the initialattachment difference of Pseudomonas aeruginosa PAO1 on polydimethylsiloxane (PDMS) surface andthe infused silicone slippery surface (i-PDMS). RNA sequencing (RNA-seq) was used to investigate the differencesin the expression of PAO1 gene on elastomer surface during initial adhesion before and after oilinjection. Compared with PDMS, bacterial attachment on i-PDMS was remarkably decreased 98.0 ± 0.7 %within 10 mins. And the antifouling ability of i-PDMS significantly outperformed PDMS throughout theentire culture period of PAO1 (14 days) in static conditions. RNA-seq reveals that the down-regulatedPA1382 of PAO1 in bulk near the i-PDMS surfaces may inhibit bacterial initial adhesion. PA1382 geneencodes type II secretion outer membranes (OM) secretin, also known as type II secretion system(T2SS) protein GspD, which is involved in regulating the opening or closing of exoprotein channels, influencingbacterial adhesion and biofilm formation by controlling the secretion of toxins or effectors. Ourfindings provide a deeper understanding of the mechanism by which SLIPS inhibits initial bacterialadhesion.

A Rapid and Effective Colony PCR Procedure for Screening Transformants in Several Common Mushrooms

( Yuanyuan Wang ),( Danyun Xu ),( Dongmei Liu ),( Xueyan Sun ),( Yue Chen ),( Lisheng Zheng ),( Liguo Chen ),( Aimin Ma ) 한국균학회 2019 Mycobiology Vol.47 No.3

In the post-genomic era, gene function analysis has attracted much attention. Transformation is often needed to investigate gene function. In this study, an easy, rapid, reliable, and cost-effective colony polymerase chain reaction (PCR) method for screening mushroom transformants was developed: picking up a suitable amount of transformant’s tissue (1-10 lg) to 20 ll 0.25% Lywallzyme solution, and vortexing for 10 s followed by incubation at 34 ℃ for 15 min. Finally, 2 ll of the suspension was used as templates to perform PCR and single target bands were successfully amplified from respective transformants of Tremella fuciformis, Pleurotus ostreatus, and Pleurotus tuber-regium. This procedure could be widely employed for screening transformants in mushroom transformation experiments.

Dynamic changes in carbohydrate metabolism and endogenous hormones during Tulipa edulis stolon development into a new bulb

Yuanyuan Miao,Zaibiao Zhu,Qiaosheng Guo,Xiaohua Yang,Li Liu,Yuan Sun,Changlin Wang 한국식물학회 2016 Journal of Plant Biology Vol.59 No.2

The stolon is the main asexual reproductive organ of Tulipa edulis (Miq.) Baker. It has a special morphology and can develop into a new bulb for propagation. In the current greenhouse experiment, the dynamic changes in carbohydrates and related enzymes, protein and endogenous hormones during T. edulis stolon development were investigated. The results showed that soluble sugar levels were basically declining, whereas starch and protein content rose continuously during stolon development. The adenosine diphosphoglucose pyrophosphorylase (AGPase) activity peaked in the initial swelling stage and stayed a relative high level in the middle swelling stage; sucrose synthase (SS), soluble starch synthase (SSS) and granule-bound starch synthase (GBSS) activities followed the same law that showed rising trends during stolon development. SS activity was significantly inversely related to sucrose content but had significantly positive relations with starch content, SSS and GBSS activities. Gibberellin (GA), indole-3-acetic acid (IAA) and zeatin riboside (ZR) peaked in the initial swelling stage and maintained high levels in the middle swelling stage; they then decreased significantly in the later swelling stage. A substantial increase was observed in abscisic acid (ABA) content until the middle swelling stage, followed by a significant reduction in the later swelling stage. The ratios of ABA to IAA, GA and ZR reached their lowest levels in the initial swelling stage. In conclusion, T. edulis stolon development is a process of new bulb morphogenesis along with the starch accumulation catalyzed by AGPase, SSS and GBSS, using the product of sucrose cleavage caused by SS. Initial low ABA content and low ratios of ABA to IAA, GA and ZR, together with the GA, IAA and ZR of high-content, soluble sugars worked more efficiently to induce new bulb formation.

Reliability assessment for multi-source data of mechanical parts of civil aircraft based on the model

Yuanyuan Guo,Youchao Sun,Longbiao Li,Xiaoming Tang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.7

In view of the abnormal, missing and multi-source reliability data, a complete reliability data processing method for civil machinery parts are formed. The abnormal data in the original reliability data set is screened out by Pauta criterion. The vacant data is supplemented by linear interpolation. Each subjective index weight of multi-source data is determined by analytic hierarchy process (AHP) and Euclidean distance. Each objective index weight is determined by the discrete degree of the index weight. The comprehensive reliability model about a certain mechanical part with multi-source data is established and validated to be practical through case analysis. The proposed method obtains more accurate assessment of part reliability, and is thus valuable for the safe operation and maintenance of civil aircraft.