Microstructural Stability and Creep Performance of a Novel Low-Cost Single Crystal Superalloy

Z. H. Tan,X. G. Wang,Y. L. Du,Y. M. Li,Y. H. Yang,J. L. Liu,J. D. Liu,J. G. Li,Y. Z. Zhou,X. F. Sun 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

The increasing pursuit of advanced aero-engines with lower ratio between the cost and performance has greatly promotedthe demanding of single crystal superalloys characterized by low cost and outstanding temperature capability. In this study,a novel low-cost single crystal superalloy was designed and the creep tests as well as micro-characterization were carried outon the experimental alloy. The results illustrated that the novel single crystal alloy exhibited an ideal microstructural stabilitywithout precipitating TCP phases, after long-term thermal exposure at the ultimate service temperature of third generationsingle crystal superalloys. Moreover, the experimental alloy with only 3 wt% Re addition demonstrated remarkable creepresistance and maintained a very low minimum creep rate at 1100 °C/137 MPa and 1120 °C/137 MPa, while the accumulationand coalescence of micro-pores had eventually led to the alloy fracture. Apart from that, the compact interfacial dislocationnetworks the 2nd γ′ phase were observed after high-temperature creep rupture, and the typical a < 010 > superdislocationswith relatively poor mobility was found at 1120 °C. At 760 °C/800 MPa, both the minimum creep velocity and entire creepstain was increased evidently, however, the ultimate creep rupture life of the alloy had still reached 200 h. The correspondingdeformation mechanism was identified as the combination of superdislocation pairs shearing and a/3 < 121 > partial dislocationcutting the γ′ phase with a SISF being generated. In general, the novel single crystal alloy characterized by remarkablemechanical properties and cost reduction possesses a great potential for future application in the advanced aircraft engines.

정신분열병 환자에서 정신병적 증상과 위스콘신카드 분류검사와의 관계

엄양기,김철권,조진석,변원탄 大韓神經精神醫學會 1996 신경정신의학 Vol.35 No.5

The purpose of this study was to investigate 1) the difference of performance on the Wisconsin Card Sorting Test(WCST) between schizophrenecs and normal controls, 2) and the change of performance while clinically improved. WCSTs were administered in 28 schizophrenics and 32 normal controls. The results were as follows. 1) Schizophrenic patients performed poorly on the WCST compared to normal controls. 2) There was no significant change of performance in WCST as clinical symptoms improved 3) There was no significant correlation between the performance of the Wisconsin Card Sorting Test and age, sex, education level and volcabulary test in both groups. These findings suggest that the WCST mat be an indicator of vulnerability to schizophrenia.

Direct Determination of Uric Acid in Human Serum Samples Using Polypyrrole Nanoelectrode Ensembles

Yang, Guangming,Tan, Lin,Shi, Ya,Wang, Suiping,Lu, Xuxiao,Bai, Huiping,Yang, Yunhui Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.2

Polypyrrole (PPy) nanotubes have been synthesized by chemical oxidative polymerization of pyrrole within the pores of polycarbonate membrane using the technology of diffusion of solutes. The nanotubes array prepared by the proposed method can be considered as nanoelectrode ensembles (NEEs). An amperometric uric acid sensor based on PPy NEEs has been developed and used for determination of uric acid in human serum samples. The electrode can direct response to uric acid at potential of 0.60V vs. SCE with wide linear range of $1.52{\times}10^{-6}\;to\;1.54{\times}10^{-3}\;M.\;The\;detection\;limit\;is \;3.02{\times}10^{-7}$ M. This sensor has been used to determine uric acid in real serum samples. PPy NEEs is thought of as a good application in the foreground.

Thermal Stability of Carbon-Ion-Implanted Nd:YVO₄Optical Planar Waveguide

Yang Tan,Feng Chen,Lei Wang,Ke-Ming Wang 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.-

We report on the thermal stability of optical waveguides in Nd:YVO₄crystal fabricated by 6-MeV carbon ion implantation at doses of 6×10 14 or 2×10 15 ions/cm², respectively. The dark-line-mode spectroscopy of the waveguides was measured by the prism-coupling method, and the refractive-index profiles of the waveguides were reconstructed based on the reflectivity calculation method. The samples were annealed at 300 -400℃ for 1-10 h for investigation of refractive-index behaviors in the guiding regions. The results showed that the higher-dose implanted waveguide was more stable than the lower-dose implanted one. We report on the thermal stability of optical waveguides in Nd:YVO₄crystal fabricated by 6-MeV carbon ion implantation at doses of 6×10 14 or 2×10 15 ions/cm², respectively. The dark-line-mode spectroscopy of the waveguides was measured by the prism-coupling method, and the refractive-index profiles of the waveguides were reconstructed based on the reflectivity calculation method. The samples were annealed at 300 -400℃ for 1-10 h for investigation of refractive-index behaviors in the guiding regions. The results showed that the higher-dose implanted waveguide was more stable than the lower-dose implanted one.

Efficacy of perineural versus intravenous dexamethasone in prolonging the duration of analgesia when administered with peripheral nerve blocks: a systematic review and meta-analysis

Tan Elizabeth Sein Jieh,Tan Yan Ru,Liu Christopher Wei Yang 대한마취통증의학회 2022 Korean Journal of Anesthesiology Vol.75 No.3

Background: Perineural dexamethasone has been regarded as a promising adjunct for prolonging the duration of nerve blocks. However, it is uncertain whether its effects are due to local effects on the nerves or from systemic absorption. This systematic review aimed to compare the duration of postoperative analgesia associated with perineural versus intravenous dexamethasone as an adjunct to peripheral nerve blocks. Methods: A total of 2,216 relevant academic articles were identified after a comprehensive search of PubMed, Embase, Scopus, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov from 1967 until 2020. All randomized controlled trials that compared perineural and intravenous dexamethasone as adjuncts to peripheral nerve limb blocks were included.Results: Fifteen randomized controlled trials (1,467 cases; 738 perineural dexamethasone, 729 intravenous dexamethasone) were eligible. The primary outcome (duration of analgesia) was significantly longer in the perineural than in the intravenous dexamethasone group (mean difference [MD]: 2.72 h, 95% CI [1.42, 4.01], P < 0.001). Perineural dexamethasone was also found to prolong the sensory block (MD: 3.45 h, 95% CI [1.36, 5.54], P = 0.001) and lower 24 h postoperative pain scores (MD: −0.74 h, 95% CI [−1.40, −0.07], P = 0.03).Conclusions: This review confirms the greater efficacy of perineural compared to intravenous dexamethasone in prolonging the analgesic duration of peripheral nerve blocks. However, the extent of prolongation was small and may not represent a clinically meaningful difference.

The Ancient Construction Materials and Methods: The Great Wall of China in Jinshanling as a Case Study

Yang, Jin,Tan, Fabian Hadipriono,Tan, Adrian Korea Institute of Construction Engineering and Ma 2017 Journal of construction engineering and project ma Vol.7 No.1

The Jinshanling section of the Great Wall of China is a series of fortifications in northern China that was constructed for strategic military defenses. This section was first built in the beginning of the Ming Dynasty in AD 1368 and then underwent major construction, reconstruction and renovation during the late Ming Dynasty, approximately in AD 1569. The Jinshanling section is 10.5 km long, a very short section compared with the entire 21,200 km wall. The wall section is located in Luanping County, Hebei province, China. This research paper focuses on the construction methods and materials of the wall and the towers in the area. The research methodology includes site visits, knowledge acquisition of experts and 3D graphic modeling. This study reveals that the materials selected for the structure include rubbles and rammed earth, bricks, stones, timber, and mortar. The erection sequence of the wall and the towers was a bottom-up fashion using various ancient construction techniques, such as the fire-setting rock blasting techniques and the surveying techniques from the Sea Island Mathematical Manual.

Realgar transforming solution-induced differentiation of NB4 cell by the degradation of PML/RARa partially through the ubiquitin–proteasome pathway

Yang Hai,Xin Wang,Peng Song,Jian-yin Li,Longhe Zhao,Fei Xie,Xiang-min Tan,Qin-Jian Xie,Lan Yu,Yang Li,Zhengrong Wu,Hong Yu Li 대한약학회 2019 Archives of Pharmacal Research Vol.42 No.8

PML/retinoic acid receptor alpha (RARa), as ahallmark of acute promyeloid leukemia (APL), is directlyrelated to the outcome of clinical APL remedy. It isreported that arsenicals can effectively degrade PML/RARa, such as arsenic trioxide and realgar. However, thehigh toxicity or insolubility have hampered their clinicalapplications. Realgar transforming solution (RTS) wasproduced from realgar by bioleaching process in our lab. Previous studies demonstrated that RTS had a significantanti-cancer ability on chronic myeloid leukemia throughoncoprotein degradation. The capacity of RTS on treatingAPL is what is focused on in this study. The results showedthat RTS had a noticeable sensitivity in NB4 cell, and RTSremarkably down-regulated PML/RARa expression andinduced cell differentiation. Further, RTS could accumulatePML/RARa into the nuclear bodies and then executedegradation, which could be reversed by proteasomeinhibitor MG132. The results also exhibited that thereduction of RTS-induced PML/RARa expression accompaniedby the elevation of ubiquitin and SUMO-1 proteinexpression. Finally, PML and SUMO-1 had been demonstratedto be co-localized after RTS treatment byimmunofluorescence co-localization assay and immunoprecipitationassay. In conclusion, these results suggestedthat RTS-induced cell differentiation may attribute to thePML/RARa degradation partially through the ubiquitin–proteasome pathway.

Numerical semi-empirical modeling of lidar attenuation characteristics in atmosphere

Tan Zhuangbin,Zhang Yan,Yang Yang,Chen Jintao,Qu Chengzhi,Ma Feifan 한국물리학회 2022 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.81 No.12

Long-distance measurement of lidar is a critical problem in various felds, such as airborne lidar detection, surveying, and mapping. Attenuation characteristic is the key factor afecting the lidar detection capability. However, some long-distance measurement methods based on the widely used and validated theoretical models are usually inefcient, while others relying on empirical models have limited applications due to experimental difculties. This study proposes a semi-empirical model of long-distance measurement based on the Beer–Lambert–Bouguer law adopting mathematical methods. Compared to the theoretical model, the calculation efciency of the semi-empirical model we constructed has been improved by more than two orders of magnitude, and the accuracy can reach more than 98% of the theoretical model. Compared to other empirical models, its accuracy is closer to the theoretical model, and the computational efciency is similar. It can be more efectively applied to the actual long-distance detection scene.

Simultaneous separation of three isoflavones on oligo-β-cyclodextrin substituted polystyrene-based medium and evaluation adsorption characteristics using AutoDock

Li Yang,Tianwei Tan,Jinyi Luan,Xin Wei,Yongqiang Yang,Wenqing Huang,Zhi Guo,Yujie Wang 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.2

The adsorption characteristics between three isoflavones in crude soybean sample and styrene-β-cyclodextrin (S-CD) were studied by molecular mechanics calculations with AutoDock. The discriminatory ability exhibited by S-CD against glycitin, daidzin, and genistin through the differences in the interaction energies and complex geometries could potentially serve for the chromatographic separation. The chromatographic elution order of the three analytes on oligo-β-cyclodextrin substituted polystyrene-based medium (PS-CDP) was predicted depending on the binding free energy values obtained from molecular docking simulations. The experimental results of chromatographic evaluation on PS-CDP were consistent with the simulation prediction. The three isoflavones in sample can be simultaneously separated in one-step under the optimized mobile phase, which consisted of methanol/0.1mM NH4AC=65.0/35.0 (v/v) by PS-CDP column chromatography. A glycitin purity of 95.1% with a recovery of approximate 86.3% was achieved by proper peak cutting, and that of daidzin and genistin was 95.8%, 95.4% and 96.2%, 95.7%, respectively.

Robust Power Control Algorithm for Multiple Primary Users and Secondary Users in Cognitive Radio Networks

Guanglong Yang,Xiao Wang,Xuezhi Tan 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.11

Conventional distributed power control algorithms in cognitive radio (CR) are based on the assumption of perfect channel state information (CSI) which may lead to performance degradation in practical systems. In this paper, the robust distributed power control problem is investigated in CR systems by considering the uncertainty of channel gain. The objective is to maximize the sum rate of secondary users (SUs) subject to the primary users (PUs) interference power constraints and the transmission power constraint of SUs. The channel gain fluctuation is described using ellipsoid sets and the interference power constraints can be converted into robust interference power constraints. Lagrangian duality method is applied to solve the robust power control problem in a distributed way. Simulation results show that the effectiveness of the proposed robust algorithm.