Increasing Throughput in Energy-Based Opportunistic Spectrum Access Energy Harvesting Cognitive Radio Networks

Yuanyuan Yao,Chang-chuan Yin,Xiaoshi Song,Norman C. Beaulieu 한국통신학회 2016 Journal of communications and networks Vol.18 No.3

The performance of large-scale cognitive radio (CR) networkswith secondary users sustained by opportunistically harvestingradio-frequency (RF) energy from nearby primary transmissionsis investigated. Using an advanced RF energy harvester, asecondary user is assumed to be able to collect ambient primary RFenergy as long as it lies inside the harvesting zone of an active primarytransmitter (PT). A variable power (VP) transmission modeis proposed, and an energy-based opportunistic spectrum access(OSA) strategy is considered, under which a secondary transmitter(ST) is allowed to transmit only if its harvested energy is largerthan a predefined transmission threshold and it is outside the guardzones of all active PTs. The transmission probability of the STs isderived. The outage probabilities and the throughputs of the primaryand the secondary networks, respectively, are characterized. Compared with prior work, the throughput can be increased byas much as 29%. The energy-based OSA strategy can be generallyapplied to a non-CR setup, where distributed power beacons(PBs) are deployed to power coexisting wireless signal transmitters(WSTs) in a wireless powered sensor network.

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.

Polydopamine Used as Hollow Capsule and Core-Shell Structures for Multiple Applications

Xinyu Cui,Yuanyuan Yin,Zuo Ma,Yongkui Yin,Yue Guan,Shengzhong Rong,Jinxia Gao,Yingying Niu,Miaojing Li 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.5

Polydopamine (PDA) capsule and core – shell structures with tailored structures and properties are of particular interests due to their multifunctions and potential applications as new colloidal structures in diverse fields. Among the available fabrication methods, PDA film onto colloidal particles followed by selective template removal has attracted extensive attention due to its advantages of precise control over the size, wall thickness and functions of the obtained capsules. The past several years has witnessed a rapid increase of research concerning the new fabrication strategies, functionalization and applications of this kind of capsules and core – shell structures, particularly in many fields such as drug delivery, catalysis, antibacterial, etc. In this review, the very recent progress of the capsule and core – shell structures based on PDA are summarized. There are basically two sections, including the fabrication process of PDA capsules, core – shell structures, and the various applications based on PDA.

Thrust distribution characteristics of thrust systems of shield machines based on spatial force ellipse model in mixed ground

Kongshu Deng,Yuanyuan Li,Zhurong Yin 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.1

The objective of this research is to investigate force distribution characteristics for propelling system of tunneling machines in mixedground. First, a mechanical model for pushing system in composite strata is constructed. Then, eccentricity trunk is determined usingspatial force ellipse eccentricity to measure the degree of uniformity of forces applied on rear segments in a thrust system. Finally, theeccentricity trunk is used to the thrust system of a tunneling machine applied in engineering. Force distribution performance of variousarrangements with equal quantities of jacks is discussed in detail. Results from virtual prototype simulation prove the numerical analyticalresults. A theoretical foundation and support is provided for the design of non-equidistant pushing system of tunneling machines undercomposite stratum.

Hydrophilic Finishing of PET Fabrics by Applying Chitosan and the Periodate Oxidized β-cyclodextrin for Wash Resistance Improvement

Chaoqian Lou,Yuanyuan Yin,Xiuzhi Tian,Haibo Deng,Yingxia Wang,Xue Jiang 한국섬유공학회 2020 Fibers and polymers Vol.21 No.1

β-cyclodextrin (β-CD) was oxidized by sodium periodate to yield a mixture of dialdehyde oligosaccharides. Theperiodate-oxidized β-CD (O-β-CD) together with chitosan (CTS) was firstly used to finish poly(ethylene terephthalate)(PET) fabrics by immersion-padding method, in which O-β-CD acted as a hydrophilic finishing agent plus a cross-linker. Theprocesses including the periodate oxidization of β-CD and the CTS/O-β-CD hydrophilic finishing of PET fabrics were ecofriendly. The results from the hydroxylamine hydrochloride titration showed that the aldehyde content in O-β-CD was3.0 mmol/g. With increasing the CTS/O-β-CD mass ratio, the finished fabric had better hydrophilic properties. When theCTS/O-β-CD mass ratio was 1:1, the moisture regain and water drops wetting time of the finished fabric reached 1.85 % and5.06 s, respectively. They became 1.50 % and 5.70 s, respectively after 25 times of laundering cycle. The occurrence of crosslinkingbetween O-β-CD and CTS was confirmed by the gel test and FT-IR characterization. The cross-linking networkdeposited on the fiber surface brought on excellent wash resistance of the CTS/O-β-CD finished PET fabrics.

Modification of Wool via Grafting β-cyclodextrin Oxidized by Sodium Periodate

Chaoqian Lou,Yuanyuan Yin,Xiuzhi Tian,Haibo Deng,Yingxia Wang,Xue Jiang 한국섬유공학회 2020 Fibers and polymers Vol.21 No.8

The modification of wool fabrics is significant in preparation of functional textiles. Sodium periodate oxidized β-cyclodextrin was grafted onto wool fabric through Schiff base reaction to obtain fabric with controlled release property. β-cyclodextrin was oxidized to aldehyde-β-cyclodextrin, and the results show that the inclusion constant and aldehyde contentof aldehyde-β-cyclodextrin are varied with the reaction parameters such as molar ratio of reaction agents and the reactiontemperature. The degree of oxidation was confirmed by ion chromatography. The drug loading test shows that the oxidizedcyclodextrin still had inclusion ability towards phenolphthalein, while the inclusion constant was only 50 % of the original β-CD. The ATR-FTIR spectra proved the occurrence of grafting reaction between the aldehyde groups of aldehyde-β-cyclodextrin and the amino groups on wool fiber. The aldehyde-β-cyclodextrin grafted wool fabric show great washingdurability even after 5 washing cycles. Compared with the aldehyde-β-cyclodextrin power, the inclusion ability of aldehyde-β-cyclodextrin fixed on the wool fiber decreased by 60 %.

Improved Four-channel PBTDPA Control Strategy Using Force Feedback Bilateral Teleoperation System

Xin Gong,Lixiao Wang,Yuanyuan Mou,Haili Wang,Xiaoqian Wei,Wenfeng Zheng,Lirong Yin 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.3

Bilateral teleoperation robots with force feedback enable humans to accomplish these tasks without exposing them to these hazardous environments. Its stability and transparency describe the performance of bilateral teleoperation systems with force feedback. Bilateral teleoperation with force feedback enables humans to combine tactics with optesthesia. However, the force feedback may lead to bilateral teleoperation instability if the communication channels’ time delay exists. The instability of bilateral teleoperation with force feedback, which is brought in by the time delay, has become one of the complicated problems researchers need to solve. Transparency is one of the leading design objectives of the teleoperation system. There are two evaluation criteria for transparency: the accuracy of the position followed by the master mechanical arm and the accuracy of the feedback received by the slave arm from the master arm. The main content of this paper is as follows: 1) This paper researches and summarizes the control structures and control algorithms of several well-developed force-feedback bilateral teleoperation systems and decides to improve the PBTDPA algorithm, which aligns with practical application requirements. 2) The fourchannel structure makes the transparency of force-feedback bilateral teleoperation systems perfect in theory. This paper uses the four-channel structure combined with the PBTDPA algorithm to improve the transparency of the approach. 3) Moreover, the delay predictor is used to improve the four-channel power-based time domain passivity approach (PBTDPA) control strategy. The delay differential predictor is added to the communication channel. The delay change rate differential predictor can estimate the communication channel’s delay change rate instead of the maximum delay change rate to improve transparency. The simulation experiment of the improved control strategy was carried out. The results show the excellent performance of our design.

Anti-cancer Effects of a Novel Quinoline Derivative 83b1 on Human Esophageal Squamous Cell Carcinoma through Down-Regulation of COX-2 mRNA and PGE2

Ivan Ho Yuen Pun,Dessy Chan,Sau Hing Chan,Po Yee Chung,Yuanyuan Zhou,Simon Law,Alfred King Yin Lam,Chung Hin Chui,Albert Sun Chi Chan,Kim Hung Lam,Johnny Cheuk On Tang 대한암학회 2017 Cancer Research and Treatment Vol.49 No.1

Purpose 83b1 is a novel quinoline derivative that has been shown to inhibit cancer growth in human esophageal squamous cell carcinoma (ESCC). This study was conducted to comprehensively evaluate the cytotoxic effects of 83b1 on a series of ESCC cell lines and investigate the mechanisms by which 83b1 suppresses cancer growth based on molecular docking analysis. Materials and Methods A series of ESCC and nontumor immortalized cell lines were exposed to 83b1 and cisplatin (CDDP) in a dose-dependent manner, and the cytotoxicity was examined by a MTS assay kit. Prediction of the molecular targets of 83b1 was conducted by molecular docking analysis. Expression of cyclooxygenase 2 (COX-2) mRNA and COX-2–derived prostaglandin E2 (PGE2) were measured by quantitative real-time polymerase chain reaction and enzymelinked immuno-sorbent assay, respectively. In vivo anti-tumor effect was determined using a nude mice xenografted model transplanted with an ESCC cell line, KYSE-450. Results 83b1 showed the significant anti-cancer effects on all ESCC cell lines compared to CDDP; however, 83b1 revealed much lower toxic effects on non-tumor cell lines than CDDP. The predicted molecular target of 83b1 is peroxisome proliferator-activated receptor delta (PPAR), which is a widely known oncoprotein. Additionally the expression of COX-2 mRNA and COX-2–derived PGE2 were down-regulated by 83b1 in a dose-dependent manner in ESCC cell lines. Furthermore, 83b1 was shown to significantly reduce the tumor size in nude mice xenograft. Conclusion The results of this study suggest that the potential anti-cancer effects of 83b1 on human esophageal cancers occur through the possible oncotarget, PPAR, and down-regulation of the cancer related genes and molecules.