A larger nonvolatile bipolar resistive switching memory behaviour fabricated using eggshells

Guangdong Zhou,Bai Sun,Ankun Zhou,Bo Wu,Haishen Huang 한국물리학회 2017 Current Applied Physics Vol.17 No.2

Resistive random access memory (RRAM) devices have emerged as promising candidates for near future nonvolatile information storage. Eggshells, a food waste, have not been focused and recycled sustainably today. Eggshell-based devices have shown a large resistive-switching(RS) memory behaviors with favorable resistance ratio of ~103, larger memory window of ~3.5 V, and high endurance and retention performance. Redox-based Ag filament models involving the formation and rupture of the metallic conduction filaments between top and bottom electrodes are proposed to interpret the large nonvolatile bipolar RS memory behaviors. This discovery provides for the possibility of an environmentally friendly, low-cost and sustainable material application in the next-generation nonvolatile date storage device

Memory characteristics and tunneling mechanism of Pt nano-crystals embedded in HfAlOx films for nonvolatile flash memory devices

Guangdong Zhou,BoWu,Zhiling Li,Zhijun Xiao,Shuhui Li,Ping Li 한국물리학회 2015 Current Applied Physics Vol.15 No.3

A non-volatile flash memory device based on metal oxide semiconductor (MOS) capacitor structure hasbeen fabricated using platinum nano-crystals(PteNCs) as storage units embedded in HfAlOx high-ktunneling layers. Its memory characteristics and tunneling mechanism are characterized by capacitanceevoltage(CeV) and flat-band voltage-time(ΔVFB-T) measurements. A 6.5 V flat-band voltage(memory window) corresponding to the stored charge density of 2.29 × 1013 cm-2 and about 88% storedelectron reserved after apply ±8 V program or erase voltage for 105 s at high frequency of 1 MHz wasdemonstrated. Investigation of leakage currentevoltage(JeV) indicated that defects-enhanced Pool-Frenkel tunneling plays an important role in the tunneling mechanism for the storage charges. Hence,the PteNCs and HfAlOx based MOS structure has a promising application in non-volatile flash memorydevices.

Discussion and Design of Dynamic Liquid Level Intelligent Monitoring System

Guangdong Qiu,Zhijie Luo,Guofu Zhou 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.11

The problem of how to calculate the height of the liquid level under tilting status is considered. A custom algorithm for obtaining the real height of liquid level according to the difference of distance measured by ultrasonic sensors is proposed. A set of intelligent monitoring system is designed as well. The system, which takes S3C6410 processor as the control core of the front-end system, measures distance by multiple HC-SR04 ultrasonic sensors, compensates temperature via external temperature sensor ds1820, collects data via inserting driver modules, and then gets the liquid level angle by means of the difference between distance, to calculate the liquid level height, both of which will be sent via Bluetooth chip CC2541 and wireless network. The data, received by PC, will be used for graphical interface display and speech broadcasting depending on Processing software programming. The smart phone can also read data and control devices from the front-end. The results of simulation experiment of this system are considered.

Statistical characteristics of sustained wind environment for a long-span bridge based on long-term field measurement data

Youliang Ding,Guangdong Zhou,Yang Deng,Aiqun Li 한국풍공학회 2013 한국풍공학회지 Vol.17 No.1

The fluctuating wind induced vibration is one of the most important factors which has been taken into account in the design of long-span bridge due to the low stiffness and low natural frequency. Field measurement characteristics of sustained wind on structure site can provide accurate wind load parameters for wind field simulation and structural wind resistance design. As a suspension bridge with 1490 m main span, the Runyang Suspension Bridge (RSB) has high sensitivity to fluctuating wind. The simultaneous and continuously wind environment field measurement both in mid-span and on tower top is executed from 2005 up to now by the structural health monitoring system installed on this bridge. Based on the recorded data, the wind characteristic parameters, including mean wind speed, wind direction, the turbulence intensity, the gust factors, the turbulence integral length, power spectrum and spatial correlation, are analyzed in detail and the coherence functions of those parameters are evaluated using statistical method in this paper. The results indicate that, the turbulence component of sustain wind is larger than extremely strong winds although its mean wind speed is smaller; the correlation between turbulence parameters is obvious; the power spectrum is special and not accord with the Simiu spectrum and von Karman spectrum. Results obtained in this study can be used to evaluate the long term reliability of the Runyang Suspension Bridge and provide reference values for wind resistant design of other structures in this region.

Thermal Field Characteristic Analysis of Steel Box Girder Based on Long-term Measurement Data

Youliang Ding,Guangdong Zhou,Aiqun Li,Gaoxin Wang 한국강구조학회 2012 International Journal of Steel Structures Vol.12 No.2

Thermal loads are important factors that affect the serviceability of long-span bridges. In this paper, the distribution characteristics and statistical features of thermal field in flat steel box girder are presented based on long-term field measurement data collected by the structural health monitoring system (SHMS) permanently installed on the Runyang Suspension Bridge (RSB). Firstly, the daily variations as well as seasonal ones of measurement temperature and temperature differences in the box girder cross-section are summarized. Secondly, employing a combined probability distribution model defined by the weighted sum of one Weibull distribution and one normal distribution, the probability density function (PDF)of each temperature difference is formulated. Thirdly, making use of the extreme value analysis, the extreme temperature differences are predicted with a return period of bridge design working life and compared with the expected values in British standard (BS EN 1991-1-5, 2003). Finally, the critical temperature difference models in cross-section are proposed for thermal stresses calculation according to correlation analysis. The results provide a clear understanding of thermal field in flat steel box girder bridges and have reference values for structural design and evaluation.

Mechanism analysis of switching direction transformation in an Er2O3 based RRAM device

Shuangsuo Mao,Guangdong Zhou,Bai Sun,Hosameldeen Elshekh,Xiaohua Zhang,Xiaohua Zhang,Feng Yang,Yong Zhao 한국물리학회 2019 Current Applied Physics Vol.19 No.12

The resistive random access memory (RRAM) based on resistive switching effect has considered to be the most advanced next generation memory, in which the switching direction determines the order of reading-writing. In this work, the rare-earth metal Er2O3 was used as functional layer, and Ag and indium-tin-oxide (ITO) are selected as top and bottom electrode to fabricate resistive switching device. Further, it is observed that the switching direction and memory window of resistive switching device can be regulated by exchanging top and bottom electrode. Moreover, the complementary switching memory behavior in Ag/Er2O3/ITO/Er2O3/Ag structure was also observed. Through mechanism analysis, it is expected that the barrier changes and metal-ions oxidation-reduction should be responsible for the conversion of switching direction and regulation of memory window. This work opens up a way to the development of next generation new concept memory.

Statistical characteristics of sustained wind environment for a long-span bridge based on long-term field measurement data

Ding, Youliang,Zhou, Guangdong,Li, Aiqun,Deng, Yang Techno-Press 2013 Wind and Structures, An International Journal (WAS Vol.17 No.1

The fluctuating wind induced vibration is one of the most important factors which has been taken into account in the design of long-span bridge due to the low stiffness and low natural frequency. Field measurement characteristics of sustained wind on structure site can provide accurate wind load parameters for wind field simulation and structural wind resistance design. As a suspension bridge with 1490 m main span, the Runyang Suspension Bridge (RSB) has high sensitivity to fluctuating wind. The simultaneous and continuously wind environment field measurement both in mid-span and on tower top is executed from 2005 up to now by the structural health monitoring system installed on this bridge. Based on the recorded data, the wind characteristic parameters, including mean wind speed, wind direction, the turbulence intensity, the gust factors, the turbulence integral length, power spectrum and spatial correlation, are analyzed in detail and the coherence functions of those parameters are evaluated using statistical method in this paper. The results indicate that, the turbulence component of sustain wind is larger than extremely strong winds although its mean wind speed is smaller; the correlation between turbulence parameters is obvious; the power spectrum is special and not accord with the Simiu spectrum and von Karman spectrum. Results obtained in this study can be used to evaluate the long term reliability of the Runyang Suspension Bridge and provide reference values for wind resistant design of other structures in this region.

Omp16, a conserved peptidoglycan-associated lipoprotein, is involved in Brucella virulence in vitro

Feijie Zhi,Dong Zhou,Junmei Li,Lulu Tian,Guangdong Zhang,Yaping Jin,Aihua Wang 한국미생물학회 2020 The journal of microbiology Vol.58 No.9

Brucella, the bacterial agent of common zoonotic brucellosis, primarily infects specific animal species. The Brucella outer membrane proteins (Omps) are particularly attractive for developing vaccine and improving diagnostic tests and are associated with the virulence of smooth Brucella strains. Omp16 is a homologue to peptidoglycan-associated lipoproteins (Pals), and an omp16 mutant has not been generated in any Brucella strain until now. Very little is known about the functions and pathogenic mechanisms of Omp16 in Brucella. Here, we confirmed that Omp16 has a conserved Pal domain and is highly conserved in Brucella. We attempted to delete omp16 in Brucella suis vaccine strain 2 (B. suis S2) without success, which shows that Omp16 is vital for Brucella survival. We acquired a B. suis S2 Omp16 mutant via conditional complementation. Omp16 deficiency impaired Brucella outer membrane integrity and activity in vitro. Moreover, inactivation of Omp16 decreased bacterial intracellular survival in macrophage RAW 264.7 cells. B. suis S2 and its derivatives induced marked expression of IL-1β, IL-6, and TNF-α mRNA in Raw 264.7 cells. Whereas inactivation of Omp16 in Brucella enhanced IL-1β and IL-6 expression in Raw 264.7 cells. Altogether, these findings show that the Brucella Omp16 mutant was obtained via conditional complementation and confirmed that Omp16 can maintain outer membrane integrity and be involved in bacterial virulence in Brucella in vitro and in vivo. These results will be important in uncovering the pathogenic mechanisms of Brucella.

Polymorphism of the Promoter Region of Hsp70 Gene and Its Relationship with the Expression of HSP70mRNA, HSF1mRNA, Bcl-2mrna and Bax-AMrna in Lymphocytes in Peripheral Blood of Heat Shocked Dairy Cows

Cai, Yafei,Liu, Qinghua,Xing, Guangdong,Zhou, Lei,Yang, Yuanyuan,Zhang, Lijun,Li, Jing,Wang, Genlin Asian Australasian Association of Animal Productio 2005 Animal Bioscience Vol.18 No.5

The blood samples were collected from dairy cows at the same milking stage. The single-strand conformation polymorphism (PCR-SSCP) method was used to analyze for polymorphism at the 5'flanking region of the hsp70 gene. The mRNA expression levels of HSP70, HSF1, Bcl-2 and Bax-$\alpha$ at different daily-mean-temperature were analyzed by relative quantitative RTPCR. The DNA content, cell phase and the ratio of apoptosis of lymphocytes in peripheral blood of dairy cattle at different daily-meantemperature were determined by FCM. The PCR-SSCP products of primer pair 1 showed polymorphisms and could be divided into four genotypes: aa, ab, ac, cc, with the cis-acting element (CCAAT box) included. Mutations in the hsp70 5'flanking region (468-752 bp) had different effects on mRNA expression of HSP70, HSF1, Bcl-2 and Bax-$\alpha$. The ac genotypic cows showed higher expressions of HSP70mRNA, HSF1mRNA and Bcl-2mRNA/Bax-$\alpha$mRNA and lower ratio of apoptosis. These mutation sites can be used as molecular genetic markers to assist selection for anti-heat stress cows.

Bond behaviour at concrete-concrete interface with quantitative roughness tooth

Ayinde, Olawale O.,Wu, Erjun,Zhou, Guangdong Techno-Press 2022 Advances in concrete construction Vol.13 No.3

The roughness of substrate concrete interfaces before new concrete placement has a major effect on the interface bond behaviour. However, there are challenges associated with the consistency of the final roughness interface prepared using conventional roughness preparation methods which influences the interface bond performance. In this study, five quantitative interface roughness textures with different roughness tooth angles, depths, and tooth distribution were created to ensure consistency of interface roughness and to evaluate the bond behaviour at a precast and new concrete interface using the splitting tensile test, slant shear test, and double-shear test. In addition, smooth interface specimens and two separate the pitting interface roughness were also utilized. Obtained results indicate that the quantitative roughness has a very limited effect on the interface tensile bond strength if no extra micro-roughness or bonding agent is added at the interface. The roughness method however causes enhanced shear bond strength at the interface. Increased tooth depth improved both the tensile and shear bond strength of the interfaces, while the tooth distribution mainly influenced the shear bond strength. Major failure modes of the test specimens include interface failure, splitting cracks, and sliding failure, and are influenced by the tooth depth and tooth distribution. Furthermore, the interface properties were obtained and presented while a comparison between the different testing methods, in terms of bond strength, was performed.