Potential rocky desertification simulation for the karst plateau area using CA-Markov model

Panpan Zhang,Yuanman Hu,Duning Xiao,Xiuzhen Li,Jie Yin 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

It has been recognized that karst rocky desertification is one of the most serious geo-ecological problem in Southwestern China. Understanding the development trend of karst rocky desertification is of fundamental importance in rocky desertification management and control. More attention should be paid to karst areas with potential rocky desertification. In this paper, ARFGIS software was used to discribe the historical and current situation of potential rocky desertification spatial pattern in the middle and lower reaches of houzhai stream, a typical karst plateau area. Remote sensing images from the study area, Remote sensing images from the study area, collected in 1987,1955 and 2004 were used for spatial pattern simulation of potential rocky desertification subdivided into six types: none, extreme slightly, slightly, moderately, severely and extreme severely. The result showed that the potential rocky desertification landscape distributed unevenly; a little more than half of the are showed gradual rocky desertification trend and about 60% of those regions had emarkable rocky desertification trend; Slightly potential rocky desertification was increasing all the time, while the other five types of potential rocky desertification had different change tendencies during different states. Then based on CA-Markov model, the potential rocky desertification spatial pattern was predicted. Verification with investigation based on map in 2004 indicated that 87.2% of the simulation was consistant with real data. therefore the model is robust in prediction potential rocky desertification spatial pattern in this study area.

One-pot Modification on Cotton Fabric Using an Emulsion of Ag NPs Protected by Mercaptosuccinic Acid to Achieve Durably Antibacterial Effect

Panpan Duan,Qingbo Xu,Shuyang Shen,Yanyan Zhang,Lei Zhang,Feiya Fu,Xiangdong Liu 한국섬유공학회 2019 Fibers and polymers Vol.20 No.9

We presented a one-pot approach for fabrication of antibacterial cotton fabric using an emulsion of silvernanoparticles (Ag NPs) protected by mercaptosuccinic acid (MSA). The emulsion was used to finish cotton fabrics via a paddry-cure process, making the MSA molecules covalently linked to the cotton fibers by ester linkages with the hydroxylgroups of cellulose. The coordination bonds between the MSA molecules and the Ag NPs provide stable and durable effecton the immobilization of the Ag NPs on the cotton fabric, endowing its antibacterial function with an outstanding launderingdurability. Even experienced 50 consecutive laundering tests, the modified cotton fabric exhibits satisfactory bacterialreduction rates against both Staphylococcus aureus and Escherichia coli. This paper provides a simple fabricationmethodology to mitigate the safety risk and environmental impact that are typically found in the antimicrobial cotton textilesbased on Ag NPs.

MODULATION OF PTCDA NANOSTRUCTURE AND OPTICAL PROPERTY: DEPENDENCE ON GROWTH TEMPERATURE

PANPAN GUO,FAQIANG XU,Wenhua Zhang,LINGYUN LIU,KAI WANG,YUYAN HAN 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.6

3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) nanostructures with di®erent mor-phologies are prepared on glass substrates at di®erent substrate temperature ( T s Þ in a molecularbeam epitaxy (MBE) system. Scanning/transmission/scanning transmission electron microscopy(SEM/TEM/STEM), X-ray di®raction (XRD), selected area electron di®raction (SAED) andnanobeam di®raction (NBD) techniques are employed in the systematical characterizations of thenanostructures. It is found that the PTCDA nanosheets (NSs), nanowires and nanorods are facileto produce at T s ¼ 350?C, 330?C and 240?C, respectively; the continuous ¯lms are obtained at180?C and 50?C. XRD studies indicate that only the ? -phase polymorph is formed regardless ofthe T s. SAED and NBD results show that the nanowire and NS are single crystalline. The opticalproperties of the prepared PTCDA nanostructures are also found to be in°uenced by T s and arecorrelated with the crystal quality and size. PTCDA nanowires and NSs exhibit an obviousredshift and broadening in the adsorption spectra, and enhanced emission intensity. Theimproved optical properties facilitate potential applications of these nanostructures in organicoptoelectronic devices.

A simple preparation method for rare-earth phosphate nano materials using an ionic liquid-driven supported liquid membrane system

Panpan Zhao,Fan Yang,Zhigang Zhao,Qiuxiao Liao,Yang Zhang,Peng Chen,Wanghuan Guo,Ruixi Bai 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.54 No.-

For the first time, our group has developed a novel, high-flux strategy for shape-controlled synthesis of rare earth nano-materials (CePO4) using ionic liquid(IL)-driven supported liquid membrane (HVHP, DUPAPORE1) system. The system contains three phases including a supply phase of rare earth ions, a feed phase of phosphates, and ionic liquid-driven supporting liquid membrane phase. The imidazolium IL-driven supported liquid membrane is promising for nano-synthetic reaction of CePO4. The anion types of immersed imidazolium IL have a critical role in the formation rate of CePO4 nano-materials. Moreover, the adding SO4 2 anion or adjustment of pH in supply phase containing Ce(III) ions could control effectively the morphology of the CePO4 nano-materials. The result can be regarded as a good example, the IL:[C4mim][Tf2N] driven support liquid membrane systems can be used to prepare nano-wire and nano-sphere structures of CePO4 with high efficiency and flux. Besides, the IL-driven supported liquid membrane can be cycled many times by using the back flush activation method.

Polyaniline/Cerium Oxide Hybrid Modified Carbon Paste Electrode for Non-Enzymatic Glucose Detection

Jie Zhang,Panpan Guan,Yongjian Li,Wei Li,Qingping Guo 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.7

Exploring COVID-19 in mainland China during the lockdown of Wuhan via functional data analysis

Li, Xing,Zhang, Panpan,Feng, Qunqiang The Korean Statistical Society 2022 Communications for statistical applications and me Vol.29 No.1

In this paper, we analyze the time series data of the case and death counts of COVID-19 that broke out in China in December, 2019. The study period is during the lockdown of Wuhan. We exploit functional data analysis methods to analyze the collected time series data. The analysis is divided into three parts. First, the functional principal component analysis is conducted to investigate the modes of variation. Second, we carry out the functional canonical correlation analysis to explore the relationship between confirmed and death cases. Finally, we utilize a clustering method based on the Expectation-Maximization (EM) algorithm to run the cluster analysis on the counts of confirmed cases, where the number of clusters is determined via a cross-validation approach. Besides, we compare the clustering results with some migration data available to the public.

Stiffness matching method for the ball screw feed drive system of machine tools

Gaiyun He,Panpan Shi,Dawei Zhang,Guangming Sun 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.7

The static stiffness of machine tools plays an important role in ensuring the performance of machine tools and improving the machining accuracy. In the design stage, stiffness matching provides a theoretical basis for determining the stiffness of each component. This study proposed a stiffness matching design method for machine tools. First, the deformation model of machine tools is established on the basis of the state space model. Through force analysis, the relationships between the deformations and stiffness of each part are determined. Second, the stiffness model of the machine tool is established by combining these relationships with the deformation model. Third, the objective function is determined by performing sensitivity analysis after obtaining the stiffness range. The stiffness matching design results are obtained through multi-objective linear programming. Lastly, the stiffness simulations, theoretical model, and experimental results are analyzed. The maximum errors among the experimental, simulation, and theoretical results (18.8 % and 19.9 %) are within the acceptable range. In conclusion, the proposed method is suitable for designing ball screw feed drive systems that requires rigidity.

Research on fault diagnosis of rolling bearing based on the MCKD-SSD-TEO with optimal parameters

Ben Cui,Panpan Guo,Wenbin Zhang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.1

To address challenges in fault diagnosis of rolling bearing caused by great noise contamination and difficult extraction of fault character frequency, a fault diagnosis method of rolling bearing based on the maximum correlation kurtosis deconvolution (MCKD), singular spectral decomposition (SSD) and teager energy operator (TEO) with optimal parameters was proposed in this study. First of all, denoising was performed as a preprocessing to the original vibration signals which were collected by using the MCKD with optimal parameters to highlight the impact component. Next, SSD was performed to the preprocessed signals and the optimal components were selected according to variance contribution. Finally, the energy spectra of optimal components were calculated and characteristic frequency was extracted to realize fault diagnosis of bearing. Through simulation and experimental analysis, the proposed method was proved feasible. It was further compared with empirical mode decomposition (EMD) and ensemble empirical mode decomposition (EEMD), which proved superiority and validity of the proposed method.

Double Protect Copper Nanoparticles Loaded on L-cysteine Modified Cotton Fabric with Durable Antibacterial Properties

Qingbo Xu,Panpan Duan,Yanyan Zhang,Feiya Fu,Xiangdong Liu 한국섬유공학회 2018 Fibers and polymers Vol.19 No.11

In this work, we developed a new method that can achieve immobilization and protection of the Cu NPs coating on the cotton fabrics by a simple two-step impregnation method. Firstly, L-cysteine (Cys) was grafted onto cotton fabric via esterification with the hydroxyl groups of cellulose, then Cu NPs were introduced on the fabric surface in the presence of a protective reagent, citric acid. Due to the doubled stabilization acts of Cys and citric acid, the Cu NPs immobilized on the fabric surface showed an excellent antibacterial effect and outstanding laundering durability. As a result, the mean size of the Cu NPs coating on the cotton fabric is about 62.4 nm, and the modified cotton fabrics showed satisfactory antibacterial ability against both S. aureus and E. coli, which the bacterial reduction rates are all higher than 98 % even withstand 50 washing cycles. Therefore, this method to prepare antibacterial cotton fabrics showed great potential applications in socks, cosmetic, and medical textiles.

The Oligomer Polyacrylic Acid Effect on Immobilization of Silver Nanoparticles onto Cotton Fabric to Achieve a Durably Antibacterial Function

Lin Li,Panpan Duan,Qingbo Xu,XuJun Zhang,JiaNing Chen,Feiya Fu,HongYan Diao,Xiangdong Liu 한국섬유공학회 2020 Fibers and polymers Vol.21 No.9

Aiming to a durably antibacterial function, stable immobilization of silver nanoparticles (Ag NPs) on cottontextiles still represents challenging in textile industry. In the present work, by grafting oligomeric polyacrylic acid (PAA) ontocotton fiber surfaces, we effectively prepared the Ag NPs with controllable size on the fiber surface, which are of average sizeof 16.43 nm, and therefore achieved a desirable antibacterial durability. The oligomer PAA binder can give the modifiedfabrics with a remarkable antibacterial durability against washing, as the bacterial reduction rates against bothStaphylococcus aureus and Escherichia coli remained over 90 % even after 50 laundering cycles. Moreover, this graft toapproach using oligomeric PAA shows merits in maintaining the desired cotton properties such as flexibility, waterabsorptivity and vapor permeability. Finally, this finishing process ensures a reliable safety for human skin.