The formation and stability of junctions in single-wall carbon nanotubes

Zhang, Xiuyun,Dong, Jichen,Gong, Xiaoshu,Ding, Feng IOP 2018 Nanotechnology Vol.29 No.48

<P>The structure and stability of molecular junctions, which connect two single-wall carbon nanotubes (SWCNTs) of different diameters and chiral angles, (<I>n</I> <SUB>1</SUB>, <I>m</I> <SUB>1</SUB>)-(<I>n</I> <SUB>2</SUB>, <I>m</I> <SUB>2</SUB>), are systematically investigated by density functional tight binding calculations. More than 100 junctions, which connect well-aligned SWCNTs, were constructed and calculated. For a highly stable junction between two chiral (<I>n</I> <SUB>1</SUB>, <I>m</I> <SUB>1</SUB>) and (<I>n</I> <SUB>2</SUB>, <I>m</I> <SUB>2</SUB>) SWCNTs with opposite handedness, the number of pentagon–heptagon (5/7) pairs required to build the junction can be denoted as ∣∣<I>n</I> <SUB>2</SUB>?−?<I>n</I> <SUB>1</SUB>∣?−?∣<I>m</I> <SUB>2</SUB>?−?<I>m</I> <SUB>1</SUB>∣∣+min{∣<I>n</I> <SUB>2</SUB>?−?<I>n</I> <SUB>1</SUB>∣, ∣<I>m</I> <SUB>2</SUB>?−?<I>m</I> <SUB>1</SUB>∣} with (<I>n</I> <SUB>2</SUB>, <I>m</I> <SUB>2</SUB>) rotating <I>π</I>/3 angle or not. While for a junction connected by two zigzag, armchair or two chiral SWCNTs with the same handedness, the number of 5/7 pairs is equal to ∣<I>n</I> <SUB>1</SUB>?−?<I>n</I> <SUB>2</SUB>∣?+?∣<I>m</I> <SUB>1</SUB>?−?<I>m</I> <SUB>2</SUB>∣. Similar to the formation energies of grain boundaries in graphene, the curve of the formation energies vs. chiral angle difference present an ‘M’ shape indicating the preference of ∼30 degree junctions. Moreover, the formation energies of the zigzag-type and armchair-type junctions with zero misorientation angles are largely sensitive to the diameter difference of two sub-SWCNTs.</P>

Fast position predictive control with current and speed limits for permanent magnet motor systems without weight coefficients

Xiuyun Zhang,Zhiqiang Wang,Genghuang Yang 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.4

To solve the problems that the weight coefficient of the cost function in the traditional position predictive control is difficultto adjust, and the calculation efficiency of the voltage vector selection is low under the traditional ergodic method, this paper proposes a fast position predictive control strategy with current and speed limits without a weight coefficient. First, the reference voltage vector is predicted. Then the cost function is converted to the voltage dimension to leave out the weight coefficient. After that, the candidate vector selection and the cost function optimization are carried out according to the sector location where the reference voltage vector is located to reduce the number of calculations. Then according to actual system needs, the current and speed limits are integrated into the selection of the alternative voltage vector. At this point, the selected optimal voltage vector is improved through the relationship between the voltage limit circle and the rectangular area to realize the current and speed limit. Finally, experimental results verify that the proposed control strategy has better motion control accuracy and dynamic response speed, without adjusting weight coefficients.

Inheritance of Downy Mildew Resistance at Different Developmental Stages in Chinese Cabbage via the Leaf Disk Test

Shengju Zhang,Shuancang Yu,Fenglan Zhang,Longting Si,Yangjun Yu,Xiuyun Zhao,Deshuang Zhang,Weihong Wang 한국원예학회 2012 Horticulture, Environment, and Biotechnology Vol.53 No.5

Downy mildew, caused by Hyaloperonospora parasitica, is a destructive disease of the Chinese cabbage (Brassica rapa ssp. pekinensis). A rapid resistance/susceptibility test for H. parasitica was established by the inoculation of a leaf disk test. Four conditions were tested and the optimal condition was found when the inoculated leaf disk was placed into dark conditions at 16℃ for the first 24 hours after inoculation, followed by 5 days of light at 20℃and 23℃ for 4 hours and 5 hours, respectively, dark at 16℃ and 12℃ for 3 hours and 12 hours, respectively, and a final temperature of 16℃ for 24 hours. There was a good correlation between the resistance levels of leaf disks and the resistance of seedlings or adult plants, which indicated that testing leaf disks should be the preferred methods to predict the resistance of adult plants. Using this method, downy mildew resistance was investigated in a double haploid (DH) population at four developmental stages. The results showed that the genetic pattern, which was deduced from the DH segregation, was relatively similar, but varied slightly during plant development.

Critical effects of long non-coding RNA on fibrosis diseases

Yue Zhang,Gang Luo,Yi Zhang,Mengjie Zhang,Jian Zhou,Weiwu Gao,Xiuyun Xuan,Xia Yang,Di Yang,Zhiqiang Tian,Bing Ni,Jun Tang 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

The expression or dysfunction of long non-coding RNAs (lncRNAs) is closely related to various hereditary diseases, autoimmune diseases, metabolic diseases and tumors. LncRNAs were also recently recognized as functional regulators of fibrosis, which is a secondary process in many of these diseases and a primary pathology in fibrosis diseases. We review the latest findings on lncRNAs in fibrosis diseases of the liver, myocardium, kidney, lung and peritoneum. We also discuss the potential of diseaserelated lncRNAs as therapeutic targets for the clinical treatment of human fibrosis diseases.

Investigation on the Preparation and Adsorption Performance of Bamboo Fiber Based Activated Carbon

Qing Zhang,Yue Zeng,Xiuyun Xiao,Penghu Deng,Qing He,Tonghua Zhang 한국섬유공학회 2019 Fibers and polymers Vol.20 No.2

In this work, an approach was explored to make natural fiber based activated carbon with high adsorption capacity for treating dyeing wastewater. Bamboo fiber based activated carbon (BFAC) was prepared by bamboo fiber extracted from bamboo strips by extracting technique. An orthogonal experiment was carried out to obtain optimum preparation condition for the best dye adsorption. The microstructures of BFAC were characterized by scanning electron microscopy, N2 adsorption-desorption analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. Adsorption mechanism of BFAC to methylene blue (MB) was studied and the adsorption isotherm followed the Langmuir model, with maximum monolayer adsorption capacity of 651.7 mg g-1. The adsorption kinetic was better described by the pseudo-second-order model. Microstructure characterization showed lots of opened pores and cracks with different size on BFAC, with Brunauer-Emmett-Teller (BET) surface area of 1370 m2 g-1 and total pore volume of 0.9411 cm3 g-1. The analysis indicated that cellulose crystal of bamboo fiber was severely destroyed in the preparation process, which could contribute to the formation of pores. Moreover, -OH and -C=O functional groups on BFAC are beneficial for adsorbing MB in aqueous solution. As a result, adopting bamboo fiber may help form BFAC with high BET surface area, which proved to be an effective idea to prepare activated carbon with high adsorption performance.

Two-Dimensional Unilamellar Cation-Deficient Metal Oxide Nanosheet Superlattices for High-Rate Sodium Ion Energy Storage

Xiong, Pan,Zhang, Xiuyun,Zhang, Fan,Yi, Ding,Zhang, Jinqiang,Sun, Bing,Tian, Huajun,Shanmukaraj, Devaraj,Rojo, Teofilo,Armand, Michel,Ma, Renzhi,Sasaki, Takayoshi,Wang, Guoxiu American Chemical Society 2018 ACS NANO Vol.12 No.12

<P>Cation-deficient two-dimensional (2D) materials, especially atomically thin nanosheets, are highly promising electrode materials for electrochemical energy storage that undergo metal ion insertion reactions, yet they have rarely been achieved thus far. Here, we report a Ti-deficient 2D unilamellar lepidocrocite-type titanium oxide (Ti<SUB>0.87</SUB>O<SUB>2</SUB>) nanosheet superlattice for sodium storage. The superlattice composed of alternately restacked defective Ti<SUB>0.87</SUB>O<SUB>2</SUB> and nitrogen-doped graphene monolayers exhibits an outstanding capacity of ∼490 mA h g<SUP>-1</SUP> at 0.1 A g<SUP>-1</SUP>, an ultralong cycle life of more than 10000 cycles with ∼0.00058% capacity decay per cycle, and especially superior low-temperature performance (100 mA h g<SUP>-1</SUP> at 12.8 A g<SUP>-1</SUP> and −5 °C), presenting the best reported performance to date. A reversible Na<SUP>+</SUP> ion intercalation mechanism without phase and structural change is verified by first-principles calculations and kinetics analysis. These results herald a promising strategy to utilize defective 2D materials for advanced energy storage applications.</P> [FIG OMISSION]</BR>

Solution-processed WOx hole injection layer for efficient fluorescent blue organic light-emitting diode

Wanshu Li,Yan Zhang,Qinghong Zheng,Kai Xu,Xiuyun Zhang,Liming Liu,Bin Wei,Lihui Wang,Jiwen Xu,Xiaowen Zhang 한국물리학회 2018 Current Applied Physics Vol.18 No.5

Solution-processed tungsten oxide (s-WOx) interfacial layer for efficient hole injection in fluorescent blue organic light-emitting diode (OLED) is demonstrated. The OLED using 2-methyl-9,10-bis(naphthalen-2- yl)anthracene (MADN) as emitter shows luminous efficiency of 3.3 cd/A, power efficiency of 2.5 lm/W and external quantum efficiency of 4.6% with Commission Internationale d'Eclairage (CIE) color coordinates of (0.154, 0.102). Using MADN doped 1-4-di-[4-(N,N-diphenyl)amino]styryl-benzene as emitter, luminous efficiency of 10.8 cd/A, power efficiency of 6.4 lm/W and external quantum efficiency of 7.2% with CIE color coordinates of (0.167, 0.283) are achieved. Atomic force microscopy and X-ray photoelectron spectroscopy show that s-WOx features superior film morphology and non-stoichiometry with slight oxygen deficiency. Current-voltage characteristics and impedance spectroscopy analysis indicate that s-WOx behaves slightly enhanced hole injection and accordingly contributes to improved device performance in comparison with conventional vacuum thermal evaporation WOx. Our results pave an alternative way for broadeningWOx application with solution process and advancing fluorescent blue OLEDs.

Genetic diversity and marker‐trait associations in a collection of Pak‐choi (Brassica rapa L. ssp. chinensis Makino) Accessions

Shuancang Yu,Xiaoyi Wang,Xiuyun Zhao,Deshuang Zhang,Yangjun Yu,Jiabing Xu,Fenglan Zhang 한국유전학회 2010 Genes & Genomics Vol.32 No.5

Pak‐choi (Brassica rapa L. ssp. chinensis Makino) is one of the most important vegetable, especially in southern China. Morphological traits of Pak‐choi vary widely, and the genetic basis of these variations is largely undescribed. In this study,we evaluated eighty Pak‐choi accessions for genetic diversity based on 29 morphological descriptors and 20 microsatellite (SSR) loci. Our data reveal a high level of diversity in this set of Pak‐choi accessions. Euclidean distance was used for cluster analysis. The UPGMA dendrogram grouped the Pakchoi accessions into five major clusters based on morphological characteristics. As expected, similar morphological characteristics grouped together in cluster branches. Further,population structure was explored to identify subpopulations based on allele frequency. Five groups were identified, and showed considerable correlation with the morphological clusters. Associations between SSR markers and agronomic traits were further investigated using a non‐parametric Kruskal–Wallis K‐test and six additional parametric models. Significant associations were found between 18 SSR loci and 28 morphological traits. This study provides evidence that marker‐trait associations can be validated in segregating populations and exploited through marker‐assisted selection.

Optimal placement of collocated actuators and sensors for active vibration control of cable-network antenna reflectors

Yang Liu,Weizhong Zhang,Xiuyun Meng 제어로봇시스템학회 2016 제어로봇시스템학회 국제학술대회 논문집 Vol.2016 No.10

This paper is aimed at finding the optimal locations of collocated actuator and sensor pairs for active vibration control of cable-network antenna reflectors. The front cable net of the antenna is considered as the control plant. The optimal criterion for placement of actuator and sensor pairs is to choose locations that simultaneously maximize the H₂ norms of each dominant mode, and simultaneously minimize the H₂ norms of the residual modes when spillover effect is considered. Direct velocity feedback is applied to verify the effectiveness of the optimized locations. Numerical simulations indicate that the method proposed in this paper is feasible.

The alum-processing mechanism attenuating toxicity of Araceae Pinellia ternata and Pinellia pedatisecta

Hongli Yu,Hao Wu,Yaozong Pan,Xiuyun Ge,Qian Zhang,Fagen Zhu,Baochang Cai 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.10

The present study aimed at investigating thealum-processing mechanism attenuating toxicity of AraceaePinellia ternata and Pinellia pedatisecta. Animalretroperitoneal inflammatory model in vivo andmacrophagocyte release inflammatory factor model in vitrowere used to detect the effect of alum processing onraphides and lectin. Scanning electron microscopy wasused to observe the change in raphides during processing;HPLC method was used to determine the correlation betweenthe dissolution and corrosion of raphides and ion inthe alum solution; 27Al-NMR technology was used to detectthe relationship between aluminum oxalate complexformation and the dissolved and corrosion of raphides. Thechange in protein peptide sequence of lectin during theprocessing of alum solution was determined by ShotgunLC–MS assay. Raphides induced severe rabbit conjunctivaledema and an intraperitoneal injection of lectin increasedPGE2 and protein in mice peritoneal exudate, whiledecreased after treatment with alum solution processing. During the processing raphides was dissolved and corroded,then its structure was damaged. Raphides was soaked inthe alum solution and significantly decreased the oxalatecontent, and the effect was related with Al3? in the alum. Al3? in the alum combined with C2O42- of raphides into astable complex compound promoted the dissolution ofcalcium oxalate. Raphides soaked in the alum made lectinproteins dissolve, whereas protein peptide sequence oflectin was changed and the protein structure was damaged. Conclusion: Alum solution could decrease the toxicity ofP. ternata (Thunb.) Breit. and P. pedatisecta Schott. Sinceit made a special crystal structure of raphides damage andthe protein of lectin dissolve. The structure of toxic substancessignificantly changed, which decreased the inflammatoryeffect.