The Element Segregation Between γ/γʹ Phases in a Ni-Based Single Crystal Superalloy Studied by 3D-APT and Its Potential Impact on Local Interfacial Misfit Strain

Wenchao Yang,Pengfei Qu,Ruirong Zhang,Jiarun Qin,Chen Liu,Jun Zhang,Lin Liu 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.6

Three-dimensional atom-probe tomography was used to characterize the γ/γʹ interface structure in a third-generation Nibasedsingle crystal superalloy with Re addition. It was found that an element-segregation layer with Re, Co and Cr wasformed in the γ phase close to the γ/γ′ interface, resulting in a more negative local interface misfit (− 0.29%) compared tothe measured result (− 0.16%) from high-resolution X-ray diffraction. Furthermore, the total reduction of interfacial freeenergy due to the solute atom segregation based on the Gibbsian interfacial excess was calculated to indicate that Re elementwas the most beneficial element in producing this more negative local misfit with the largest interfacial free energy reduction(13.67 ± 0.21 mJ/m2). Simultaneously, because of the co-segregation of Re, Co and Cr, and the depletion of Ni in the γphase close to the γ/γ′ interface, it was also deduced that some harmful topologically close-packed phases might be easierto nucleate and grow in the γ phase close to the γ/γ′ interface in service.

On Extended State Predictor Observer based Active Disturbance Rejection Control for Uncertain Systems with Sensor Delay

Wenchao Xue,Ping Liu,Sen Chen,Yi Huang 제어로봇시스템학회 2016 제어로봇시스템학회 국제학술대회 논문집 Vol.2016 No.10

This paper considers the control problem for a class of sensor delay systems with nonlinear unknown dynamics and external disturbances. The extended state predictor observer (ESPO) based active disturbance rejection control (ADRC) is first proposed to timely estimate and compensate for the “total disturbance” under sensor delay. The timedomain stability of the closed-loop system is rigorously studied by discussing the bound of tracking error between state and its desired trajectory. More importantly, it is proven that the proposed method can greatly improve the existing PO based control in dealing with the “total disturbance” in the low frequency range. Also, the simulation results show the effectiveness of the ESPO based ADRC for tackling several kinds of uncertainties.

Roles of Surface Steps on Pt Nanoparticles in Electro-oxidation of Carbon Monoxide and Methanol

Lee, Seung Woo,Chen, Shuo,Sheng, Wenchao,Yabuuchi, Naoaki,Kim, Yong-Tae,Mitani, Tadaoki,Vescovo, Elio,Shao-Horn, Yang American Chemical Society 2009 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.131 No.43

<P>Design of highly active nanoscale catalysts for electro-oxidation of small organic molecules is of great importance to the development of efficient fuel cells. Increasing steps on single-crystal Pt surfaces is shown to enhance the activity of CO and methanol electro-oxidation up to several orders of magnitude. However, little is known about the surface atomic structure of nanoparticles with sizes of practical relevance, which limits the application of fundamental understanding in the reaction mechanisms established on single-crystal surfaces to the development of active, nanoscale catalysts. In this study, we reveal the surface atomic structure of Pt nanoparticles supported on multiwall carbon nanotubes, from which the amount of high-index surface facets on Pt nanoparticles is quantified. Correlating the surface steps on Pt nanoparticles with the electrochemical activity and stability clearly shows the significant role of surface steps in enhancing intrinsic activity for CO and methanol electro-oxidation. Here, we show that increasing surface steps on Pt nanoparticles of approximately 2 nm can lead to enhanced intrinsic activity up to approximately 200% (current normalized to Pt surface area) for electro-oxidation of methanol.</P>

Novel Nucleotide Variations, Haplotypes Structure and Associations with Growth Related Traits of Goat AT Motif-Binding Factor (ATBF1) Gene

Xiaoyan Zhang,Xianfeng Wu,Wenchao Jia,Chuanying Pan,Xiangcheng Li,Chuzhao Lei,Hong Chen,Xianyong Lan 아세아·태평양축산학회 2015 Animal Bioscience Vol.28 No.10

The AT motif-binding factor (ATBF1) not only interacts with protein inhibitor of activated signal transducer and activator of transcription 3 (STAT3) (PIAS3) to suppress STAT3 signaling regulating embryo early development and cell differentiation, but is required for early activation of the pituitary specific transcription factor 1 (Pit1) gene (also known as POU1F1) critically affecting mammalian growth and development. The goal of this study was to detect novel nucleotide variations and haplotypes structure of the ATBF1 gene, as well as to test their associations with growth-related traits in goats. Herein, a total of seven novel single nucleotide polymorphisms (SNPs) (SNP 1-7) within this gene were found in two well-known Chinese native goat breeds. Haplotypes structure analysis demonstrated that there were four haplotypes in Hainan black goat while seventeen haplotypes in Xinong Saanen dairy goat, and both breeds only shared one haplotype (hap1). Association testing revealed that the SNP2, SNP5, SNP6, and SNP7 loci were also found to significantly associate with growth-related traits in goats, respectively. Moreover, one diplotype in Xinong Saanen dairy goats significantly linked to growth related traits. These preliminary findings not only would extend the spectrum of genetic variations of the goat ATBF1 gene, but also would contribute to implementing marker-assisted selection in genetics and breeding in goats.

Optical Design of a Snapshot Nonmydriatic Fundus-imaging Spectrometer Based on the Eye Model

Xuehui Zhao,Jun Chang,Wenchao Zhang,Dajiang Wang,Weilin Chen,Jiajing Cao 한국광학회 2022 Current Optics and Photonics Vol.6 No.2

Fundus images can reflect ocular diseases and systemic diseases such as glaucoma, diabetes mellitus, and hypertension. Thus, research on fundus-detection equipment is of great importance. The fundus camera has been widely used as a kind of noninvasive detection equipment. Most existing devices can only obtain two-dimensional (2D) retinal-image information, yet the fundus of the human eye also has spectral characteristics. The fundus has many pigments, and their different distributions in the eye lead to dissimilar tissue penetration for light waves, which can reflect the corresponding fundus structure. To obtain more abundant information and improve the detection level of equipment, a snapshot nonmydriatic fundus imaging spectral system, including fundus-imaging spectrometer and illumination system, is studied in this paper. The system uses a microlens array to realize snapshot technology; information can be obtained from only a single exposure. The system does not need to dilate the pupil. Hence, the operation is simple, which reduces its influence on the detected object. The system works in the visible and near-infrared bands (550–800 nm), with a volume less than 400 mm × 120 mm × 75 mm and a spectral resolution better than 6 nm.

Novel Nucleotide Variations, Haplotypes Structure and Associations with Growth Related Traits of Goat AT Motif-Binding Factor (ATBF1) Gene

Zhang, Xiaoyan,Wu, Xianfeng,Jia, Wenchao,Pan, Chuanying,Li, Xiangcheng,Lei, Chuzhao,Chen, Hong,Lan, Xianyong Asian Australasian Association of Animal Productio 2015 Animal Bioscience Vol.28 No.10

The AT motif-binding factor (ATBF1) not only interacts with protein inhibitor of activated signal transducer and activator of transcription 3 (STAT3) (PIAS3) to suppress STAT3 signaling regulating embryo early development and cell differentiation, but is required for early activation of the pituitary specific transcription factor 1 (Pit1) gene (also known as POU1F1) critically affecting mammalian growth and development. The goal of this study was to detect novel nucleotide variations and haplotypes structure of the ATBF1 gene, as well as to test their associations with growth-related traits in goats. Herein, a total of seven novel single nucleotide polymorphisms (SNPs) (SNP 1-7) within this gene were found in two well-known Chinese native goat breeds. Haplotypes structure analysis demonstrated that there were four haplotypes in Hainan black goat while seventeen haplotypes in Xinong Saanen dairy goat, and both breeds only shared one haplotype (hap1). Association testing revealed that the SNP2, SNP5, SNP6, and SNP7 loci were also found to significantly associate with growth-related traits in goats, respectively. Moreover, one diplotype in Xinong Saanen dairy goats significantly linked to growth related traits. These preliminary findings not only would extend the spectrum of genetic variations of the goat ATBF1 gene, but also would contribute to implementing marker-assisted selection in genetics and breeding in goats.

Wind characteristics of a strong typhoon in marine surface boundary layer

Song, Lili,Li, Q.S.,Chen, Wenchao,Qin, Peng,Huang, Haohui,He, Y.C. Techno-Press 2012 Wind and Structures, An International Journal (WAS Vol.15 No.1

High-resolution wind data were acquired from a 100-m high offshore tower during the passage of Typhoon Hagupit in September, 2008. The meteorological tower was equipped with an ultrasonic anemometer and a number of cup anemometers at heights between 10 and 100 m. Wind characteristics of the strong typhoon, such as mean wind speed and wind direction, turbulence intensity, turbulence integral length scale, gust factor and power spectra of wind velocity, vertical profiles of mean wind speed were investigated in detail based on the wind data recorded during the strong typhoon. The measured results revealed that the wind characteristics in different stages during the typhoon varied remarkably. Through comparison with non-typhoon wind measurements, the phenomena of enhanced levels of turbulence intensity, gust factors, turbulence integral length scale and spectral magnitudes in typhoon boundary layer were observed. The monitored data and analysis results are expected to be useful for the wind-resistant design of offshore structures and buildings on seashores in typhoon-prone regions.

Wind characteristics of a strong typhoon in marine surface boundary layer

Lili Song,Q. S. Li,Wenchao Chen,Peng Qin,Haohui Huang,Y.C. He 한국풍공학회 2012 Wind and Structures, An International Journal (WAS Vol.15 No.1

High-resolution wind data were acquired from a 100-m high offshore tower during the passage of Typhoon Hagupit in September, 2008. The meteorological tower was equipped with an ultrasonic anemometer and a number of cup anemometers at heights between 10 and 100 m. Wind characteristics of the strong typhoon, such as mean wind speed and wind direction, turbulence intensity, turbulence integral length scale, gust factor and power spectra of wind velocity, vertical profiles of mean wind speed were investigated in detail based on the wind data recorded during the strong typhoon. The measured results revealed that the wind characteristics in different stages during the typhoon varied remarkably. Through comparison with non-typhoon wind measurements, the phenomena of enhanced levels of turbulence intensity, gust factors, turbulence integral length scale and spectral magnitudes in typhoon boundary layer were observed. The monitored data and analysis results are expected to be useful for the wind-resistant design of offshore structures and buildings on seashores in typhoon-prone regions.

Atomically thin p–n junctions with van der Waals heterointerfaces

Lee, Chul-Ho,Lee, Gwan-Hyoung,van der Zande, Arend M.,Chen, Wenchao,Li, Yilei,Han, Minyong,Cui, Xu,Arefe, Ghidewon,Nuckolls, Colin,Heinz, Tony F.,Guo, Jing,Hone, James,Kim, Philip Nature Publishing Group, a division of Macmillan P 2014 Nature nanotechnology Vol.9 No.9

Semiconductor p–n junctions are essential building blocks for electronic and optoelectronic devices. In conventional p–n junctions, regions depleted of free charge carriers form on either side of the junction, generating built-in potentials associated with uncompensated dopant atoms. Carrier transport across the junction occurs by diffusion and drift processes influenced by the spatial extent of this depletion region. With the advent of atomically thin van der Waals materials and their heterostructures, it is now possible to realize a p–n junction at the ultimate thickness limit. Van der Waals junctions composed of p- and n-type semiconductors—each just one unit cell thick—are predicted to exhibit completely different charge transport characteristics than bulk heterojunctions. Here, we report the characterization of the electronic and optoelectronic properties of atomically thin p–n heterojunctions fabricated using van der Waals assembly of transition-metal dichalcogenides. We observe gate-tunable diode-like current rectification and a photovoltaic response across the p–n interface. We find that the tunnelling-assisted interlayer recombination of the majority carriers is responsible for the tunability of the electronic and optoelectronic processes. Sandwiching an atomic p–n junction between graphene layers enhances the collection of the photoexcited carriers. The atomically scaled van der Waals p–n heterostructures presented here constitute the ultimate functional unit for nanoscale electronic and optoelectronic devices.

新时代大学生奋斗精神培育研究 : 以创新创业教育和思政教育融合研究为视角

褚庆柱,陈刚,王帅,刘奕辰,尹文超,邹亚平,Chu, Qingzhu,Chen, Gang,Wang, Shuai,Liu, Yichen,Yin, Wenchao,Zou, Yaping Institute of Management Research 2021 Journal of East Asia Management Vol.2 No.1

Struggle refers to the process of overcoming various difficulties for a goal. The spirit of struggle is a positive attitude and reaction reflected in the process of struggle. Cultivating the spirit of struggle of college students is the call of the new era. In essence, the cultivation of the spirit of struggle is a process of learning, which is in line with Bandura's Observation Learning Theory(Bandura, 1977):Attention, Maintenance, Reproduction and Motivation. The cultivation of College Students' spirit of struggle in the new era is also a learning process of enriched experience. It is necessary to cultivate the spirit of struggle into the soul of college students and make it become a habit of students. Moreover, it is crucial to carry out adaptive transformation of Bandura's observation learning theory. By studying the mechanism of the spirit of struggle of college students, taking innovation and entrepreneurship education as a means, and aiming at cultivating the connotation of President Xi's thought on socialism with Chinese characteristics for a new era, this paper constructs the AIST model for cultivating the spirit of struggle of college students in the new era. This model includes online learning acceptance platform(Acceptance), classroom experience stimulation platform(Inspiration), iterative training solidified platform (Solidification), and competition practice transfer platform(Transfer). The purpose of this model is to provide a practical way for universities to fulfill the fundamental task of moral education and cultivate qualified socialist builders and successors. The number of students using the online learning acceptance platform ranked the first among that of the similar courses in China; The classroom experience stimulation platform and the iterative training solidified platform support each other, with an effective rate of 97%; The competition practice transfer platform has realized the continuous growth of the number of awards won in competitions for three years. The direction of future efforts is to establish the external mechanism of the spirit of struggle, to ensure the effectiveness of classroom experience and iterative training, to cultivate teachers with coaching skills, and to accurately measure the transformation point of external and endogenous motivation.