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XIN-SHENG CHAI,JINGHONG ZHOU,HONGXIANG ZHU,XIANNAN HUANG 한국펄프·종이공학회 2006 한국펄프종이학회 기타 간행물 Vol.- No.-
This paper describes a technique combining chemometrics with UV spectroscopy for the determination of the concentrations of two tissue additives (i.e., wet strength and softening agents) in a cellulose fiber containing solution. In single agent solutions, the concentration of the additive can be measured by UV spectroscopy at the wavelength where the species having absorption. For a binary (i.e., containing two additives) solution system, the spectral characterization is very complicated. However, if aided by a chemometrical calibration technique, each additive in the binary solution can be qua ntified simultaneously. The present method is very rapid and simple, it can easily perform a continuous measurement in the changes in the additives’ concentration after fiber addition, and therefore this becomes a valuable tool for the adsorption kinetics study of chemical additives onto the cellulose fibers. The time-dependent adsorption behaviors of the wet-strength, softening agent, and their both on fiber were also presented.
Experimental Study on Seepage and Stress of Single-fracture Radiation Flow
Xin Zhang,Junrui Chai,Yuan Qin,Jing Cao,Cheng Cao 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.3
Studying the stress distribution and water flow law of rocks under stress and seepage pressure in different directions can provide a certain basis for rock stability. In this experiment, a test system instrument for coupling direct shear and seepage of rock joints was developed to analyze the fracture seepage and shear stress of the relatively smooth surface formed by gypsum specimens. The seepage considered in this study refers to the groundwater at a depth of 80–150 m below the surface. Moreover, a radiation flow model was established, and a new law was obtained by fitting the relationship between flow rate and mechanical aperture. The shear process was divided into three phases. Normal stress and contact surface undulation had a considerable influence on shear stress. A two-dimensional numerical model showed that the vortices were the important cause of damage to the radiation flow. Increasing the seepage pressure increased the flow velocity between the fractures. The maximum flow velocity on one side of the same shear direction was larger than that on the other side.
Metabolomics reveals abundant flavonoids in edible insect Antheraea pernyi
Fu Xin,Chai Chun-Li,Li Yu-Ping,Li Peng,Luo Shi-Hong,Li Qun,Li Muwang,Liu Yan-Qun 한국응용곤충학회 2021 Journal of Asia-Pacific Entomology Vol.24 No.3
The natural flavonoids in foods of plant origin have been well-characterized due to their beneficial biological properties. However, the information regarding the flavonoid compounds in edible insects remains severely limited. In the present study, we used a metabolomics approach to identify the flavonoid compounds in the Chinese oak silkworm, Antheraea pernyi Guérin-Méneville (Lepidoptera: Saturniidae), an traditional edible insect. Our study identified over 200 flavonoid metabolites in the larval midgut of A. pernyi with LC-ESI-MS/MS system. These flavonoid metabolites come from eight subclasses, including flavones (1 0 3), flavonols (34), flavonoids (28), flavanones (20), polyphenols (19), isoflavones (9), anthocyanins (9), and proanthocyanidins (4). The relative content of the flavones is the most abundant, with a value of 36.74% of the total. The top five flavonoid components in A. pernyi are hyperoside, isoquercitroside, tricin 7-O-hexoside, hesperetin 5-O-glucoside and protocatechuic acid, accounting for 51.17% of the total flavonoids. Hyperoside is the most abundant flavonoid compound (18.07% of the total) in A. pernyi. Our findings indicated targeted metabolomics is a useful approach to identify flavonoids in edible insects which contain abundant flavonoids than we already knew.
Planning and Execution of Dynamic Whole-body Locomotion for a Wheeled Biped Robot on Uneven Terrain
Yaxian Xin,Jiuhong Ruan,Yibin Li,Hui Chai,Xuewen Rong 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.4
To improve the adaptability of the wheeled biped robot (WBR) to uneven terrain, firstly an integrated modeling method for wheeled-legs is proposed. The under-actuated part is effectively restrained by defining the interaction force between the WBR and the trunk. The mapping relationship between the wheeled leg’s end force and the joint torques in the balanced state is built. Based on this premise, a control framework that does not rely on external sensors is proposed, and the trunk pose is used as the task space to plan the generalized force output of the wheeled legs and calculate the joint torques. Since the joint space position is not constrained, the leg wheels will be based on the terrain conditions and are adaptively stretched and adjusted back and forth. To further improve the terrain adaptability, a slope estimator and a stabilizer are constructed to deal with the attitude fluctuation caused by the sudden change of terrain. The control framework is proved to verify by simulations and experiment.
Qingxi Hou,Xin-sheng Chai,Junyong Zhu 한국펄프·종이공학회 2006 한국펄프종이학회 기타 간행물 Vol.- No.-
This paper reports an improved headspace gas chromatographic method for the determination of carboxyl group content in wood fibers. Pretreatment of wood fibers was applied using dilute HCl to convert carboxyl groups to carboxylic acid groups and then using deionized water to wash fiber samples thoroughly. The samples were finally air dried. Sodium bicarbonate solution was used to react with carboxylic acid groups of the pretreated fibers in a closed testing vial to release carbon dioxide. The content of carboxyl groups in fibers was accurately quantified by determining the amount of carbon dioxide released by a headspace gas chromatograph equipped with a thermal conductivity detector. The modified process for fiber sample pretreatment increased the reliability and accuracy in measuring carboxylic acid groups. The present method is simple, accurate.
Hui-Chao Hu,Xin-Sheng Chai,Ying-Xin Tian,Wei-Feng Si,Gang Chen 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.3
This paper reports on a headspace gas chromatographic method (HS-GC) for the determination of residual formaldehyde in formaldehyde related polymer latexes. The method is based on the reaction between formaldehyde and borohydride in a sodium hydroxide solution (1 mol/L), in which formaldehyde is quantitatively converted to methanol within 30 min at 90 8C and then determined by HS-GC. The results showed that the repeatability of the method had a relative standard deviation of less than 5.0%; the limit of quantification (LOQ) was 17.3 mg, and the recovery ranged from 96.2–102%. The present method is simple, rapid, and accurate.