Efficient Immobilization of Enzymes on Amino Functionalized MIL-125-NH2 Metal Organic Framework

Zichen Wang,Yang Liu,Jinhong Li,Guoqing Meng,Daoyu Zhu,Jiandong Cui,Shi Ru Jia 한국생물공학회 2022 Biotechnology and Bioprocess Engineering Vol.27 No.1

As a series of metal organic framework (MOFs), materials of institute lavoisier frameworks (MILs) are expected to be excellent supports for enzyme immobilization due to their good water-stability and acid tolerance. However, enzyme loading on MIL-125-NH2 is very low due to small pore size and few amino groups on the surface of the MIL-125-NH2. In this work, catalase (CAT) was immobilized on the MIL-125-NH2 and amino functionalized MIL-125-NH2 by adsorption (CAT@MIL-125-NH2) and covalent binding (CAT@Amino MIL-125-NH2), respectively. Compared with the CAT@MIL-125-NH2 and free CAT, the CAT@Amino MIL-125-NH2 displayed high activity recovery, good pH stability, stability against denaturants, and thermostability. Furthermore, activity recovery of CAT@Amino MIL-125-NH2 was 56% higher than CAT@MIL-125-NH2. The CAT@Amino MIL-125-NH2 still retained 50% residual activity for 14 days at room temperature, whereas free CAT lost activity after storage for 1 day at the same storage conditions. Furthermore, the CAT@Amino MIL-125-NH2 maintained 62% of its initial activity after 4 consecutive uses, showing good reusability. The results showed that the amino functionalized MIL- 125-NH2 is an excellent carrier of enzyme immobilization.

Grey fuzzy PI control for packing pressure during injection molding process

Shuo Wang,Ji Ying,Zichen Chen,Kan Cai 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.4

This study presents a grey fuzzy PI (GFPI) controller for packing pressure control during the injection process. The novel controller was designed for solving the problems of large overshoot, static error, and long delay time on servo motor-driven injection molding machines. Based on reasonable assumptions, a mathematical model of injection system was established. According to the nonlinear, severe interferences, and long delay time characteristics in injection process, this paper integrates predictive grey system, robust fuzzy ratiocination,and PI control. Using these mathematical model and control algorithms, a GFPI controller is implemented into an MCU using C programming techniques. The integral discrete PID controller and solid fuzzy controller were realized for contrast experiments. The experimental results show that GFPI controller had better performance on reducing overshoot and static error, increasing both response rate and repeatable accuracy. Such a developed technology would provide helpful references for designing the controller of energy-saving servo motor-driven injection molding equipment.

Fabrication and Characterization of Electrospun Gelatin-Heparin Nanofibers as Vascular Tissue Engineering

Heyun Wang,Yakai Feng,Zichen Fang,Ruofang Xiao,Wenjie Yuan,Musammir Khan 한국고분자학회 2013 Macromolecular Research Vol.21 No.8

In this paper, heparin was introduced into electrospun gelatin nanofibrous scaffold for assessment as a controlled delivery device in vascular tissue engineering application. Hybrid gelatin-heparin fibers with smooth surfaces and no bead defects were produced from gelatin solutions with 18% w/v in acetic acid aqueous solution. A significant decrease in fiber diameter was observed when the heparin content was increased from 1 to 5 wt%. The properties of composite gelatin-heparin scaffolds were confirmed by Fourier transform infrared spectroscopy (FTIR)and differential scanning calorimetry (DSC) measurement. The gelatin-heparin fibrous scaffolds were also cross-linked using 1 wt% glutaraldehyde vapor-phase for 7 days. A sustained release of heparin could be achieved from gelatinheparin scaffolds over 14 days. The results of the biocompatibility in vitro tests carried out using human umbilical vein endothelial cells indicated good cell viability and proliferation on the gelatin-heparin scaffolds. The results demonstrated that the use of electrospun gelatin fibers as heparin carriers could be promising for vascular tissue applications.

UDGAN: A new urban design inspiration approach driven by using generative adversarial networks

干薇,Zhao Zichen,Wang Yuankai,Zou Yixuan,Zhou Shiqi,오지강 한국CDE학회 2024 Journal of computational design and engineering Vol.11 No.1

The morphological design of urban space affects the quality of the environment. The traditional experience-based design approach was greatly improved by introducing computational design tools. However, the existing urban design tools are mostly developed on pre-set rules or given targets, which have few contributions to enhance creativity or generate inspiring schemes. Therefore, this paper proposes a new computational urban design approach named UDGAN, integrating generative adversarial networks (GANs) and multi-objective optimization algorithms. This model utilizes urban design scheme plans over the past 20 years from a particular designer as training datasets. Four preference models were trained to autonomously generate stylized urban design schemes. Eight morphological parameters were used to analyze the model performance by comparing generated results with the ground truth. This GAN-based surrogate approach is combined with a morphological indicator alignment process using multi-objective optimization model to obtain better results. The result shows that the R2 predicted by the improved Pix2Pix model reaches 0.798, and the similarity of the generated results can be stably distributed between 0.7 and 0.8, so the design scheme of this preferred style can be effectively learned. At the same time, the pre-trained model greatly reduces the time consumption of the design scheme generation, taking 5 min approximately to complete a generation process. This approach quickly generated the design scheme with preferred features, supporting the designer with creativity and greatly saving the time of design creation, transforming computational design into an inspiration-driven process.

Optimization of Capacity Configuration of Wind–Solar–Diesel–Storage Using Improved Sparrow Search Algorithm

Dong Jun,Dou Zhenhai,Si Shuqian,Wang Zichen,Liu Lianxin 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.1

In order to reasonably allocate the capacity of distributed generation and realize the goal of stable, economic and clean operation of the system, a multi-objective optimization model with investment cost, environmental protection and power supply quality as indicators has been established, and the multi-objective sparrow search algorithm is used to optimize the solution. Although the multi-objective search algorithm is more effi cient than the traditional single objective algorithm, it is easy to fall into local optimum. To this end, the niche optimization technology is used to improve the optimization eff ect of multi-objective sparrow search algorithm, and the Levy fl ight strategy is introduced to enhance the ability of multi-objective sparrow search algorithm to jump out of local optimum. The calculation example uses the traditional multi-object search algorithm and the niche multi-objective sparrow search algorithm with levy disturbance to solve the proposed model. The simulation results verify the eff ectiveness of the multi-objective sparrow search algorithm improved by levy disturbance and niche optimization technology

Mechanism of Synergetic Growth of Flexibility and Strength of Biomimetic Nanocomposite Fibre

Xiangyu Duan,Pan Li,Jingyu Ouyang,Zichen Gao,Jiaxin Liu,Jie Wang,Zhigang Xia,Weilin Xu 한국섬유공학회 2022 Fibers and polymers Vol.23 No.3

Nanocomposites with carbon nanotubes (CNTs) can combine the stiffness and multi-functionality of carbonnanotubes with the advantages of high toughness and processability of polymers giving rise to properties different from thatof general composites. However, when the content of CNTs increases gradually, the flexibility of the composite fibre canreduce. In this paper, we propose a simple method of softening the composite fibre via dimensional helical deformation offibre inner macromolecule bundles to avoid the deterioration of fibre flexibility. The theoretical simulations were conductedto predict proper helical deformations of the single fibre to increase fibre softness, followed by practical softening of thepolyvinylidene difluoride (PVDF)/CNTs composite by tensional twisting of the single fibres. The fibres with and withouttensional twisting were tested by Fourier-transformed infrared spectroscopy, scanning electron microscopy, X-ray diffractionand mechanical drawing. Results showed the reinforcement of the PVDF/multi-walled CNTs composite fibres (tensilestrength enhanced from 4.71 to 5.19 cN/dtex) with an evident softness reduction (initial modulus increased from 16.8 to20.52 cN/dtex) as the CNTs content increased from 0 to 1.5 wt%. After the tensional twisting, the initial modulus of thecomposite fibre was reduced by 62.5 % while the fibre strength remained reinforced because biomimetic helix formationimproved the internal structure deformation ability of the fibre.

Biomimetic-inspired highly sensitive flexible capacitive pressure sensor with high-aspect-ratio microstructures

Zhao Le,Yu Shihui,Li Junjun,Song Zichen,Wu Muying,Wang Xiuyu,Wang Xiaohu 한국물리학회 2021 Current Applied Physics Vol.31 No.-

The high sensitivity flexible capacitive pressure sensor (FCPS) manufactured in a fast and efficient way has friendly man-machine interaction function. In this paper, a high-sensitivity FCPS is developed by using a twostep template method to reproduce biomimetic microtower polydimethylsiloxane (PDMS) from the lotus leaf surface. The capacitive sensor is composed of a PDMS dielectric layer and the Cu nanowire electrodes sandwiching in the middle, with a high sensitivity of ~1.207 kPa 1, a low detection limit of less than 0.02 kPa and a fast response time of 61.6 ms. Particularly, the sensing performance can be kept basically unchanged when bent at a 5 mm radius. Moreover, the FCPS can withstand 4000 repeated tests and maintain stable performance, and the sensitivity is almost the same in the process of loading and unloading, suggesting the high robustness. These results demonstrates the FCPSs have potential applications in electronic wearables, human health monitoring and uneven surface applications.