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Microfluidic step emulsification techniques based on spontaneous transformation mechanism: A review
Ziwei Liu,Cong Duan,Shaokun Jiang,Chunying Zhu,Youguang Ma,Taotao Fu 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.92 No.-
Rapid and robust generation of uniformly sized droplets is a research hotspot for emulsificationtechnology. Compared with conventional microfluidic devices such as cross-junction andflow-focusing,the size of the droplets generated in the step emulsifiers based on the spontaneous transformationmechanism is independent of theflowfluctuation, making this type of devices have many advantagesand important application value. To introduce the research progress of step emulsification technology inrecent years, this review discusses the device configurations, interfacial evolution for droplet formationmechanism,flow pattern classification, the influence of control variables on the emulsification processand the application advantages of such devices, and illustrates the design and selection principles of suchdevices, the control laws of manipulation variables, and the future applicationfields and directions.
Effect of phosphorus deficiency on erythrocytic morphology and function in cows
Ziwei Zhang,Mingyu Bi,Jie Yang,Haidong Yao,Zhonghua Liu,Shiwen Xu 대한수의학회 2017 Journal of Veterinary Science Vol.18 No.3
The aim of this study was to evaluate the influence of phosphorus (P) deficiency on the morphological and functional characteristics of erythrocytes in cows. Forty Holstein-Friesian dairy cows in mid-lactation were randomly divided into two groups of 20 each and were fed either a low-P diet (0.03% P/kg dry matter [DM]) or a control diet (0.36% P/kg DM). Red blood cell (RBC) indices results showed RBC and mean corpuscular hemoglobin decreased while mean corpuscular volume increased significantly (p < 0.05) in P-deficient cows. Erythrocyte morphology showed erythrocyte destruction in P-deficient cows. Erythrocytes’ functional characteristics results showed total bilirubin and indirect bilirubin concentrations and aspartate transaminase and alanine transaminase activity levels in the serum of P-deficient cows were significantly higher than those in control diet-fed cows. Activities of superoxide dismutase and glutathione peroxidase in erythrocytes were lower, while the malondialdehyde content was greater, in P-deficient cows than in control diet-fed cows. Na+/K+-ATPase and Mg2+-ATPase activities were lower in P-deficient cows than in control diet-fed cows; however, Ca2+-ATPase activity was not significantly different. The phospholipid composition of the erythrocyte membrane changed and membrane fluidity rigidified in P-deficient cows. The results indicate that P deficiency might impair erythrocyte integrity and functional characteristics in cows.
Enhanced Formaldehyde Gas Sensing Properties of ZnO Nanosheets Modified with Graphene
Ziwei Chen,Yuyuan Hong,Zhidong Lin,Li-Ming Liu,Xiao-Wen Zhang 대한금속·재료학회 2017 ELECTRONIC MATERIALS LETTERS Vol.13 No.3
In this study, pure ZnO (ZnO-1, ZnO-2) with two different morphologies, andgraphene doped ZnO-2 (G-ZnO-2) were synthesized using a simplehydrothermal process at 150 °C. The formaldehyde gas sensing performanceof the G-ZnO-2 composite, synthesized by an in-situ method was investigated. The morphologies and the structures of the nanomaterials were characterizedby X-ray diffraction, field emission scanning electronic microscopy, andtransmission electron microscopy. The experimental results indicate that the GZnO-2 based sensor exhibits unique advantages for the sensing offormaldehyde gas at concentrations in the range of 2 to 2000 ppm, such as fastresponse/recovery time and good selectivity, at an optimal workingtemperature of 200 °C. The improved sensing performance of the G-ZnO-2composite indicates that the addition of graphene is effective in improving theformaldehyde sensing performance of ZnO-based sensors.
Ziwei Sun,Qingtao Liu,Zhen Wang,Baobao Zhao,Quan Feng,Yanyan Sun,Min Zhong 한국고분자학회 2023 Macromolecular Research Vol.31 No.12
A hierarchical chitosan/polyvinyl alcohol/polyethylene glycol/nonwoven fabric (CS/PVA/PEG/NWF) micro/nanofiber composite membrane (CM) was prepared via electrospinning as a potential wound dressing. The polyester/viscose NWF acting as a substrate to receive the nanofiber layer was modified by alkali deweighting. Meanwhile, PEG with various additive amount was used to afford morphological regulation and control. As a result, the NWF modified with 7.5% NaOH solution exhibited a good hydrophilia and a superior dimensional stability based on smaller elongation at break and higher peel strength. In addition, the morphology of the nanofiber layer was closely related to PEG content. CS/PVA/PEG nanofiber with smaller diameter was spun when PEG content reached to 3.0%. Accordingly, the micro/nanofiber CM showed an opportune water absorption and good air permeability. Furthermore, neither hemolysis nor cytotoxicity phenomena appeared for the resultant CM, since the hemolysis rate and the cell viability were less than 5% and more than 70%, respectively.
Anti-sparse representation for structural model updating using l∞ norm regularization
Ziwei Luo,Ling Yu,Huan-Lin Liu,Zexiang Chen 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.75 No.4
Finite element (FE) model based structural damage detection (SDD) methods play vital roles in effectively locating and quantifying structural damages. Among these methods, structural model updating should be conducted before SDD to obtain benchmark models of real structures. However, the characteristics of updating parameters are not reasonably considered in existing studies. Inspired by the l∞ norm regularization, a novel anti-sparse representation method is proposed for structural model updating in this study. Based on sensitivity analysis, both frequencies and mode shapes are used to define an objective function at first. Then, by adding l∞ norm penalty, an optimization problem is established for structural model updating. As a result, the optimization problem can be solved by the fast iterative shrinkage thresholding algorithm (FISTA). Moreover, comparative studies with classical regularization strategy, i.e. the l2 norm regularization method, are conducted as well. To intuitively illustrate the effectiveness of the proposed method, a 2-DOF spring-mass model is taken as an example in numerical simulations. The updating results show that the proposed method has a good robustness to measurement noises. Finally, to further verify the applicability of the proposed method, a six-storey aluminum alloy frame is designed and fabricated in laboratory. The added mass on each storey is taken as updating parameter. The updating results provide a good agreement with the true values, which indicates that the proposed method can effectively update the model parameters with a high accuracy.
Correction method for calculating junction temperature considering parasitic effects in SiC MOSFETs
Fan Liu,Mingxing Du,Jinliang Yin,Chao Dong,Ziwei Ouyang 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.4
The turn-on change rate of drain current diDS(on)/dt is an electrical parameter that is suitable for the online monitoring of junction temperature in SiC MOSFETs. In practical applications, the change of an external circuit changes the temperature-sensitive characteristic of diDS(on)/dt. In this paper, a SiC MOSFET in a Buck converter is taken as the research object. First, it is theoretically derived and experimentally verified that the power loop inductance and drive loop resistance are parasitic parameters that affect the temperaturesensitive characteristic of diDS(on)/dt. Second, according to the spectrum peak characteristics caused by the drain–source turn-off oscillation voltage of the SiC MOSFET, the theoretical relationship between the diDS(on)/dt temperature-sensitive characteristic and the peak of the drain–source turn-off oscillation voltage is studied. It is concluded that the spectrum peak can reflect the change of the diDS(on)/dt temperature-sensitive characteristic caused by the change of the parasitic parameters. Based on the above research, a model of a modified diDS(on)/dt temperature-sensitive characteristic considering parasitic effect is established in this paper. Through experimental verification, this model can largely eliminate the junction temperature monitoring error caused by the change of the external circuit.
Thoughts on China s Construction of Community of Shared Future for Mankind under the New Situation
Chen Ziwei,Liu Di 아시아사회과학학회 2021 Jornal of Asia Social Science Vol.3 No.2
On July 1, 2021, General Secretary Xi Jinping delivered an important speech at the conference celebrating the centenary of the founding of the Communist Party of China(CPC). 4The July 1st Speech is a programmatic document that fully exudes the charm of Marxism. It is a political declaration and action guide that stands at the historical intersection of the two centennial goals, focuses on the theme of realizing the great rejuvenation of the Chinese nation, learns from history, creates the future, and mobilizes and inspires us to move forward towards the goal of the second centennial. In the past 100 years, under the leadership of the Communist Party of China (CPC), and with the joint efforts of generations of Chinese people, we have witnessed the ambiguous Chinese Dream , which has gradually gained a clear outline. In the past one hundred years, the Communist Party of China(CPC) has created countless human miracles, and has set heavy footprints on the historical land. At the centenary of the founding of the Party, which is the node of the next century, how to presume the construction of human community is a major goal of our struggle.