Analysis on Seal Capacity of Magnetic Fluid Seal Using Ring Magnet

Jiawei Liu,Decai Li 한국자기학회 2022 Journal of Magnetics Vol.27 No.1

Magnetic fluid seal is one of the most mature applications of magnetic fluid. When the shaft has a large radial runout, the classical pole piece is easily damaged. Due to its small size, the commonly used pole piece structure harbors problems like poor seal performance under a large gap and poor processability. By exploring the distribution law of the magnetic field on the magnet’s surface, we provided theoretical support for the magnetic fluid seal using axially-magnetized ring magnets. New structures for the magnetic fluid seal using axially-magnetized slotted ring magnets and the magnetic fluid seal using radially-magnetized ring magnets were proposed. Then, comparisons were made between the classical magnetic fluid seal and the magnetic fluid seal using ring magnets. The results revealed that the magnetic fluid seal using axially-magnetized slotted ring magnets and the magnetic fluid seal using radially-magnetized ring magnets exhibited a certain seal capacity, which could replace the classical magnetic fluid seal structure.

Biomimetic functional hydrogel particles with enhanced adhesion characteristics for applications in fracture conformance control

Jiawei Liu,Lin Li,Zhongzheng Xu,Yongpeng Sun,Yining Wu,Caili Dai 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.106 No.-

Fracture conformance control in reservoir can effectively improve water channel to increase crude oil displacementefficiency of subsequent waterflooding. Inspired by the remarkable underwater wet adhesionof mussel byssus, hydrogel particles which can adhere stably on the fracture rock surface in reservoir conditionscould achieve long-lasting reservoir control effect. In this work, the size-controllable biomimeticfunctional hydrogel particles were prepared by mechanical shearing after bulk hydrogel was constructedby catechol-functionalized polyacrylamide and phenolic resin crosslinking agent. The influence of solutionsalinity on the aggregation and adhesion of hydrogel particles was investigated via scanning electronmicroscope (SEM), colloidal probe atomic force microscope (AFM) and quartz crystal microbalance withdissipation (QCM-D). The results showed that hydrogel particles maintained well-dispersed state in lowsalinitywater, while exhibited significant adhesion and adsorption capacity to the silica surface in simulatedreservoir salinity water. This is of great importance to the practical applications that the hydrogelparticles would not show enhanced adhesion to rock surfaces until the reservoir salinity water was met,which was beneficial to the in-depth migration of hydrogel particles to achieve effective deep reservoirprofile control. Furthermore, the visible micro-model was designed and applied to evaluate profile controleffect of hydrogel particles, and the results showed that hydrogel particles could withstand waterflushing and adhere stably to the fracture surface. The waterflooding sweep efficiency was increasedremarkably from 20.3% ± 2.0% to 38.8% ± 2.0%. This work would help better understand the functionmechanism of hydrogel particles in reservoir control and provide novel and efficient method for the practicalapplication in enhanced oil recovery.

Anwulignan alleviates D-galactose induced renal damage by regulating Nrf2/ARE signaling pathway in mice

Chunna Liu,Huijiao Lin,Liu Jiawei,Yao Wang,Chunmei Wang,Jinghui Sun,Chunyan Yu,Ying Dong,Wenyue Zhuang,Shu Jing,JianGuang Chen,He Li 한국식품과학회 2021 Food Science and Biotechnology Vol.30 No.8

Free radical accumulation in the body will cause oxidative stress damages including the renal damage. Schisandrae Sphenantherae Fructus (Schisandra), a traditional Chinese herbal medicine, has been used throughout the world. Anwulignan, a monomer extracted from Schisandra, has been shown in our previous studies to possess antioxidant and protective effects on the liver, brain and spleen damages in the aging mice. However, its effect on the renal damage caused by aging is not clear. This study showed that anwulignan could significantly increase the kidney index, the creatinine clearance, the activities of superoxide dismutase, catalase and glutathione peroxidase; reduce the urinary protein concentration, the serum urea nitrogen and creatinine content, the content of malondialdehyde and 8-hydroxylated deoxyguanosine in the renal tissue; and improve the renal tissue damage. Moreover, anwulignan increased the production of Nrf2, HO-1 and NQO1 proteins and decreased the production level of Keap1 protein in the renal tissue in the D-galactose induced aging mice. These results suggest that anwulignan significantly alleviates the renal damage by its antioxidant effect through regulating the production of Nrf2/ARE pathway-related proteins in the renal tissue in the D-galactose induced aging mice.

공익연계 마케팅에서 공익적 속성의 현저성 및 상징성이 브랜드 태도와 구매의도에 미치는 영향에 관한 연구

유가휘 ( Liu Jiawei ),송재도 ( Song Jae-do ) 한국고객만족경영학회 2018 고객만족경영연구 Vol.20 No.1

본 연구는 기업들이 실행하는 공익연계 마케팅 상황에서 공익적 속성의 현저성과 구매상황의 상징성이 브랜드 태도와 구매의도에 미치는 영향을 검토한다. 연구결과 공익연계 마케팅이 브랜드 태도와해당 브랜드의 구매의도에 긍정적인 영향을 미친다는 것을 확인하였으며, 브랜드 태도는 공익연계 마케팅이 구매의도에 미치는 영향을 매개하였다. 또한 공익연계 마케팅 상황에서 공익적 속성의 현저성이 높은 경우 소비자의 브랜드 태도와 브랜드의 구매의도가 높게 나타났으며, 브랜드 태도는 공익적 속성의 현저성이 구매의도에 미치는 영향을 부분 매개하였다. 마지막으로 구매상황의 상징성은 브랜드 태도에 대해 유의미한 영향을 미치지 않았으나 구매의도에는 긍정적이고 유의한 영향을 미쳤다. 이런 결과는 공익연계 마케팅 상황에서 제품정보들 대비 공익적 속성이 강조되어야 함을 보여준다는 의미가 있다. 또한 구매상황의 상징성이 브랜드 태도에 영향을 미치지 않았으나 구매의도에 직접 영향을 미친 것은 소비자들이 공익연계 마케팅을 통해 바람직한 자아를 타인들에게 과시하려는 의도를 가짐을 암시하는 것이다. The purpose of this study is to investigate the effects of the cause-related marketing, symbolism, and prominence on brand attitude and purchase intention. For this purpose, a survey-based experiment was carried out. The results of this study were as follows: First, it was found that cause-related marketing positively influence brand attitude and purchase intention of the brand, and brand attitude mediates the influence of cause-related marketing on purchase intention. Second, when prominence of cause attribute is high, consumers' brand attitude is more favorable and their purchase intention is higher, and brand attitude plays a mediating role in the relationship between prominence and purchase intention. Third, the symbolism of purchase situation has no significant effect on brand attitude but positively influence the purchase intention. The results of this study show that companies need to actively consider cause-related marketing and emphasize the cause attribute in selling products or services. Further, the result that symbolism of purchase situation has no significant effect on brand attitude but positively influence the purchase intention means that consumers have propensity for conspicuous consumption to show their ideal self in cause-related marketing.

Rotor Profile Design and Motion Simulation Analysis of Hydrogen Circulating Pump

Jiawei Lin,Lixin Zhang,Liang Dong,Houlin Liu,Cui Dai 한국유체기계학회 2021 International journal of fluid machinery and syste Vol.14 No.4

With the development of automotive fuel cells towards high power and high efficiency, higher requirements are put forward for the speed and boost ratio of hydrogen circulation pump, while high speed and boost ratio increase the pulsation characteristics and accelerate the aging of hydrogen fuel cells. Cam type hydrogen cycle pump has the advantages of compact structure, high efficiency under low boost ratio, and good adaptability to low temperature, so it has become an important research direction. The efficient and reasonable rotor profile design can improve the volumetric efficiency of the cam rotor pump. It can reduce the pressure pulsation and flow pulsation in the pump. The equation of multi-stage circular arc rotor profile is established according to the meshing principle of the rotor. Motion Simulation module in UG NX is employed to conduct dynamic interference detection of rotor mechanism and simulation analysis of rotor mechanism meshing motion on the rotating parts of the hydrogen circulating pump. So the angular velocity curve and meshing force change curve of the driven gear is obtained. In order to verify the rationality of rotor profile design, the meshing force is compared with the standard spur gear.

The length of guide RNA and target DNA heteroduplex effects on CRISPR/Cas9 mediated genome editing efficiency in porcine cells

Jiawei Lv,Shuang Wu,Renyue Wei,Yan Li,Junxue Jin,Yanshuang Mu,Yu Zhang,Qingran Kong,Xiaogang Weng,Zhonghua Liu 대한수의학회 2019 Journal of Veterinary Science Vol.20 No.3

The clustered regularly interspaced short palindrome repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system is a versatile genome editing tool with high efficiency. A guide sequence of 20 nucleotides (nt) is commonly used in application of CRISPR/Cas9; however, the relationship between the length of the guide sequence and the efficiency of CRISPR/ Cas9 in porcine cells is still not clear. To illustrate this issue, guide RNAs of different lengths targeting the EGFP gene were designed. Specifically, guide RNAs of 17 nt or longer were sufficient to direct the Cas9 protein to cleave target DNA sequences, while 15 nt or shorter guide RNAs had loss-of-function. Full-length guide RNAs complemented with mismatches also showed loss-of-function. When the shortened guide RNA and target DNA heteroduplex (gRNA:DNA heteroduplex) was blocked by mismatch, the CRISPR/Cas9 would be interfered with. These results suggested the length of the gRNA:DNA heteroduplex was a key factor for maintaining high efficiency of the CRISPR/Cas9 system rather than weak bonding between shortened guide RNA and Cas9 in porcine cells.

Design and analysis of mechanical flux‑weakening device of axial flux permanent magnet machines

Shaopeng Wang,Jiawei Lu,Bin Li,Chengcheng Liu,Youhua Wang,Gang Lei,Youguang Guo,Jianguo Zhu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.4

Due to the low inductance of an axial flux permanent magnet machine (AFPMM), the constant power speed regulation range is small. A new mechanical flux-weakening method for single-rotor single-stator AFPMMs is proposed in this paper. By installing a mechanical flux-weakening device on one side of the stator and rotating it certain angle, the speed regulation of the flux-weakening can be realized. The device is simple in structure, easy to operate, and can be operated in the process of machine operation. The validity of the device is verified by applying it to a machine. Finite-element software is used to calculate and analyze the performances of two machines with the device.

MSC p43 required for axonal development in motor neurons.

Zhu, Xiaodong,Liu, Yang,Yin, Yanqing,Shao, Aiyun,Zhang, Bo,Kim, Sunghoon,Zhou, Jiawei National Academy of Sciences 2009 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.106 No.37

<P>Neuron connectivity and correct neural function largely depend on axonal integrity. Neurofilaments (NFs) constitute the main cytoskeletal network maintaining the structural integrity of neurons and exhibit dynamic changes during axonal and dendritic growth. However, the mechanisms underlying axonal development and maintenance remain poorly understood. Here, we identify that multisynthetase complex p43 (MSC p43) is essential for NF assembly and axon maintenance. The MSC p43 protein was predominantly expressed in central neurons and interacted with NF light subunit in vivo. Mice lacking MSC p43 exhibited axon degeneration in motor neurons, defective neuromuscular junctions, muscular atrophy, and motor dysfunction. Furthermore, MSC p43 depletion in mice caused disorganization of the axonal NF network. Mechanistically, MSC p43 is required for maintaining normal phosphorylation levels of NFs. Thus, MSC p43 is indispensable in maintaining axonal integrity. Its dysfunction may underlie the NF disorganization and axon degeneration associated with motor neuron degenerative diseases.</P>

Size-Controlled Silver Nanoparticles Confined in Ordered Mesoporous Silica and Their Enhanced Catalytic Activities

Xiaofei Zhou,Jiawei Wan,Yefeng Liu,Di Liu,Hong Wang,Xiaoyong Lai,Yanzhao Zou,Guo Lin,Jian Chen 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.9

A cooperative assembly route has been developed, by which silver nanoparticles with controlled sizes are incorporated into the channels of ordered cubic mesoporous silica (KIT-6) with different pore sizes (4.3–6.4 nm). The samples were characterized by XRD, TEM, FT-IR, UV-Vis and N2 physisorption. The pore wall of mesoporous silica can efficiently confine the growth of silver nanoparticles within the channels and their average sizes decreased with the pore size reduction of KIT-6. Catalytic activities of the resultant Ag/KIT-6-x (x stands for hydrothermal temperature) composite for reducing harmful organic dye Rhodamine B (Rh B) by sodium borohydride (NaBH4) were investigated. All the Ag/KIT-6 composite samples show great catalytic activities, among which Ag/KIT-6-80 with higher loading and smaller size of Ag nanoparticles exhibits higher catalytic activity than those of Ag/KIT-6-60 and Ag/KIT-6-100.

Derivation of endothelial cells from porcine induced pluripotent stem cells by optimized single layer culture system

Renyue Wei,Jiawei Lv,Xuechun Li,Yan Li,Qianqian Xu,Junxue Jin,Yu Zhang,Zhonghua Liu 대한수의학회 2020 Journal of Veterinary Science Vol.21 No.1

Regenerative therapy holds great promise in the development of cures of some untreatable diseases such as cardiovascular diseases, and pluripotent stem cells (PSCs) including induced PSCs (iPSCs) are the most important regenerative seed cells. Recently, differentiation of human PSCs into functional tissues and cells in vitro has been widely reported. However, although porcine reports are rare they are quite essential, as the pig is an important animal model for the in vitro generation of human organs. In this study, we reprogramed porcine embryonic fibroblasts into porcine iPSCs (piPSCs), and differentiated them into cluster of differentiation 31 (CD31)-positive endothelial cells (ECs) (piPSC-derived ECs, piPS-ECs) using an optimized single-layer culture method. During differentiation, we observed that a combination of GSK3β inhibitor (CHIR99021) and bone morphogenetic protein 4 (BMP4) promoted mesodermal differentiation, resulting in higher proportions of CD31-positive cells than those from separate CHIR99021 or BMP4 treatment. Importantly, the piPS-ECs showed comparable morphological and functional properties to immortalized porcine aortic ECs, which are capable of taking up low-density lipoprotein and forming network structures on Matrigel. Our study, which is the first trial on a species other than human and mouse, has provided an optimized single-layer culture method for obtaining ECs from porcine PSCs. Our approach can be beneficial when evaluating autologous EC transplantation in pig models.