Molybdenum Dioxide-Anchored Graphene Foam as a Negative Electrode Material for Supercapacitors

Xuemei Mu,Xiaozhi Liu,Ke Zhang,Jian Li,Jinyuan Zhou,ER-QING XIE,Zhenxing Zhang 대한금속·재료학회 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.2

Molybdenum dioxide nanoparticles of diameter 100 nm were anchoreduniformly to a three-dimensional (3D) graphene foam using an ultrasonicationassisteddeposition method. X-ray diffraction and Raman spectroscopyindicated that the molybdenum dioxide nanoparticles had a monoclinic crystalstructure. The 3D graphene/MoO2 nanoparticle composite showed excellentpseudocapacitive ability as its specific capacitance reached 404 F g−1 at a scanrate of 2 mV s−1 in the negative potential range, −1.0 to −0.2 V, in a neutralsolution. Overall, the 3D graphene/MoO2 nanoparticle composite has greatpotential as an anode material for the next generation of high-performancesupercapacitors.

BK Knockout by TALEN-Mediated Gene Targeting in Osteoblasts: KCNMA1 Determines the Proliferation and Differentiation of Osteoblasts

Xuemei Zhang,Hongya Hei,Jianjun Gao,Jibin Dong,Jie Tao,Lulu Tian,Wanma Pan,Hongyu Wang 한국분자세포생물학회 2016 Molecules and cells Vol.39 No.7

Large conductance calcium-activated potassium (BK) channels participate in many important physiological functions in excitable tissues such as neurons, cardiac and smooth muscles, whereas the knowledge of BK channels in bone tissues and osteoblasts remains elusive. To investigate the role of BK channels in osteoblasts, we used transcription activator-like effector nuclease (TALEN) to establish a BK knockout cell line on rat ROS17/2.8 osteoblast, and detected the proliferation and mineralization of the BK-knockout cells. Our study found that the BK-knockout cells significantly decreased the ability of proliferation and mineralization as osteoblasts, compared to the wild type cells. The overall expression of osteoblast differentiation marker genes in the BK-knockout cells was significantly lower than that in wild type osteoblast cells. The BK-knockout osteoblast cell line in our study displays a phenotype decrease in osteoblast function which can mimic the pathological state of osteoblast and thus provide a working cell line as a tool for study of osteoblast function and bone related diseases.

Knockout of Myostatin by Zinc-finger Nuclease in Sheep Fibroblasts and Embryos

Zhang, Xuemei,Wang, Liqin,Wu, Yangsheng,Li, Wenrong,An, Jing,Zhang, Fuchun,Liu, Mingjun Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.10

Myostatin (MSTN) can negatively regulate the growth and development of skeletal muscle, and natural mutations can cause "double-muscling" trait in animals. In order to block the inhibiting effect of MSTN on muscle growth, we transferred zinc-finger nucleases (ZFN) which targeted sheep MSTN gene into cultured fibroblasts. Gene targeted colonies were isolated from transfected fibroblasts by serial dilution culture and screened by sequencing. Two colonies were identified with mono-allele mutation and one colony with bi-allelic deletion. Further, we introduced the MSTN-ZFN mRNA into sheep embryos by microinjection. Thirteen of thirty-seven parthenogenetic embryos were targeted by ZFN, with the efficiency of 35%. Our work established the technical foundation for generation of MSTN gene editing sheep by somatic cloning and microinjection ZFN into embryos.

Co-opetition and the Stability of Competitive Contractual Strategic Alliance: Thinking Based on the Modified Lotka-Voterra Model

Xuemei Qing,Weiguo Zhang 보안공학연구지원센터(IJUNESST) 2015 International Journal of u- and e- Service, Scienc Vol.8 No.1

MCT2 overexpression promotes recovery of cognitive function by increasing mitochondrial biogenesis in a rat model of stroke

Xiaorong Yu,Rui Zhang,Cunsheng Wei,Yuanyuan Gao,Yanhua Yu,Lin Wang,Junying Jiang,Xuemei Zhang,Junrong Li,Xuemei Chen 한국통합생물학회 2021 Animal cells and systems Vol.25 No.2

Monocarboxylate transporter 2 (MCT2) is the predominant monocarboxylate transporter expressed by neurons. MCT2 plays an important role in brain energy metabolism. Stroke survivors are at high risk of cognitive impairment. We reported previously that stroke-induced cognitive impairment was related to impaired energy metabolism. In the present study, we report that cognitive function was impaired after stroke in rats. We found that MCT2 expression, but not that of MCT1 or MCT4, was markedly decreased in the rat hippocampus at 7 and 28 days after transient middle cerebral artery occlusion (tMCAO). Moreover, MCT2 overexpression promoted recovery of cognitive function after stroke. The molecular mechanism underlying these effects may be related to an increase in adenosine monophosphate-activated protein kinase-mediated mitochondrial biogenesis induced by overexpression of MCT2. Our findings suggest that MCT2 activation ameliorates cognitive impairment after stroke.

Control Algorithm of Static Loading Test for Wind Turbine Blades Based on Fuzzy Theory

Zhang Leian,Huang Xuemei,Yuan Guangming 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.4

In the process of full-scale static loading test of wind turbine blades, the loading forces all had relatively strong coupling effect, which seriously affected the accuracy of the test result. In order to eliminate this effect, firstly, a vertical static loading device for 10MW wind turbine blades was established and the coupling rule of loading force was obtained. Then, a control algorithm was put forward based on fuzzy theory. This algorithm took the error of loading force, error’s change rate as the input variables and the opening degree of proportional valve as the output variable. A control strategy based on this algorithm was constructed. In the end, the static device took the max flapwise of aeroblade5.0-62 wind turbine blade as example to conduct loading test. The result suggested the algorithm in this paper could ensure that the loading forces on five nodes always kept uniform changing and the control errors were respectively less than±2KN, ±2KN,± 2KN,± 2KN and±1KN. When in the 100% phase, the loading force could be finely maintained at the set value. The statistical results showed that the error rates of loading force with control algorithm were smaller than those without control algorithm. The test results verified the feasibility of control strategy applying to full-scale static loading test for wind turbine blades.

Improved Image Denoising Based on 3D Collaborative Filtering

Xuemei Wang,Dengyin Zhang,Min Zhu,Yingtian Ji,Jin Wang 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.4

As the state-of-art denoising method, BM3D is capable of achieving good denoising performance by exploiting both the non-local characteristics and sparsity prior knowledge of images. Nevertheless, experimental results show that the dissimilarity measurement defined in BM3D sometimes results in grouping patches with distinct structure. Inspired by the fact about the different impact of noise on patches with various structures, we propose a structure-adaptive image denoising method with 3D collaborative filtering by optimizing the block matching procedure. In our method, the similarity in the variance between patches is incorporated in block matching procedure. Besides, based on the prior knowledge of correlation among patches in the same neighborhood, the spatial distance between the reference patch and the candidate is also taken into account when measuring patches’ dissimilarity. Several numerical experiments demonstrate that the proposed approach achieve better results in PSNR and visual effect than original BM3D.

Calculating Wind Variability Costs with Considering Ramping Costs of Conventional Power Plants

Xuemei Dai,Kaifeng Zhang,Jian Geng,Ying Wang,Kun Yuan 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.3

Due to the variability of the wind power, conventional power plants are required to ramp more frequently to mitigate the imbalance of generation and supply, which increase the total cost of power systems. The increase of the cost is termed the “variability cost” of wind power. Generally, it includes the additional ramping cost, reserve cost and fuel cost of conventional plants. In this paper, we propose an alternative scenario construction method to calculate the “variability cost” of wind power from the viewpoint of the power system schedule. Firstly, in the alternative scenario, a new energy proxy with zero wind variability costs is constructed. Then, a unit commitment optimization model considering ramping costs is developed. The operation costs of power systems under two scenarios (alternative one and real one) are calculated and the diff erence between two costs is the variability cost. Furthermore, we apply the proposed method to calculate the variability costs of the wind farm cluster. The simulations show that the variability cost increases with higher penetration and higher variability of wind power. Meanwhile, it is found that the variability cost of the wind farm cluster as a whole is lower than the sum of variability costs of each wind farm.

Reconfigurable Intelligent Surface assisted massive MIMO systems based on phase shift optimization

Xuemei Bai,Congcong Hou,Chenjie Zhang,Hanping Hu Korean Society for Internet Information 2024 KSII Transactions on Internet and Information Syst Vol.18 No.7

Reconfigurable Intelligent Surface (RIS) is an innovative technique to precisely control the phase of incident signals with the help of low-cost passive reflective elements. It shows excellent potential in the sixth generation of mobile communication systems, which not only extends wireless coverage but also boosts channel capacity. Considering that multipath propagation and a high number of antennas are involved in RIS in assisted mega multiple-input multiple-output (MIMO) systems, it suffers from severe channel fading and multipath effects, which in turn lead to signal instability and degradation of transmission performance. To overcome this obstacle, this essay suggests an improved gradient optimization algorithm to dynamically and optimally adjust the phase of the reflective elements to counteract channel fading and multipath effects as a strategy. In order to overcome the optimization problem of falling into local minima, this paper proposes an adaptive learning rate algorithm based on Adagrad improvement, which searches for the global optimal solution more efficiently and improves the robustness of the optimization algorithm. The suggested technique helps to enhance the estimate of channel efficiency of RIS-assisted large MIMO systems, according to simulation results.

Modeling and Control of a New Spherical Robot with Cable Transmission

Lufeng Zhang,Xuemei Ren,Dongdong Zheng 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.3

This paper presents a new spherical robot with a cable transmission mechanism. Cable transmission mechanism replaces conventional gear train to eliminate the influence of gear backlash, reduce the robot mass, lower the costs on mechanical customization and can be arranged flexibly. By projection method, the 3D robot dynamic model with structural asymmetry is decoupled into balance subsystem and velocity subsystem, and the kinetics equations are established based on Newton-Euler’s law. For the balance control, an adaptive law is designed to estimate the upper bound instead of the exact value of the uncertainty caused by the structural asymmetry online firstly, then a finite-time adaptive hierarchical sliding mode control (FAHSMC) strategy is proposed based on the estimation result to minimize the convergence time. For the velocity control, a hierarchical sliding mode controller (HSMC) and a tracking differentiator (TD)-based nonlinear disturbance observer are designed, leading to enhanced disturbance rejection capability and a reduced steady-state error. Simulations and experiments on a real spherical robot are conducted to demonstrate the efficacy of the proposed control strategies.