Proactive and reactive strategic flexibility in coping with environmental change in innovation

Zhigang Fan,Dong Wu,Xiaobo Wu 기술경영경제학회 2013 ASIAN JOURNAL OF TECHNOLOGY INNOVATION Vol.21 No.2

This study examines the effects of strategic flexibility on innovation performance byincorporating proactive and reactive strategic flexibility into the framework of strategicflexibility and the moderating effects of environmental change by subdividing this constructinto rate and turbulence. An empirical study of 180 sample Chinese manufacturing firmsshows that: (1) both proactive and reactive strategic flexibility have positive effects oninnovation performance, (2) rate of environmental change significantly positively moderatesthe relationship between proactive strategic flexibility and innovation performance as well assignificantly negatively moderates the relationship between reactive strategic flexibility andinnovation performance and (3) turbulence of environmental change significantly positivelymoderates the relationship between reactive strategic flexibility and innovation performance. The results indicate that firms that face a fast rate of environmental change should directmore attention to proactive strategic flexibility; however, firms that face a high turbulence ofenvironmental change should pay more attention to reactive strategic flexibility.

Research on the Calculation of Rotor’s Convective Heat Transfer Coefficient of High-Speed Drive Motor for EVs Based on Multiple Scenarios

Wu Zhigang,Li Weili,Tang Haoyue,Luo Shifan,Zhang Liangliang 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.6

In order to adapt the development demand of electric vehicle (EV) drive motor with high power density, high-speed motor is an inevitable trend. There have been numerous studies on the optimisation of cooling structures and losses in high-speed motor, but little has been said about the mechanism of heat transfer problems. Especially in the context of diverse driving scenarios and high-speed drive for EVs, it is crucial to study the differences in heat transfer mechanisms between high-speed motors and normal-speed motors. The research work is based on a principle prototype with a maximum speed of 50 kW-30,000 rpm. A dynamic calculation method is proposed for the rotor’s convective heat transfer coefficient (CHTC) over a wide speed range and multiple scenarios. This method has the advantages of simplicity and high efficiency in calculating the CHTC of rotor, and avoids the complex preprocessing and difficult convergence problems of the fluid–solid coupling calculation. Finally, the accuracy of the calculation results is verified by the temperature rise test of the high-speed motor.

Wnt pathway is involved in 5-FU drug resistance of colorectal cancer cells

Lingfeng He,Hong Zhu,Shiying Zhou,Ting Wu,Huan Wu,Huan Yang,Huiwen Mao,Chandra SekharKathera,Avilala Janardhan,Ashlin M. Edick,Anna Zhang,Zhigang Hu,Feiyan Pan,Zhigang Guo 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

Colorectal cancer (CRC) is one of the leading causes of cancer-related death worldwide. 5-Fluorouracil (5-FU) is widely used in the treatment of cancers, but its antineoplastic activity is limited in drug-resistant cancer cells. To investigate the detailed mechanism of 5-FU resistance, we developed a model of 5-FU-resistant cells from HCT-8 cells, a wellestablished colorectal cancer cell line. We found that the drug-resistant cells demonstrated high expression of TCF4 and β-catenin, indicating an upregulated Wnt pathway. A microarray analysis revealed that the suppression of the checkpoint kinase 1 (CHK1) pathway explained the resistance to 5-FU, especially in p53 wild-type cancer cells such as HCT-8. Our data also demonstrated that the CHK1 pathway is suppressed by the Wnt pathway in 5-FU-resistant cells. In summary, we have discovered a novel mechanism for 5-FU resistance mediated by histone deacetylation, which also revealed the crosstalk between the Wnt pathway and CHK1 pathway.

Molecular Characterization and Expression Analysis of S6K1 in Cashmere Goats (Capra hircus)

Wu, Manlin,Bao, Wenlei,Hao, Xiyan,Zheng, Xu,Wang, Yanfeng,Wang, Zhigang Asian Australasian Association of Animal Productio 2013 Animal Bioscience Vol.26 No.8

p70 ribosomal S6 kinase (p70S6K) can integrate nutrient and growth factor signals to promote cell growth and survival. We report our molecular characterization of the complementary DNA (cDNA) that encodes the goat p70S6K gene 40S ribosomal S6 kinase 1 (S6K1) (GenBank accession GU144017) and its 3' noncoding sequence in Inner Mongolia Cashmere goats (Capra hircus). Goat S6K1 cDNA was 2,272 bp and include an open reading frame (ORF) of 1,578 bp, corresponding to a polypeptide of 525 amino acids, and a 694-residue 3' noncoding sequence with a polyadenylation signal at nucleotides 2,218 to 2,223. The relative abundance of S6K1 mRNA was measured by real-time PCR in 6 tissues, and p70S6K expression was examined by immunohistochemistry in heart and testis. The phosphorylation of p70S6K is regulated by mitogen-activated protein kinase (MAPK) signaling in fetal fibroblasts.

Applying a sensor energy supply communication scheme to big data opportunistic networks

( Zhigang Chen ),( Jia Wu ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.5

Energy consumption is an important index in mobile ad hoc networks. Data packet transmission increases among nodes, particularly in big data communication. However, nodes may be unable to transmit data packets because of energy over-consumption. Consequently, information may be lost and network communication may block. While opportunistic network is a kind of mobile ad hoc networks, researchers do not focus on energy consumption in opportunistic network communication. This study proposed an effective sensor energy supply scheme that can be applied in opportunistic networks. This scheme considers nodes sensor requests and communication model. In this scheme, nodes do not only accomplish energy supply in communication, but also extend communication time in opportunistic networks. Compared with the Spray and Wait algorithm and the Binary Spray and Wait algorithm in simulations, the proposed scheme extends communication time, increases data packet transmission, and accomplishes energy supply among nodes.

Numerical analysis of flow in a Francis turbine on an equal critical cavitation coefficient line

Yulin Wu,Jintao Liu,Yuekun Sun,Shuhong Liu,Zhigang Zuo 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.6

Numerical simulation and model test were applied to study the cavitation flow in Francis turbines. The SST k-ω turbulence model and the mixture model were used to simulate the cavitating flow in the Francis turbine. An equal critical cavitation coefficient line was calculated and the flow in the Francis turbine was analyzed. Simulation results show reasonable agreement with the experimental data. It is confirmed that these cavitation model and numerical method is a useful way to study the two-phase cavitation flow in Francis turbines. On the equal critical cavitation coefficient line, the energy loss in the turbine may be caused by the rotating of vortex rope in the draft tube or flow separation in the runner. The study of equal critical cavitation coefficient line can provide a basic guidance for industry practice.

Cytotoxic isocoumarin derivatives from the mangrove endophytic fungus Aspergillus sp. HN15-5D

Yingnan Wu,Senhua Chen,Xishan Huang,Yayue Liu,Yiwen Tao,Zhigang She,Senhua Chen 대한약학회 2019 Archives of Pharmacal Research Vol.42 No.4

Five isocoumarin derivatives including three new compounds, aspergisocoumrins A–C (1–3), together with two known analogues, 8-dihydroxyisocoumarin-3-carboxylic acid (4) and dichlorodiaportin (5) were obtained from the culture of the endophytic fungus Aspergillus sp. HN15-5D derived from the fresh leaves of the mangrove plant Acanthus ilicifolius. Their structures were elucidated using comprehensive spectroscopic methods. The double bond geometry of compounds 1 and 2 were assigned as E and Z on the basis of the distinct coupling constants, respectively. Compounds 1 and 2 showed cytotoxicity against MDA-MB-435 with IC50 values of 5.08 ± 0.88 and 4.98 ± 0.74 μM, respectively.

An improved resonantly driven piezoelectric gas pump

Yue Wu,Yong Liu,Jian-Fang Liu,Long Wang,Xiaoyang Jiao,Zhigang Yang 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.3

Piezoelectric pumps have the potential to be used in a variety of applications, such as in air circulation and compression. However, piezoelectric membrane pumps do not have enough driving capacity, and the heat induced during the direct contact between the driving part and the gas medium cannot be dissipated smoothly. When the gas is blocked, the piezoelectric vibrator generates heat quickly, which may eventually lead to damage. Resonantly driven piezoelectric stack pumps have high performance but no price advantage. In this situation, a novel, resonantly driven piezoelectric gas pump with annular bimorph as the driver is presented. In the study, the working principle of the novel pump was analyzed, the vibration mechanics model was deter-mined, and the displacement amplified theory was studied. The outcome indicates that the displacement amplification factor is related with the original displacement provided by the piezoelectric bimorph. In addition, the displacement amplification effect is related to the stiffness of the spring lamination, adjustment spring, and piezoelectric vibrator, as well as to the systematic damping factor and the driving frequency. The experimental prototypes of the proposed pump were designed, and the displacement amplification effect and gas output performance were measured. At 70 V of sinusoidal AC driving voltage, the improved pump amplified the piezoelectric vibrator displacement by 4.2 times, the maximum gas output flow rate reached 1685 ml/min, and the temperature of the bimorph remained normal after 2000 hours of operation when the gas medium was blocked.

Natural History of Untreated Coronary Total Occlusions Revealed with Follow-Up Semi-Automated Quantitative Coronary CT Angiography: The Morphological Characteristics of Initial CT Predict Occlusion Shortening

Qian Wu,Mengmeng Yu,Yuehua Li,Wenbin Li,Zhigang Lu,Meng Wei,Jing Yan,Jiayin Zhang 대한영상의학회 2018 Korean Journal of Radiology Vol.19 No.2

Objective: To investigate the morphological changes of coronary chronic total occlusion (CTO) as determined by coronary computed tomography angiography (CCTA) follow-up using semi-automated quantitative analysis. Materials and Methods: Thirty patients with 31 CTO lesions confirmed by invasive coronary angiography and baseline/follow-up CCTA were retrospectively included. CTOs were quantitatively analyzed by a semi-automated coronary plaque analysis software (Coronary Plaque Analysis, version 2.0, Siemens) after manually determining the lesion border. Recanalized lumen was defined as the linear-like enhanced opacity traversing the non-opacified occluded segment. Other parameters, such as total occlusion length, total occlusion volume, volume with low attenuation component (< 30 Hounsfield unit [HU]), volume with middle to high attenuation component (30−190 HU) as well as the calcification volume, were also recorded. Results: Recanalized lumen was found within 48.4% (15/31) occlusions on the follow-up CCTA, compared to 45.2% (14/31) occlusions on the baseline CCTA. Eleven of 14 lesions (78.6%) with CT-visible recanalized lumen within CTOs had a shorter occlusion length on follow-up compared to only 3 of 17 lesions (17.6%) without CT-visible recanalized lumen (odds ratio, 17.1, p < 0.001). The percentage of low attenuation component of occlusions was smaller on follow-up CCTA compared to baseline value (18.1 ± 20.1% vs. 22.6 ± 19.6%, p = 0.033). Conclusion: Coronary computed tomography angiography enables non-invasive characterization of natural progression of untreated CTO lesions. Recanalized lumen within CTOs observed at baseline CCTA was associated with shortening of occlusion length on follow-up. Compared to their earlier stage, occlusions of later stage were presented with higher density of non-calcified components.

Observer-based Adaptive Fuzzy Control for Strict-feedback Nonlinear Systems with Prescribed Performance and Dead Zone

Wen Zeng,Zhigang Li,Chuang Gao,Libing Wu 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.5

This paper proposes an observer-based fuzzy controller for strict-feedback nonlinear systems. A fuzzy state observer is designed to estimate unmeasurable system states via a fuzzy logic system to approximate the unknown nonlinear functions of the system. A tangent prescribed performance function is utilized to gather the tracking error in a small neighborhood of the origin. The control input is designed to deal with the dead-zone property of the system. The proposed controller can guarantee that all the signals in the closed-loop system are semi-globally, uniformly, and ultimately bounded. Simulation results demonstrate the effectiveness of the proposed controller