Characteristics and significance of heterogeneity of sea−land transitional facies shale gas reservoir in North Guizhou, China

Ran Wang,Shuxun Sang,Jun Jin,Lingyun Zhao,Wei Gao,Wei Fu,Fulun Shi,Ende Deng 한국지질과학협의회 2019 Geosciences Journal Vol.23 No.1

In order to identify the characteristics of the longitudinal heterogeneity of the sea–land transitional facies shale gas reservoir in the upper Yangtze region of North Guizhou, studies on the lithological combination, rock and mineral composition, geochemical parameters and reservoir microanisotropy characteristics of Longtan Formation in the study area are conducted on the basis of core observation, testing of geochemistry and reservoir physical property and well logging interpretation. The studies show that the lithological assemblages of the Longtan Formation are diverse and form an amina interbedding of “sand-mud-coal” with obvious cyclicity characteristics. There is a large longitudinal difference in rock and mineral composition and the average mass fraction of the clay mineral is 39.83%, which is obviously higher than that of the marine shale in North America and South China; the longitudinal heterogeneity of the organic matter abundance is high, with an average of 2.17% in the upper part, and 4.51% in the lower part; in accordance with the results observed with the scanning electron microscope and results calculated through pore fractal, the microscopic pore heterogeneity of the reservoir is high. The comparison and analysis of connecting wells with different scales in the study area show that the control effect of the depositional environment on longitudinal macroscopic heterogeneity of Longtan Formation is obvious, and the longitudinal microscopic heterogeneity is controlled through diagenesis. Meanwhile, studies with main coal mining seam as the seam section division method conclude that the heterogeneity of Coal Seam Sections 4 to 5 and Coal Seam Sections 13 to 15 is significantly smaller than that in other seam sections, and the Coal Seam Sections 4 to 5 and Coal Seam Sections 13 to 15 can be considered as a priority key seam section during development of shale gas.

Finite Element Simulation and Experiment Verification of Rolling Forming for the Truck Wheel Rim

Gang Fang,Wei-Ran Gao,Xiao-Ge Zhang 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

The present research aims to investigate general laws of three-pass roll forming of steel wheel rim by finite element simulation. Firstly, finite element models of the rolling process were built on ABAQUS. To ensure the validity of models, some important settings as multistep construction, flexible boundary conditions of side rolls and nonlinear loading curves were considered, which provide the basis for high-accuracy numerical simulation of rim forming. Based on the results of simulation, each pass of the rim forming process was then analyzed. Especially, the investigations of wall thickness distribution and equivalent plastic strain on formed wheel rim are conducted, from which the role of three rolling passes and characteristics of rim forming can be summarized. Moreover, experiment results verified the reliability of finite element model. Subsequently, for analyzing the problems of welding-line cracking, model of flaring dies with various flaring angles were tried in simulations to discuss their influences on forming results of the wheel rim.

The novel gene LRP15 is regulated by DNA methylation and confers increased efficiency of DNA repair of ultraviolet-induced DNA damage

( Zhou Min Xu ),( Wei Ran Gao ),( Qi Mei Jian ),( Chen Jing Lu ) 생화학분자생물학회 2008 BMB Reports Vol.41 No.3

Global Synchronous Pulse Width Modulation of Distributed Inverters

Tao Xu,Feng Gao,Ran Wei 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

Traditionally, the parallel-connected multi-leg inverter could assume the interleaved PWM to attenuate the switching frequency harmonics by using a single controller to generate the corresponding interleaved switching sequences. However, the interleaved PWM cannot be employed in multiple distributed inverters installed at different locations with their own controllers because the multiple independent controllers cannot work synchronously and the operational conditions are variable among the distributed inverters. The summed current harmonics of multiple distributed inverters could vary at the point of common coupling (PCC) and worsen the power quality of consumers. This paper therefore proposes a global synchronous pulse width modulation (GSPWM) method for the distributed inverters to attenuate the high frequency current harmonics at PCC meanwhile improve the PCC voltage quality. The optimal interleaved switching angles among the distributed inverters are calculated by fully considering the line impedances, the modulation indexes, the switching frequencies, the number of distributed systems and etc. Then the low frequency synchronous operation will synchronize the pulse width modulation sequences in the wanted variation range. Experimental results are presented to prove the validity of this method.

Kinesin Family Member 11 Enhances the Self-Renewal Ability of Breast Cancer Cells by Participating in the Wnt/β-Catenin Pathway

Yuan-yuan Pei,Gao-chi Li,Jian Ran,Xin-hong Wan,Feng-xiang Wei,Lan Wang 한국유방암학회 2019 Journal of breast cancer Vol.22 No.4

Purpose: Our previous studies have shown that kinesin family member 11 (KIF11) is markedly overexpressed in human breast cancer cells or tissues and positively correlated with distant metastasis and prognosis in patients with breast cancer, suggesting an important role in the regulation of cancer stem cells. Herein, we examined the role of KIF11 in breast cancer stem cells. Methods: In the current study, we validated our previous findings through analysis of data collected in The Cancer Genome Atlas. Endogenous KIF11 was stably silenced in MCF-7 and SKBR-3 cells. Flow cytometry was used to measure the proportion of side-population (SP) cells. Mammosphere culture and tumor implantation experiments in immunodeficient mice were used to assess the self-renewal ability of breast cancer cells. Real-time polymerase chain reaction, western blot, immunofluorescence staining, luciferase reporter assays and Wnt agonist treatment were conducted to investigate the signaling pathways regulated by KIF11. Results: We found that the expression level of KIF11 was positively correlated with stem cell-enrichment genes. The proportion of SP cells was significantly reduced in KIF11-silenced cells. Silencing endogenous KIF11 not only reduced the size and number of mammospheres in vitro, but also reduced the ability of breast cancer cells to form tumors in mice. Simultaneously, we found that KIF11 was involved in regulating the activation of the Wnt/β-catenin signaling pathway. Conclusion: Endogenous KIF11 enhances the self-renewal of breast cancer cells by activating the Wnt/β-catenin signaling pathway, thereby enhancing the characteristics of breast cancer stem cells.

Numerical modeling and global performance analysis of a 15-MW Semisubmersible Floating Offshore Wind Turbine (FOWT)

Da Li,Ikjae Lee,Cong Yi,Wei Gao,Chunhui Song,Shenglei Fu,Moohyun Kim,Alex Ran,Tuanjie Liu Techno-Press 2023 Ocean systems engineering Vol.13 No.3

The global performance of a 15 MW floating offshore wind turbine, a newly designed semisubmersible floating foundation with multiple heave plates by CNOOC, is investigated with two independent turbine-floater-mooring coupled dynamic analysis programs CHARM3D-FAST and OrcaFlex. The semisubmersible platform hosts IEA 15 MW reference wind turbine modulated for VolturnUS-S and hybrid type (chain-wire-chain with clumps) 3×2 mooring lines targeting the water depth of 100 m. The numerical free-decay simulation results are compared with physical experiments with 1:64 scaled model in 3D wave basin, from which appropriate drag coefficients for heave plates were estimated. The tuned numerical simulation tools were then used for the feasibility and global performance analysis of the FOWT considering the 50-yr-storm condition and maximum operational condition. The effect of tower flexibility was investigated by comparing tower-base fore-aft bending moment and nacelle translational accelerations. It is found that the tower-base bending moment and nacelle accelerations can be appreciably increased due to the tower flexibility.

Nanoarchitectonics of tannic acid based injectable hydrogel regulate the microglial phenotype to enhance neuroplasticity for poststroke rehabilitation

Zongjian Liu,Shulei Zhang,Yuanyuan Ran,Huimin Geng,Fuhai Gao,Guiqin Tian,Zengguo Feng,Jianing Xi,Lin Ye,Wei Su 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Stroke is the second leading cause of mortality and disability worldwide. Poststroke rehabilitation is still unsatisfactory in clinics, which brings great pain and economic burdens to stroke patients. In this study, an injectable hydrogel in which tannic acid (TA) acts as not only a building block but also a therapeutic drug, was developed for poststroke rehabilitation. Methods TA is used as a building block to form an injectable hydrogel (TA gel) with carboxymethyl chitosan (CMCS) by multivalent hydrogen bonds. The morphology, rheological properties, and TA release behavior of the hydrogel were characterized. The abilities of the TA gel to modulate microglial (BV2 cells) polarization and subsequently enhance the neuroplasticity of neuro cells (N2a cells) were assessed in vitro. The TA gel was injected into the cavity of stroke mice to evaluate motor function recovery, microglial polarization, and neuroplasticity in vivo. The molecular pathway through which TA modulates microglial polarization was also explored both in vitro and in vivo. Results The TA gel exhibited sustainable release behavior of TA. The TA gel can suppress the expression of CD16 and IL-1β, and upregulate the expression of CD206 and TGF-β in oxygen and glucose-deprived (OGD) BV2 cells, indicating the regulation of OGD BV2 cells to an anti-inflammatory phenotype in vitro. This finding further shows that the decrease in synaptophysin and PSD95 in OGD N2a cells is effectively recovered by anti-inflammatory BV2 cells. Furthermore, the TA gel decreased CD16/iNOS expression and increased CD206 expression in the periinfarct area of stroke mice, implying anti-inflammatory polarization of microglia in vivo. The colocalization of PSD95 and Vglut1 stains, as well as Golgi staining, showed the enhancement of neuroplasticity by the TA gel. Spontaneously, the TA gel successfully recovered the motor function of stroke mice. The western blot results in vitro and in vivo suggested that the TA gel regulated microglial polarization via the NF-κB pathway. Conclusion The TA gel serves as an effective brain injectable implant to treat stroke and shows promising potential to promote poststroke rehabilitation in the clinic.