Simulating Strength Parameters and Size Effect of Stochastic Jointed Rock Mass using DEM Method

Chong Ma,Wenmin Yao,Yuan Yao,Jun Li 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.12

The strength parameters and the size effect of stochastic jointed limestone rock mass is investigated in this paper. Based on extensive statistics of joint parameters of rock mass in the research region, the probable distribution of geometric characteristic parameters of discontinuities are obtained by the probability graph method. Then the Monte-Carlo method is used for discontinuities network modeling. In addition, 3DEC software and its built-in FISH programming language are used to establish the stochastic jointed rock mass network model based on discrete element method. Triaxial numerical simulation tests under variable confining pressure are conducted with different model sizes and dip angles of bedding planes. The numerical simulation results indicate that the jointed rock mass exhibits weak anisotropy property and significant size effect when it is cut by stochastic discontinuities; the mechanical strength parameters of rock mass begins to fluctuate distinctly as the model size increases, and tend to be stable once the model size reaches or exceeds 4 m × 4 m × 8 m. Besides, the comprehensive mechanical parameters of rock mass in the research region are determined and failure modes of rock mass are analyzed as well based on the numerical simulation results.

Correlation analysis of factors influencing the electronic unit pump cycle fuel injection quantity under overall operating conditions for diesel engines

Yao Chong,Fan Li-yun,Dong Quan,Song En-zhe,Tian Bing-qi 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.9

Electronic unit pump (EUP) can satisfy both diesel engine emission legislation and fuel economy by improving injection pressure and numerical control. Fluctuations in cycle fuel injection quantity (CFIQ) of EUP determine the coherence and stability of the EUP fuel injection system. The EUP simulation model is developed in the AMESim environment. The method for the simulation experiment is designed in the MODDE environment using the design of experiments method. The results of the simulation reveal the variation laws of correlation between parameters with interaction or no interaction under overall operating conditions of diesel engines. In addition, the results also show the EUP system is a complex nonlinear system. Under overall operating conditions, all the characteristic parameters,such as fuel supply pressure, cam profile velocity, control valve lift, injector opening pressure, injector needle lift, and injector flow coefficient,have significant correlation with CFIQ. The interacting first-order factors exhibit the most significant correlation with CFIQ. The self-interacting second-order factors have significant secondary correlation with CFIQ.

A comprehensive analysis and comparison between vacuum and electric oven drying methods on Chinese saffron (Crocus sativus L.)

Chong Yao,Xiao-Dong Qian,Gui-Fen Zhou,Shu-Wei Zhang,Li-Qin Li,Qiaosheng Guo 한국식품과학회 2019 Food Science and Biotechnology Vol.28 No.2

The red stigmas of saffron are one of the mostexpensive spices in the world and serve as a traditionalChinese medicine. More saffron has been cultivated inChina, and different drying technologies have been studied. However, a comprehensive and comparative analysis ofdifferent drying approaches has not been well studied. Inthis study, we compared electric oven and vacuum ovendrying approaches on saffron. We found saffron was driedquicker under high vacuum drying mode with high temperatureand the quicker drying rate provided, the moreopen microstructural interstices on the saffron surface. Both methods were best fit to Midilli and Kucuk model. Besides, the coloring, aroma and bitterness strength afterdrying showed the similar results. In sum, our data suggestedthe optimal drying temperature was 100 C for20 min for two evaluated methods, however consideringthe machine cost, the electric oven drying would be the firstchoice.

Ginseng berry polysaccharides on infl ammation-associated colon cancer: inhibiting T-cell differentiation, promoting apoptosis, and enhancing the effects of 5-fl uorouracil

Chong-Zhi Wang,Lifei Hou,Jin-Yi Wan,Haiqiang Yao,Jinbin Yuan,Jinxiang Zeng,Chan Woong Park,Su Hwan Kim,Dae Bang Seo,Kwang-Soon Shin,Chun-Feng Zhang,Lina Chen,Qi-Hui Zhang,Zhi Liu,Clara Sava-Segal,Chun 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.2

Background: Ginseng is a commonly used herbal medicine in treating various medical conditions. Chronic gut inflammation is a recognized factor for the development of colorectal cancer (CRC). In thisproject, Asian ginseng berry polysaccharide preparations were used to assess their effects on CRC andrelated immune regulation mechanisms. Methods: Ginseng berry polysaccharide extract (GBPE) and purified ginseng berry polysaccharideportion (GBPP) were used to evaluate their activities on human HCT-116 and HT-29 CRC cell proliferation. Interleukin-8 secretion analysis was performed on HT-29 cells. Naive CD4 cell isolation and T-helper celldifferentiation were performed and determined using flow cytometry for Th1 and Treg in addition to cellcycle and apoptotic investigation. Results: GBPE and GBPP significantly inhibited interleukin-8 secretion and cancer cell proliferation,inhibited CD4þIFN-gþ cell (Th1) differentiation, and decreased CD4þFoxP3þ cell (Treg) differentiation. Compared to the GBPE, GBPP showed more potent antiinflammatory activities on the malignant cells. This is consistent with the observation that GBPP can also inhibit Th1-cell differentiation better, suggestingthat it has an important role in antiinflammation, whereas Treg cells hinder the body’s immuneresponse against malignancies. Supported by cell cycle and apoptosis data, GBPE and GBPP, at variousdegrees, remarkably enhanced the anticancer activities of 5-fluorouracil. Conclusion: Data from this project suggested that Asian ginseng berry potentially has clinical utility inmanaging enteric inflammation and suppressing CRC through immunomodulation mechanisms.

Cloning, Annotation and Expression Analysis of Mycoparasitism- Related Genes in Trichoderma harzianum 88

Lin Yao,Qian Yang,Jinzhu Song,Chong Tan,Changhong Guo,Li Wang,Lianhai Qu,Yun Wang 한국미생물학회 2013 The journal of microbiology Vol.51 No.2

Trichoderma harzianum 88, a filamentous soil fungus, is an effective biocontrol agent against several plant pathogens. High-throughput sequencing was used here to study the mycoparasitism mechanisms of T. harzianum 88. Plate confrontation tests of T. harzianum 88 against plant pathogens were conducted, and a cDNA library was constructed from T. harzianum 88 mycelia in the presence of plant pathogen cell walls. Randomly selected transcripts from the cDNA library were compared with eukaryotic plant and fungal genomes. Of the 1,386 transcripts sequenced, the most abundant Gene Ontology (GO) classification group was “physiological process”. Differential expression of 19 genes was confirmed by real-time RT-PCR at different mycoparasitism stages against plant pathogens. Gene expression analysis revealed the transcription of various genes involved in mycoparasitism of T. harzianum 88. Our study provides helpful insights into the mechanisms of T. harzianum 88-plant pathogen interactions.

A Novel Unsteady Fractal Derivative Creep Model for Soft Interlayerswith Varying Water Contents

Wenmin Yao,Bin Hu,Hongbin Zhan,Chong Ma,Nenghao Zhao 대한토목학회 2019 KSCE Journal of Civil Engineering Vol.23 No.12

Creep properties of soft interlayers are key factors associated with the long-term stability of geological bodies. An experimental and theoretical study on the ring shear creep properties of soft interlayers collected from Esheng, Sichuan province, China are performed in this study. Ring shear creep tests of soft interlayers, which are remolded into over-consolidated samples having various water contents and the same initial dry density, are performed in laboratory, to analyze the creep deformation characteristics of samples in detail. The calculated long-term shear strength of samples is close to residual strength. By substituting the dashpot with a new unsteady fractal dashpot, a novel unsteady fractal derivative creep (UFDC) model, which can be defined in series with an improved Maxwell model and an improved viscoplastic model, is proposed based on theory of fractal derivative. The new model can efficiently explain the soft interlayers creep deformation. The results indicate that most model parameters are sensitive to the shear stress. However, at the accelerated creep stage, the fractional order of the second dashpot in the UFDC model has little effect on the fitting of experimental data.

Ginseng berry polysaccharides on inflammation-associated colon cancer: inhibiting T-cell differentiation, promoting apoptosis, and enhancing the effects of 5-fluorouracil

Wang, Chong-Zhi,Hou, Lifei,Wan, Jin-Yi,Yao, Haiqiang,Yuan, Jinbin,Zeng, Jinxiang,Park, Chan Woong,Kim, Su Hwan,Seo, Dae Bang,Shin, Kwang-Soon,Zhang, Chun-Feng,Chen, Lina,Zhang, Qi-Hui,Liu, Zhi,Sava-Se The Korean Society of Ginseng 2020 Journal of Ginseng Research Vol.44 No.2

Background: Ginseng is a commonly used herbal medicine in treating various medical conditions. Chronic gut inflammation is a recognized factor for the development of colorectal cancer (CRC). In this project, Asian ginseng berry polysaccharide preparations were used to assess their effects on CRC and related immune regulation mechanisms. Methods: Ginseng berry polysaccharide extract (GBPE) and purified ginseng berry polysaccharide portion (GBPP) were used to evaluate their activities on human HCT-116 and HT-29 CRC cell proliferation. Interleukin-8 secretion analysis was performed on HT-29 cells. Naive CD4 cell isolation and T-helper cell differentiation were performed and determined using flow cytometry for Th1 and Treg in addition to cell cycle and apoptotic investigation. Results: GBPE and GBPP significantly inhibited interleukin-8 secretion and cancer cell proliferation, inhibited CD4⁺IFN-γ⁺ cell (Th1) differentiation, and decreased CD4⁺FoxP3⁺ cell (Treg) differentiation. Compared to the GBPE, GBPP showed more potent antiinflammatory activities on the malignant cells. This is consistent with the observation that GBPP can also inhibit Th1-cell differentiation better, suggesting that it has an important role in antiinflammation, whereas Treg cells hinder the body's immune response against malignancies. Supported by cell cycle and apoptosis data, GBPE and GBPP, at various degrees, remarkably enhanced the anticancer activities of 5-fluorouracil. Conclusion: Data from this project suggested that Asian ginseng berry potentially has clinical utility in managing enteric inflammation and suppressing CRC through immunomodulation mechanisms.

Adaptive Second-order Sliding Mode Control of Electrical Throttles Based on Online Zero-crossing Checking

Yun Long,Chong Yao,En-Zhe Song,Quan Dong,Yan-Min Wang 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.2

In this paper, an adaptive second-order sliding mode control approach is proposed for the performance improvement of electronic throttles (ET). Based on the traditional twisting approach, a novel adaptation mechanism based on the online zero-crossing checking is contained in the modified approach to make the control magnitude of the controller at the minimum admissible level. The idea behind it is to calculate the number of zero-crossings of the sliding surface in real time. The guaranteed stability condition and convergence region of the system are also deduced. In order to further prove its high adaptation capability, the commonly used adaptation mechanism called the Lyapunov-based type is also introduced for comparative study. Simulations and experiments validate the proposed approach with the advantages of chattering elimination, high speed and accuracy in the control of ET systems.

Commonly Used Surfactant, Tween 80, Improves Absorption of P-Glycoprotein Substrate, Digoxin, in Rats

Zhang, Hongjian,Yao, Ming,Morrison, Richard-A.,Chong, Sae-Ho The Pharmaceutical Society of Korea 2003 Archives of Pharmacal Research Vol.26 No.9

Tween 80 (Polysorbate 80) is a hydrophilic nonionic surfactant commonly used as an ingredient in dosing vehicles for pre-clinical in vivo studies (e.g., pharmacokinetic studies, etc.). Tween 80 increased apical to basolateral permeability of digoxin in Caco-2 cells suggesting that Tween 80 is an in vitro inhibitor of P-gp. The overall objective of the present study was to investigate whether an inhibition of P-gp by Tween 80 can potentially influence in vivo absorption of P-gp substrates by evaluating the effect of Tween 80 on the disposition of digoxin (a model P-gp substrate with minimum metabolism) after oral administration in rats. Rats were dosed orally with digoxin (0.2 mg/kg) formulated in ethanol (40%, v/v) and saline mixture with and without Tween 80 (1 or 10%, v/v). Digoxin oral AUC increased 30 and 61% when dosed in 1 % and 10% Tween 80, respectively, compared to control (P<0.05). To further examine whether the increase in digoxin AUC after oral administration of Tween 80 is due, in part, to a systemic inhibition of digoxin excretion in addition to an inhibition of P-gp in the GI tract, a separate group of rats received digoxin intravenously (0.2 mg/kg) and Tween 80 (10% v/v) orally. No significant changes in digoxin IV AUC was noted when Tween 80 was administered orally. In conclusion, Tween 80 significantly increased digoxin AUC and Cmax after oral administration, and the increased AUC is likely to be due to an inhibition of P-gp in the gut (i.e., improved absorption). Therefore, Tween 80 is likely to improve systemic exposure of P-gp substrates after oral administration. Comparing AUC after oral administration with and without Tween 80 may be a viable strategy in evaluating whether oral absorption of P-gp substrates is potentially limited by P-gp in the gut.

Control Method for Grid-Connected/Islanding Switching of Hybrid AC/DC Microgrid

Qu Zheng-Wei,Chong Zhen-Xiao,Wang Yun-Jing,Shi Zhe,Yao Yun-Xiao 대한전기학회 2023 Vol.18 No.1

For hybrid AC/DC microgrid (HMG) under master–slave control strategy, DGs usually adopt constant power control (P control) in gird-connected mode and at least one DG adopts constant voltage control (V control) in islanding mode. However, when unplanned islanding happens, the voltage and current of the HMG will experience remarkable fl uctuations, which aff ects the system’s stability. This paper presents a control method to achieve smooth switching from grid-connected to islanding mode by introducing state tracking control between P control and V control. The state tracking control can make the current reference signal of the V control track that of the P control in grid-connected mode. When unplanned islanding happens, the mutation of the current reference signal can be tuned into a smooth transition by the voltage loop’s PI controller, and the transient oscillations can be eliminated to realize smooth switching. The eff ectiveness of the proposed control method is verifi ed by simulation results using MATLAB/Simulink.