Coring Damage Extent of Rock Cores Retrieved from High In-situ Stress Condition: A Case Study

Peng Yan,Qi He,Wenbo Lu,Yanli He,Wei Zhou,Ming Chen 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.7

The distribution of damage in deep rock cores is critical for assessing its influence on rock mechanical characteristics. This paper presents a case study on estimating the coring damage extent induced by the stress redistribution through a combined method of numerical simulation and X-ray Computed Tomography (CT) scanning. Rock cores are taken at 1900 m depth from the test tunnel at Jin-ping Second Stage Hydropower Station (JPII) in China. Firstly, the stress path experienced by the rock core during coring has been examined by the numerical simulation, and the distribution of tensile zone in the cross-section of rock core is also discussed. Then two kinds of samples, collected from the same position under different stress levels, are scanned to obtain CT images, and a special CT value analysis strategy was adopted to evaluate coring damage intensities of these samples. The result indicates that the stress state can be regarded as the principal factor for the distribution of coring damage. During coring in the Test Tunnel of JPII under the quasi-hydrostatic stress condition, high tensile stresses (over 5 MPa) are observed at the exterior edge of rock cores, which may lead to the nucleation of microcracks around the core boundary, and the coring damage then propagates to the core centre. The CT scanning also illustrates that the coring damage zone may cover approximately 70~80% of the entire cross-section from the outside inside (stress level of 50 MPa), and that the central part of the core is less damaged or eventually undisturbed. Thus, intact rock samples can be expected to be obtained by overcoring the original rock cores. However, the applicability of the overcoring method seems to be largely dependent on the state of in-situ stress at the coring site. The whole core may be damaged if the lateral stress coefficient reaches a critical value (e.g. greater than 3.0), in which case a special coring equipment should be adopted to improve the stress state during coring.

Recombinant Expression and Characterization of Thermoanaerobacter tengcongensis Thermostable α-Glucosidase with Regioselectivity for High-Yield Isomaltooligosaccharides Synthesis

Cheong Zhou,Yan Fen Xue,Yue Ling Zhang,Yan Zeng,Yan He Ma 한국미생물 · 생명공학회 2009 Journal of microbiology and biotechnology Vol.19 No.12

A Fault Tolerant Structure and Control Strategy for Electromagnetic Stirring Supplies

Yan Li,An Luo,Xinxing Xiang,Yandong Chen,Zhixing He,Fayun Zhou,Zhiyong Chen 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.5

A fault tolerant structure and its corresponding control strategy for electromagnetic stirring power supplies are proposed in this paper. The topology structure of the electromagnetic stirring power supply contains two-stages. The fore-stage is the PWM rectifier. The back-stage is the fault tolerant inverter, which is a two-phase three-bridge orthogonal inverter circuit while operating normally. When the power switch devices in the inverter are faulty, the structure of the inverter is reconfigured. The two-phase half bridge inverter circuit is constructed with the remaining power switch devices and DC-link capacitors to keep the system operating after cutting the faulty power switch devices from the system. The corresponding control strategy is proposed to let the system work under both normal and fault conditions. The reliability of the system is improved and the requirement of the electromagnetic stirring process is met. Finally, simulation and experimental results verify the feasibility of the proposed fault tolerant structure and corresponding control strategy.

Saponins from Panax japonicus ameliorate age-related renal fibrosis by inhibition of inflammation mediated by NF-κB and TGF-β1/Smad signaling and suppression of oxidative stress via activation of Nrf2-ARE signaling

Yan Gao,Ding Yuan,Liyue Gai,Xuelian Wu,Yue Shi,Yumin He,Chaoqi Liu,Changcheng Zhang,Gang Zhou,Chengfu Yuan 고려인삼학회 2021 Journal of Ginseng Research Vol.45 No.3

Background: The decreased renal function is known to be associated with biological aging, of which the main pathological features are chronic inflammation and renal interstitial fibrosis. In previous studies, we reported that total saponins from Panax japonicus (SPJs) can availably protect acute myocardial ischemia. We proposed that SPJs might have similar protective effects for aging-associated renal interstitial fibrosis. Thus, in the present study, we evaluated the overall effect of SPJs on renal fibrosis. Methods: Sprague-Dawley (SD) aging rats were given SPJs by gavage beginning from 18 months old, at 10 ㎎/㎏/d and 60 ㎎/㎏/d, up to 24 months old. After the experiment, changes in morphology, function and fibrosis of their kidneys were detected. The levels of serum uric acid (UA), β2-microglobulin (β2-MG) and cystatin C (Cys C) were assayed with ELISA kits. The levels of extracellular matrix (ECM), matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), inflammatory factors and changes of oxidative stress parameters were examined. Results: After SPJs treatment, SD rats showed significantly histopathological changes in kidneys accompanied by decreased renal fibrosis and increased renal function; As compared with those in 3-month group, the levels of serum UA, Cys C and β2-MG in 24-month group were significantly increased (p < 0.05). Compared with those in the 24-month group, the levels of serum UA, Cys C and β2-MG in the SPJ-H group were significantly decreased. While ECM was reduced and the levels of MMP-2 and MMP-9 were increased, the levels of TIMP-1, TIMP-2 and transforming growth factor-β1 (TGF-β1)/Smad signaling were decreased; the expression level of phosphorylated nuclear factor kappa-B (NF-κB) was down-regulated with reduced inflammatory factors; meanwhile, the expression of nuclear factor erythroid 2-related factor 2-antioxidant response element (Nrf2-ARE) signaling was aggrandized. Conclusion: These results suggest that SPJs treatment can improve age-associated renal fibrosis by inhibiting TGF-β1/Smad, NFκB signaling pathways and activating Nrf2-ARE signaling pathways and that SPJs can be a potentially valuable anti-renal fibrosis drug.

Genetic Variation in PDCD6 and Susceptibility to Lung Cancer

He, Yan-Qi,Zhou, Bin,Shi, Shao-Qing,Zhang, Lin,Li, Wei-Min Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.9

Lung cancer is the most common type of cancer and one of the leading causes of death in the world. Genetic factors play an important role in its development. PDCD6, the encoding gene for programmed cell death protein 6, may function as a tumor suppressor gene. Non-small cell lung cancer (NSCLC) contributes about 80% to newly histologically diagnosed lung cancer patients. To explore the relationship between PDCD6 and NSCLC, we examined two single nucleotide polymorphisms(rs3756712 G/T andrs4957014 G/T, both in the intron region) of the PDCD6gene.A hospital-based case-control study was carried out including 302 unrelated NSCLC patients and 306 healthy unrelated subjects. Significantly increased NSCLC risk was found to be associated with the T allele of rs4957014 (P=0.027, OR=0.760, 95%CI=0.596-0.970). The genotype and allele frequencies of rs3756712 did not shown any significant difference between NSCLC group and controls (P=0.327, OR=0.879, 95%CI=0.679-1.137). In conclusion, we firstly demonstrated the association between the PDCD6 gene and risk of NSCLC in a Chinese Han population.

New Compounds from Euphorbia helioscopia and Absolute Configuration Determination by Computational Methods

He, Jiang-Bo,Zhu, Hua-Jie,Luo, Gui-Fen,Liu, Guang-Ming,Chen, Hao,Li, Yan,Chen, Shaopeng,Lu, Xin,Zhou, Guochun,Cheng, Yong-Xian Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.8

The whole plant of Euphorbia helioscopia is an important traditional Chinese medicine. Fom its BuOH soluble extract, one new lactam (1), three new terpenoids (2-4) including a new naturally occurring compound, and three known compounds were isolated. Their structures were identified by spectroscopic evidences. In particular, the absolute configurations of side chain of compounds 1 and 2 were determined using computational methods.

Benefit of Post-mastectomy Radiotherapy of the Supra-/infraclavicular Lymphatic Drainage Area in Breast Cancer Patients

He, Zhen-Yu,Wu, San-Gang,Zhou, Juan,Sun, Jia-Yuan,Li, Feng-Yan,Lin, Qin,Guo, Ling,Lin, Huan-Xin Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.14

Background: This study investigated the survival benefit of radiotherapy (RT) of the supra- and infraclavicular lymphatic drainage area in Chinese women with T1-2N1M0 breast cancer receiving mastectomy. Methods: A total of 593 cases were retrospectively reviewed from 1998 to 2007. The relationship between supra- or infraclavicular fossa relapse (SCFR) and post-operative RT at the supra-/infraclavicular lymphatic drainage area was evaluated. Results: The majority of patients (532/593; 89. 8%) received no RT while 61 patients received RT. The median follow-up was 85 months. Among patients without RT, 54 (10. 2%) developed recurrence in the chest wall or ipsilateral SCFR. However, none of the 61 patients who underwent RT demonstrated SCFR. One patient who received RT (1. 6%) experienced recurrence in the chest wall. Univariate analysis revealed that age and molecular subtype (both P < 0. 05) were two prognostic factors related to supraclavicular and infraclavicular fossa relapse-free survival (SFRFS). Multivariate analysis revealed that only Her-2 positive status (P = 0. 011) was an independent predictor of SFRFS. RT had no influence on distant metastasis (P = 0. 328) or overall survival (P = 0. 541). SCFR significantly affected probability of distant metastasis (P < 0. 001) and overall survival (P < 0. 001). Conclusion: Although RT was not significantly associated with SFRFS, postoperative RT was significantly associated with a lower locoregional (i. e., supraclavicular/infraclavicular and chest wall) recurrence rate. SCFR significantly influenced distant metastasis-free survival, which significantly influenced the overall survival of T1-2N1M0 breast cancer patients after mastectomy. Thus, prophylactic RT is recommended in T1-2N1M0 breast cancer patients, especially those who have Her-2 positive lesions.

A 3D analytical model for the probabilistic characteristics of self-healing model for concrete using spherical microcapsule

He-hua Zhu,Shuai Zhou,Zhi-guo Yan,Woody Ju,Qing Chen 사단법인 한국계산역학회 2015 Computers and Concrete, An International Journal Vol.15 No.1

In general, cracks significantly deteriorate the in-situ performance of concrete members and structures, especially in urban metro tunnels that have been embedded in saturated soft soils. The microcapsule self-healing method is a newly developed healing method for repairing cracked concrete. To investigate the optimal microcapsule parameters that will have the best healing effect in concrete, a 3D analytical probability healing model is proposed; it is based on the microcapsule self-healing method’s healing mechanism, and its purpose is to predict the healing efficiency and healing probability of given cracks. The proposed model comprehensively considers the radius and the volume fraction of microcapsules, the expected healing efficiency, the parameters of cracks, the broken ratio and the healing probability. Furthermore, a simplified probability healing model is proposed to facilitate the calculation. Then, a Monte Carlo test is conducted to verify the proposed 3D analytical probability healing model. Finally, the influences of microcapsules’ parameters on the healing efficiency and the healing probability of the microcapsule self-healing method are examined in light of the proposed probability model.

Co2+-coordination-assisted enhancement of mechanical and iodynamic properties of 3D graphene-based double network hydrogels for all-solid-state supercapacitors

He Binhong,Wen Shuntao,Wen Zhiming,Liang Yan,Yang Qianxi,Zhou Minjie,Wang Wei,Wang Guo-Xiang 한국탄소학회 2024 Carbon Letters Vol.34 No.3

This paper reports an enhanced strategy for improving the mechanical flexibility and ionic kinetic properties of a double network hydrogel based on Co2+-coordination assistance. The modified double-network hydrogel was obtained by using acrylic acid and N, N-dimethylacrylamide as monomers, adding cross-linking agents and 3D nitrogen-doped graphenes. The tensile fracture rate of the modified hydrogel was 1925% and its tensile strength was 1696 kPa. In addition, the hydrogel exhibited excellent ionic dynamics, and its application to an all-solid-state supercapacitor was able to achieve a specific capacitance of up to 182.8 F g−1. The supercapacitor exhibited an energy density of 34.2 Wh kg−1, even when operating at a power density of 5 kW kg−1, highlighting its significant potential for practical applications.

Competition and Coordination for the Dual-channel Supply Chain with Channel Preference

ZHOU Yong-wei,FAN He-hua,LI Yan-chao 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.2

Aiming at the dual-channel supply chain system with the manufacturer owned direct channel and retail channel simultaneously, the consumers are divided into retail channel loyalty and brand loyalty two parts, under the condition of market demand are depend on the consumers’ channel preference, we studied to the pricing game and coordination between the manufacturer and retailer. The research result showed that the Nash equilibrium of price exists in centralized and decentralized supply chain system, the channel preference degree of consumers, the number of brand loyalty consumers are all have certain influence on supply chain’s optimal pricing strategy, and the price markup contract can realize the coordination of supply chain. The numerical experiment has showed the effectiveness of the conclusions.