Analysis on Geo-stress and casing damage based on fluid-solid coupling for Q9G3 block in Jibei oil field

Ji, Youjun,Li, Xiaoyu Techno-Press 2018 Geomechanics & engineering Vol.15 No.1

Aimed at serious casing damage problem during the process of oilfield development by injecting water, based on seepage mechanics, fluid mechanics and the theory of rock mechanics, the multi-physics coupling theory was also taken into account, the mathematical model for production of petroleum with water flooding was established, and the method to solve the coupling model was presented by combination of Abaqus and Eclipse software. The Q9G3 block in Jibei oilfield was taken for instance, the well log data and geological survey data were employed to build the numerical model of Q9G3 block, the method established above was applied to simulate the evolution of seepage and stress. The production data was imported into the model to conduct the history match work of the model, and the fitting accuracy of the model was quite good. The main mechanism of casing damage of the block was analyzed, and some wells with probable casing damage problem were pointed out, the displacement of the well wall matched very well with testing data of the filed. Finally, according to the simulation results, some useful measures for preventing casing damage in Jibei oilfield was proposed.

Combined Application Effects of Arbuscular Mycorrhizal Fungi and Biochar on the Rhizosphere Fungal Community of Allium fistulosum L.

Ji Chunxiang,Li Yingyue,Xiao Qingchen,Li Zishan,Wang Boyan,Geng Xiaowan,Lin Keqing,Zhang Qing,Jin Yuan,Zhai Yuqian,Li Xiaoyu,Chen Jin 한국미생물·생명공학회 2023 Journal of microbiology and biotechnology Vol.33 No.8

Arbuscular mycorrhizal fungi (AMF) are widespread soil endophytic fungi, forming mutualistic relationships with the vast majority of land plants. Biochar (BC) has been reported to improve soil fertility and promote plant growth. However, limited studies are available concerning the combined effects of AMF and BC on soil community structure and plant growth. In this work, a pot experiment was designed to investigate the effects of AMF and BC on the rhizosphere microbial community of Allium fistulosum L. Using Illumina high-throughput sequencing, we showed that inoculation of AMF and BC had a significant impact on soil microbial community composition, diversity, and versatility. Increases were observed in both plant growth (the plant height by 8.6%, shoot fresh weight by 12.1%) and root morphological traits (average diameter by 20.5%). The phylogenetic tree also showed differences in the fungal community composition in A. fistulosum. In addition, Linear discriminant analysis (LDA) effect size (LEfSe) analysis revealed that 16 biomarkers were detected in the control (CK) and AMF treatment, while only 3 were detected in the AMF + BC treatment. Molecular ecological network analysis showed that the AMF + BC treatment group had a more complex network of fungal communities, as evidenced by higher average connectivity. The functional composition spectrum showed significant differences in the functional distribution of soil microbial communities among different fungal genera. The structural equation model (SEM) confirmed that AMF could improve the microbial multifunctionality by regulating the rhizosphere fungal diversity and soil properties. Our findings provide new information on the effects of AMF and biochar on plants and soil microbial communities.

Healthy eating-out options are related to healthy eating intention in adults residing in Daqing (China)

Xiaoyu Ma,Seungwoo Lee,Ji-Yun Hwang 한국영양학회 2023 Journal of Nutrition and Health Vol.56 No.1

An Empirical Study on Chinese College Graduates’ Employability Skills and Employment Quality

조현준,Xiaoyu Ji 한국동북아경제학회 2016 동북아경제연구 Vol.28 No.1

This study, based on a survey of Chinese youth who graduated from universities in Shandong Province in 2012, empirically analyzed the relationship between employability skills and employment quality. Especially, we reviewed whether there was a difference in the employability skills or employment quality between the ‘Project 211’ (front-rank) university graduates and general ones. The main conclusions are as follows: (1) The employability skills are found to mainly consist of four factors - SAC(self-awareness and cognition), SMA(self-management abilities), CST (communication skills and teamwork), and PSA (problem-solving abilities). (2) The employability skills of the graduates of the Project 211 universities are found to be better than that of general universities. (3) The employment quality of the graduates of the Project 211 universities is found to be better than that of general universities. (4) Three factors of SAC, SMA and PSA are found to have a statistically significant positive correlations with the employment quality. (5) SAC is found to have the highest influence on the employment quality of the Project 211 graduates. (6) PSA is found to have the highest influence on the employment quality of general university graduates.

The Mechanism of Rockbolt in the Jointed Rock Under Uniaxial Tension

Shen Zhou,Xiaoyu Ji,Li-Ping Li,Hong-liang Liu,Chun Zhu,Hongyun Fan,Qi Zhang,Caihua Shi,Xutong Zhang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.11

In this research, the rockbolt mechanism of a jointed rock mass under uniaxial tension was systematically revealed with a laboratory test and a numerical simulation. It was found that the rockbolt rock mass experienced five stages under uniaxial tension, the densification stage, elastic stage, plastic deformation stage, progressive debonding stage, and complete debonding stage. The stress-strain curve and ultimate tensile strength of a rockbolt rock mass were analyzed by taking the rockbolt spacing and rockbolt angle as variables. It was found that the improvement effect of the reduction of the rockbolt spacing on the ultimate tensile strength was limited. When the rockbolt spacing was reduced to a certain limit, the stress concentration area between adjacent rockbolts was connected and destroyed, resulting in the increase of the rockbolt rock strength becoming smaller, and even having a downward trend. The increase of the rockbolt angle led to the change of the stress mode and failure mode of the whole structure, and the ultimate tensile strength first increased and then decreased. The optimal rockbolt angle was between 60° and 70°. It is worth noting that there was an obvious mechanical occlusion between the thread on the rockbolt surface and the rock mass, resulting in the multi-stage step-down characteristic of the stress-strain curve in the complete debonding stage. The results of this study can provide a reference for the design and construction of similar projects.

Enrichment of linoleic acid from yellow horn seed oil through low temperature crystallization followed by urea complexation method and hypoglycemic activities

Kang Yang,Ying Tang,Huayu Xue,Xiaoyue Ji,Fu-Liang Cao,Shouke Li,Li Xu 한국식품과학회 2024 Food Science and Biotechnology Vol.33 No.1

Yellow horn (Xanthoceras sorbifolia Bunge) contained abundant linoleic acid (LA), accounting for about 44% of its lipid. Here, LA was enriched by low temperature crystallization followed by urea complexation, and the optimal enrichment conditions were optimized with response surface methods (3:1 ratio of EtOH/FFA, crystallization at − 25 °C for 24.5 h; 2:1 ratio of urea/FFA1, 6.6:1 ratio of EtOH/urea, crystallization at − 10 °C for 22.4 h). Under these conditions, the final LA content and recovery were 97.10% and 62.09%, respectively. In vitro hypoglycemic studies suggested that the LA extract with stronger inhibition on α-glucosidase and lower one on α-amylase than acarbose exhibited a positive control for carbohydrate digestion with lower adverse effects. The enzyme kinetics and Lineweaver–Burk plots analyses revealed a reversible competitive inhibition on α-amylase and α-glucosidase. The findings of this research provided insights for the development of the LA extract as the functional component of health food.

Prevalence of NAFLD in Asia: A Systematic Review and Meta-Analysis of 195 Studies and 1,753,168 Subjects from 13 Countries

( Jie Li ),( Biyao Zou ),( Hideki Fujii ),( Yee Hui Yeo ),( Fanpu Ji ),( Dong Hyun Lee ),( Yuemin Feng ),( Xiaoyu Xie ),( Wanhua Ren ),( Qiang Zhu ),( Mindie H. Nguyen ) 대한간학회 2018 춘·추계 학술대회 (KASL) Vol.2018 No.1

Aims: NAFLD is generally correlated with the obesity epidemic. Asia is a heterogeneous region with varying socioeconomic levels and obesity prevalence; therefore, our goal was to estimate the prevalence of NAFLD in Asia through a meta-analytic approach. Methods: PubMed and EMBASE databases were searched from 1989 to 2017 for relevant studies reporting NAFLD prevalence in Asia. All studies were reviewed by three independent investigators. We used random-effects models to provide point estimates with 95% confidence interval (CI) of prevalence. Publication bias was assessed by Egger weighted regression Methods. Results: From the 2700 titles and abstracts reviewed, 195 papers from 13 countries met the inclusion criteria and included 1,753,168 subjects. The overall pooled prevalence for NAFLD in Asia was 31% (95% CI: 29-32). Individual country prevalence was shown in Table 1. In countries with more than 3 studies, the lowest prevalence was seen in Japan (24%, 95% CI: 21-28) and the highest in Iran (36%, 95%CI 31-41). Notably, pooled prevalence from studies with sample <1,000 subjects was much higher (34%, 95% CI: 31-38, 45 studies, n=23,857) than estimate from larger studies (≥1,000 subjects) (30%, 95% CI: 28- 31, 150 studies, n=172,9311). By sub-regions within Asia (Table 2), there was significant regional differences (P<0.01) with the highest NAFLD prevalence seen in West Asia (33%, 95% CI: 28-39, 13 studies, n=32,142) and the lowest in Southeast Asia (24%, 95% CI: 15-33, 5 studies, n=3457). By country income levels, NAFLD prevalence was 30% (95% CI: 29-32, 89 studies, n=1,005,409) for high-income countries and 31% (95% CI: 29-33, 106 studies, n=747,759) for middle-income countries (P<0.63). Conclusions: Overall NAFLD prevalence in Asia is 31% similar to Western countries and by country-income levels within Asia but varies by some sub-regions or Asia with the highest prevalence in West Asia (33%).