An Analytical Model and Its Application in Reliability Analysis of Formation Failure during Hydrate Production in Deep-sea Areas

Mingjing Jiang,Jiajia Huang,Huaning Wang 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.1

Methane hydrates (MHs) have potential economic and environmental significance. However, due to the sharp reduction in the mechanical properties of methane hydrate-bearing sediments (MHBS) caused by hydrate dissociation, the risk of formation failure in marine MHs exploitation is higher than that in conventional oil and gas exploitation. Formation failure in marine hydrate production probably leads to serious sand production or subsequent formation instability. A simplified and efficient analytical model is proposed at first for prediction of formation failure as well as the displacement around the wellbore during hydrate production, and then the reliability analysis for formation failure is performed by the Advanced First Order Second Moment Method based on the analytical solutions. This model considers the key factors affecting the formation failure, including 1) the partial coupling of multiple fields (the influence of pore pressure on mechanical field and the influence of hydrate dissociation on pore pressure, temperature and mechanical field), 2) the effect of gas/water or heat absorption caused by hydrate dissociation on pore pressure or temperature, 3) the change of mechanical properties of formation induced by hydrate dissociation and 4) the casing-formation interaction. The analytical solutions are verified and validated by numerical models. According to the analysis, the casing is sufficiently safe in the cross section due to its high stiffness, while the formation would be failure at the wellbore or dissociated front due to the stiffness/strength deterioration induced by hydrate dissociation. Hydrate dissociation leads to an increase in formation failure probability by approximately 20%. The probability of formation failure at the wellbore is about 30% higher than that at the dissociated front. The uncertainties in the internal friction angle and elastic modulus ratio have the greatest effect on formation failure probability.

Rapid Detection of Clostridium tetani by Recombinase Polymerase Amplification Using an Exo Probe

( Mingjing Guo ),( Pan Feng ),( Liqun Zhang ),( Chunfeng Feng ),( Jie Fu ),( Xiaoyun Pu ),( Fei Liu ) 한국미생물 · 생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.1

Tetanus is a potentially fatal public health illness resulted from the neurotoxins generated by Clostridium tetani. C. tetani is not easily culturable and culturing the relevant bacteria from infected wounds has rarely been useful in diagnosis; PCR-based assays can only be conducted at highly sophisticated laboratories. Therefore, a real-time recombinase polymerase amplification assay (Exo-RPA) was constructed to identify the fragments of the neurotoxin gene of C. tetani. Primers and the exo probe targeting the conserved region were designed, and the resulting amplicons could be detected in less than 20 min, with a detection limit of 20 copies/reaction. The RPA assay displayed good selectivity, and there were no cross-reactions with other infectious bacteria common in penetrating wounds. Tests of target-spiked serum and pus extract revealed that RPA is robust to interfering factors and has great potential for further development for biological sample analysis. This method has been confirmed to be reliable for discriminating between toxic and nontoxic C. tetani strains. The RPA assay dramatically improves the diagnostic efficacy with simplified device architecture and is a promising alternative to real-time PCR for tetanus detection.

Evaluating Kinetics of Enzymatic Saccharification of Lignocellulose by Fractal Kinetic Analysis

Mingjing Yao,Zhilong Wang,Zhenqiang Wu,Hanshi Qi 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.6

The effects of impacting factors, including cellulase loading, operation temperature, product glucose inhibition, and high solid pretreated biomass loading were examined systemically on the enzymatic saccharification of lignocellulose (dilute acid pretreated corn stover) in the presence and absence of tri-block copolymer L64 (also referred to polymeric nonionic surfactant). The complex kinetics of enzymatic saccharification of cellulose were subjected to fractal kinetic analysis based on a fractal kinetic model, which is described with fractal kinetic parameters of the rate constant and fractal exponent. The results indicate that glucose inhibition including high lignocellulose loading is indexed by decreasing rate constant while lignin inhibition and high operation temperature is indexed by increasing fractal exponent. The effect of a nonionic surfactant on the enzymatic saccharification of lignocellulose mainly contributed to the elimination of lignin inhibition by decreasing the corresponding fractal exponent. However, the effect of the nonionic surfactant on cellulase activity and stability was very limited.

An Aptamer-based Self-Catalytic Colorimetric Assay for Carcinoembryonic Antigen

Mingjing Zou,Shuyu Wang 대한화학회 2017 Bulletin of the Korean Chemical Society Vol.38 No.10

We report a visualization assay for carcinoembryonic antigen (CEA). The assay was prepared based on target-specific recognition, aptamer-based DNAzyme self-catalysis, and colorimetric reaction. Aptamer of CEA was gathered at the surface of magnetic beads for sandwiched co-conjugate when CEA was added. The second aptamer (Apt2) on the beads was folded into G-quadruplex by KCl to make G-quadruplex-hemin DNAzyme with hemin. Apt2-based DNAzyme catalyzed H2O2-mediated oxidation of 3,3′,5,5′-tetramethylbenzidine, resulting in color changes and significant increase in absorption intensity at 450 nm (ΔA450nm). Yellow products can be observed with naked eyes when over 1.0 ng/mL CEA was added and there was a linear correlation between ΔA450 nm and CEA concentrations in the range of 0.1–8.0 ng/mL with the detection limit of 0.06 ng/mL. The proposed method was then used to determine CEA in human serum from healthy people and tumor patients, revealing a correlation with data from the electrochemiluminescent immunoassay. Owing to its simplicity, selectivity, and low-cost, this method is a promising candidate for detecting CEA and clinical diagnosis of cancer.

FEM and Experimental Analysis of Lunar Soil Excavation Test

Mingjing Jiang,Banglu Xi,Zhenyu Guo,Huayang Lei 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.8

A series of soil cutting tests was firstly carried out on the Earth on a ground composed of Tongji-1 lunar soil simulant (TJ-1 simulant) to experimentally investigate the effects of cutting depth, blade width, rake angle and blade arc angle on the excavation force. Then the tests were numerically simulated with the Finite Element Method (FEM), where a constant velocity was applied to the soil in contact with the blade, namely the soil cutting method or a rigid blade was generated and moved to cut the soil, namely the blade cutting method. The results show that the FEM simulation using the soil cutting method can provide excavation forces close to the experimental data when the rake angle is 0°, and well capture the effects of cutting depth, blade width and blade arc angle except the rake angle. The FEM simulation using the blade cutting method can capture the effect of rake angle while the predicted excavation forces are much larger than the experimental data. Nevertheless, both the methods cut the soil to a small displacement beyond which the analysis is unable to meet the convergence requirement.

A Strength Criterion for Deep Rock with Stochastic Fractures via DEM Simulations

Mingjing Jiang,Asen Liu,Huaning Wang,Guowen Lu,Lei Li 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.2

Criteria for rock strength mostly focus on macromechanical parameters, which cannot directly explain the relationship between microscopic fracture characteristics and strength. This paper analyses the strength characteristics of deep jointed rock with stochastic fractures by the distinct element method (DEM) and proposes a new strength criterion. First, an improved bond contact model and the smooth-joint contact model are implemented within the framework of DEM to simulate the characteristics of deep rock. Then, triaxial compression tests on Berea sandstone are also numerically simulated under various confining pressures and fracture intensities (P32). Finally, a strength criterion is proposed and validated based on thenumerical and experimental results. The criterion can capture the nonlinear relationshipbetween the major principal stress and the confining pressure and reveal the microscopic fracture characteristics of deep rock. However, the criterion does not consider the influence of the intermediate principal stress. The average deviation between all the predicted strengths and the experimental results is 5.12%, which demonstrates that the criterion has good applicability.

现代汉语“越X,越Y”构式中动词词汇语义制约条件研究

Mingjing(明晶) Li(李),Wenting(文婷) Hong(洪) 한국중국언어학회 2022 중국언어연구 Vol.- No.103

“越X,越Y”构式作为现代汉语的常见构式之一,一直备受学界关注。目前学界在句法、语义、历时研究、跨语言研究等方面都取得了一定的成果,但是对于该构式中谓词的词汇语义特征,研究薄弱,尚待进一步探究。针对前人的研究的不足,本文以构式意义和词汇意义的互动关系为理论基础,分析“越”后动词的语义特征,旨在探索“越X,越Y”构式中的词汇语义制约条件。 本文从动词的量性特征出发,采取语义分析结合形式标准的方法,探究“越”后谓词成分的词汇语义特征的制约条件,并结合定量统计进行验证,在全面考察1003个现代汉语常用动词的基础上,以语言事实为支撑探究该构式的词汇语义特征与其构式意义的相容性,揭示句法实现与谓词的词汇语义投射之间的关系。 经过研究,本文发现影响动词充当“越”后成分的最重要的因素是与时间量相关的终点确定性特征。具有明确的[+telic]特征的动词基本无法充当“越”后成分。具有[-telic]特征的动词可充当“越”后成分,[-telic]特征越明确,充当“越”后成分的能力越强,但总体都保持在较高水平。动词的其他量性特征如动作的反复量、空间量、性状程度量,动词否定式表达的主观量特征和性状程度量,以及动补成分和动词直接宾语的[+count]属性对动词短语终点确定性特征的影响,也会制约动词充当“越”后成分的能力。

Evaluation on the Implementation Effect of Centralized Drug Volume-based Procurement in China —Take a General Public Hospital in Chongqing as an Example

Luo Mingjing 아시아사회과학학회 2022 International Science Research Vol.2 No.2

Objective: To evaluate and make recommendations on the effectiveness of the implementation of the "4+7" volume-based procurement policy. Methods: Taking a third-class general hospital in Chongqing as an example, to analyze the changes in indicators such as the quantity, amount, defined daily doses (DDDs), and defined daily cost (DDC) of drugs purchased before and after the implementation of the policy. Results: Among the 23 drugs included in the analysis, the highest increase was 1357.58% in DDDS, the highest decrease was 76.41% in DDC; drug expenses increased by 2.4435 million yuan, but usage increased by 413.11 kilograms (more than 7 times before purchase), with the trend of decreasing prices and increasing volumes, the overall increase in drug costs has been effectively controlled. Conclusion: Volume-based procurement execution effect achieved significant results in China, through the policy measures of exchange of volume for price, the drug burden of the people has been effectively eased.

Impact of Assimilating Aircraft Reconnaissance Observations on Tropical Cyclone Initialization and Prediction Using Operational HWRF and GSI Ensemble-Variational Hybrid Data Assimilation

Tong, Mingjing,Sippel, Jason A.,Tallapragada, Vijay,Liu, Emily,Kieu, Chanh,Kwon, In-Hyuk,Wang, Weiguo,Liu, Qingfu,Ling, Yangrong,Zhang, Banglin American Meteorological Society 2018 Monthly weather review Vol.146 No.12

Simple test study on anti-freeze additives selection for railway asphalt mixture (RAM) in cold region

Fang, Mingjing,Wu, Shaopeng,Park, Daewook,Chen, Hao,Xie, Jun Elsevier 2017 Construction and Building Materials Vol.154 No.-

<P><B>Abstract</B></P> <P>The impermeability and moisture damage resistance should be enhanced if railway asphalt mixture (RAM) applied in seasonal frozen area. This paper presents an selection of anti-freeze additives for RAM by conducting highway-based laboratory tests. Five powder alternatives, hydrated lime, fly ash, red clay brick powder, Portland cement and U-type expensive agent (UEA) with different ratio and components, were prepared in terms of concepts with filling, bonding, waterproofing, reinforcing, anti-freezing and self-impermeability. Replacing 50% by weight of mineral filler was proposed in the fabrication of RAM, and the other test conditions were kept in consistence. By experiencing Marshall test, permeability test, indirect tensile test and linear shrinkage test, the results indicated that (i) the bituminous cement made from asphalt binder, mineral filler and different additives can significantly influence the performance of RAM; (ii) A potential combination with hydrated lime (40%), fly ash (20%), red clay brick powder (20%) and Portland cement (20%) can enhance the anti-freeze ability and water damage resistance of RAM; (iii) UEA commonly used in concrete with the concept of self-compaction is not appropriate for being as anti-freeze additive component for RAM.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A clear definition to railway asphalt mixture (RAM) was made. </LI> <LI> Five expected abilities of anti-freeze additive selection for RAM were proposed. </LI> <LI> A combination of four components is recommended for anti-freeze additive. </LI> <LI> UEA is not suitable for being as anti-freeze additives for RAM. </LI> </UL> </P>