Responses of Buried Pipelines to Tunnelling Underneath Considering Effect of Gap Formation: an Analytical Approach

Bing-qiang Zhang,Qi-wen Chen,Feng-wen Lai,Fu-Quan Chen,Bin-bin Qi 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.1

A gap formation underneath pipelines could be observed during tunneling beneath existing buried pipelines, thus altering the pipeline-soil interaction behavior. However, the most existing analytical approaches typically do a full contact assumption for brevity. For such purpose, we aim to present an analytical approach coupling the effect of gap formation underneath pipelines by considering the buried pipeline as an Euler-Bernoulli beam on tensionless foundation. The pipeline can be divided into three segments according to pipeline-soil interaction behavior, and then the bending behaviors of each segment are formulated. The deflection and bending moment of the pipeline caused by tunnelling underneath from the proposed approach are compared and validated with centrifuge testing data and existing analytical solutions. The effects of pipeline-soil stiffness ratio, pipeline buried depth, tunnel buried depth, tunneling induced volume loss, and tunnel-pipeline intersection angle on the pipeline responses are further discussed. The results indicate that gap formation underneath pipeline can be observed indeed for shallowly buried pipeline and/or larger pipeline-soil stiffness ratio. The proposed analytical approach provides a theoretical guideline to predict the responses of existing pipelines to tunnelling underneath.

재한 중국인 대학생의 지각된 차별감이 학업성취에 미치는 영향

제빙석(Qi, Bings),김빛여울(Kim Bityeoul),조경숙(Cho Kyungsuk),강진령(Kang Jinryung) 학습자중심교과교육학회 2018 학습자중심교과교육연구 Vol.18 No.13

본 연구의 목적은 재한 중국인 대학생의 지각된 차별감이 학업성취에 미치는 영향을 확인하고 자기존중감과 한국어 수준을 매개변인으로 투입하여 매개효과를 살펴보는 것이다. 이를 위해, 2017년 10월부터 11월까지 서울특별시 소재한 5개 4년제 대학 교에서 재학 중인 중국인 대학생 308명을 대상으로 오프라인 및 온라인 설문조사를 실시하였으며, SPSS 24.0을 이용하여 Pearson 상관분석을 실시하고 3단계 위계적 회귀분석과 Sobel test를 실시하여 매개효과를 검증하였다. 연구결과는 다음과 같다. 첫째, 재한 중국인 대학생의 지각된 차별감은 자기존중감과 한국어 수준, 학업성취에 부적으로 유의한 영향을 미치는 것으로 나타났으며, 자기존중감과 한국어 수준은 학업성취에 정적으로 유의한 영향을 미치는 것으로 나타났다. 둘째, 재한 중국인 대학생의 지각된 차별감과 학업성취의 관계에서 자기존중감과 한국어 수준의 매개효과를 검증한 결과, 자기존중감과 한국어 수준은 지각된 차별감과 학업성취의 관계에서 부분매개 효과를 나타내었다. 본 연구는 재한 중국인 대학생의 지각된 차별감이 학업성취에 어떻게 영향을 미치는지 그 과정을 설명해냈다는 데 그 의의가 있다. The purpose of this study was to examine the mediating effects of self-esteem and Korean language level on the relationship between perceived discrimination and academic achievement among the Chinese university students in Korea. We conducted offline and online surveys for Chinese students attending five universities in Seoul so that a total of 340 data were collected. Then, 32 cases were excluded due to insincere and unresponsive items and final 308 data were analyzed. The collected data were analyzed by SPSS 24.0 in order to verify the Pearson correlation analysis. Then three-step mediated regression analysis by Baron and Kenny(1986) and Sobel test were performed to verify the mediating effect. The results of verification showed as follow. First, the perceived discrimination of Chinese university students showed significantly negative correlation with self-esteem, Korean language level and academic achievement. Moreover, self-esteem and Korean language level showed a statistically positive correlation with academic achievement of students. Second, the self-esteem and Korean language level showed partial mediating effects on between perceived discrimination and academic achievement. This study is meaningful in that it explains the process of how the perceived discrimination of Chinese university students affects academic achievement.

Discrimination of neutrons and gamma-rays in plastic scintillator based on spiking cortical model

Liu Bing-Qi,Liu Hao-Ran,Chang Lan,Cheng Yu-Xin,Zuo Zhuo,Li Peng 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.9

In this study, a spiking cortical model (SCM) based n-g discrimination method is proposed. The SCMbased algorithm is compared with three other methods, namely: (i) the pulse-coupled neural network (PCNN), (ii) the charge comparison, and (iii) the zero-crossing. The objective evaluation criteria used for the comparison are the FoM-value and the time consumption of discrimination. Experimental results demonstrated that our proposed method outperforms the other methods significantly with the highest FoM-value. Specifically, the proposed method exhibits a 34.81% improvement compared with the PCNN, a 50.29% improvement compared with the charge comparison, and a 110.02% improvement compared with the zero-crossing. Additionally, the proposed method features the second-fastest discrimination time, where it is 75.67% faster than the PCNN, 70.65% faster than the charge comparison and 38.4% slower than the zero-crossing. Our study also discusses the role and change pattern of each parameter of the SCM to guide the selection process. It concludes that the SCM's outstanding ability to recognize the dynamic information in the pulse signal, improved accuracy when compared to the PCNN, and better computational complexity enables the SCM to exhibit excellent n-g discrimination performance while consuming less time.

Machining Surface Quality Analysis of Aluminum Alloy Thin-Walled Parts in Aerospace

Dai Bing,Yu Guang-bin,Guan Yan-qi,Shao Jun-peng,Guan Yan-qi,Wu Xue-mei,Liu Yu-xin 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.11

There are many key parts in the field of aerospace with aluminum alloy thin-walled parts, the problem of breaking the low efficiency in production that’s also followed. There will be a lot of deformation in processing because of its poor rigidity, poor process, which will lead to low processing efficiency. It is of great significance to improve the machining efficiency of the aluminum alloy thin-walled parts, and a series of analysis of the surface quality of aluminum alloy thin-walled parts there are carried out clamping, cutting tools, take the knife route so on, and the problems of low machining efficiency and poor surface quality are solved.

Curcumol Induces Apoptosis in SPC-A-1 Human Lung Adenocarcinoma Cells and Displays Anti-neoplastic Effects in Tumor Bearing Mice

Tang, Qi-Ling,Guo, Ji-Quan,Wang, Qi-You,Lin, Hai-Shu,Yang, Zhou-Ping,Peng, Tong,Pan, Xue-Diao,Liu, Bing,Wang, Su-Jun,Zang, Lin-Quan Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.6

Curcumol is a sesquiterpene originally isolated from curcuma rhizomes, a component of herbal remedies commonly used in oriental medicine. Its beneficial pharmacological activities have attract significant interest recently. In this study, anti-cancer activity of curcumol was examined with both in vitro and in vivo models. It was found that curcumol exhibited time- and concentration-dependent anti-proliferative effects in SPC-A-1 human lung adenocarcinoma cells with cell cycle arrest in the G0/G1 phase while apoptosis-induction was also confirmed with flow cytometry and morphological analyses. Interestingly, curcumol did not display growth inhibition in MRC-5 human embryonic lung fibroblasts, suggesting the anti-proliferative effects of curcumol were specific to cancer cells. Anti-neoplastic effects of curcumol were also confirmed in tumor bearing mice. Curcumol (60 mg/ kg daily) significantly reduced tumor size without causing notable toxicity. In conclusion, curcumol appears a favorable anti-cancer candidate for further development.

Computation of pressure fluctuation frequency in electronic unit pump for diesel engine

Tian Bing-qi,Fan Li-yun,Qaisar Hayat,Ma Xiuzhen,Song En-zhe,Hao Wang 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.4

Pressure variations inside a fuel injection system can lead to fluctuations in injected fuel quantity during injections and therefore candirectly impact the stability and performance coherence of the fuel injection system and the engine it matched. Concepts of hydrauliccapacitance and hydraulic inductance are introduced into fuel injection system by referencing LC oscillator electric circuit. A LC undampedhydraulic mathematical model is developed based on the structural parameters of the electronic unit pump (EUP). Pressure fluctuationfrequency during injection process at different operating conditions of the EUP is computed by the LC undamped model. It isobserved that the frequencies of pressure fluctuations tend to increase with the fuel injection process. Pressure curves and pressure fluctuationfrequencies obtained by experiments at different operating conditions validated the results predicted by the LC undampedmathematical model.

The MTHFR C677T Polymorphism and Prostate Cancer Risk: New Findings from a Meta-analysis of 7306 Cases and 8062 Controls

Zhang, Wei-Bing,Zhang, Jun-Hong,Pan, Zheng-Qi,Yang, Qi-Sheng,Liu, Bo Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.6

Methylenetetrahydrofolate reductase (MTHFR) is an essential enzyme involved in folate metabolism; a single nucleotide polymorphism (SNP) C677T has been reported to be linked with altered incidences of several diseases. We here conducted a meta-analysis of 15 published epidemiological studies with a total of 7306 cases and 8062 controls to evaluate its association with prostate cancer risk with overall and subgroup analyses. No statistical relationship was found overall with any genetic model (TT vs. CC: OR = 0.80, 95%CI = [0.62, 1.04], P = 0.094; CT vs. CC: OR = 0.97, 95%CI = [0.84; 1.12], P = 0.667; Dominant: OR = 0.94, 95%CI = [0.82; 1.07], P = 0.343; Recessive: OR = 0.81, 95%CI = [0.64; 1.04], P = 0.104), but after the exclusion of several studies, we could observe the homozygote TT to confer less susceptibility to prostate cancer in carriers; moreover, different effects of the polymorphism on prostate cancer risk was detected from subgroup analysis stratified by participants' residential region: significant reduced prostate cancer risk was found to be associated with the polymorphism from Asian studies (TT vs. CC: OR = 0.47, 95%CI = [0.33; 0.67], P < 0.001; CT vs. CC: OR = 0.73, 95%CI = [0.60; 0.90], P = 0.002; Dominant: OR = 0.67, 95%CI = [0.56; 0.82], P < 0.001; Recessive: OR = 0.55, 95%CI = [0.40; 0.76], P < 0.001) while studies from Europe indicated a slight increased risk under dominant model with marginal significance (OR = 1.14, 95%CI = [0.99; 1.30], P = 0.064). Moreover, the protective effect of the polymorphism against prostate cancer was also shown by studies performed in yellow Asians (TT vs. CC: OR = 0.48, 95%CI = [0.31; 0.75], P = 0.001; CT vs. CC: OR = 0.68, 95%CI = [0.51; 0.90], P = 0.006; Dominant: OR = 0.63, 95%CI = [0.48; 0.82], P < 0.001; Recessive: OR = 0.57, 95%CI = [0.39; 0.84], P = 0.004). We propose that these phenomena should be viewed with the consideration of folate metabolism profile and different gene background as well as living habits of different populations, and more relevant studies should be conducted to confirm our hypothesis and provide a comprehensive and clear picture concerning this topic.

Changes in Dust Activity in Spring over East Asia under a Global Warming Scenario

Qi Zong,Rui Mao,Dao-Yi Gong,Chenglai Wu,Bing Pu,Xingya Feng,Yijie Sun 한국기상학회 2021 Asia-Pacific Journal of Atmospheric Sciences Vol.57 No.4

Dust activity not only influences human health through dust storms but also affects climate at local and regional scales through the direct effects of dust aerosols on both solar and longwave radiative heating. In this study, based on dust simulations from seven Coupled Model Intercomparison Project Phase 5 (CMIP5) models, the spatial and temporal changes in dust activity over East Asia under a Representative Concentration Pathway 8.5 global warming scenario were examined for the periods of 2016– 2035 (P1), 2046–2065 (P2) and 2080–2099 (P3). The results show that the multimodel ensemble mean (MME) of the CMIP5 models largely captures the spatial distribution of dust emissions and dust optical depth (DOD) over East Asia during 1986–2005 (P0). The MME reproduces the increasing trend in dust emissions and DOD over dust sources in East Asia during P0. Accompanying emission reductions during P1 to P3, the DOD simultaneously decreases, and the evident DOD decline can also be found over downwind areas in eastern China and the Korean Peninsula. Simulations project increases in precipitation and the LAI (leaf area index). Simultaneously, the weakened East Asian trough leads to anomalous southerly winds and lower wind speeds at the surface. All these results indicate unfavorable conditions for dust emissions over the sources regions, resulting in a decreased DOD over East Asia during P1 to P3.

Construction of antibacterial nano-silver embedded bioactive hydrogel to repair infectious skin defects

Qi Dong,Dan Zu,Lingqiang Kong,Sunfang Chen,Jun Yao,Jiawei Lin,Lei Lu,Bing Wu,Bin Fang 한국생체재료학회 2022 생체재료학회지 Vol.26 No.3

Background: Hydrogels loaded with antimicrobial agents have been widely used for treating infected wound defects. However, hydrogels derived from a porcine dermal extracellular matrix (PADM), containing silver nanoparticles (AgNPs), have not yet been studied. Therefore, we investigated the therapeutic effect of an AgNP-impregnated PADM (AgNP–PADM) hydrogel on the treatment of infected wounds. Methods: An AgNP–PADM hydrogel was synthesized by embedding AgNPs into a PADM hydrogel. We examined the porosity, moisture retention, degradation, antibacterial properties, cytotoxicity, antioxidant properties, and ability of the PADM and AgNP–PADM hydrogels to treat infected wounds in animals. Results: The PADM and AgNP–PADM hydrogels were pH sensitive, which made them flow dynamically and solidify under acidic and neutral conditions, respectively. The hydrogels also exhibited porous network structures, satisfactory moisture retention, and slow degradation. Additionally, the AgNP–PADM hydrogel showed a slow and sustained release of AgNPs for at least 7 days without the particle size changing. Thus, the AgNPs exhibited adequate antibacterial ability, negligible toxicity, and antioxidant properties in vitro. Moreover, the AgNP–PADM hydrogel promoted angiogenesis and healed infected skin defects in vivo. Conclusions: The AgNP–PADM hydrogel is a promising bioderived antibacterial material for clinical application to infected wound dressings

Synthesis, Structure and Green Fluorescence of a Isonicotinic Coordination Polymer Containing a Silver(I) Isonicotinate Array and a Two-coordination Cadmium(II)

Qi Yuan,Bing Liu* 대한화학회 2006 Bulletin of the Korean Chemical Society Vol.27 No.1