Time Series Prediction on Settlement of Metro Tunnels Adjacent to Deep Foundation Pit by Clustering Monitoring Data

Qi Zhang,Yanning Ma,Bin Zhang,Longgang Tian,Guozhu Zhang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.5

High requirements are put forward for the settlement control of metro tunnel to ensure the normal and safe operation of adjacent metro line during the process of deep foundation pit construction. Monitoring and predicting could constantly monitor the settlement of the tunnel and make safety early-warning, and massive data to be processed is collected by sensors in this process. In the study, an improved clustering method based on Gaussian mixture model (GMM) is proposed to deal with a large amount of monitoring data. Four initial eigenvalues are defined and the initial core points of clustering are selected by grouping monitoring sensors based on the characteristics of the project site and sensors. An improved method is utilized to the metro tunnel of Metro Line 9 near Xujiahui station. Compared with the traditionalclustering method, the improved method has more reliable results, and reduces the operation time by 57.9%. Representative monitoring sensors are selected from each cluster to predict based on Long Short-Term Memory (LSTM) neural network. The prediction results well agree with the measured value and the prediction accuracy is reaching to 99.3%. Compared with other sensor selection ways, the data of representative sensors exhibits good representativenessand effectiveness. Finally, the prediction result after data update is more consistent with the monitoring data than the prediction result without data update. Increasing the data update frequency improves the accuracy of the prediction results in practical engineering application.

Utilization of electron beam to modulate electron injection over Schottky barrier

Qi Zhang,Junjie Qi,Yunhua Huang,Huifeng Li,Xin Li,Ruoshui Wang,Yue Zhang 한국물리학회 2011 Current Applied Physics Vol.11 No.3

Modulation of electron injection over Schottky barrier was realized by employing electron beam irradiation on the metal/ZnO-nanowire contact. The structure revealed a good response to the illumination at a scanning frequency of 0.1 Hz, which can be enhanced by increasing bias and decreased with the increase of electron beam energy. These phenomena can be attributed to the Schottky barrier formed at the metal/ZnO-nanowire interface which limits the electron transport across the contact. The electron beam irradiation gives rise to high efficiency of electron injection over the barrier, while the interplay between charge discreteness, coherent scattering, and Coulomb interaction may reduce the conductivity.

Risk Factors for Cervical Cancer in Rural Areas of Wuhan China: a Matched Case-control Study

Zhang, Bin,Zhou, Ai-Fen,Zhu, Chang-Cai,Zhang, Ling,Xiang, Bing,Chen, Zhong,Hu, Rong-Hua,Zhang, Ya-Qi,Qiu, Lin,Zhang, Yi-Ming,Xiong, Chao-Du,Du, Yu-Kai,Shi, Yu-Qin Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12

Cervical cancer is a serious public health problem in developing countries. We investigated possible risk factors for cervical cancer in rural areas of Wuhan China using a matched case-control study with 33 women diagnosed with cervical cancer and 132 healthy women selected from the same area as matched controls. A questionnaire, which included questions about general demography conditions, environmental and genetic factors, the first sexual intercourse, first marriage age, age at first pregnancy, pregnancy first child's age, female personal health history, social psychological factors, dietary habits, smoking and alcohol status and other living habits was presented to all participants. At the same time, HPV infection of every participant was examined in laboratory testing. Results showed HPV infection (P<0.000, OR=23.4) and pregnancy first child's age (P<0.000, OR=13.1) to be risk factors for cervical cancer. Menopause (P=0.003, OR=0.073) was a protective factor against cervical cancer. However, there was no indication of associations of environmental (drinking water, insecticide, disinfectant) genetic (cancer family history), or life-style factors (smoking status, alcohol status, physical training, sleep quality), including dietary habits (intake of fruit and vegetable, meat, fried food, bean products and pickled food) or social psychological factors with cervical cancer. The results suggest that the risk of cervical cancer in Chinese rural women may be associated with HPV infection, menopause and the pregnancy first child's age.

Which Indicator Among Lumbar Vertebral Hounsfield Unit, Vertebral Bone Quality, or Dual-Energy X-Ray Absorptiometry-Measured Bone Mineral Density Is More Efficacious in Predicting Thoracolumbar Fragility Fractures?

Bo Zhang,Lu-Ping Zhou,Xian-Liang Zhang,Dui Li,Jia-Qi Wang,Chong-Yu Jia,Hua-Qing Zhang,Liang Kang,Ren-Jie Zhang,Cai-Liang Shen 대한척추신경외과학회 2023 Neurospine Vol.20 No.4

Objective: Hounsfield units (HU), vertebral bone quality (VBQ), and bone mineral density (BMD) can all serve as predictive indicators for thoracolumbar fragility fractures. This study aims to explore which indicator provides better risk prediction for thoracolumbar fragility fractures. Methods: Patients who have received medical attention from The First Affiliated Hospital of Anhui Medical University for thoracolumbar fragility fractures were selected. A total of 78 patients with thoracolumbar fragility fractures were included in the study. To establish a control group, 78 patients with degenerative spinal diseases were matched to the fracture group on the basis of gender, age, and body mass index. The lumbar vertebral HU, the VBQ, and the BMD were obtained for all the 156 patients through computed tomography, magnetic resonance imaging, and dual-energy x-ray absorptiometry (DEXA). The correlations among these parameters were analyzed. The area under curve (AUC) analysis was employed to assess the predictive efficacy and thresholds of lumbar vertebral HU, VBQ, and BMD in relation to the risk of thoracolumbar fragility fractures. Results: Among the cohort of 156 patients, lumbar vertebral HU exhibited a positive correlation with BMD (p < 0.01). Conversely, VBQ showed a negative correlation with HU, BMD (p < 0.05). HU and BMD displayed a favorable predictive efficacy for thoracolumbar fragility fractures (p < 0.01), with HU (AUC = 0.863) showcasing the highest predictive efficacy, followed by the DEXA-measured BMD (AUC = 0.813). VBQ (AUC = 0.602) ranked lowest among the 3 indicators. The thresholds for predicting thoracolumbar fragility fractures were as follows: HU (88),VBQ (3.37), and BMD (0.81). Conclusion: All 3 of these indicators, HU, VBQ, and BMD, can predict thoracolumbar fragility fractures. Notably, lumbar vertebral HU exhibits the highest predictive efficacy, followed by the BMD obtained through DEXA scanning, with VBQ demonstrating the lowest predictive efficacy.

Testing Investigation of Protective Coatings for Downhole Oil Tube

( Li Ping Zhang ),( Qi Bin Zhang ),( Yan Jun Zhang ),( Bei Bei Xie ),( Ying Ying Zhang ) 한국부식방식학회(구 한국부식학회) 2008 Corrosion Science and Technology Vol.7 No.1

Blooms of the woloszynskioid dinoflagellate Tovellia diexiensis sp. nov. (Dinophyceae) in Baishihai Lake at the eastern edge of Tibetan Plateau

Zhang, Qi,Zhu, Huan,Hu, Zhengyu,Liu, Guoxiang The Korean Society of Phycology 2016 ALGAE Vol.31 No.3

Freshwater red tides due to dinoflagellates have caused spectacular and regular “summer reddening” in recent years in Baishihai Lake, a temperate, meromictic, meso- or oligotrophic, high-altitude, landslide-dammed, deep lake located at the eastern edge of Tibetan Plateau in China. Based on morphological and molecular analyses, the causative organism has been identified as a new woloszynskioid dinoflagellate, Tovellia diexiensis Q. Zhang et G. X. Liu sp. nov. The vegetative cells are 20-32 μm long and 16-24 μm wide. They have a hemispherical episome and a broadly rounded hyposome with a short characteristic antapical spine. Usually cells are bright red due to the presence of numerous red-pigmented bodies, which often masked the yellowish green discoid chloroplasts. The amphiesma of motile cells comprise mainly quadrilateral, pentagonal or hexagonal thin plates, arranged in 4-5 latitudinal series on the episome, 1 in the cingulum and 4 on the hyposome. Molecular phylogenies based on small subunit ribosomal DNA and large subunit ribosomal DNA (LSU) indicate T. diexiensis from Baishihai Lake to belong to the family Tovelliaceae, which was monophyletic in our LSU phylogenies. During the bloom-forming period in 2005, cell density of T. diexiensis reached 9.15 × 10⁵ cells L⁻¹. Astaxanthin and its diester were found to be the major pigments in T. diexiensis, resulting in a characteristic blood-red color of the water in Baishihai Lake.

The Evaluation of Contact Fatigue Strength for 20MnCr5 Carburized Gear

Qi Zhang,류성기,Jing Zhang,Zhe-Zhu Xu,Changhong Wu 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

A FZG test rig for determining the contact fatigue characteristics of gear teeth was used in this paper. Under the range of operating conditions, experiments were performed by using standard spur gear test specimens which were made from 20MnCr5 gear alloy steel. Test rig, spur gear test specimens, the properties of the gear material were also introduced as well as the method to determine the stress levels. After the test, a small spalling pitting phenomenon was observed in the vicinity of the test pinion pitch line which is close to the gear tooth root portion. The tooth is subjected to the highest load due to the single tooth pair contact. The test data was analyzed and processed by statistical methods, and the equation parameters of gear contact fatigue and the contact fatigue limit were obtained. The analyzed results showed that the three-parameter Weibull distribution was best to fit the given stress for the contact fatigue life of 20MnCr5 carburized gear with better precision and adaptability. Finally, the P-S-N (Probability-Stress-Life) curves for the contact fatigue strength had been obtained by the reliability theory. It would provide a reliable basis for the reliability design for 20MnCr5 carburized gear fatigue life.

Guerrilla Capitalism: Revolutionary Legacy, Political Cleavage, and the Preservation of the Private Economy in Zhejiang

Qi Zhang,Mingxing Liu,Victor Shih 동아시아연구원 2013 Journal of East Asian Studies Vol.13 No.3

In this article, we propose a causal relationship between a region’s communist revolutionary legacy before 1949 and the variation in private sector development after 1949. In the case of Zhejiang, the pre-1949 revolutionary experience led to the power struggle between two elite groups, the guerrilla cadre group and the southbound cadre group, in the province after 1949. As the weak side, guerrilla cadres were willing to protect local economic interests in exchange for local popular support, which improved their odds of political survival. As a result, in contrast with counties where the guerrilla forces were historically weak, counties with strong guerrilla forces before 1949 saw significantly more robust private sector development throughout much of the Mao and post-Mao periods. In this article we provide preliminary historical and statistical evidence to support this hypothesis.

〈Save Our Endangered Species〉 Poster

Zhang Qi Ru 한국콘텐츠학회 2016 ICCC International Digital Design Invitation Exhib Vol.2016 No.-

Heterogeneous Cellular Networks With LoS and NLoS Transmissions—The Role of Massive MIMO and Small Cells

Zhang, Qi,Yang, Howard H.,Quek, Tony Q. S.,Lee, Jemin IEEE 2017 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS Vol.16 No.12

<P>We develop a framework for downlink heterogeneous cellular networks with line-of-sight (LoS) and non-LoS transmissions. Using stochastic geometry, we derive tight approximation of average downlink rate that enables us to compare the performance between densifying small cells and expanding base station (BS) antenna arrays. Interestingly, we find that adding small cells into the network improves the downlink rate much faster than expanding antenna arrays at the macro BS. However, when the small cell density exceeds a critical threshold, the spatial densification will lose its benefits and further impair the network capacity. To this end, we provide the optimal small cell density that maximizes the rate via numerical results for practical deployment guidance. In contrast, expanding macro BS antenna array can always benefit the capacity until an upper bound caused by pilot contamination, and this bound also surpasses the peak rate obtained from the deployment of small cells. Furthermore, we find that allocating part of antennas to distributed small cell BSs works better than centralizing all antennas at the macro BS, and the optimal allocation proportion is also given numerically for practical configuration reference. In summary, this paper provides a further understanding on how to leverage small cells and massive MIMO in future heterogeneous cellular networks deployment.</P>