Research on vibration of ceramic motorized spindle influenced by interference and thermal displacement

Zinan Wang,Ke Zhang,Zhan Wang,Xiaotian Bai,Qingyuan Wang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6

The vibration of ceramic motorized spindle determines the machining quality of CNC machine tools. The dynamic characteristics of a motorized spindle were explored under the influence of interference fit and thermal displacement. Using heat transfer theory and bearing Harris theory, the temperature field model of motorized spindle was established, which aims to find the relationship of thermal displacement and interference. In addition, the dynamic and thermal factors were coupled to the dynamic model of the ceramic motorized spindle rotor system, of which the variation rules of bearing stiffness and rotor vibration characteristics were calculated and analyzed. The accuracy of the motorized spindle rotor system dynamic model was verified by experiments. The results show that the interference fit of shaft and bearing decreases with the rotating speed increase under the combined influence of centrifugal force, load and thermal displacement. The vibration was calculated by the dynamic model of motorized spindle rotor system considering dynamic and thermal factors. The maximum error was 3.9 %, which is well consistent with the experimental results. The dynamic characteristics of ceramic motorized spindle can be improved by appropriately increasing the degree of interference tightness at high speed.

Molecular and Cellular Microbiology / Biomedical Sciences : Alteration of the Metabolome Profile in Endothelial Cells by Overexpression of miR-143/145

( Wenshuo Wang ),( Ye Yang ),( Yiqing Wang ),( Liewen Pang ),( Jiechun Huang ),( Hongyue Tao ),( Xiaotian Sun ),( Chen Liu ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.3

Communication between endothelial cells (ECs) and smooth muscle cells (SMCs) via miR-143/145 clusters is vital to vascular stability. Previous research demonstrates that miR-143/145 released from ECs can regulate SMC proliferation and migration. In addition, a recent study has found that SMCs also have the capability of manipulating EC function via miR-143/145. In the present study, we artificially increased the expression of miR-143/145 in ECs, to mimic a similar change caused by miR-143/145 released by SMCs, and applied untargeted metabolomics analysis, aimed at investigating the consequential effect of miR-143/145 overexpression. Our results showed that miR-143/145 overexpression alters the levels of metabolites involved in energy production, DNA methylation, and oxidative stress. These changed metabolites indicate that metabolic pathways, such as the SAM cycle and TCA cycle, exhibit significant differences from the norm with miR-143/145 overexpression.

Overexpression of miR-191 Predicts Poor Prognosis and Promotes Proliferation and Invasion in Esophageal Squamous Cell Carcinoma

Xiaotian Gao,Zeqing Song,Zhanqiang Xie,Zhigang Wang,Keluo Cheng,Ke Liang 연세대학교의과대학 2017 Yonsei medical journal Vol.58 No.6

Purpose: Accumulating evidence has shown that dysregulation of microRNA-191 (miR-191) is closely associated with tumorigenesisand progression in a wide range of cancers. This study aimed to explore the potential role of miR-191 in esophageal squamous cell carcinoma (ESCC). Materials and Methods: miR-191 expression was assessed in 93 ESCC tissue specimens by real-time polymerase chain reaction, and survival analysis was performed via Kaplan-Meier and Cox regression analyses. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide, plate colony-forming, BrdU, and Transwell assays were conducted to observe the effect of miR-191 on ESCC proliferation and invasion. Luciferase reporter and western blot assays were taken to identify target genes of miR-191. Results: miR-191 was overexpressed in 93 cases of ESCC, compared with adjacent normal tissues, and miR-191 expression was significantly related to differentiation, depth of invasion, TNM stage, lymph node metastasis, and distant metastasis of tumor. Kaplan-Meier and Cox regression analyses demonstrated that overexpression of miR-191 was an independent and significant predictorof ESCC prognosis. Both gain-of-function and loss-of-function experiments showed that miR-191 promoted ESCC cell proliferation and invasion activities in vitro. Early growth response 1 (EGR1), a tumor suppressor, was predicted as a direct target of miR-191. Luciferase reporter and western blot assays proved that miR-191 reduced EGR1 expression by directly binding its 3' untranslated region. Moreover, EGR1 knockdown by siRNA enhanced ESCC cell growth and invasion. Conclusion: Our findings provide specific biological roles of miR-191 in ESCC survival and progression. Targeting the novel miR-191/EGR1 axis represents a potential new therapeutic way to block ESCC development.

LncRNA XLOC_006390 facilitates cervical cancer tumorigenesis and metastasis as a ceRNA against miR-331-3p and miR-338-3p

Xiaotian Luan,Yankui Wang 대한부인종양학회 2018 Journal of Gynecologic Oncology Vol.29 No.6

Objective: Cervical cancer is one of the most common malignant tumors. Our previous results showed that long non-coding RNA (lncRNA) XLOC_006390 plays an important role in cervical cancer. In this study, we have explored the mechanism of action of lncRNA XLOC_006390. Methods: LncRNA XLOC_006390 was proposed to exercise its function as a competing endogenous RNA (ceRNA), and its potential targeted miRNAs was predicted through the database LncBase Predicted v.2. Two miRNAs, miR-331-3p, and miR-338-3p, were chosen for the study. Expression of miRNAs and lncRNA in cervical cancer cells and tissues was detected by reverse transcription polymerase chain reaction. To determine the correlation, silencing of XLOC_006390, over-expression of miR-331-3p, and miR-338-3p was performed in SiHa and Caski cell lines, respectively. Results: Based on the interactive effect between miRNA and lncRNA, miR-331-3p and miR-338-3p were significantly downregulated in cervical cancer cells and tissues, and their expression levels were negatively related to that of lncRNA. Our results also showed that the expression of miR-331-3p target gene NRP2, miR-338-3p target genes PKM2, EYA2 was significantly downregulated when the XLOC_006390 was knocked down. Further, XLOC_006390 was found to facilitate cervical cancer tumorigenesis and metastasis by downregulating miR-331-3p and miR-338-3p expression. Conclusion: Taken together, our study demonstrated that XLOC_006390 may serve as a ceRNA and reversely regulates the expression of miR-331-3p and miR-338-3p, thus facilitating cervical cancer tumorigenesis and metastasis.

A novel Fabry-Perot fiber optic temperature sensor for early age hydration heat study in Portland cement concrete

Xiaotian Zou,Xingwei Wang,Alice Chao,Nan Wu,Tzu-Yang Yu 국제구조공학회 2013 Smart Structures and Systems, An International Jou Vol.12 No.1

Concrete is known as a heterogeneous product which is composed of complex chemical composition and reaction. The development of concrete thermal effect during early age is critical on its future structural health and long term durability. When cement is mixed with water, the exothermic chemical reaction generates hydration heat, which raises the temperature within the concrete. Consequently, cracking may occur if the concrete temperature rises too high or if there is a large temperature difference between the interior and the exterior of concrete structures during early age hydration. This paper describes the contribution of novel Fabry-Perot (FP) fiber optic temperature sensors to investigate the thermal effects of concrete hydration process. Concrete specimens were manufactured under various water-to-cement (w/c) ratios from 0.40 to 0.60. During the first 24 hours of concreting, two FP fiber optic temperature sensors were inserted into concrete specimens with the protection of copper tubing to monitor the surface and core temperature change. The experimental results revealed effects of w/c ratios on surface and core temperature developments during early age hydration, as well as demonstrating that FP fiber optic sensors are capable of capturing temperature variation in the concrete with reliable performance. Temperature profiles are used for calculating the apparent activation energy (Ea) and the heat of hydration (H(t)) of concrete, which can help us to better understand cement hydration.

A Study of Leveraging Memory Level Parallelism for DRAM System on Multi-Core Architecture

Yuxuan Wang,Yingping Zhang,Xiaotian Zhang,Jian Yin,Licheng Chen 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.4

DRAM system has been more and more critical on modern multi-core architecture where the Moore’s law has been made effect on increasing the number of cores integrated in a processor chip. The performance of DRAM system is usually measured in term of bandwidth and latency, which are regarded as inherently depending on Row Buffer Hit Rate (RBHR) according to previous studies. In this paper, we find that Memory Level Parallelism (MLP) exhibits a stronger correlation with the performance of DRAM system on multi-core/many-core architecture than RBHR, and promoting MLP significantly improves DRAM system performance. In order to exploit the MLP, we have evaluated various approaches including multi-bank, multi-row-buffers, multi-memory-controllers and the obsolete Virtual Channel Memory (VCM). The experimental results show that VCM is a better alternative to traditional DRAM chip on multicore/many-core architecture than the other three approaches because VCM has almost all the advantages of the others: 1) it can improve homogeneous workloads’ IPC by 2.21X on a 16-core system with 32 virtual channels due to leveraging unexploited MLP. 2) It can also promote Quality-of-Service (QoS) of DRAM system by removing unfairness while memory controllers serve memory requests. 3) It can save energy and has low area costs. Unfortunately, VCM, which was proposed in the late 1990s, faded away before multi-core/manycore became dominated. Therefore, we suggest memory chip vendors reconsider the VCM technology for multi-core architecture.

In-site Experiments on the Swelling Characteristics of a Shield Tunnel in Expansive Clay: A Case Study

Jianxiu Wang,Jiaxing Liu,Xiaotian Liu,Yunhua Jiang,Xuezeng Liu 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.3

Expansive soil swells, softens, and disintegrates when absorbing water, whereas it shrinks when losing water. Understanding the swelling characteristics of a shield tunnel in expansive soil is important. However, most in-site experiences on the swelling characteristics of a tunnel are obtained from the NATM tunnels constructed in swelling rock using drill and blast method; most laboratory experiments or theoretical analyses on the swelling characteristics of a shield tunnel in expansive soil are under certain hypotheses which have not been verified in actual situation. To solve the problems, the Slender West Lake tunnel was selected as the background, laboratory and in-site experiments were performed to understand the swelling characteristics of a shield tunnel in expansive clay. Four experimental sections were constructed in the actual tunnel. The measuring gauges were pre-installed in the segments in factory and the segments were installed in-site to observe the actual earth pressure and temperature during construction. The influences of expansive soil to the distributions and variations of earth pressure, bending moment, and temperature were analyzed. The increasing earth pressure was divided into three stages. Large earth pressure was detected at the top, bottom, left, and right sides of the tunnel. The earth pressure at the left and right sides was larger than that at the top and bottom. Large negative bending moment was detected at the top and bottom of the tunnel, whereas large positive bending moment was detected at the left and right sides of the tunnel. The minimum bending moment appeared at 45° oblique. The largest negative bending moment was larger than the largest positive bending moment. Based on the observations, a load mode of swelling pressure for a beam-spring model was suggested. It can be referred by the similar tunnels.

A novel Fabry-Perot fiber optic temperature sensor for early age hydration heat study in Portland cement concrete

Zou, Xiaotian,Chao, Alice,Wu, Nan,Tian, Ye,Yu, Tzu-Yang,Wang, Xingwei Techno-Press 2013 Smart Structures and Systems, An International Jou Vol.12 No.1

Concrete is known as a heterogeneous product which is composed of complex chemical composition and reaction. The development of concrete thermal effect during early age is critical on its future structural health and long term durability. When cement is mixed with water, the exothermic chemical reaction generates hydration heat, which raises the temperature within the concrete. Consequently, cracking may occur if the concrete temperature rises too high or if there is a large temperature difference between the interior and the exterior of concrete structures during early age hydration. This paper describes the contribution of novel Fabry-Perot (FP) fiber optic temperature sensors to investigate the thermal effects of concrete hydration process. Concrete specimens were manufactured under various water-to-cement (w/c) ratios from 0.40 to 0.60. During the first 24 hours of concreting, two FP fiber optic temperature sensors were inserted into concrete specimens with the protection of copper tubing to monitor the surface and core temperature change. The experimental results revealed effects of w/c ratios on surface and core temperature developments during early age hydration, as well as demonstrating that FP fiber optic sensors are capable of capturing temperature variation in the concrete with reliable performance. Temperature profiles are used for calculating the apparent activation energy ($E_a$) and the heat of hydration (H(t)) of concrete, which can help us to better understand cement hydration.

Dewatering of a 32.55 m Deep Foundation Pit in MAMA Under Leakage Risk Conditions

Jianxiu Wang,Xiaotian Liu,Jiaxing Liu,Linbo Wu,Qingfeng Guo,Qian Yang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.8

A 2,250 mm whirlpool foundation pit is located in Donghai Island, Zhanjiang City, Guangdong Province, China. The layers of theisland are composed of multi-aquifers and multi-aquitards (MAMA). The aquifers are intersected by partial aquitard lenses. A largeconfined aquifer is frequently interbedded and separated into several sub-confined aquifers by partial aquitards. In the 2,250 mmfoundation pit, the water level of two confined aquifers was reduced to satisfy excavation requirements and prevent water inrush. Construction of the 32.55 m deep foundation pit encountered MAMA and potential defects of the diaphragm wall. The pumpingwells in the second confined aquifer were used to reduce the water level to ensure the safety of bottom excavation. The pumpingwells in the first confined aquifer were used to reduce the water level under emergency conditions to prevent potential water inrushand piping from the defects of the diaphragm wall. Field pumping tests and numerical simulations were performed to determine therisk of leakage and verify the capability of the pumping wells to reduce the water level. Quicksand occurred during shallowexcavation because of leakage although the confined aquifer had been cut off and pumped for a long time. Three pumping wells wereinstalled to reduce the water level. When the foundation pit was excavated to a depth of 24 m, water inrush occurred at the middle ofthe pit bottom although the water level of the dewatered aquifer had been reduced to below the excavation face. A 90 m deepborehole was found where the underlying confined aquifer below the first aquifer induced the water inrush. Although the upper waterlevel was reduced, the high water level in the deep part still induced water inrush. The pumping wells in the second aquifer were allopened, and the water level of the underlying confined aquifer was reduced. After the water level was reduced to below the pitbottom, the borehole was filled, and the water inrush stopped. However, water inrush occurred on the cracks of the diaphragm wall aspredicted. The pre-installed pumping wells were opened to control the water inrush. The deepest foundation pit on the island wasconstructed successfully after dealing with the water inrush and leakages.

Spatio-Temporal Saliency Fusion Based Small Infrared Moving Target Detection Under Sea-Sky Background

Li Shaoyi,Wang Xiaotian,Zhang Kai,Niu Saisai,Zou Yijun 제어로봇시스템학회 2019 제어로봇시스템학회 국제학술대회 논문집 Vol.2019 No.10

Small infrared moving target detection has an important role in the sea-based infrared search and tracking, maritime area surveillance and other applications. This method aims to detect the small infrared moving targets with the sea-sky background. The present study proposes a detection algorithm for small infrared targets based on the spatio-temporal saliency fusion. The contourlet analysis and edge extraction are carried out in the concurrent design. In order to effectively suppress the background and improve the target signal-clutter ratio, the spectral residual method is combined with the abovementioned methods to reconstruct the target fusion saliency image. Then the target motion region is estimated based on the optical flow method for the fusion saliency image and it is matched with the target area of interest to achieve the moving target detection. Moreover, the pipeline filtering is introduced to achieve the target confirmation by multi-frame judgment, reduce false alarm rate and complete the moving target detection for the infrared image sequence. Experimental results show that the proposed algorithm can achieve continuous target detection and have a higher detection precision via real long wave infrared image sequences.