Morphology characterization of micro-gap oil film of tilting pad hydrostatic bearing under extreme working conditions

Xiaodong Yu,Yanan Feng,Yan Zhao,Dianbin Huang,Jianhua Jiao 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.12

Taking the hydrostatic support of the tiltable oil pad double rectangular cavity as the object, the fluid-thermal-solid coupling deformation analysis of the friction pair is carried out, and the three-dimensional morphology of the micro-gap oil film is obtained. An oil film thickness test device is built to verify the rationality of the numerical simulation method. It is found that the elastic deformations of rotational workbench and base under extreme loads are both concave deformations, the thermal deformations are both convex deformations, and the maximum thermal deformation is mainly concentrated on the outer oil sealing edge. The deformation of the downstream side oil sealing edge is higher than that of the reverse side oil sealing edge. The minimum oil film thickness is the minimum distance between the downstream side oil sealing edge and the lower surface of the hydrostatic guideway of the rotational workbench, where tribological failure is prone to occur.

A bi-directional valveless piezoelectric micropump based on the Coanda effect

Zheng Zhang,Lipeng He,Jianwen Zhou,Dianbin Hu,Yi Hou,Guangming Cheng 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.2

In this paper, the hydrodynamic characteristics of a piezoelectric micropump operate on the Coanda effect, and the mechanism of bi-directional pumping are analyzed by numerical simulation and experiments. The research focuses on the different positions of the fluid deflector and the influence on the output of the micropump. The results show that a closer fluid deflector to the inlet can produce greater vortices in the suction process due to the Coanda effect, and the backflow diminishing is more significant as well. Moreover, the different positions of the fluid deflector can cause a phenomenon that the micropump will achieve bi-directional pumping. As a finding, vortices arranged in pairs could improve the rectification efficiency of the micropump. The micropump achieves a maximum flow rate of 40.5 ml/min and back pressure of 5.76 cmH 2 o. In addition, the maximum flow rate per unit area can reach 305.2 μl/(min mm 2 ).

Distribution of diagenetic alterations within depositional facies and sequence stratigraphic framework of fan delta and subaqueous fan sandstones: evidence from the Lower Cretaceous Bayingebi Formation, Chagan sag, China–Mongolia frontier area

Wei Wei,Xiaomin Zhu,Mingxuan Tan,Chenbingjie Wu,Dianbin Guo,Hui Su 한국지질과학협의회 2016 Geosciences Journal Vol.20 No.1

Linking siliciclastic diagenesis to sequence stratigraphy allows a better understanding of the parameters controlling the spatial and temporal distribution of diagenetic alterations. A study of the subaqueous fan and fan delta sandstones of the Bayingebi Formation, Lower Cretaceous, Chagan sag (China), reveals that the distribution of diagenetic alterations can be constrained within a sequence stratigraphic framework. Eogenetic alterations, which were encountered in the sandstones of subaqueous fan and fan delta, include: (1) replacement of detrital silicates and mud matrix by kaolinites in sandstones of the late highstand systems tract (HST) and the lowstand systems tract (LST). The formation of kaolinites is attributed to the influx of meteoric water when the base level fell and the channels migrated laterally on preexisting floodplains or channel deposits. (2) Infiltrated clays, which rim around detrital grains, mainly occur in channel sandstones of the LST due to the percolation of mud-rich surface waters. (3) Calcite I (δ18OVPDB = –20.19‰ to −3.64‰ and δ13CVPDB = –0.67‰ to –3.1‰), Calcite II (δ18OVPDB = –14‰ to –18.28‰ and δ13CVPDB = –2.2‰ to –3.60‰), dolomite (δ18OVPDB = –17.91‰ to –21.04‰ and δ13CVPDB = –0.46‰ to –1.66‰) and ankerite (δ18OVPDB = –15.02 to –20.42‰ and δ13CVPDB = –0.074 to –1.43‰), which are associated with palaeosol horizons mainly developed on top of overbank and channel sandstones of transgressive systems tract (TST) and early stage of the HST. Such extensive eogenetic calcite cements may act as potential layers for the formation of reservoir compartments for underlying sandstones. Mesogenetic alterations include: (1) abundant quartz overgrowths in the overbank sandstones of subaqueous fan in the LST and pro-fan-delta sandstones in the HST, in which early carbonate cements are lacking and grain-coats are thin. (2) Illite, chlorite and albitized feldspars, which occur in small amounts, are most common in the LST and late stage of the HST sandstones. Such cementation by calcite, dolomite, quartz overgrowths and formation of illite led to porosity and permeability deterioration during mesodiagenesis. This study revealed the importance of integration of diagenesis with sequence stratigraphy of subaqueous fan and fan delta sandstones in improving our ability to predict the spatial and temporal distribution of eogenetic alterations and their subsequent impact on mesogenetic alterations, and thus on reservoir quality modifications.

A flow rate on-line monitoring method for piezoelectric pump based on self-sensing circuit

Hong Jiang,Guohui Wu,Lipeng He,Yuecheng Wang,Dianbin Hu,Zheng Zhang,Guangming Cheng 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.5

This paper presents a new flow rate monitoring method for a piezoelectric micropump based on a self-sensing circuit. Utilizing the voltage generated by the secondary direct piezoelectric effect as the sensing voltage, a soft sensor of the piezoelectric actuator can be implemented onto the piezoelectric micropump. A bridge-type circuit is proposed as the selfsensing circuit, the piezoelectric micropump is fabricated with a circular piezoelectric actuator, the characteristics of the self-sensing voltage and the flow rate are experimentally investigated under different excitation voltages and frequencies. The results show that the method can accurately determine optimal frequency of the micropump (100 Hz, 280 Hz), and for a fixed frequency of 100 Hz and a voltage range of 50-180 V, the correlation between the self-sensing voltage and the flow rate is 0.9732. As a result, the method demonstrated in this paper allows precise monitoring of the flow rate of the piezoelectric micropump without using external sensors.

Thermal management analysis of serial-connection three-chamber piezoelectric pump

Lipeng He,Xiaoqiang Wu,Zheng Zhang,Jingran Wang,Dianbin Hu,Yamei Liu,Guangming Cheng 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.10

The design of a micropump with high performance and excellent reliability on thermal management still remains a challenge for electronic cooling. The performance of a piezoelectric pump with 3 chambers connected in series on thermal management was investigated for electronic cooling in this study. Two S-shaped channel heat sinks and the piezoelectric pump with 3 chambers connected in series were combined to form a loop cooling system. With water as the pumping medium, the tested pump has a flow rate most up to 690.6 ml/min at an input voltage of 220 V and an input frequency of 110 Hz. Suitability of the system has been demonstrated through simulation analysis and experimental verification for temperature control. A temperature reduction of 3 °C of CPU could be achieved at 250 mL/min flow rate generated by the piezoelectric pump with 3 chambers connected in series.

Genomic Correlates of Unfavorable Outcome in Locally Advanced Cervical Cancer Treated with Neoadjuvant Chemoradiation

Yuchun Wei,Chuqing Wei,Liang Chen,Ning Liu,Qiuxiang Ou,Jiani C. Yin,Jiaohui Pang,Zhenhao Fang,Xue Wu,Xiaonan Wang,Dianbin Mu,Yang Shao,Jinming Yu,Shuanghu Yuan 대한암학회 2022 Cancer Research and Treatment Vol.54 No.4

Purpose Neoadjuvant therapy modality can increase the operability rate and mitigate pathological risks in locally advanced cervical cancer, but treatment response varies widely. It remains unclear whether genetic alterations correlate with the response to neoadjuvant therapy and disease-free survival (DFS) in locally advanced cervical cancer. Materials and Methods A total of 62 locally advanced cervical cancer (stage IB-IIA) patients who received neoadjuvant chemoradiation plus radical hysterectomy were retrospectively analyzed. Patients’ tumor biopsy samples were comprehensively profiled using targeted next generation sequencing. Pathologic response to neoadjuvant treatment and DFS were evaluated against the association with genomic traits. Results Genetic alterations of PIK3CA were most frequent (37%), comparable to that of Caucasian populations from The Cancer Genome Atlas. The mutation frequency of genes including TERT, POLD1, NOS2, and FGFR3 was significantly higher in Chinese patients whereas RPTOR, EGFR, and TP53 were underrepresented in comparison to Caucasians. Germline mutations were identified in 21% (13/62) of the cohort and more than half (57%) had mutations in DNA damage repair genes, including BRCA1/2, TP53 and PALB2. Importantly, high tumor mutation burden, TP53 polymorphism (rs1042522), and KEAP1 mutations were found to be associated with poor pathologic response to neoadjuvant chemoradiation treatment. KEAP1 mutations, PIK3CA-SOX2 co-amplification, TERC copy number gain, and TYMS polymorphism correlated with an increased risk of disease relapse. Conclusion We report the genomic profile of locally advanced cervical cancer patients and the distinction between Asian and Caucasian cohorts. Our findings highlight genomic traits associated with unfavorable neoadjuvant chemoradiation response and a higher risk of early disease recurrence. PurposeNeoadjuvant therapy modality can increase the operability rate and mitigate pathological risks in locally advanced cervical cancer, but treatment response varies widely. It remains unclear whether genetic alterations correlate with the response to neoadjuvant therapy and disease-free survival (DFS) in locally advanced cervical cancer.Materials and MethodsA total of 62 locally advanced cervical cancer (stage IB-IIA) patients who received neoadjuvant chemoradiation plus radical hysterectomy were retrospectively analyzed. Patients’ tumor biopsy samples were comprehensively profiled using targeted next generation sequencing. Pathologic response to neoadjuvant treatment and DFS were evaluated against the association with genomic traits.ResultsGenetic alterations of <i>PIK3CA</i> were most frequent (37%), comparable to that of Caucasian populations from The Cancer Genome Atlas. The mutation frequency of genes including <i>TERT, POLD1, NOS2</i>, and <i>FGFR3</i> was significantly higher in Chinese patients whereas <i>RPTOR, EGFR</i>, and <i>TP53</i> were underrepresented in comparison to Caucasians. Germline mutations were identified in 21% (13/62) of the cohort and more than half (57%) had mutations in DNA damage repair genes, including <i>BRCA1/2, TP53</i> and <i>PALB2</i>. Importantly, high tumor mutation burden, <i>TP53</i> polymorphism (rs1042522), and <i>KEAP1</i> mutations were found to be associated with poor pathologic response to neoadjuvant chemoradiation treatment. <i>KEAP1</i> mutations, <i>PIK3CA-SOX2</i> co-amplification, <i>TERC</i> copy number gain, and <i>TYMS</i> polymorphism correlated with an increased risk of disease relapse.ConclusionWe report the genomic profile of locally advanced cervical cancer patients and the distinction between Asian and Caucasian cohorts. Our findings highlight genomic traits associated with unfavorable neoadjuvant chemoradiation response and a higher risk of early disease recurrence.