Active Damping Stability Control Method Based on Voltage Compensation for IPMSM Drives with Small DC-Link Capacitor

Song Jian,Song Wen-Xiang,Liu Zhan-Jun,Ma Shao-Cai 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.2

Aiming at the unstable phenomena such as high DC-link voltage ripple that occur in the interior permanent magnet synchronous motor drive system of the small DC-link capacitor when the rotor speed is high or the load power is large, this paper proposes an active damping control method based on voltage compensation. The method starts from the mathematical model of the driving system, based on the characteristic equation of the driving system, and according to the Rouse stability criterion, the driving system is stabilized by applying a virtual resistance to change the coefficient of the characteristic equation. The proposed method only needs a bandpass filter to extract the DC-link voltage ripple, which is then compensated to the motor stator voltage axis by the damping coefficient. In order to obtain high damping performance, considering the time constant and the delay of the control loop, the theoretical design basis for a reasonable value of the damping coefficient is given, and the influence of the proposed method on the performance of the drive system is evaluated. Simulation and experimental results verify the effectiveness of the proposed method.

Progressive Collapse Resistance of RC Frames under a Side Column Removal Scenario

Jian Hou,Li Song 한국콘크리트학회 2016 International Journal of Concrete Structures and M Vol.10 No.2

Progressive collapse resistance of RC buildings can be analyzed by considering column loss scenarios. Using finite element analysis and a static test, the progressive collapse process of a RC frame under monotonic vertical displacement of a side column was investigated, simulating a column removal scenario. A single-story 1/3 scale RC frame that comprises two spans and two bays was tested and computed, and downward displacement of a side column was placed until failure. Our study offers insight into the failure modes and progressive collapse behavior of a RC frame. It has been noted that the damage of structural members (beams and slabs) occurs only in the bay where the removal side column is located. Greater catenary action and tensile membrane action are mobilized in the frame beams and slabs, respectively, at large deformations, but they mainly happen in the direction where the frame beams and slabs are laterally restrained. Based on the experimental and computational results, the mechanism of progressive collapse resistance of RC frames at different stages was discussed further. With large deformations, a simplified calculation method for catenary action and tensile membrane action is proposed.

Model-Based Prediction of Pulsed Eddy Current Testing Signals from Stratified Conductive Structures

Jian-Hai Zhang,Sung-Jin Song,Woong-Ji Kim,Hak-Joon Kim,Jong-Duk Chung 한국비파괴검사학회 2011 한국비파괴검사학회지 Vol.31 No.6

Excitation and propagation of electromagnetic field of a cylindrical coil above an arbitrary number of conductive plates for pulsed eddy current testing(PECT) are very complex problems due to their complicated physical properties. In this paper, analytical modeling of PECT is established by Fourier series based on truncated region eigenfunction expansion(TREE) method for a single air-cored coil above stratified conductive structures(SCS) to investigate their integrity. From the presented expression of PECT, the coil impedance due to SCS is calculated based on analytical approach using the generalized reflection coefficient in series form. Then the multilayered structures manufactured by non-ferromagnetic (STS301L) and ferromagnetic materials (SS400) are investigated by the developed PECT model. Good prediction of analytical model of PECT not only contributes to the development of an efficient solver but also can be applied to optimize the conditions of experimental setup in PECT.

Is There a Correlation between the Presence of a Spiculated Mass on Mammogram and Luminal A Subtype Breast Cancer?

Song Liu,Xiao-Dong Wu,Wen-Jian Xu,Qing Lin,Xue-Jun Liu,Ying Li 대한영상의학회 2016 Korean Journal of Radiology Vol.17 No.6

Objective: To determine whether the appearance of a spiculated mass on a mammogram is associated with luminal A subtype breast cancer and the factors that may influence the presence or absence of the spiculated mass. Materials and Methods: Three hundred seventeen (317) patients who underwent image-guided or surgical biopsy between December 2014 and April 2015 were included in the study. Radiologists conducted retrospective assessments of the presence of spiculated masses according to the criteria of Breast Imaging Reporting and Data System. We used combinations of estrogen receptor (ER), progesterone receptor (PR), human epithelial growth factor receptor 2 (HER2), and Ki67 as surrogate markers to identify molecular subtypes of breast cancer. Pearson chi-square test was employed to measure statistical significance of correlations. Furthermore, we built a bi-variate logistic regression model to quantify the relative contribution of the factors that may influence the presence or absence of the spiculated mass. Results: Seventy-one percent (71%) of the spiculated masses were classified as luminal A. Masses classified as luminal A were 10.3 times more likely to be presented as spiculated mass on a mammogram than all other subtypes. Patients with low Ki67 index (< 14%) and HER2 negative were most likely to present with a spiculated mass on their mammograms (p < 0.001) than others. The hormone receptor status (ER and PR), pathology grade, overall breast composition, were all associated with the presence of a spiculated mass, but with less weight in contribution than Ki67 and HER2. Conclusion: We observed an association between the luminal A subtype of invasive breast cancer and the presence of a spiculated mass on a mammogram. It is hypothesized that lower Ki67 index and HER2 negativity may be the most significant factors in the presence of a spiculated mass.

Apple RING finger E3 ubiquitin ligase MdMIEL1 negatively regulates salt and oxidative stresses tolerance

Jian-Ping An,Xin Liu,Lai-Qing Song,Chun-Xiang You,Xiao-Fei Wang,Yu-Jin Hao 한국식물학회 2017 Journal of Plant Biology Vol.60 No.2

RING-finger-containing E3 ubiquitin ligases play important roles in plant response to biotic and abiotoc stresses. In this study, through homology analysis, a Malus× domestica MYB30-Interacting E3 Ligase 1 gene, MdMIEL1, was identified and subsequently cloned from apple ‘Gala’ (Malus×domestica). MdMIEL1 contained a zinc finger domain close to N-terminus and a RING finger domain close to Cterminus. Expression of MdMIEL1 was significantly induced by NaCl and H2O2 treatments. Further study demonstrated that the MdMIEL1-overexpressing Arabidopsis and apple calli were less tolerance to salt stress than wild-type control. In addition, transgenic plants had higher levels of reactive oxygen species (ROS) (H2O2 and O2 –). And transgenic Arabidopsis and apple calli exhibited more sensitive phenotype to H2O2 treatment, which was associated with increased levels of ROS. These findings indicate MdMIEL1 is an important regulator involved in plant response to salt and oxidative stresses tolerance.

Analysis of Wind Turbine Fatigue Load Data Model

Jian Yang,Songyue Zheng,Dongran Song,Guoxun Xiao,Junye Ma,Young Hoon Joo 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

The mutual coupling between the average wind speed, the turbulence intensity and the active power regulation affects the fatigue load of the wind turbine (WT), and the time series of the wind speed is random, which causes the uncertainty of the fatigue load. In order to clarify the influence of multiple factors on the fatigue load of WT, this paper discusses the fatigue load of WT and its influencing factors based on data mining method. The Bladed software is used to combine various factors, and a large number of simulation experiments are carried out to obtain the fatigue load data distributed in the three directions of the four components of the blade, hub, yaw and tower. Kernel density function is employed to analyzed distribution of fatigue load data. The fatigue load data model is established to find out the influence of average wind speed, turbulence intensity and active power regulation on fatigue load.

Maximum power extraction for wind turbines through a novel yaw control solution using predicted wind directions

Song, Dongran,Yang, Jian,Fan, Xinyu,Liu, Yao,Liu, Anfeng,Chen, Guo,Joo, Young Hoon Elsevier 2018 Energy conversion and management Vol.157 No.-

<P><B>Abstract</B></P> <P>For modern horizontal axis wind turbines (WTs), a yaw drive mechanism is utilized to adjust the nacelle position to face the wind direction. Depending on historical signals from wind direction sensors, conventional yaw control methods could not provide sufficient performance in tracking winds, and thus result in a reduction of wind power extraction. This issue needs to be tackled using advanced control solutions. Taking advantage of predicted wind directions, a novel control solution is proposed in this study. Specifically, the proposed solution refers to a novel control structure that consists of a wind direction predictive model and a novel yaw control method. Under the proposed control structure, a hybrid autoregressive integrated moving average method-based Kalman filter (ARIMA-KF) model is used to predict the wind direction, and two novel yaw control methods are proposed: one created by using the predicted wind direction as the tracking reference, and the other based on a model predictive control (MPC) using a finite control set. To demonstrate the feasibility and the superiority of the proposed solution, two novel yaw controllers are developed and tested through some simulation tests using industrial data. Their performance is compared to the one of two industrial yaw controllers. Comparison results show that the two novel yaw controllers are capable of reducing yaw error, and thus increase wind power extraction for the WTs. Meanwhile, it is noticeable that the MPC-based controller has an advantage in the aspect of reducing yaw actuator usage.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel yaw control solution using predicted wind direction is proposed. </LI> <LI> An ARIMA-KF based model is used to predict the wind direction. </LI> <LI> One novel yaw control method uses the predicted wind direction as the tracking reference. </LI> <LI> The other one is based on a model predictive control using a finite control set. </LI> <LI> The novel yaw control solution extracts 1% more wind power. </LI> </UL> </P>

Arrays of Sealed Silicon Nanotubes As Anodes for Lithium Ion Batteries

Song, Taeseup,Xia, Jianliang,Lee, Jin-Hyon,Lee, Dong Hyun,Kwon, Moon-Seok,Choi, Jae-Man,Wu, Jian,Doo, Seok Kwang,Chang, Hyuk,Park, Won Il,Zang, Dong Sik,Kim, Hansu,Huang, Yonggang,Hwang, Keh-Chih,Roge American Chemical Society 2010 NANO LETTERS Vol.10 No.5

<P>Silicon is a promising candidate for electrodes in lithium ion batteries due to its large theoretical energy density. Poor capacity retention, caused by pulverization of Si during cycling, frustrates its practical application. We have developed a nanostructured form of silicon, consisting of arrays of sealed, tubular geometries that is capable of accommodating large volume changes associated with lithiation in battery applications. Such electrodes exhibit high initial Coulombic efficiencies (i.e., >85%) and stable capacity-retention (>80% after 50 cycles), due to an unusual, underlying mechanics that is dominated by free surfaces. This physics is manifested by a strongly anisotropic expansion in which 400% volumetric increases are accomplished with only relatively small (<35%) changes in the axial dimension. These experimental results and associated theoretical mechanics models demonstrate the extent to which nanoscale engineering of electrode geometry can be used to advantage in the design of rechargeable batteries with highly reversible capacity and long-term cycle stability.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2010/nalefd.2010.10.issue-5/nl100086e/production/images/medium/nl-2010-00086e_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl100086e'>ACS Electronic Supporting Info</A></P>

Age of Diagnosis of Breast Cancer in China: Almost 10 Years Earlier than in the United States and the European Union

Song, Qing-Kun,Li, Jing,Huang, Rong,Fan, Jin-Hu,Zheng, Rong-Shou,Zhang, Bao-Ning,Zhang, Bin,Tang, Zhong-Hua,Xie, Xiao-Ming,Yang, Hong-Jian,He, Jian-Jun,Li, Hui,Li, Jia-Yuan,Qiao, You-Lin,Chen, Wan-Qin Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.22

Background: The study aimed to describe the age distribution of breast cancer diagnosis among Chinese females for comparison with the United States and the European Union, and provide evidence for the screening target population in China. Materials and Methods: Median age was estimated from hospital databases from 7 tertiary hospitals in China. Population-based data in China, United States and European Union was extracted from the National Central Cancer Registry, SEER program and GLOBOCAN 2008, respectively. Age-standardized distribution of breast cancer at diagnosis in the 3 areas was estimated based on the World Standard Population 2000. Results: The median age of breast cancer at diagnosis was around 50 in China, nearly 10 years earlier than United States and European Union. The diagnosis age in China did not vary between subgroups of calendar year, region and pathological characteristics. With adjustment for population structure, median age of breast cancer at diagnosis was 50~54 in China, but 55~59 in United States and European Union. Conclusions: The median diagnosis age of female breast cancer is much earlier in China than in the United States and the European Union pointing to racial differences in genetics and lifestyle. Screening programs should start at an earlier age for Chinese women and age disparities between Chinese and Western women warrant further studies.

Three New 29 Carbon Skeletons Pentacyclic Triterpenoids and S-equol from Biogas Slurry

Jian-Feng Xu,Hui-Bin Wu,Ding-Cai Liu,Long Sha,Wen-Hui Wu,Hua Fan,Yishan Song,Hong-Guang Zhu 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.12

Bioactive natural products were firstly obtained from biogas slurry. Three new 29 carbon skeletons of the pentacyclic triterpenoid compounds 24-norolean-12-ene-3,22-dione (1), 3β-hydroxy-24-norolean-12-ene-22-one (2), 3α-hydroxy-24-norolean-12-ene-22-one (3), as well as one known compound S-equol (4) were isolated and purified from the MeOH extract of chicken manure biogas slurry. The molecular structures of the four compounds were elucidated based on the extensive spectroscopic data analysis, and the structure of Compound 1 was further confirmed by single-crystal X-ray diffraction. The structures of Compounds 1, 2, and 3 are similar with oleanolicum and hederagenin that has excellent anti-tumor activities. The cytotoxicity against five cancer cell lines (Hela, A549, MCF7, PC3, and B16) of Compounds 1–4 was tested. Similar to Compound 4 (S-equol), Compounds 1–3 (pentacyclic triterpenoids) showed cytotoxicity activity against different tumor cell lines. Compounds 1–3 showed slightly lower cytotoxicity activities than Compound 4. The IC50 of Compound 4 was determined to be 9.7–27.6 μM, while the IC50 values of 1–3 were 17.6–65.3 μM. There are no significant differences in the cytotoxicity capacities between Compounds 1, 2, and 3.