A negative stiffness inerter system (NSIS) for earthquake protection purposes

Zhipeng Zhao,Qingjun Chen,Ruifu Zhang,Yiyao Jiang,Chao Pan 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.26 No.4

The negative stiffness spring and inerter are both characterized by the negative stiffness effect in the force-displacement relationship, potentially yielding an amplifying mechanism for dashpot deformation by being incorporated with a series tuning spring. However, resisting forces of the two mechanical elements are dominant in different frequency domains, thus leading to necessary complementarity in terms of vibration control and the amplifying benefit. Inspired by this, this study proposes a Negative Stiffness Inerter System (NSIS) as an earthquake protection system and developed analytical design formulae by fully utilizing its advantageous features. The NSIS is composed of a sub-configuration of a negative stiffness spring and an inerter in parallel, connected to a tuning spring in series. First, closed-form displacement responses are derived for the NSIS structure, and a stability analysis is conducted to limit the feasible domains of NSIS parameters. Then, the dual advantageous features of displacement reduction and the dashpot deformation amplification effect are revealed and clarified in a parametric analysis, stimulating the establishment of a displacement-based optimal design framework, correspondingly yielding the design formulae in analytical form. Finally, a series of examples are illustrated to validate the derived formulae. In this study, it is confirmed that the synergistic incorporation of the negative stiffness spring and the inerter has significant energy dissipation efficiency in a wide frequency band and an enhanced control effect in terms of the displacement and shear force responses. The developed displacement-based design strategy is suitable to utilize the dual benefits of the NSIS, which can be accurately implemented by the analytical design formulae to satisfy the target vibration control with increased energy dissipation efficiency.

Efficiently targeted therapy of glioblastoma xenograft via multifunctional biomimetic nanodrugs

Zhipeng Yao,Xiaochun Jiang,Hong Yao,Yafeng Wu,Fan Zhang,Cheng Wang,Chenxue Qi,Chenhui Zhao,Zeyu Wu,Min Qi,Jia Zhang,Xiaoxiang Cao,Zhichun Wang,Fei Wu,Chengyun Yao,Songqin Liu,Shizhang Ling,Hongping Xi 한국생체재료학회 2022 생체재료학회지 Vol.26 No.4

Background: Glioblastoma multiforme (GBM) is a fatal malignant primary brain tumor in adults. The therapeutic efficacy of chemotherapeutic drugs is limited due to the blood-brain barrier (BBB), poor drug targeting, and short biological half-lives. Multifunctional biomimetic nanodrugs have great potential to overcome these limitations of chemotherapeutic drugs. Methods: We synthesized and characterized a biomimetic nanodrug CMS/PEG-DOX-M. The CMS/PEG-DOX-M effectively and rapidly released DOX in U87 MG cells. Cell proliferation and apoptosis assays were examined by the MTT and TUNEL assays. The penetration of nanodrugs through the BBB and anti-tumor efficacy were investigated in the orthotopic glioblastoma xenograft models. Results: We showed that CMS/PEG-DOX-M inhibited cell proliferation of U87 MG cells and effectively induced cell apoptosis of U87 MG cells. Intracranial antitumor experiments showed that free DOX hardly penetrated the BBB, but CMS/PEG-DOX-M effectively reached the orthotopic ntracranial tumor through the BBB and significantly inhibited tumor growth. Immunofluorescence staining of orthotopic tumor tissue sections confirmed that nanodrugs promoted apoptosis of tumor cells. This study developed a multimodal nanodrug treatment system with the enhanced abilities of tumor-targeting, BBB penetration, and cancer-specific accumulation of chemotherapeutic drugs by combining chemotherapy and photothermal therapy. It can be used as a flexible and effective GBM treatment system and it may also be used for the treatment of other central nervous systems (CNS) tumors and extracranial tumors.

A Lexical and Syntactic Analysis System for Chinese Electronic Medical Record

Zhipeng Jiang,Xue Dai,Yi Guan,Fangfang Zhao 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.9

Lexical and syntactic analysis, including word segmentation, part-of-speech (POS) tagging, shallow parsing and full parsing, are essential for medical language processing (MLP). However, research on full parsing, even shallow parsing and POS tagging for Chinese electronic medical record (CEMR), has not been carried out because of the lack of annotated corpus on CEMR. In this paper, we built a corpus of 5,024 sentences from CEMR with word segmentation, POS tags and phrase tags, of them, 2,553 are annotated as full parsing trees. Inter-annotator agreement results: Chinese word segmentation (97.56%), POS tagging (93.34%), shallow parsing (96.5%), full parsing (91.22%). A lexical and syntactic analysis system for CEMR is developed and evaluated based on above corpus. Of its components, we proposed a joint model for word segmentation and POS tagging with the transformation-based error-driven model as correction postprocessing to alleviate the problem of error accumulation, the F1-score of word segmentation and POS tagging were 94.39% and 93.2%, respectively. A shallow parsing model under the framework of group learning we proposed was developed, which enriched word features by word embedding from large unlabeled CEMRs and achieved the F1-score of 96.3%. At last, we presented a state-of-art full parser combining the Berkeley parser and the Stanford parser to outperform the best single parser by 3.68%. The evaluation results show a substantial benefit to statistical machine learning models from the annotated CEMR. These works are the foundation for natural language processing (NLP) technologies applied to CEMR.

Decoupled SVPWM for Five-Phase Permanent Magnet Machines with Trapezoidal Back-EMF

Zhipeng Lin,Guohai Liu,Wenxiang Zhao,Qian Chen 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.5

This paper presents a novel space vector pulse-width modulation (SVPWM) to synthesize an arbitrary non-sinusoidal phase voltage. The key of the proposed method is that the switching vectors used to comprise the reference vectors in the α₁-β₁ frame and the α₃-β₃ frame are decoupled. In the α₁-β₁ frame, the reference vector is comprised by near two large vectors. The corresponding vector comprised by the two vectors in the α₃-β₃ frame is considered as a disturbance, which is restrained by close-loop control. In the α₃-β₃ frame, there are two methods to comprise the reference vector. Method I is a near two middle vectors method. Method II uses near four vectors (two middle and two little vectors). The proposed SVPWM using decoupled switching vectors can guarantee a maximum modulation index in the α₁-β₁ frame. The effectiveness of the proposed method is verified by simulated and experimental results under various operation conditions.

A Survey of Knowledge Hierarchies for Image Analysis

Zhipeng Ye,Peng Liu,Wei Zhao,Xianglong Tang 한국산학기술학회 2015 SmartCR Vol.5 No.3

More images are available nowadays because of the development of techniques to effectively and automatically analyze images. These techniques have become a key challenge in computer vision. In this paper, we focus on the structure of knowledge representation for image analysis from a global perspective, which can also be applied to image classification, retrieval, and object recognition. The structure is divided into two hierarchies, implicit and explicit knowledge representation. Implicit knowledge representation utilizes low-level features to directly categorize an image, whereas explicit knowledge representation depends on the inference process based on corresponding rules in a constructed knowledge base. Popular datasets for image analysis are also grouped and introduced. Contributions in the field and future research directions are reported in the conclusions.

A helix slope deviation compensation model for milling small modulus copper electrode gears

Zhipeng Feng,Zhao-Yao Shi,Shoujin Lin,Aijun Tong,Peng Wang,Guoqing Wu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.7

When a milling tool is used to mill small modulus copper electrode gears (SMCEG), the deformation is inevitable, thus leading to the helix slope deviation (HSD) of copper electrode gears (CEG). To compensate the influence of milling tool deflection (MTD) on the HSD, a universal HSD compensation model was established for different sizes of milling tools. First, using the principle of orthogonal experiment, a linear regression model of milling parameters and milling tool radius is established. Secondly, the average value of the HSD obtained by the gear measuring instrument is converted into the maximum of MTD according to the principle of helix line formation. The maximum deflections of the milling tools are used as the response value of the regression analysis to fit the maximum deflection curve of the milling tool. Through the reverse adjustment of the rotation angle of the rotating motor, the HSD compensation is realized. Finally, the model was verified by the milling tests. The results showed that the helix deviation reached the requirements of level 4 to 5 in GB/T 38192-2019, and proved the correctness of the established MTD model. The model is significant for milling SMCEG.

Detection for Operation Chain: Histogram Equalization and Dither-like Operation

( Zhipeng Chen ),( Yao Zhao ),( Rongrong Ni ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.9

Many sorts of image processing software facilitate image editing and also generate a great number of doctored images. Forensic technology emerges to detect the unintentional or malicious image operations. Most of forensic methods focus on the detection of single operations. However, a series of operations may be used to sequentially manipulate an image, which makes the operation detection problem complex. Forensic investigators always want to know as much exhaustive information about a suspicious image`s entire processing history as possible. The detection of the operation chain, consisting of a series of operations, is a significant and challenging problem in the research field of forensics. In this paper, based on the histogram distribution uniformity of a manipulated image, we propose an operation chain detection scheme to identify histogram equalization (HE) followed by the dither-like operation (DLO). Two histogram features and a local spatial feature are utilized to further determine which DLO may have been applied. Both theoretical analysis and experimental results verify the effectiveness of our proposed scheme for both global and local scenarios.

Evolution and recovery of original total organic carbon for muddy source rocks with different total organic carbon in the Western Sichuan Depression, Sichuan Basin, China

Zhipeng Huo,Yan Gao,Yi Zhao,Tianyu Zheng,Jinchuan Zhang,Jianghui Ding 한국지질과학협의회 2019 Geosciences Journal Vol.23 No.1

According to the new quantitative model for original total organic carbon (TOCo) evolution and recovery of source rocks, The TOCo evolution of muddy source rocks with different TOCs (MSRDTOC) (0.5% < TOC ≤ 1.5%, 2.5% < TOC ≤ 3.5% and 4.0% < TOC ≤ 6.0%, and their average values were 1.0%, 3.0% and 5.0%, respectively) and type III kerogen were investigated in the Western Sichuan Depression (WSD) of Sichuan Basin, China, finally recovery coefficients of TOCo were calculated. Studies showed that TOCo evolution of the MSRDTOC have similarities and differences. The similarities reveal that with the increase of thermal evolution level, varied TOC all reduce gradually and the sharp reduction occurs at the stage of a large number of hydrocarbon generation and expulsion (0.7% ≤ vitrinite reflectance (VR) ≤ 1.3%). The differences indicate that the starting time and decrease range for varied TOC are different. For TOCo = 1.0%, 3.0% and 5.0%, their starting time of TOC reduction are VR = 1.05%, 0.80% and 0.60%, respectively. When VR reaches to 3.0%, their TOC decrease ranges are 30.54%, 38.52% and 44.00% and their recovery coefficients are 1.44, 1.63 and 1.79, respectively. The higher the TOC is, the earlier the starting time of TOC reduction is, the bigger the range of TOC reduction and recovery coefficient are. It must restore TOCo when we evaluate source rocks at high-over mature stage and predict oil and gas resources. The MSRDTOC and their TOCo recovery should be evaluated, respectively.

Investigation on fixture design and precision stability of new-type double collect chuck for machining of long ladder shaft gear

Zhipeng Liang,Chunju Zhao,Huawei Zhou,Yihong Zhou 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.1

To solve the problems of poor positioning accuracy and non-automatic processing seen in the machining of long ladder shaft gears, a fixture structure scheme with a new type of double collect chuck (DCC) is proposed. The design rationality, clamping stability, and repeat clamping positioning accuracy of the proposed DCC were analyzed and investigated based on theory calculation, simulation analysis, and engineering application tests. First, the clamping performance of DCC was investigated through theory calculation and simulation analysis. The test results showed that the structure of DCC maintained effective clamping and the repeat clamping positioning accuracy was steadily controlled within 0.008 mm. Meanwhile, efficiently automated machining of long ladder shaft gear was realized based on extended design and engineering application of automatic up and down mechanism when the structure of DCC was applied. Furthermore, the machining accuracy of the gear was steadily controlled within DIN8 (DIN5480-2 standard). Additionally, based on extended design and engineering tests, the automatic up and down machining improves production efficiency and machining accuracy. Thus, the novel fixture structure scheme provides a new approach for automatic up and down machining of long ladder shaft gear.

MnOx Nanowires@MnOx Nanosheets Core–Shell Heterostructure Electrode for Superior Performance in Supercapacitor

Zhipeng Ma,Fengyang Jing,Liyin Hou,Lukai Fan,Yao Zhao,Yuqian Fan,Xiujuan Qin 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2020 NANO Vol.15 No.03

Manganese-based oxides are one of the most promising high-performance supercapacitor (SC) electrode materials. In this work, a stable MnOx nanowires@MnOx nanosheets core–shell heterostructure electrode material consisting of MnOx nanosheets grown uniformly on the surface of MnOx nanowires has been prepared by a simple liquid phase method followed by thermal treatment. The electrode displays a specific capacity of 336 F g -1 at 1 A g -1 and exhibits a good cycling life of 83% capacitance retention after 5000 cycles. This is mainly due to the synergy effect between the one-dimensional MnOx nanowires as the backbone structure and the two-dimensional MnOx nanosheets with large specific surface area provide more active sites and the rapid transmission of electrons.