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Performance prediction of switched reluctance generator with time average and small signal models

Jyoti KOUJALAGI, B. UMAMAHESWARI, R. ARUMUGAM

《能源前沿（英文）》 2013年第7卷第1期页码 56-68 doi: 10.1007/s11708-012-0216-8

摘要： This paper presents the complete mathematical model and predicts the performance of switched reluctance generator with time average and small signal models. The complete mathematical model is developed in three stages. First, a switching model is developed based on quasi-linear inductance profile. Next, based on the switching behaviour, a time average model is obtained to measure the difference between the excitation and generation time in each switching cycle. Finally, to track control voltage and current wave shapes, a small signal model is designed. The effectiveness of the complete multilevel model combining electrical machine, power converter, load and control with programming language is demonstrated through simulations. A PI controller is used for controlling the voltage of the generator. The results presented show that the controller exhibits accurate tracking control of load voltage under different operating conditions. This demonstrates that the proposed model is able to perform an accurate control of the generated output voltage even in transient situations. The simulation is performed to choose the control parameters and study the performance of switched reluctance generator prior to its actual implementation. Initial experimental results are presented using NI-Data acquisition card to control the output power according to load requirements.

关键词： generator reluctance switching model small signal model time average model

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Cutting Force Model for a Small-diameter Helical Milling Cutter

LI Xiwen, YANG Shuzi, YANG Mingjin, XIE Shouyong

《机械工程前沿（英文）》 2007年第2卷第3期页码 272-277 doi: 10.1007/s11465-007-0047-1

摘要： In the milling process, the major flank wear land area (two-dimensional measurement for the wear) of a small-diameter milling cutter, as wear standard, can reflect actual changes of the wear land of the cutter. By analyzing the wearing characteristics of the cutter, a cutting force model based on the major flank wear land area is established. Characteristic parameters such as pressure parameter and friction parameter are calculated by substituting tested data into their corresponding equations. The cutting force model for the helical milling cutter is validated by experiments. The computational and experimental results show that the cutting force model is almost consistent with the actual cutting conditions. Thus, the cutting force model established in the research can provide a theoretical foundation for monitoring the condition of a milling process that uses a small-diameter helical milling cutter.

关键词： computational corresponding helical milling theoretical foundation Characteristic

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Piezoelectric inertial robot for operating in small pipelines based on stick-slip mechanism: modeling

《机械工程前沿（英文）》 2022年第17卷第3期 doi: 10.1007/s11465-022-0697-z

摘要： Small pipes exist in industrial and biomedical fields, and require microrobots with high operational precision and large load capacity to inspect or perform functional tasks. A piezoelectric inertial pipeline robot using a “stick-slip” mechanism was proposed to address this requirement. In this study, the driving principle of the proposed robot was analyzed, and the strategy of the design scheme was presented. A dynamics model of the stick-slip system was established by combining the dynamics model of the driving foot system and the LuGre friction model, and the simulation analysis of the effect of system parameters on the operating trajectory was performed. An experimental system was established to examine the output characteristics of the proposed robot. Experimental results show that the proposed pipeline robot with inertial stick-slip mechanism has a great load capacity of carrying 4.6 times (70 g) its own mass and high positioning accuracy. The speed of the pipeline robot can reach up to 3.5 mm/s (3 mm/s) in the forward (backward) direction, with a minimum step distance of 4 μm. Its potential application for fine operation in the pipe is exhibited by a demonstration of contactless transport.

关键词： pipeline robot piezoelectric inertial drive stick-slip large load capacity dynamics model small pipeline

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Roles of integrin β3 cytoplasmic tail in bidirectional signal transduction in a trans-dominant inhibitionmodel

null

《医学前沿（英文）》 2016年第10卷第3期页码 311-319 doi: 10.1007/s11684-016-0460-0

摘要：

We evaluated the roles of calpain cleavage-related mutations of the integrin β3 cytoplasmic tail in integrin αIIbβ3 bidirectional signaling using a trans-dominant inhibition model. Chimeric Tac-β3 proteins (i.e., Tac-β3, Tac-β3D741, Tac-β3D747, Tac-β3D754, Tac-β3D759, and Tac-β3DNITY) consisting of the extracellular and transmembrane domains of human IL-2 receptor (Tac) and the human integrin β3 cytoplasmic domain were stably expressed in the 123 CHO cells harboring human glycoprotein Ib-IX and wild-type integrin αIIbβ3. The different cells were assayed for stable adhesion and spreading on immobilized fibrinogen, and for binding soluble fibrinogen representing outside-in and inside-out signaling events, respectively. The chimeric protein Tac-β3 inhibited, and Tac-β3DNITY partially attenuated stable adhesion and spreading. Tac-β3, Tac-β3D759, Tac-β3DNITY, and Tac-β3D754, but not Tac-β3D747 or Tac-β3D741, impaired the soluble fibrinogen binding. Results indicated that the bidirectional signaling was significantly inhibited by Tac-β3 and Tac-β3DNITY, albeit to a much lesser extent. Moreover, only inside-out signaling was impaired in the 123/Tac-β3D759 and 123/Tac-β3D754 cells in contrast to an intact bidirectional signaling in the 123/Tac-β3D747 and 123/Tac-β3D741 cells. In conclusion, the calpain cleavage of integrin β3 resulted in the regulatory effects on signaling by interrupting its interaction with cytoplasmic proteins rather than altering its conformation, and may thus regulate platelet function.

关键词： integrin β3 signal transduction trans-dominant inhibition model

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小型农业生态工程——庭院经济发展的数学模型

卞有生

《中国工程科学》 2000年第2卷第5期页码 60-65

摘要：

农业生态工程数学模型的任务在于提供对于系统现状及其功能、结构的认识，并用于预测系统即将发生的行为，进一步外加某种措施，对系统实施控制，以求达到它的最优化。文章通过理论研究和实践试验，建立了小型农业生态工程的数学模型。并以北京市大兴县留民营村一家农户为例，介绍小型农业生态工程的数学模型，及其在指导实际建设中的应用。

关键词：庭院经济数学模型农业生态工程

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A ruptured recurrent small bowel gastrointestinal stromal tumour causing hemoperitoneum

null

《医学前沿（英文）》 2015年第9卷第1期页码 108-111 doi: 10.1007/s11684-014-0344-0

摘要：

Hemoperitoneum is a rare and potentially life-threatening complication of GIST. We reported a 54-year-old man who developed disseminated intra-abdominal recurrence from a previously resected gastrointestinal stromal tumour (GIST) of the small bowel, and the patient presented with hemoperitoneum. Emergent debulking surgery was performed. A high dose imatinib was prescribed. Despite the presence of residual disease, the patient was well clinically 8 months after the operation. Even though, there is no evidence to support the routine use of debulking surgery in the management of GIST. In our patient, disease progression after second line targeted therapy and the absence of alternative treatment options for spontaneous rupture and hemoperitoneum prompted us to treat the patient aggressively. Resection of the ruptured GIST was carried out for control of bleeding and to prevent recurrent bleeding in this patient with good surgical risks. During the treatment decision-making, the patient’s general condition, the risk of surgery and the extent of dissemination were taken into consideration. In this patient who presented with spontaneous rupture of a small intestinal GIST, the novel use of targeted therapy and aggressive surgical treatment produced reasonably good survival outcome.

关键词： gastrointestinal stromal tumour hemoperitoneum small bowel GIST small bowel neoplasm imatinib

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Simulation and experimental improvement on a small-scale Stirling thermo-acoustic engine

Mao CHEN,Yonglin JU

《能源前沿（英文）》 2016年第10卷第1期页码 37-45 doi: 10.1007/s11708-015-0390-6

摘要： Compared with the traditional engines, the thermo-acoustic engines are relatively new and can act as the linear compressors for refrigerators. Many institutes have shown great interest in this kind of machine for its absence of moving mechanical part. In this paper, the influence of the dimensions of the main parts of the small-scale Stirling thermo-acoustic engine was numerically simulated using a computer code called DeltaEC. The resonator and the resonator cavity were found to be the most convenient and effective in improving the performance of the engine. Based on the numerical simulation, a small-scale Stirling thermo-acoustic engine were constructed and experimentally investigated. Currently, with a resonator length of only 1 m, the working frequency of the engine was decreased to 90 Hz and the onset temperature difference was decreased to 198.2 K.

关键词： thermo-acoustic Stirling engine small-scale simulation experiment

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CHARACTERISTICS OF HERBIVORY/WOUND-ELICITED ELECTRICAL SIGNAL TRANSDUCTION IN TOMATO

《农业科学与工程前沿（英文）》 2021年第8卷第2期

摘要：

Electrical signals commonly occur in plants in response to various environmental changes and have a dominant function in plant acclimation. The transduction of wound-elicited electrical signals in the model plant species Arabidopsis has been characterized but the characteristics of electrical signal transduction in response to herbivory or wounding in crop species remain unknown. Here, the features of electrical signals elicited by insect herbivory and wounding in tomato were investigated. Unlike those in Arabidopsis, wounding tomato leaves did not cause leaf-to-leaf electrical signal transduction. In contrast, electrical signals elicited in response to petiole wounding were stronger and more strongly transduced. Leaflet wounding also activated electrical signal transduction and jasmonic acid (JA) signaling within the whole compound leaf. It was also demonstrated that tomato glutamate receptor-like 3.3 (GLR3.3) and GLR3.5 mediated leaflet-to-leaflet electrical signal transduction. Herbivory-induced JA accumulation and Helicoverpa armigera resistance were reduced in glr3.3/3.5 plants. This work reveals the nature of electrical signal transduction in tomato and emphasizes the key roles of GLR3.3 and GLR3.5 in electrical signal transduction and JA signaling activation.

关键词： electrical signal / glutamate receptor-like / herbivory / jasmonic acid / tomato

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Discovery of small molecule degraders for modulating cell cycle

《医学前沿（英文）》页码 823-854 doi: 10.1007/s11684-023-1027-5

摘要： The cell cycle is a complex process that involves DNA replication, protein expression, and cell division. Dysregulation of the cell cycle is associated with various diseases. Cyclin-dependent kinases (CDKs) and their corresponding cyclins are major proteins that regulate the cell cycle. In contrast to inhibition, a new approach called proteolysis-targeting chimeras (PROTACs) and molecular glues can eliminate both enzymatic and scaffold functions of CDKs and cyclins, achieving targeted degradation. The field of PROTACs and molecular glues has developed rapidly in recent years. In this article, we aim to summarize the latest developments of CDKs and cyclin protein degraders. The selectivity, application, validation and the current state of each CDK degrader will be overviewed. Additionally, possible methods are discussed for the development of degraders for CDK members that still lack them. Overall, this article provides a comprehensive summary of the latest advancements in CDK and cyclin protein degraders, which will be helpful for researchers working on this topic.

关键词： PROTAC molecular glue degrader cell cycle CDK cyclin

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Fine-tuning cell organelle dynamics during mitosis by small GTPases

《医学前沿（英文）》 2022年第16卷第3期页码 339-357 doi: 10.1007/s11684-022-0926-1

摘要： During mitosis, the allocation of genetic material concurs with organelle transformation and distribution. The coordination of genetic material inheritance with organelle dynamics directs accurate mitotic progression, cell fate determination, and organismal homeostasis. Small GTPases belonging to the Ras superfamily regulate various cell organelles during division. Being the key regulators of membrane dynamics, the dysregulation of small GTPases is widely associated with cell organelle disruption in neoplastic and non-neoplastic diseases, such as cancer and Alzheimer’s disease. Recent discoveries shed light on the molecular properties of small GTPases as sophisticated modulators of a remarkably complex and perfect adaptors for rapid structure reformation. This review collects current knowledge on small GTPases in the regulation of cell organelles during mitosis and highlights the mediator role of small GTPase in transducing cell cycle signaling to organelle dynamics during mitosis.

关键词： small GTPase cell organelle mitosis

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Acoustic fault signal extraction via the line-defect phononic crystals

《机械工程前沿（英文）》 2022年第17卷第1期页码 10-10 doi: 10.1007/s11465-021-0666-y

摘要： Rotating machine fault signal extraction becomes increasingly important in practical engineering applications. However, fault signals with low signal-to-noise ratios (SNRs) are difficult to extract, especially at the early stage of fault diagnosis. In this paper, 2D line-defect phononic crystals (PCs) consisting of periodic acrylic tubes with slit are proposed for weak signal detection. The defect band, namely, the formed resonance band of line-defect PCs enables the incident acoustic wave at the resonance frequency to be trapped and enhanced at the resonance cavity. The noise can be filtered by the band gap. As a result, fault signals with high SNRs can be obtained for fault feature extraction. The effectiveness of weak harmonic and periodic impulse signal detection via line-defect PCs are investigated in numerical and experimental studies. All the numerical and experimental results indicate that line-defect PCs can be well used for extracting weak harmonic and periodic impulse signals. This work will provide potential for extracting weak signals in many practical engineering applications.

关键词： phononic crystals line-defect fault signal extraction acoustic enhancement

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Concurrent fatigue crack growth simulation using extended finite element method

Zizi LU, Yongming LIU,

《结构与土木工程前沿（英文）》 2010年第4卷第3期页码 339-347 doi: 10.1007/s11709-010-0078-2

摘要： In this paper, a concurrent simulation framework for fatigue crack growth analysis is proposed using a novel small time scale model for fatigue mechanism analysis and the extended finite element method (X-FEM) for fatigue crack growth simulation. The proposed small time scale fatigue model does not require the cycle counting as those using the classical fatigue analysis methods and can be performed concurrently with structural/mechanical analysis. The X-FEM greatly facilitates crack growth simulation without remeshing requirements ahead of the crack tip as in the classical finite element method. The basic concept and theory of X-FEM was briefly introduced and numerical predictions of stress intensity factors are verified with reference solutions under both uniaxial and multiaxial loadings. The small time scale fatigue model is integrated into the numerical simulation algorithm for concurrent fatigue crack growth analysis. Model predictions are compared with available experimental observations for model validation.

关键词： small time scale model extended finite element method (X-FEM) crack growth multiaxial

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Gut microbiota and its implications in small bowel transplantation

null

《医学前沿（英文）》 2018年第12卷第3期页码 239-248 doi: 10.1007/s11684-018-0617-0

摘要：

The gut microbiota is mainly composed of a diverse population of commensal bacterial species and plays a pivotal role in the maintenance of intestinal homeostasis, immune modulation and metabolism. The influence of the gut microbiota on solid organ transplantation has recently been recognized. In fact, several studies indicated that acute and chronic allograft rejection in small bowel transplantation (SBT) is closely associated with the alterations in microbial patterns in the gut. In this review, we focused on the recent findings regarding alterations in the microbiota following SBT and the potential roles of these alterations in the development of acute and chronic allograft rejection. We also reviewed important advances with respect to the interplays between the microbiota and host immune systems in SBT. Furthermore, we explored the potential of the gut microbiota as a microbial marker and/or therapeutic target for the predication and intervention of allograft rejection and chronic dysfunction. Given that current research on the gut microbiota has become increasingly sophisticated and comprehensive, large cohort studies employing metagenomic analysis and multivariate linkage should be designed for the characterization of host–microbe interaction and causality between microbiota alterations and clinical outcomes in SBT. The findings are expected to provide valuable insights into the role of gut microbiota in the development of allograft rejection and other transplant-related complications and introduce novel therapeutic targets and treatment approaches in clinical practice.

关键词： gut microbiota small bowel transplantation acute rejection chronic rejection mucosal immunity biomarker microbiota-targeted therapy

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提高地下金属管振动波测试中冲击响应信号的信噪比

韩修廷,王洁春,焦振强,高飞,宋宇波

《中国工程科学》 2005年第7卷第10期页码 64-68

摘要：

提出了在套损振动波检测过程中提高信号信噪比的方法。检测过程中，在井口敲击套管并接收、分析套管的回波，以了解介质的变化情况。由于反射波信号强度较微弱，单纯用一组接收信号无法进行正确的套损分析，采用信号增强方法，即利用多个类似信号进行叠加，增强反射波的有效信号，降低背景噪声，从而得到有用信息，进行正确的套损状况分析。开发了相应的信号处理软件，提高了信号处理速度。通过10井次的测试表明，技术原理可行，软件工作稳定、可靠，便于操作，可以进行多种方法的信号处理，极大地提高了工作效率。

关键词：振动波反射波信号增强信号叠加