Research Cage Wind Turbines’ Dynamic Characteristics Based on Time-varying Parameters

Gu Bo,Liu Yongqian,Xu Qiang,Kang Shun 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.10

According to the characteristics of cage wind turbines’ dynamic characteristics which change following the wind speed changes, the dynamic mathematical models of cage wind turbines major subsystems have been established, including the aerodynamic subsystem model, drive train subsystem model and generator subsystem model. Then these nonlinear dynamic models with time-varying parameters have been integrated and linearized to obtain the whole linear time-varying parameters dynamic mathematical model. To take the 2MW cage wind turbines wind turbine as example, the proposed model is validated by the study on the dynamic characteristics of cage wind turbines with wind speed variation , and the results show that the proposed model could provide a theoretical support for optimal control of the cage wind turbines.

A structure-based approach to evaluation product adaptability in adaptable design

Qiang Cheng,Guojun Zhang,Zhifeng Liu,Peihua Gu,Ligang Cai 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.5

Adaptable design, as a new design paradigm, involves creating designs and products that can be easily changed to satisfy different requirements. In this paper, two types of product adaptability are proposed as essential adaptability and behavioral adaptability, and through measuring which respectively a model for product adaptability evaluation is developed. The essential adaptability evaluation proceeds with analyzing the independencies of function requirements and function modules firstly based on axiomatic design, and measuring the adaptability of interfaces secondly with three indices. The behavioral adaptability reflected by the performance of adaptable requirements after adaptation is measured based on Kano model. At last, the effectiveness of the proposed method is demonstrated by an illustrative example of the motherboard of a personal computer. The results show that the method can evaluate and reveal the adaptability of a product in essence, and is of directive significance to improving design and innovative design.

Damage constitutive model of brittle rock considering the compaction of crack

Gu, Qingheng,Ning, Jianguo,Tan, Yunliang,Liu, Xuesheng,Ma, Qing,Xu, Qiang Techno-Press 2018 Geomechanics & engineering Vol.15 No.5

The deformation and strength of brittle rocks are significantly influenced by the crack closure behavior. The relationship between the strength and deformation of rocks under uniaxial loading is the foundation for design and assessment of such scenarios. The concept of relative crack closure strain was proposed to describe the influence of the crack closure behavior on the deformation and strength of rocks. Considering the crack compaction effect, a new damage constitutive model was developed based on accumulated AE counts. First, a damage variable based on the accumulated AE counts was introduced, and the damage evolution equations for the four types of brittle rocks were then derived. Second, a compaction coefficient was proposed to describe the compaction degree and a correction factor was proposed to correct the error in the effective elastic modulus instead of the elastic modulus of the rock without new damage. Finally, the compaction coefficient and correction factor were used to modify the damage constitutive model obtained using the Lemaitre strain equivalence hypothesis. The fitted results of the models were then compared with the experimental data. The results showed that the uniaxial compressive strength and effective elastic modulus decrease with an increase in the relative crack closure strain. The values of the damage variables increase exponentially with strains. The modified damage constitutive equation can be used to more accurately describe the compressive deformation (particularly the compaction stage) of the four types of brittle rocks, with a coefficient of determination greater than 0.9.

Three new species of spiders of Erigoninae(Araneae:Linyphiidae)from China

Xia Qiang,Zhang Gu-Ren,Gao Jiu-Chun,Fei Rui,Joo-Pil Kim 한국거미연구소 2001 한국거미 Vol.17 No.2

Cyclic behavior of steel beam-concrete wall connections with embedded steel columns (I): Experimental study

Guo-Qiang Li,Fulin Gu,Jian Jiang,Feifei Sun 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.23 No.4

This paper experimentally studies the cyclic behavior of hybrid connections between steel coupling beams and concrete shear walls with embedded steel columns. Four beam-to-wall connection specimens with short and long embedded steel columns are tested under monotonic and cyclic loads, respectively. The influence of embedment length of columns on the failure mode and performance of connections is investigated. The results show that the length of embedded steel columns has significant effect on the failure mode of connections. A connection with a long embedded column has a better stiffness, loadbearing capacity and ductility than that of a short embedded column. The former fails due to the shear yielding of column web in the joint panel, while failure of the latter is initiated by the yielding of horizontal reinforcement in the wall due to the rigid rotation of the column. It is recommended that embedded steel columns should be placed along the entire height of shear walls to facilitate construction and enhance the ductility.

Effect of Mechanical Alloying and Sintering Behavior on the Microstructure and Properties of NbMoTaWRe Refractory High Entropy Alloy

Tao Gu,Li‑Min Wang,Qiang Hu,Xiu‑Bing Liang,Dong‑Xing Fu,Yong‑Xiong Chen,Xin‑Ming Zhao,Yan‑Wei Sheng 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.11

An equiatomic refractory high-entropy alloy (RHEA) NbMoTaWRe is prepared by mechanical alloying (MA) and sparkplasma sintering (SPS). The effects of mechanical alloying and sintering behaviors on the microstructure and propertiesof the RHEA are investigated. After ball-milling for 30 h, the metastable and supersaturated MA powders with the bodycenteredcubic (BCC) structure are obtained. Then, the MA powders are sintered using the SPS method under the sinteringtemperature range of 1700–1900 °C, and the C atoms and WC introduced by the MA process reacts with the metastable andsupersaturated Ta/Nb phase of the MA powers to form the face-centered cubic (FCC) structure (Nb, Ta)C particles alongthe BCC matrix boundaries during the SPS process. The NbMoTaWRe alloy sintered at 1800 °C consisted of BCC matrixand FCC-type (Nb, Ta)C particles has high compactness (porosity fraction is 0.32%), fracture strength (2630 MPa), plasticstrain (6.82%), and hardness (992 ± 20 HV). These excellent properties of this RHEA are mainly attributed to the combinationof multi-effects, including sintering densification, grain refinement strengthening from the refined sizes (3.80 μm) BCCmatrix, precipitation strengthening from the (Nb, Ta)C particles, solid solution strengthening from multi-principal elementsand interstitial solid solution strengthening from C atoms dissolving into BCC matrix.

Ancient Chinese Fangzhongshu (Sexual Skills and Methods) Therapy for Premature Ejaculation

Yong Zhu,Qiang Chen,Yuexing Gu,Jin Yue,Qingqi Zeng 대한남성과학회 2016 The World Journal of Men's Health Vol.34 No.3

Premature ejaculation (PE) is a common male sexual dysfunction that can have significant effects on a couple’s relationship. Behavioral therapy and psychotherapy are both safe and effective methods of treating PE. Ancient Chinese fangzhongshu (sexual skills and methods), which reflects a summary of expert experiences in sexology, contains many therapies for sexual dysfunction that are similar to those used in behavioral therapy or psychotherapy. A brief introduction dealing with the latest definitions of PE and treatment strategies drawn from behavioral therapy and psychotherapy is provided. Typical therapies for PE from ancient Chinese fangzhongshu are listed and briefly analyzed in order to define their domain of applicability and instructions for use. Ancient Chinese fangzhongshu contains many effective and safe therapies for PE. It should be incorporated into modern medical practice after critical analysis, and its scientific aspects should be promoted as a way of improving reproductive health, both to benefit individuals affected by PE and to promote traditional Chinese culture. Based on an analysis of the condition of the individual patient, one or multiple therapies guided by fangzhongshu can be expected to have an effect on the patient. Ancient Chinese fangzhongshu is of great value and should to be popularized and applied as a remedy for PE.

Expression of the Arabidopsis vacuolar $H^+$-pyrophosphatase gene AVP1 in peanut to improve drought and salt tolerance

Qin, Hua,Gu, Qiang,Kuppu, Sundaram,Sun, Li,Zhu, Xunlu,Mishra, Neelam,Hu, Rongbin,Shen, Guoxin,Zhang, Junling,Zhang, Yizheng,Zhu, Longfu,Zhang, Xianlong,Burow, Mark,Payton, Paxton,Zhang, Hong 한국식물생명공학회 2013 Plant biotechnology reports Vol.7 No.3

The Arabidopsis gene AVP1 encodes an $H^+$-pyrophosphatase that functions as a proton pump at the vacuolar membranes, generating a proton gradient across vacuolar membranes, which serves as the driving force for many secondary transporters on vacuolar membranes such as $Na^+/H^+$-antiporters. Overexpression of AVP1 could improve drought tolerance and salt tolerance in transgenic plants, suggesting a possible way in improving drought and salt tolerance in crops. The AVP1 was therefore introduced into peanut by Agrobacterium-mediated transformation. Analysis of AVP1-expressing peanut indicated that AVP1-overexpression in peanut could improve both drought and salt tolerance in greenhouse and growth chamber conditions, as AVP1-overexpressing peanuts produced more biomass and maintained higher photosynthetic rates under both drought and salt conditions. In the field, AVP1-overexpressing peanuts also outperformed wild-type plants by having higher photosynthetic rates and producing higher yields under low irrigation conditions.

Bonding and Etchback Silicon-on-Diamond Technology

Jin, Zengsun,Gu, Changzhi,Meng, Qiang,Lu, Xiangyi,Zou, Guangtian,Lu, Jianxial,Yao, Da,Su, Xiudi,Xu, Zhongde The Korean Ceramic Society 1997 The Korean journal of ceramics Vol.3 No.1

The fabrication process of silicon-diamond(SOD) structure wafer were studied. Microwave plasma chemical vapor deposition (MWPCVD) and annealing technology were used to synthesize diamond film with high resistivity and thermal conductivity. Bonding and etchback silicon-on-diamond (BESOD) were utilized to form supporting substrate and single silicon thin layer of SOD wafer. At last, a SOD structure wafer with 0.3~1$\mu\textrm{m}$ silicon film and 2$\mu\textrm{m}$ diamond film was prepared. The characteristics of radiation for a CMOS integrated circuit (IC) fabricated by SOD wafer were studied.

Expression of the Arabidopsis vacuolar H+-pyrophosphatase gene AVP1 in peanut to improve drought and salt tolerance

Huaqin Sun,Qiang Gu,Sundaram Kuppu,Li Sun,Xunlu Zhu,Neelam Mishra,Rongbin Hu,Guoxin Shen,Junling Zhang,Yizheng Zhang,Longfu Zhu,Xianlong Zhang,Mark Burow,Paxton Payton,Hong Zhang 한국식물생명공학회 2013 Plant biotechnology reports Vol.7 No.3

The Arabidopsis gene AVP1 encodes an H?-pyrophosphatase that functions as a proton pump at thevacuolar membranes, generating a proton gradient acrossvacuolar membranes, which serves as the driving force formany secondary transporters on vacuolar membranes suchas Na?/H?-antiporters. Overexpression of AVP1 couldimprove drought tolerance and salt tolerance in transgenicplants, suggesting a possible way in improving drought andsalt tolerance in crops. The AVP1 was therefore introducedinto peanut by Agrobacterium-mediated transformation. Analysis of AVP1-expressing peanut indicated that AVP1-overexpression in peanut could improve both droughtand salt tolerance in greenhouse and growth chamberconditions, as AVP1-overexpressing peanuts producedmore biomass and maintained higher photosynthetic ratesunder both drought and salt conditions. In the field, AVP1-overexpressing peanuts also outperformed wild-type plantsby having higher photosynthetic rates and producing higheryields under low irrigation conditions.