Seismic Performance of Welded Steel Beam-to-Column Connections with Initial Weld Defects

Jiaming Li,Haoran Yu,Weibin Li,Weijia Cheng 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.2

Based on the research of steel structures destroyed in earthquakes, it is often found that brittle fractures of the bottom beam fl anges of welded beam-to-column connections are caused by welding defects. In this study, artifi cial surface notches in the welds of single beam fl anges were prepared, and four experimental specimens of welded steel beam-to-column connections were tested to explore the eff ects of the initial crack and three diff erent connection types on the seismic performance of the connections. Through extended fi nite element methods, the factor of the depth of the initial crack was discussed. The results showed that the fracture mode and the rate and location of crack propagation are signifi cantly changed, and the seismic performance of the connections is reduced when there is an initial crack existing in the weld of a single beam fl ange. The fracture in box beam to box column connections shows brittle failure regardless of the initial crack, but the depth of the initial crack has the least infl uence on their seismic performance among the three connection types. The seismic performance of H-shaped beam to H-shaped column connections is the most sensitive to the depth of the initial crack. It should be noted that the weld quality of steel beam-to-column connections, especially the connections with H-shaped columns, should be carefully checked and monitored during the welding construction process and after earthquakes to ensure the bearing and deformation capacities meeting the requirements.

Unidirectional sensitive flexible sensor for bending measurements

Li Mengmeng,Liang Jiaming,Min Zhang 한국물리학회 2021 Current Applied Physics Vol.23 No.-

The measurement of bending direction and bending angles is essential in the multiaxial servo-controlled system, especially for collaborative robots. However, most flexible sensors developed for bending measurements cannot distinguish bending directions due to their sensitivity to both positive and negative bending. Also, these sensors usually exhibit simultaneous response to normal pressure, which results in additional calibration. Here, a unidirectional-sensitive flexible capacitive sensor is proposed. A simple asymmetric pyramidal microstructure was designed to create uneven responses to positive and negative bending and minimum response to normal pressure based on the fringe effect. The fabricated sensor shows a relative capacitance change of nearly 0.9 in the sensitive direction and only 0.05 in the other direction as the sensor bends from flat to the curvature radius of 10 mm. Also, the sensor shows negligible sensitivity even under a normal pressure force as high as 16 N, either in planar or bending condition.

Novel impedance matching method based on negative resistors for WPT

Li, Yang,Liu, Jiaming,Jiang, Shan,Ni, Xin,Ma, Jingnan,Wang, Rui,Sha, Lin The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.4

In a wireless power transfer (WPT) system via coupled magnetic resonance, the transmission power and efficiency dramatically decrease with increased in the transfer distance and load variations. In the conventional impedance matching method, different resistors are matched by adjusting passive devices such as capacitors and inductors. The corresponding matching range changes with different topological network structures. In particular, there exists a matching forbidden zone. In this paper, a novel impedance matching method based on a negative resistor is proposed to match the impedance in the forbidden zone. First, the conventional impedance matching network is analyzed based on circuit theory. Then, the feasibility of the proposed method is verified. In addition, the receiving power obtained using the conventional matching method is compared with that obtained using the proposed method. It is theoretically verified that the novel method can break the upper power limit related to the conventional method, which realizes a higher receiving power. A prototype was built in the laboratory. Experimental results show the feasibility of the novel method. Moreover, derived simulation results were basically consistent with the experimental values, which also demonstrates the validity of the proposed method.

Calibration of Underwater Polarization Image Based on the Radian of Distorted Curves in the Checkboard

Jiaming Wei,Qi Li,Lili Zhang 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.8

The calibration of polarization imaging system is the premise to obtain target polarization information accurately, in this paper, we propose a method of calibration based on the radian of distorted curves in the checkboard to solve the problem of losing polarization information in the underwater distorted polarization images. Firstly, we use the radian of distorted curves in the checkboard to calculate the coordinates of distortion center, and calibrate the region near the distortion center. Then we use the calibrated region to reconstruct the whole image. Finally, we combine the distorted image, the reconstructed image and the distortion model to obtain the calibration parameters. With these parameters we can get the calibrated polarization images. The experiments show that our method can calibrate the polarization image accurately, reduce the coupled error and calculate parameters independently.

Adaptive Pinning Synchronization of Complex Networks with Partial Delay and Noise Coupling

Wang Li,Yue Qiao,Jiaming Wu,Hongjun Shi,Yongzheng Sun 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.1

In this paper, we investigate the adaptive pinning synchronization of complex networks with partial delay and noise coupling. First, more realistic complex networks with partial delay and noise perturbation are established. Combining the advantages of the adaptive control method and pinning control technology, a novel coupling is designed to realize the synchronization. Several sufficient criteria for almost sure outer synchronization are developed based on the LaSalle invariance principle for stochastic differential equations. Finally, numerical simulations are performed to verify the effectiveness of the proposed synchronization scheme.

Changes in Enteric Neurons of Small Intestine in a Rat Model of Irritable Bowel Syndrome with Diarrhea

( Shan Li ),( Guijun Fei ),( Xiucai Fang ),( Xilin Yang ),( Xiaohong Sun ),( Jiaming Qian ),( Jackie D Wood ),( Meiyun Ke ) 대한소화기기능성질환·운동학회 2016 Journal of Neurogastroenterology and Motility (JNM Vol.22 No.2

Background/Aims Physical and/or emotional stresses are important factors in the exacerbation of symptoms in irritable bowel syndrome (IBS). Several lines of evidence support that a major impact of stress on the gastrointestinal tract occurs via the enteric nervous system. We aimed to evaluate histological changes in the submucosal plexus (SMP) and myenteric plexus (MP) of the distal ileum in concert with the intestinal motor function in a rat model of IBS with diarrhea. Methods The rat model was induced by heterotypic chronic and acute stress (CAS). The intestinal transit was measured by administering powdered carbon by gastric gavage. Double immunohistochemical fluorescence staining with whole-mount preparations of SMP and MP of enteric nervous system was used to assess changes in expression of choline acetyltransferase, vasoactive intestinal peptide, or nitric oxide synthase in relation to the pan neuronal marker, anti-Hu. Results The intestinal transit ratio increased significantly from control values of 50.8% to 60.6% in the CAS group. The numbers of enteric ganglia and neurons in the SMP were increased in the CAS group. The proportions of choline acetyltransferase- and vasoactive intestinal peptide-immunoreactive neurons in the SMP were increased (82.1 ± 4.3% vs. 76.0 ± 5.0%, P = 0.021; 40.5 ± 5.9% vs 28.9 ± 3.7%, P = 0.001), while nitric oxide synthase-immunoreactive neurons in the MP were decreased compared with controls (23.3 ± 4.5% vs 32.4 ± 4.5%, P = 0.002). Conclusions These morphological changes in enteric neurons to CAS might contribute to the dysfunction in motility and secretion in IBS with diarrhea. (J Neurogastroenterol Motil 2016;22:310-320)

T-spline surface smoothing based on 1-ring neighborhood space angle

Wang Aizeng,Li Ling,Chang Heng,Zhao Gang,Wang Wei,Yang Jiaming 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.4

The prominent properties owned by T-spline, such as flexibility, continuity, local refinement, water tightness, make it extensively applied in Computer Aided Design (CAD)- and Computer Aided Engineering (CAE)-integrating scenarios. But the local fairness may dissatisfy in damaged areas or even on the entire surface of industry applications. Under these circumstances, local protrusion and sharp features appeared seriously affect the fairness of T-spline surfaces. Derived from the geometric properties of T-spline control points, we propose a smoothing algorithm based on the 1-ring neighborhood space angle to deal with local abruptions of T-spline surfaces. We also demonstrate the availability of the proposed algorithm through several experiments. Results show that this method is suitable for removing sharp features and smoothing unstructured T-spline surfaces.

Optimization design of graphene with adjustable hydrophilic properties by finite elements analysis

Shixun Sun,Jiaming Song,Naiyu Cui,Xinyue Lu,Xuehan Li,Heng Zhang,Heng Bo Jiang 대한치과재료학회 2021 대한치과기재학회 학술대회 Vol.2021 No.4

PREPARATION OF FOLATE-CONJUGATED BOVINE SERUM ALBUMIN NANOPARTICLES ADSORBING EPIRUBICIN HYDROCHLORIDE

XIUHUA ZHAO,JIAMING TANG,YUANGANG ZU,WEIGUO WANG,NA LI,WENJIA XU 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2013 NANO Vol.8 No.6

This work investigated the preparation process of folate-conjugated bovine serum albumin nanoparticles (FA–BSANPs) adsorbing epirubicin hydrochloride (EPI) nanoparticles (FA–EPI–BSANPs), a specific-targeting drug delivery system in cancer chemotherapy. The BSANPs were prepared by desolvation as a drug carrier system and conjugated with folate to produce FA–EPI–BSANPs that specifically target tumors by cross-linking. EPI, an anticancer drug, was adsorbed by this drug carrier system. The influences of six experimental parameters, namely, the adsorption time, FA–BSANPs solution-adsorbed EPI concentration, stirring speed, FA–BSANPs solution pH, the ratio of glutaraldehyde and BSA, and mass ratio of FA–BSANPs to EPI, on the drug loading efficiency (DLR) and drug entrapment efficiency (DER) of FA–EPI–BSANPs were investigated via the single factor method. The results indicated that the optimum operation conditions were obtained with 145.4 nm±0.5 nm MPS, 23.41% DLR and 98.93% DER. The N-hydroxysuccinimide-folate content associated with BSANPs was up to 0.9757% (wt). The DLR and DER of EPI increased with increasing adsorption time, FA–BSANPs solution concentration, and pH value, peaking at 1750 rpm with increasing stirring speed, but decreasing thereafter. The FA–EPI–BSANPs obtained were characterized by laser light scattering, scanning electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction and thermogravimetric analysis. Drug release in vitro was investigated, as well. The characterization results showed that EPI in FA–EPI–BSANPs existed in an amorphous, instead of crystalline state. Most of the EPI was enclosed by FA–BSANPs, and a small amount was adsorbed onto the surface of the FA–BSANPs. The FA–EPI–BSANPs particles are nearly ellipsoidal and significantly affect sustained release. The inhibitory rate of FA–EPI–BSANP was mensurated by MTT method. The inhibitory rate of FA–EPI–BSANPs for SMMC 7721 cell developed with raise of concentration and was higher than other samples. The IC50 values of FA–EPI–BSANPs and EPI were 11.5 μg/mL and 18.8 μg/mL, respectively. The target ability of FA–EPI–BSANP for SMMC 7721 cell was mensurated by fluorescence (FITC) modified albumin techniques. The uptake rate of FA–EPI–BSANPs was higher than samples without folate conjugated, and increased with increased concentration.

Low-Power, Self-Rectifying, and Forming-Free Memristor with an Asymmetric Programing Voltage for a High-Density Crossbar Application

Kim, Kyung Min,Zhang, Jiaming,Graves, Catherine,Yang, J. Joshua,Choi, Byung Joon,Hwang, Cheol Seong,Li, Zhiyong,Williams, R. Stanley American Chemical Society 2016 NANO LETTERS Vol.16 No.11

<P>A Pt/NbOx/TiOy/NbOx/TiN stack integrated on a 30 nm contact via shows a programming current as low as 10 nA and 1 pA for the set and reset switching, respectively, and a self-rectifying ratio as high as similar to 10(5), which are suitable characteristics for low-power memristor applications. It also shows a forming-free characteristic. A charge-trap-associated switching model is proposed to account for this self-rectifying memrisive behavior. In addition, an asymmetric voltage scheme (AVS) to decrease the write power consumption by utilizing this self-rectifying memristor is also described. When the device is used in a 1000 x 1000 crossbar array with the AVS, the programming power can be decreased to 8.0% of the power consumption of a conventional biasing scheme. If the AVS is combined with a nonlinear selector, a power consumption reduction to 0.31% of the reference value is possible.</P>