Synthesis and Application of a Polyamide-containing Phosphorous and Sulfur Flame-retardant for Nylon Fabric

Xiangdong Zhou,Yufa Sun,Yingchun Chen,Bing Sun 한국고분자학회 2018 폴리머 Vol.42 No.2

Monomer of polyamide (PA66) and flame-retardant intermediate product (FR) were firstly synthesized, and the flame-retardant (PA-FR) was further gained by polymerization of PA66 and FR. The structure of PA-FR was confirmed by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), X-ray photoelectron spectroscopy (XPS), and gel permeation chromatography (GPC). The thermal properties of PA-FR and the finished fabric were evaluated by thermal gravity analysis (TGA) and differential scanning calorimetry (DSC). Moreover, X-ray diffraction analysis (XRD) showed that melting eutectic reaction occurred between PA-FR and nylon fabric. The experimental results showed that the limiting oxygen index (LOI) value of PA-FR treated fabric and PA-FR treated fabric after 10 laundries were improved to 28.8% and 26.4%, respectively. It implied that PA-FR had a good and durable function of imparting fire-resistance to nylon fabric.

Variable frequency triple-phase-shift modulation strategy for minimizing RMS current in dual-active-bridge DC-DC converters

Sun, Xiangdong,Wang, Zhixuan,Zhang, Qi,Chen, Guitao The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.2

For dual-active-bridge (DAB) DC-DC converters, a variable frequency triple-phase-shift (VF-TPS) modulation strategy based on a particle swarm optimization (PSO) algorithm was proposed to solve the problem of the low efficiency of TPS modulation in larger power conditions. To facilitate the implementation of the PSO algorithm, the mathematical expressions between the transmission power or the RMS square of the inductance current and four control variables including the switching frequency and three phase-shift duty cycles are simplified by the Fourier series decomposition method. An objective function of the particle fitness is presented to find the optimal control variables at any reference transmission power, which achieves the minimum inductance RMS current in the full power range and improves the efficiency under heavy loads. In addition, the PSO algorithm is used to design the appropriate switching frequency range and inductance. Finally, a 1.2 kW DAB converter prototype was established, and experimental results verify the correctness and feasibility of the modulation strategy.

Neural Network of Plume and Spatter for Monitoring High-Power Disk Laser Welding

Xiangdong Gao,Yan Sun,Seiji Katayama 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.1 No.4

Using multi-characteristic information fusion based on a BP (back propagation) NN (neural network) of the plume and spatters to monitor the high-power disk laser welding of type 304 austenitic stainless steel is presented. An ultraviolet and visible sensitive high-speed video camera was used to capture the dynamic images of laser welding plume and spatters during laser welding. The number and area of spatters, and the area, height, tilt angle and centroid of plume were calculated by using image processing technology and defined as the characteristic parameters of plume and spatters, which were used as inputs of the neural network. The weld bead width was considered as a parameter reflecting the welding status, which was used as output of the neural network. Relations of plume and spatters with laser welding status was established by a BP neural network and experimental results showed that the proposed method could effectively estimate the high-power disk laser welding status when the laser power ranged from 2 kW to 10 kW.

중국 섬서성에서 산출된 오르도비스기 산호해면 화석

Ning Sun,이동진,R.J. Elias,Xiangdong Wang 한국고생물학회 2009 정기총회 및 학술발표회 Vol.2009 No.-

Matching network design for input impedance optimization of four‑coil magnetic resonance coupling wireless power transfer systems

Zhixuan Wang,Xiangdong Sun,Qi Zhang,Zechi Chen 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.9

The input impedance of a four-coil magnetic resonance coupling wireless power transfer (MRC–WPT) system is in the form of parallel resonance at the optimal operating frequency. When the operating frequency deviates slightly, the system input impedance decreases rapidly. At this time, if a voltage source radio frequency power amplifier (RFPA) is used as the excitation power supply, the operating current is increased, which is not conducive to device safety. In this paper, a matching network is designed and inserted between the power supply and the MRC–WPT circuit to convert the input impedance into a series resonant form, so the MRC–WPT circuit can be safely connected to the voltage source RFPA. Finally, an experimental prototype is built to verify the applicability of the proposed matching network.

Value of Exhaled Nitric Oxide and FEF25–75 in Identifying Factors Associated With Chronic Cough in Allergic Rhinitis

Xiaofang Liu,Xiangdong Wang,Xiujuan Yao,Yuhong Wang,Yongchang Sun,Luo Zhang 대한천식알레르기학회 2019 Allergy, Asthma & Immunology Research Vol.11 No.6

Purpose: Chronic cough in allergic rhinitis (AR) patients is common with multiple etiologies including cough variant asthma (CVA), non-asthmatic eosinophilic bronchitis (NAEB), gastroesophageal reflux-related cough (GERC), and upper airway cough syndrome (UACS). Practical indicators that distinguish these categories are lacking. We aimed to explore the diagnostic value of the fraction of exhaled nitric oxide (FeNO) and forced expiratory flow at 25% and 75% of pulmonary volume (FEF25–75) in specifically identifying CVA and NAEB in these patients. Methods: Consecutive AR patients with chronic cough were screened and underwent induced sputum, FeNO, nasal nitric oxide, spirometry, and methacholine bronchial provocation testing. All patients also completed gastroesophageal reflux disease questionnaires. Results: Among 1,680 AR patients, 324 (19.3%) were identified with chronic cough, of whom 316 (97.5%) underwent etiology analyses. Overall, 87 (27.5%) patients had chronic cough caused by NAEB, 78 (24.7%) by CVA, 16 (5.1%) by GERC, and 81 (25.6%) by UACS. Patients with either NAEB or CVA (n = 165, in total) were further assigned to a common group designated as CVA/NAEB, because they both responded to corticosteroid therapy. Receiver operating characteristic curves of FeNO revealed obvious differences among CVA, NAEB, and CVA/NAEB (area under the curve = 0.855, 0.699, and 0.923, respectively). The cutoff values of FeNO at 43.5 and 32.5 ppb were shown to best differentiate CVA and CVA/NAEB, respectively. FEF25–75 was significantly lower in patients with CVA than in those with other causes. A FEF25–75 value of 74.6% showed good sensitivity and specificity for identifying patients with CVA. Conclusions: NAEB, CVA, and UACS are common causes of chronic cough in patients with AR. FeNO can first be used to discriminate patients with CVA/NAEB, then FEF25–75 (or combined with FeNO) can further discriminate patients with CVA from those with CVA/NAEB.

Study of the sympathetic detonation reaction behavior of a fuze explosive train under the impact of blast fragments

Youcai Xiao,Xiangdong Xiao,Chenyang Fan,Yanyi Xiong,Zhijun Wang,Yi Sun 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6

Insensitive munitions (IM) assessments are required to carry out the sympathetic detonation (SD) experiments. The impact of blast fragments or strong shock waves is the cause of sympathetic detonation. In this paper, a numerical simulation method is developed to predict the sympathetic detonation behavior of fuze explosive trains under the impact of blast fragments, which includes the ignition and growth (I&G) model, the JonesWilkins-Lee (JWL) equations of state, and a constitutive relationship. The experimental and numerical results were compared and analyzed, and the validity of the numerical simulation method was proven. The sympathetic detonation behavior of a fuze was studied for a single donor and multiple acceptors. The critical distance was obtained with the presence of fragments using numerical simulation. A critical distance model was developed, which provides a theoretical model for relating the detonation sequence and the placement distance of the fuze explosive train. The simulated results agreed with the theoretical calculations, and thus the model can provide the support for sympathetic detonation experiments.

Neutral Point Voltage-Balanced Control Method Based on Discontinuous Pulse Width Modulation for a NPC 3-level Inverter

Shaoliang An,Lu Lai,Xiangdong Sun,Yanru Zhong,Biying Ren,Qi Zhang 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

A neutral point voltage-balancing control algorithm is proposed for a neutral-point-clamped (NPC) three-level photovoltaic (PV) grid-connected inverter. The mathematical model of the neutral point current was deduced. The influence on the neutral point voltage for discontinuous pulse width modulation(DPWM) methods was analyzed. Comparison of the error between feedback neutral point voltages and the hysteresis width was used to choose a DPWM method to control the neutral point voltage. Simulation and experimental results verify the correctness and validity of the proposed neutral point voltage-balancing control algorithm.

On-line Identification Methods of Parameters for Permanent Magnet Synchronous Motors Based on Cascade MRAS

Yanqing Zhang,Zhonggang Yin,Xiangdong Sun,Yanru Zhong 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

Motor parameters should be on-line estimated to realize precise control of PMSM in sensorless vector control system. In this paper, an on-line identification method for PMSM parameters based on cascade MRAS is proposed by analyzing the conventional MRAS. By means of Popov’s hyper-stability theory, the model of motor parameters identification is built in synchronous d-q coordinates, and PMSM stator voltage, stator current and their errors are used to obtain the adaptive laws of motor parameters, and it is realizable to estimate rotor speed, stator resistance and rotor flux at the same time. The simulation results demonstrate the correctness and effectiveness of the proposed method.

Synthesis and Application of Polyurethane-Modified Silicone as Finishing Agent for Cotton Fabric

Wenwen Lei,Yufa Sun,Bin Huang,Xiangdong Zhou 한국섬유공학회 2018 Fibers and polymers Vol.19 No.5

The polyurethane modified organic silicone (PU-SA) was successfully synthesized via step-by-step polymerization with isophorone diisocyanate (IPDI) and polypropylene glycol (PPG) used as monomers, dibutyltindilaurate (DBTDL) as the catalyst, trimethylolpropane (TMP) and N-methyldiethanolamine (MDEA) as the chain extender, and amino-terminated siloxane (SA) as the blocking agent. The chemical structure of PU-SA was characterized by Fourier transform infrared spectroscopy (FT-IR). X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) showed that PUSA had been successfully finished on the surface. Additionally, the thermogravimetric analysis (TGA) demonstrated that the PU-SA treated fabrics showed low decomposition temperature and slightly high char residue. As a finishing agent, the effect of PU-SA on the handle of cotton fabrics was also studied by using a Kawabata Evaluation System for Fabrics (KES-F). The experimental results found that PU-SA had a significant improvement on the bending properties, surface properties, and compressional properties. Moreover, the mechanical and anti-wrinkle properties of the cotton fabrics were also enhanced.