Regional Landslide Susceptibility Assessment Based on Combined Model with Certainty Factor Method

( Peihua Xu ),( Guang Yang ),( Chen Cao ),( Wen Zhang ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2

This paper takes the case of Diexi Township to Shidaguan Township, Maoxian County, Sichuan Province as the research area. According to the field data and the basic conditions of the study area, 10 impact factors such as the slope, slope direction, section curvature, elevation, undulation, stratum, distance from the river, distance from the fault, land type and vegetation coverage are selected. Using GIS technology as the operating platform, three methods, i.e., deterministic coefficient + analytic hierarchy process (CF-AHP), deterministic coefficient + logistic regression method (CF-LR) and deterministic coefficient + multi-layer perceptron method of neural network (CF-MLP), were used to evaluate the sensitivity of landslide hazard in the study area. The landslide hazard in this area was divided into four categories: extremely low, low, medium and high sensitive areas, and the effect of the model was tested by receiver operating characteristic curve (ROC). The under-line area (AUC) of the ROC curves of the CF-AHP, CF-LR and CF-MLP combined models were 0.850, 0.884 and 0.867, respectively. The CF-LR combination model worked best. In the CF-LR combination model, the areas of high sensitive area, medium sensitive area, low sensitive area and extremely low sensitive area accounted for 11.3%, 25.1%, 22.5% and 41.1% of the total area, respectively. The results show that the high sensitive area is mainly concentrated around the main water system and the concentrated area of the fault. The results are close to the actual situation and play an important role in the geological disaster risk assessment.

Synthesis of a novel triazine flame retardant containing sulfur and its application to cotton fabrics

Peihua Zhao,Mei Zhang,Denghui Wu,Yaqing Liu 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.9

A novel triazine flame retardant (FR) has been successfully synthesized by the reaction of cyanuric chloride with sodium sulfanilate followed by diethanol amine. Its structure has been fully characterized by IR and 1H NMR spectroscopy. The effects of reaction solvent, acid-binding agent, reaction temperature, and molar ratio of starting materials on the yield of FR were investigated in detail. Experiments showed that when the molar ratio of intermediate I to diethanol amine is 1 to 1.2 in the presence of sodium carbonate as acid-binding agent in acetone-water at 45 oC, the yield of the obtained FR reaches 81.4%. Thermogravimetry (TG) test indicated that the FR has good thermostability and char-forming ability. In addition, the flame retardancy and thermal behavior of the cotton fabrics treated with FR were studied by limiting oxygen index (LOI), vertical flammability test, and thermogravimetry (TG) to evaluate the flameretardant performance of the target FR. These results demonstrated that the flame retardancy and thermal stability of the cotton fabrics treated with FR were clearly improved.

Highly flame-retarding cotton fabrics with a novel phosphorus/nitrogen intumescent flame retardant

Peihua Zhao,Yaqing Liu,Xinhang Li,Mei Zhang,Shengnan Liu,Wenjun Liang 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.9

A novel phosphorus/nitrogen intumescent flame retardant, namely 6-chloro-4-(diethylamino phosphoratephosphoryl chloride)-2-(sodium 4-aminobenzensulfonate)-1,3,5-triazine (APPCABT), has been synthesized and charac-terized by elemental analysis, FT-IR,1H-NMR and31P{H}-NMR spectroscopies. To investigate the flame-retardingproperties of the treated cotton fabrics, APPCABT was applied to the chemical treatment of the cotton fabrics surface. The flame-retarding performance of the treated samples with APPCABT was evaluated by limiting oxygen index (LOI). The thermal degradation behavior of the treated samples was studied using thermogravimetric analysis (TGA). Thesurface morphology of the treated samples was observed by scanning electron microscopy (SEM). These results showthat APPCABT is both an intumescent flame retardant with high efficiency and an excellent char-forming agent forthe flame-retarding treatment of cotton fabrics.

Surface Coating Modified Polyglycolide (PGA) Braided Threads as Potential Thread-embedding Materials

Shaoju Fu,Peihua Zhang 한국섬유공학회 2020 Fibers and polymers Vol.21 No.10

Polyglycolic acid (PGA) braided threads offer numerous advantages, including good biocompatibility andbiodegradability for the application of acupoint catgut-embedding therapy (ACET). However, the surfaces of PGA threadsare relatively smooth and lack some function characteristics in the clinical practice. In this study, four types of PGA braidedthreads with different strands (n=2, 4, 6 and 8) were fabricated firstly, and then to deposit chitosan molecules on theirsurfaces. Afterwards, characterizations such surface morphology, swelling, mechanical, antibacterial and cytotoxicityproperties of threads were fully explored. The results showed that PGA threads after chitosan coating treatment showed largerweight and diameter changing, and swelling ratio. Mechanical properties (breaking strength, breaking elongation andflexibility) had been greatly improved after coating treatment. As for the biological experiments, modified PGA threads havebetter cell viability and antibacterial activity comparted to that of unmodified ones. In conclusion, surface coating methodwarrant further study to develop novel PGA embedding materials with outstanding clinical efficacy.

Plasma Modification of PLA/PGA Embedding Threads with Different Proportions: A Strategy for Developing Novel ACET Materials

Shaoju Fu,Peihua Zhang 한국섬유공학회 2021 Fibers and polymers Vol.22 No.3

Polylactic acid (PLA) and polyglycolic acid (PGA) have been widely used in the acupoint catgut embeddingtherapy (ACET) field. However, some defects such as hydrophobicity, poor swelling and cell adhesion properties whichsignificantly limit their further applications. Herein, we report a strategy for developing ACET materials via 3D fabrication andplasma treatment. The results showed that modified samples showed rougher surface morphology and better hydrophilicity. Sample L4G0 (PLA strands: PGA strands=4:0) showed the largest tensile strength and elongation values at 32.15±5.26 cN/dtexand 56.37±4.38 %, respectively. Samples were proved to be non-toxicity and had better cell attachment and tissue growthability after modification. In sum, the strategy of plasma modified PLA/PGA is deserved to be further studied with outstandingclinical efficacy.

Commutation Compensation Strategy for Brushless DC Motor Based on Terminal Voltage Reconstruction

Li Guidan,Zhang Tianqi,Li Bin,Fu Tongling,Duan Peihua 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.4

In the sensorless brushless DC (BLDC) motor control system, the commutation signal is the key to measure the system performance. To improve the commutation accuracy, a commutation compensation strategy based on terminal voltage reconstruction is proposed. By analyzing the commutation process, the integral of ideal terminal voltage is adopted to determine the commutation error. Then considering the voltage clamping of the freewheel diode, the actual terminal voltage is analyzed in diff erent periods. In the non-commutation period, a PWM cycle is divided into three regions, and the corresponding duration can be calculated by fl oating phase current, and then the equality of actual and ideal terminal voltage integrals is revealed. In the commutation period, the instantaneous value of back-electromotive force (back-EMF) at commutation point is used to construct the ideal terminal voltage and the commutation time is determined by the edge detection. In this way, the integral of terminal voltage can be calculated precisely. Then the error index is introduced and the relationship between the commutation error and the error index is presented. To eliminate the commutation error, the PI controller is adopted which outputs the compensation angle. The proposed strategy avoids the phase shift errors and the accumulation of integral errors, moreover the feasibility and eff ectiveness are verifi ed by simulations and experiments under diff erent conditions. In addition, the strategy can also be used to correct the installation error of Hall sensor

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.

Effect of Knitting Structure and Polyethylene Content on Thermalwet Comfort and Cooling Properties of Polyethylene/polyester Fabrics

Juan Qian,Ting Xie,Liqun Chen,Zhijiang Li,Ning Guo,Shaoju Fu,Peihua Zhang 한국섬유공학회 2022 Fibers and polymers Vol.23 No.11

Polyethylene is getting tremendous attention in personal thermal management textiles for summer, but there is lackof systematical coolness and thermal-wet comfort research in wearing knitting fabrics. In this work, two group of knittingstructure were designed following a sandwich structure model that consisted of a middle layer of multifilament and twoasymmetric outer layers. Nine bi-layer samples interknitted with polyester were fabricated with one face composed ofpolyester filaments and the other face built of polyethylene and polyester filaments. Textile parameters, such as knittingstructure, polyethylene fractions and distribution in the inner layer, yarn composition and relative porosity, were considered. Breathability, thermal transfer properties, moisture management performance and dynamic cooling performance wasmeasured and evaluated to investigate the thermal-wet and coolness relevant comfort properties of these fabrics. It was foundthat the fabrics knitted with tuck stitches have better air permeability, contact coolness, overall moisture management anddynamic cooling performance in comparison to the fabrics knitted with float stitches. The air permeability became better withthe increasing proportion of polyethylene and the decreasing ratio of tuck stitch. The effective contact area of polyethylenewith skin was beneficial to promote the transient thermal conductivity and dynamic cooling performance of fabric. The resultalso suggested that an asymmetric structure with meshes in the inner layer were beneficial to promote moisture management. Meanwhile, when the proportion of tuck stitch in inner layer was 6.25 %, the air permeability and heat transfer properties offabric were the best. Moreover, independent tests had proved that the performance of transient and steady thermalconductivity of polyethylene/polyester fabric was the best when the mass ratio of polyethylene was 49.3 % in this study.