Silicone rubber/polyacrylate sequential interpenetrating polymer networks(IPNs) were prepared by silicone rubber sheet dipped into the solution composed of different acrylate monomers and benzoyl peroxides(BPOs) for d...Silicone rubber/polyacrylate sequential interpenetrating polymer networks(IPNs) were prepared by silicone rubber sheet dipped into the solution composed of different acrylate monomers and benzoyl peroxides(BPOs) for different time at room temperature and then acrylate polymerized at 80℃for 2 h. The molecular structure and damping properties of sequential IPNs were studied by means of FT-IR and dynamic mechanical analysis(DMA), respectively. The FT-IR spectrum shows that polyacrylate distributes unevenly along the thickness direction of IPNs, i.e. the concentration of polyacrylate decreases from the midst to the surface of the IPNs. The DMA shows that cold crystallization of silicone in the temperature range from -47℃to -30℃is reduced and loss factor of IPNs is improved after interpenetrating with polyacrylate. This suggestes that IPNs can be used as damping materials.展开更多
Interpenetrating polymer networks （IPNs） composed of acrylate-modified polyurethane （PU）/unsaturated polyester （UP） resin via simultaneous polymerization with various component ratios of PU/UP were prepared. The...Interpenetrating polymer networks （IPNs） composed of acrylate-modified polyurethane （PU）/unsaturated polyester （UP） resin via simultaneous polymerization with various component ratios of PU/UP were prepared. The polymerization processes of IPNs were traced through infrared spectrum （IR） techniques, by which the phase separation in systems could be controlled effectively. Results for the morphology and miscibility among multiple phases of IPNs, obtained by transmission electron microscope （TEM） indicated that the domains between two phases were constricted in nanometer scales. The dynamic mechanical thermal analyzer （DMTA） detection results revealed that the loss factor （tanS） and loss modulus （E″） increased with the polyurethane amounts in system, and the peak value in curves of tanδ and E″ appeared toward low temperature ranges. Maximum tanδ values of all samples were above 0.3 in the nearly 50℃ ranges. Also, the mechanical properties of PU/UP IPNs were studied in detail.展开更多
As air descends the intake shaft, its infrastructure, lining and the strata will emit heat during the night when the intake air is cool and, on the contrary, will absorb heat during the day when the temperature of the...As air descends the intake shaft, its infrastructure, lining and the strata will emit heat during the night when the intake air is cool and, on the contrary, will absorb heat during the day when the temperature of the air becomes greater than that of the strata. This cyclic phenomenon, also known as the "thermal damping effect" will continue throughout the year reducing the effect of surface air temperature variation. The objective of this paper is to quantify the thermal damping effect in vertical underground airways. A nonlinear autoregressive time series with external input(NARX) algorithm was used as a novel method to predict the dry-bulb temperature(Td) at the bottom of intake shafts as a function of surface air temperature. Analyses demonstrated that the artificial neural network(ANN) model could accurately predict the temperature at the bottom of a shaft. Furthermore, an attempt was made to quantify typical "damping coefficient" for both production and ventilation shafts through simple linear regression models. Comparisons between the collected climatic data and the regression-based predictions show that a simple linear regression model provides an acceptable accuracy when predicting the Tdat the bottom of intake shafts.展开更多
According to the configuration and absorption theory of polymer macromolecule materials, a kind of IPN with wider temperature range and higher damping property was designed and synthesized. By using the spectrum of dy...According to the configuration and absorption theory of polymer macromolecule materials, a kind of IPN with wider temperature range and higher damping property was designed and synthesized. By using the spectrum of dynamic mechanical thermal analysis （DMTA） and acoustic pulse tube device, the microstructure, phase separation degree, phase size and phase continuity of IPN with different components were analyzed. The experimental results show that the nano size grade of phase, the continuous and homogeneous IPN phase can provide higher absorption coefficient. The absorption coefficient of optimized sample I09 is 0.7 in 2 kHz, and the absorption peak is 0.9 in 4 kHz. Then the underwater acoustic properties of modified IPN filled with mica, micro-balloon and nano-SiO2 were discussed respectively to indicate that the inhomogeneous property of filler-modified IPN can improve the underwater acoustic stealth performance effectively, and the micro size grade of these filler-modified IPN can work well in low frequency acoustic stealth.展开更多
This paper presents the effect of the high voltage direct current (HVDC) transmission system based on voltage source converter (VSC) on the sub synchronous resonance (SSR) and low frequency oscillations (LFO) in power...This paper presents the effect of the high voltage direct current (HVDC) transmission system based on voltage source converter (VSC) on the sub synchronous resonance (SSR) and low frequency oscillations (LFO) in power system. Also, a novel adaptive neural controller based on neural identifier is proposed for the HVDC which is capable of damping out LFO and sub synchronous oscillations (SSO). For comparison purposes, results of system based damping neural controller are compared with a lead-lag controller based on quantum particle swarm optimization (QPSO). It is shown that implementing adaptive damping controller not only improves the stability of power system but also can overcome drawbacks of conventional compensators with fixed parameters. In order to determine the most effective input of HVDC system to apply supplementary controller signal, analysis based on singular value decomposition is performed. To evaluate the performance of the proposed controller, transient simulations of detailed nonlinear system are considered.展开更多
目的探讨轻盈祛浊汤治疗糖尿病肾病(DN)的作用机制。方法利用网络药理学预测轻盈祛浊汤治疗DN的作用机制,并通过分子对接预测活性成分的结合部位。结合网络药理学及分子对接结果,构建DN大鼠模型,2023年1—6月,将60只大鼠分为正常组、模...目的探讨轻盈祛浊汤治疗糖尿病肾病(DN)的作用机制。方法利用网络药理学预测轻盈祛浊汤治疗DN的作用机制,并通过分子对接预测活性成分的结合部位。结合网络药理学及分子对接结果,构建DN大鼠模型,2023年1—6月,将60只大鼠分为正常组、模型组、马来酸依那普利组、轻盈祛浊汤组,每组15只。治疗8周后比较四组大鼠24 h尿微量白蛋白(urinary microalbuminexcretion rate,UAER)、尿素氮、血肌酐水平和钠/葡萄糖协同转运蛋白1(recombinant sodium/glucose cotransporter 1,SGLT1),A1腺苷受体(A1 adenosine receptor,A1AR)蛋白表达水平。结果网络药理学共筛选出轻盈祛浊汤有效成分1114种,作用靶点269个,DN相关靶点2020个,其交集靶点174个。基因本体富集(GO)和基因组的京都百科全书(KEGG)分析得出主要涉及信号转导、炎症反应、细胞凋亡等一系列的生物学反应过程,主要参与丝裂原活化蛋白激酶/核因子κB(mitogen-activated protein kinase/nuclear factor kappa-B,pMAPK/NF-κB)、NOD样受体家族蛋白3/白细胞介素-1β(NOD-like receptor protein 3/interleukin-1β,NLRP3/IL-1β)、白细胞介素6/信号传导和转录激活因子3(interleukin-6/signal transducer and activator of transcription 3,IL-6/STAT3)、肿瘤坏死因子(tumor necrosis factor,TNF)、肿瘤蛋白p53(tumor protein 53,P53)和前列腺素内过氧化物合酶(prostaglandin-endoperoxide synthase 2,PTGS2)等信号通路的调控。分子对接表明,轻盈祛浊汤主要成分与DN靶点的结合活性较强。模型组大鼠24 h UAER[(4539.71±516.03)μg/24 h比(226.59±72.71)μg/24 h]、血肌酐[(85.63±12.96)mL·kg^(-1)·min^(-1)比(0.48±0.12)mL·kg^(-1)·min^(-1)]、SGLT1(1.17±0.07比0.82±0.06)高于正常组,而模型组大鼠尿素氮、A1AR低于正常组(P<0.05)。马来酸依那普利片组大鼠24 h UAER、血肌酐、SGLT1低于模型组,马来酸依那普利片组大鼠尿素氮、A1AR高于模型组(P<0.05)。轻盈祛浊汤组大鼠24 h UAER、血肌酐、SGLT1低于马来酸依那普利片组,而轻盈祛浊汤组大鼠尿素氮、A1AR高于马来酸依那普利片组(P<0.05)。结论轻盈祛浊汤可通过调节pMAPK/NF-κB、NLRP3/IL-1β、IL-6/STAT3、TNF、P53和PTGS2信号通路发挥治疗DN的作用。展开更多
基金Project (50473013) supported by the National Natural Science Foundation of China
文摘Silicone rubber/polyacrylate sequential interpenetrating polymer networks(IPNs) were prepared by silicone rubber sheet dipped into the solution composed of different acrylate monomers and benzoyl peroxides(BPOs) for different time at room temperature and then acrylate polymerized at 80℃for 2 h. The molecular structure and damping properties of sequential IPNs were studied by means of FT-IR and dynamic mechanical analysis(DMA), respectively. The FT-IR spectrum shows that polyacrylate distributes unevenly along the thickness direction of IPNs, i.e. the concentration of polyacrylate decreases from the midst to the surface of the IPNs. The DMA shows that cold crystallization of silicone in the temperature range from -47℃to -30℃is reduced and loss factor of IPNs is improved after interpenetrating with polyacrylate. This suggestes that IPNs can be used as damping materials.
基金supported by the Scientific Research Foundation of Harbin Institute of Technology(HIT.2002.56)the Postdoctoral Foundation of Heilongjiang Province,China
文摘Interpenetrating polymer networks （IPNs） composed of acrylate-modified polyurethane （PU）/unsaturated polyester （UP） resin via simultaneous polymerization with various component ratios of PU/UP were prepared. The polymerization processes of IPNs were traced through infrared spectrum （IR） techniques, by which the phase separation in systems could be controlled effectively. Results for the morphology and miscibility among multiple phases of IPNs, obtained by transmission electron microscope （TEM） indicated that the domains between two phases were constricted in nanometer scales. The dynamic mechanical thermal analyzer （DMTA） detection results revealed that the loss factor （tanS） and loss modulus （E″） increased with the polyurethane amounts in system, and the peak value in curves of tanδ and E″ appeared toward low temperature ranges. Maximum tanδ values of all samples were above 0.3 in the nearly 50℃ ranges. Also, the mechanical properties of PU/UP IPNs were studied in detail.
基金funded by National Institute for Occupational Safety and Health (NIOSH) (No. 2014-N-15795, 2014)
文摘As air descends the intake shaft, its infrastructure, lining and the strata will emit heat during the night when the intake air is cool and, on the contrary, will absorb heat during the day when the temperature of the air becomes greater than that of the strata. This cyclic phenomenon, also known as the "thermal damping effect" will continue throughout the year reducing the effect of surface air temperature variation. The objective of this paper is to quantify the thermal damping effect in vertical underground airways. A nonlinear autoregressive time series with external input(NARX) algorithm was used as a novel method to predict the dry-bulb temperature(Td) at the bottom of intake shafts as a function of surface air temperature. Analyses demonstrated that the artificial neural network(ANN) model could accurately predict the temperature at the bottom of a shaft. Furthermore, an attempt was made to quantify typical "damping coefficient" for both production and ventilation shafts through simple linear regression models. Comparisons between the collected climatic data and the regression-based predictions show that a simple linear regression model provides an acceptable accuracy when predicting the Tdat the bottom of intake shafts.
基金Funded by the National Defense Foundation Item of China
文摘According to the configuration and absorption theory of polymer macromolecule materials, a kind of IPN with wider temperature range and higher damping property was designed and synthesized. By using the spectrum of dynamic mechanical thermal analysis （DMTA） and acoustic pulse tube device, the microstructure, phase separation degree, phase size and phase continuity of IPN with different components were analyzed. The experimental results show that the nano size grade of phase, the continuous and homogeneous IPN phase can provide higher absorption coefficient. The absorption coefficient of optimized sample I09 is 0.7 in 2 kHz, and the absorption peak is 0.9 in 4 kHz. Then the underwater acoustic properties of modified IPN filled with mica, micro-balloon and nano-SiO2 were discussed respectively to indicate that the inhomogeneous property of filler-modified IPN can improve the underwater acoustic stealth performance effectively, and the micro size grade of these filler-modified IPN can work well in low frequency acoustic stealth.
文摘This paper presents the effect of the high voltage direct current (HVDC) transmission system based on voltage source converter (VSC) on the sub synchronous resonance (SSR) and low frequency oscillations (LFO) in power system. Also, a novel adaptive neural controller based on neural identifier is proposed for the HVDC which is capable of damping out LFO and sub synchronous oscillations (SSO). For comparison purposes, results of system based damping neural controller are compared with a lead-lag controller based on quantum particle swarm optimization (QPSO). It is shown that implementing adaptive damping controller not only improves the stability of power system but also can overcome drawbacks of conventional compensators with fixed parameters. In order to determine the most effective input of HVDC system to apply supplementary controller signal, analysis based on singular value decomposition is performed. To evaluate the performance of the proposed controller, transient simulations of detailed nonlinear system are considered.
文摘目的探讨轻盈祛浊汤治疗糖尿病肾病(DN)的作用机制。方法利用网络药理学预测轻盈祛浊汤治疗DN的作用机制,并通过分子对接预测活性成分的结合部位。结合网络药理学及分子对接结果,构建DN大鼠模型,2023年1—6月,将60只大鼠分为正常组、模型组、马来酸依那普利组、轻盈祛浊汤组,每组15只。治疗8周后比较四组大鼠24 h尿微量白蛋白(urinary microalbuminexcretion rate,UAER)、尿素氮、血肌酐水平和钠/葡萄糖协同转运蛋白1(recombinant sodium/glucose cotransporter 1,SGLT1),A1腺苷受体(A1 adenosine receptor,A1AR)蛋白表达水平。结果网络药理学共筛选出轻盈祛浊汤有效成分1114种,作用靶点269个,DN相关靶点2020个,其交集靶点174个。基因本体富集(GO)和基因组的京都百科全书(KEGG)分析得出主要涉及信号转导、炎症反应、细胞凋亡等一系列的生物学反应过程,主要参与丝裂原活化蛋白激酶/核因子κB(mitogen-activated protein kinase/nuclear factor kappa-B,pMAPK/NF-κB)、NOD样受体家族蛋白3/白细胞介素-1β(NOD-like receptor protein 3/interleukin-1β,NLRP3/IL-1β)、白细胞介素6/信号传导和转录激活因子3(interleukin-6/signal transducer and activator of transcription 3,IL-6/STAT3)、肿瘤坏死因子(tumor necrosis factor,TNF)、肿瘤蛋白p53(tumor protein 53,P53)和前列腺素内过氧化物合酶(prostaglandin-endoperoxide synthase 2,PTGS2)等信号通路的调控。分子对接表明,轻盈祛浊汤主要成分与DN靶点的结合活性较强。模型组大鼠24 h UAER[(4539.71±516.03)μg/24 h比(226.59±72.71)μg/24 h]、血肌酐[(85.63±12.96)mL·kg^(-1)·min^(-1)比(0.48±0.12)mL·kg^(-1)·min^(-1)]、SGLT1(1.17±0.07比0.82±0.06)高于正常组,而模型组大鼠尿素氮、A1AR低于正常组(P<0.05)。马来酸依那普利片组大鼠24 h UAER、血肌酐、SGLT1低于模型组,马来酸依那普利片组大鼠尿素氮、A1AR高于模型组(P<0.05)。轻盈祛浊汤组大鼠24 h UAER、血肌酐、SGLT1低于马来酸依那普利片组,而轻盈祛浊汤组大鼠尿素氮、A1AR高于马来酸依那普利片组(P<0.05)。结论轻盈祛浊汤可通过调节pMAPK/NF-κB、NLRP3/IL-1β、IL-6/STAT3、TNF、P53和PTGS2信号通路发挥治疗DN的作用。
