Based on a three-step kinetic mechanism, a one-dimensional, time dependent, numerical model is presented for the smoldering propagation in a horizontally packed bed of cellulosic material. The kinetic processes includ...Based on a three-step kinetic mechanism, a one-dimensional, time dependent, numerical model is presented for the smoldering propagation in a horizontally packed bed of cellulosic material. The kinetic processes include pyrolysis and oxidation degradation of fuel and oxidation of char. Heat transfer between solid and gas is taken into account, and the diffusion coefficient varies with the temperature. Radiative heat transfer is included by using the diffusion approximation. The effects of airflow velocity and oxygen concentration are simulated on the smoldering velocity and the averaged maximum temperature of smoldering fuel. The results indicate that the spread rate varies linearly with increasing airflow velocity, and the inlet air velocity has little effect on the maximum temperature. The evolutions of gas species and solid compositions are predicted. The effects of frequency factors (A1, A2 and A3) are analyzed. Simulations show that the smoldering spread rate increases with increasing A2 (fuel oxidation), but decreases with A1 (fuel pyrolysis) and A3 (char oxidation).展开更多
The coupled Korteweg-de Vries (CKdV) equation with self-consistent sources (CKdVESCS) and its Lax representation are derived. We present a generalized binary Darboux transformation (GBDT) with an arbitrary time-...The coupled Korteweg-de Vries (CKdV) equation with self-consistent sources (CKdVESCS) and its Lax representation are derived. We present a generalized binary Darboux transformation (GBDT) with an arbitrary time- dependent function for the CKdVESCS as well as the formula for the N-times repeated GBDT. This GBDT provides non-auto-Biicklund transformation between two CKdVESCSs with different degrees of sources and enables us to construct more generM solutions with N arbitrary t-dependent functions. We obtain positon, negaton, complexiton, and negaton- positon solutions of the CKdVESCS.展开更多
Trichomoniasis is the most common, sexually transmitted infection. It is caused by the flagellated protozoan parasite Trichomonas vaginalis. Symptoms include vaginitis and infections have been associated with preterm ...Trichomoniasis is the most common, sexually transmitted infection. It is caused by the flagellated protozoan parasite Trichomonas vaginalis. Symptoms include vaginitis and infections have been associated with preterm delivery, low birth weight and increased infant mortality, as well as predisposing to HIV/AIDS and cervical cancer. Trichomoniasis has the highest prevalence and incidence of any sexually transmitted infection. The 5-nitroimidazole drugs, of which metronidazole is the most prescribed, are the only approved,effective drugs to treat trichomoniasis. Resistance against metronidazole is frequently reported and crossresistance among the family of 5-nitroimidazole drugs is common, leaving no alternative for treatment, with some cases remaining unresolved. The mechanism of metronidazole resistance in T. vaginalis from treatment failures is not well understood, unlike resistance which is developed in the laboratory under increasing metronidazole pressure. In the latter situation, hydrogenosomal function which is involved in activation of the prodrug, metronidazole, is down-regulated. Reversion to sensitivity is incomplete after removal of drug pressure in the highly resistant parasites while clinically resistant strains, so far analysed, maintain their resistance levels in the absence of drug pressure. Although anaerobic resistance has been regarded as a laboratory induced phenomenon, it clearly has been demonstrated in clinical isolates. Pursuit of both approaches will allow dissection of the underlying mechanisms. Many alternative drugs and treatments have been tested in vivo in cases of refractory trichomoniasis, as well as in vitro with some successes including the broad spectrum anti-parasitic drug nitazoxanide. Drug resistance incidence in T. vaginalis appears to be on the increase and improved surveillance of treatment failures is urged.展开更多
As physicalisms of various kinds have faced difficulties in recent years, the time has come to explore possible alternatives, one of which is yinyang ontology. A yinyang theorist is expected to provide a plausible acc...As physicalisms of various kinds have faced difficulties in recent years, the time has come to explore possible alternatives, one of which is yinyang ontology. A yinyang theorist is expected to provide a plausible account of causation to replace the traditional notion of causation. The present paper is critical of the Humean tradition, which understands the relata of causal relations in terms of passive materiality so that humans use referential terms to describe causal relations constructively. But an alternative notion of reference is available according to which causal relata are active processors of the information with which they interact. On this latter view, humans use referential language to describe the structure in which the relata interrelate themselves so that the structure can be understood hermeneutically. Reference on this view is naturalized. In this article, I advance two arguments for this thesis, one concerning the informationality of states and the other related to the essentiality of properties.展开更多
In this letter,we introduce a novel passive transmission line of negative refractive index(i.e.,left-handedness)based on identical symmetrical lattice type structures thus called "lattice type transmission line&q...In this letter,we introduce a novel passive transmission line of negative refractive index(i.e.,left-handedness)based on identical symmetrical lattice type structures thus called "lattice type transmission line"(LT-TL).The dispersion characteristic and the transmission response of the proposed LT-TL are analyzed.While all the other left-handed passive transmission lines are of high pass,the present passive left-handed transmission line is of low pass.Compared with a conventional transmission line,the LT-TL has a phase shift of 180° in the entire wide pass-band.展开更多
A cobalt-free perovskite-type Ba0.5Sr0.5A10.1Fe0.9O3-δ (BSAF) chemically studied as solid oxide fuel cell (SOFC) cathode. The ductivity, and electrode polarizations in symmetrical cell based is developed and elec...A cobalt-free perovskite-type Ba0.5Sr0.5A10.1Fe0.9O3-δ (BSAF) chemically studied as solid oxide fuel cell (SOFC) cathode. The ductivity, and electrode polarizations in symmetrical cell based is developed and electro- structures, electrical con- on mixed ion conducting electrolyte were investigated, respectively. The temperature dependence of conductivity of BSAF in air shows a typical semiconductor behavior with positive temperature coefficient up to 450℃ where the conductivity reaches 14.0 S/cm while above this temperature the negative temperature coefficient dominates the total conductivity. Electrochemical charac- terizations show desirable polarization resistance of BSAF cathode in a symmetric cell based on mixed ion conducting electrolyte at 650-700℃, A single SOFC with BSAF cathode shows OCV of 1.0 V and maximum output of 420 mW/cm2 at 700 ℃ with humidified hydrogen fuel and static air oxidant.展开更多
To realize highly selective relay recognition of Fe3+ and H2PO4^- ions, a simple benzimidazole-based fluorescent chemosensor (L) was designed and synthesized. Sensor L displays rapid, highly selective, and sensitiv...To realize highly selective relay recognition of Fe3+ and H2PO4^- ions, a simple benzimidazole-based fluorescent chemosensor (L) was designed and synthesized. Sensor L displays rapid, highly selective, and sensitive recognition to Fe^3+ in H2O/DMSO (1:1, v/v) solutions. The in stitu-generated L-Fe^3+ complex solution exhibits a fast response and high selectivity toward dihydrogen phosphate anion via the Fe^3+ displacement approach. The detection limits of sensor L to Fe^3+ and L-Fe^3+complex to H2PO4 anion were estimated to be 1.0 × 10^-9 mol/L. Notably, the sensor was retrievable to indicate dihydrogen phosphate an- ions with Fe^3+, and HePO4 , in turn, increased. This successive recognition feature of sensor L makes it a potential utility for Fe^3+ and H2PO4 anion detection in aqueous media.展开更多
In order to improve the wear resistance of titanium alloys,the potential of the plasma nitriding process with a cathode assiting discharge setup was examined.Ti6Al4V alloy was nitrided by the cathode assiting discharg...In order to improve the wear resistance of titanium alloys,the potential of the plasma nitriding process with a cathode assiting discharge setup was examined.Ti6Al4V alloy was nitrided by the cathode assiting discharge nitriding(CAN) and conventional DC plasma nitriding(CPN) methods,respectively.The micro-topography,phase composition and cross-sectional microhardness distribution of two nitriding layers were studied comparatively.The sliding wear resistance of the nitriding layers was examined by a ball-on-disk test against Si3N4 balls.The results indicated that the surface roughness Ra of the CAN layer was about 1 order less than that of the CPN layer.In addition,the CAN surfaces possessed significantly greater wear resistance than the CPN layer at higher loads,and increased the wear resistance of Ti6Al4V alloy by about 2 orders due to the higher loading bearing ability,higher rate of TiN phase,greater surface microhardness and bigger microhardness improving depth.This is because the double glow discharge effect in CAN strengthened the density of the active nitrogen atoms and the nitriding efficiency.Moreover,the ion bombardment effect on the surface of the nitriding titanium alloy was reduced obviously.展开更多
Researches have shown that cancer stem cells, regulated by the niche where they reside, are the roots of oncogenesis, relapse and metastasis. To date, very few treatments have targeted on cancer stem cells. The author...Researches have shown that cancer stem cells, regulated by the niche where they reside, are the roots of oncogenesis, relapse and metastasis. To date, very few treatments have targeted on cancer stem cells. The authors study that the regulated factors in the niche share the characteristics of yin-yang in the theory of traditional Chinese medicine, which has confirmed its therapeutic effects in the prevention and treatment of cancer. So the authors presume that the mechanisms of traditional Chinese medicine on the prevention and treatment of cancer may be related to the yin-yang balance of the niche of cancer stem cells.展开更多
The cationic group distribution along the polymeric backbones of anion exchange membranes(AEMs)has significant influence on their microscopic morphology and anion conductivity.To develop high-performance AEMs for vana...The cationic group distribution along the polymeric backbones of anion exchange membranes(AEMs)has significant influence on their microscopic morphology and anion conductivity.To develop high-performance AEMs for vanadium redox flow batteries(VRFBs),a series of poly(fluorenyl ether)samples bearing di-and tri-quaternary ammonium side chains with similar ion exchange capacities(IECs)were synthesized by grafting cationic alkyl chains with tertiary amine-containing poly(fluorenyl ether)precursors.The experimental results indicate that the introduction of the multi-cationic side chains facilitates the formation of micro-phase-separated morphologies and enhances anion conductivity.Moreover,the number of spacer atoms between the quaternary ammonium groups on the side chains affects the water uptake of the membranes,thus complicating the relationship between the density of cationic group distribution and anion conductivity.The poly(fluorenyl ether)s with dicationic side chains and six spacing atoms(DQA-PFE-C6)showed the highest anion conductivity.A VRFB assembled with DQA-PFE-C6 exhibited a maximum power density of 239.80 mW cm^−2 at 250 mA cm^−2,which is significantly higher than a VRFB assembled with Nafion 212.Therefore,side chain engineering is an effective chemical approach to enhance the properties of AEMs for VRFB applications.展开更多
Although Yin-Yang Wu-Xing (Yin-Yang and Five-Elements, subsystems of human body) has been the theoretical basis of traditional Chinese medicine (TCM) for more than 5 000 years, it has been primarily analytical or ...Although Yin-Yang Wu-Xing (Yin-Yang and Five-Elements, subsystems of human body) has been the theoretical basis of traditional Chinese medicine (TCM) for more than 5 000 years, it has been primarily analytical or empirical in nature without a formal scientific foundation. Based on bipolar set theory, an equilibrium/non-equilibrium computational model of Yin-Yang Wu-Xing is proposed. The Yin-Yang Wu-Xing dynamical systems are formulated so that equilibrium and non-equilibrium conditions can be established and proved. Computer simulations of equilibrium and non-equilibrium processes show that this new approach can provide diagnostic decision support in TCM. Thus, this equilibrium-based approach provides a unique scientific basis for future research in TCM, Qi (vital energy), QiGong, Meridians and Collaterals (acupuncture channels) and herbal treatment. On the other hand, it provides a basic Yin-Yang cellular network architecture for modem scientific research in genomics such that regulation mechanisms of the ubiquitous YY1 protein for cell processes can be explained.展开更多
The different interactions between a chemosensor, 1-(naphthalen-2-yl)-3-(6-nitrobenzothiazol-2-yl)-thiourea (1), and F, acetate (AcO-), Cl-, and Br- anions have been investigated theoretically at the B3LYP/6-3...The different interactions between a chemosensor, 1-(naphthalen-2-yl)-3-(6-nitrobenzothiazol-2-yl)-thiourea (1), and F, acetate (AcO-), Cl-, and Br- anions have been investigated theoretically at the B3LYP/6-31+G(d,p) level with the basis set superposition error (BSSE) correction. It was found that the high selectivity of compound 1 for F- can be ascribed to the ability of the anion to deprotonate the N-H fragment of the host sensor, while the chemosensor also has a strong affinity for AcO- by virtue of the formation of a hydrogen-bonded complex. Intramolecular charge transfer (ICT) causes the colorimetric signaling of compound 1 after interaction with F-/AcO. A study of substituent effects suggested that the O/NH- and O/S-substituted derivatives are also expected to be promising candidates for chromogenic F3AcO chemosensors.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No.50476073)
文摘Based on a three-step kinetic mechanism, a one-dimensional, time dependent, numerical model is presented for the smoldering propagation in a horizontally packed bed of cellulosic material. The kinetic processes include pyrolysis and oxidation degradation of fuel and oxidation of char. Heat transfer between solid and gas is taken into account, and the diffusion coefficient varies with the temperature. Radiative heat transfer is included by using the diffusion approximation. The effects of airflow velocity and oxygen concentration are simulated on the smoldering velocity and the averaged maximum temperature of smoldering fuel. The results indicate that the spread rate varies linearly with increasing airflow velocity, and the inlet air velocity has little effect on the maximum temperature. The evolutions of gas species and solid compositions are predicted. The effects of frequency factors (A1, A2 and A3) are analyzed. Simulations show that the smoldering spread rate increases with increasing A2 (fuel oxidation), but decreases with A1 (fuel pyrolysis) and A3 (char oxidation).
基金The project supported by the National Fundamental Research Program of China(973 Program)under Grant No.2007CB814800National Natural Science Foundation of China under Grant No.10601028
文摘The coupled Korteweg-de Vries (CKdV) equation with self-consistent sources (CKdVESCS) and its Lax representation are derived. We present a generalized binary Darboux transformation (GBDT) with an arbitrary time- dependent function for the CKdVESCS as well as the formula for the N-times repeated GBDT. This GBDT provides non-auto-Biicklund transformation between two CKdVESCSs with different degrees of sources and enables us to construct more generM solutions with N arbitrary t-dependent functions. We obtain positon, negaton, complexiton, and negaton- positon solutions of the CKdVESCS.
文摘Trichomoniasis is the most common, sexually transmitted infection. It is caused by the flagellated protozoan parasite Trichomonas vaginalis. Symptoms include vaginitis and infections have been associated with preterm delivery, low birth weight and increased infant mortality, as well as predisposing to HIV/AIDS and cervical cancer. Trichomoniasis has the highest prevalence and incidence of any sexually transmitted infection. The 5-nitroimidazole drugs, of which metronidazole is the most prescribed, are the only approved,effective drugs to treat trichomoniasis. Resistance against metronidazole is frequently reported and crossresistance among the family of 5-nitroimidazole drugs is common, leaving no alternative for treatment, with some cases remaining unresolved. The mechanism of metronidazole resistance in T. vaginalis from treatment failures is not well understood, unlike resistance which is developed in the laboratory under increasing metronidazole pressure. In the latter situation, hydrogenosomal function which is involved in activation of the prodrug, metronidazole, is down-regulated. Reversion to sensitivity is incomplete after removal of drug pressure in the highly resistant parasites while clinically resistant strains, so far analysed, maintain their resistance levels in the absence of drug pressure. Although anaerobic resistance has been regarded as a laboratory induced phenomenon, it clearly has been demonstrated in clinical isolates. Pursuit of both approaches will allow dissection of the underlying mechanisms. Many alternative drugs and treatments have been tested in vivo in cases of refractory trichomoniasis, as well as in vitro with some successes including the broad spectrum anti-parasitic drug nitazoxanide. Drug resistance incidence in T. vaginalis appears to be on the increase and improved surveillance of treatment failures is urged.
文摘As physicalisms of various kinds have faced difficulties in recent years, the time has come to explore possible alternatives, one of which is yinyang ontology. A yinyang theorist is expected to provide a plausible account of causation to replace the traditional notion of causation. The present paper is critical of the Humean tradition, which understands the relata of causal relations in terms of passive materiality so that humans use referential terms to describe causal relations constructively. But an alternative notion of reference is available according to which causal relata are active processors of the information with which they interact. On this latter view, humans use referential language to describe the structure in which the relata interrelate themselves so that the structure can be understood hermeneutically. Reference on this view is naturalized. In this article, I advance two arguments for this thesis, one concerning the informationality of states and the other related to the essentiality of properties.
基金Project supported by the National Basic Research Program (973) of China (No. 2004CB719802)the Natural Science Foundation ofZhejiang Province (No. R104154),China
文摘In this letter,we introduce a novel passive transmission line of negative refractive index(i.e.,left-handedness)based on identical symmetrical lattice type structures thus called "lattice type transmission line"(LT-TL).The dispersion characteristic and the transmission response of the proposed LT-TL are analyzed.While all the other left-handed passive transmission lines are of high pass,the present passive left-handed transmission line is of low pass.Compared with a conventional transmission line,the LT-TL has a phase shift of 180° in the entire wide pass-band.
文摘A cobalt-free perovskite-type Ba0.5Sr0.5A10.1Fe0.9O3-δ (BSAF) chemically studied as solid oxide fuel cell (SOFC) cathode. The ductivity, and electrode polarizations in symmetrical cell based is developed and electro- structures, electrical con- on mixed ion conducting electrolyte were investigated, respectively. The temperature dependence of conductivity of BSAF in air shows a typical semiconductor behavior with positive temperature coefficient up to 450℃ where the conductivity reaches 14.0 S/cm while above this temperature the negative temperature coefficient dominates the total conductivity. Electrochemical charac- terizations show desirable polarization resistance of BSAF cathode in a symmetric cell based on mixed ion conducting electrolyte at 650-700℃, A single SOFC with BSAF cathode shows OCV of 1.0 V and maximum output of 420 mW/cm2 at 700 ℃ with humidified hydrogen fuel and static air oxidant.
基金supported by the National Natural Science Foundation of China(21064006,21161018,21262032)the Natural Science Foundation of Gansu Province(1010RJZA018)+1 种基金the Program for Changjiang ScholarsInnovative Research Teams in Universities of the Ministry of Education of China(IRT1177)
文摘To realize highly selective relay recognition of Fe3+ and H2PO4^- ions, a simple benzimidazole-based fluorescent chemosensor (L) was designed and synthesized. Sensor L displays rapid, highly selective, and sensitive recognition to Fe^3+ in H2O/DMSO (1:1, v/v) solutions. The in stitu-generated L-Fe^3+ complex solution exhibits a fast response and high selectivity toward dihydrogen phosphate anion via the Fe^3+ displacement approach. The detection limits of sensor L to Fe^3+ and L-Fe^3+complex to H2PO4 anion were estimated to be 1.0 × 10^-9 mol/L. Notably, the sensor was retrievable to indicate dihydrogen phosphate an- ions with Fe^3+, and HePO4 , in turn, increased. This successive recognition feature of sensor L makes it a potential utility for Fe^3+ and H2PO4 anion detection in aqueous media.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51171154,51101127)
文摘In order to improve the wear resistance of titanium alloys,the potential of the plasma nitriding process with a cathode assiting discharge setup was examined.Ti6Al4V alloy was nitrided by the cathode assiting discharge nitriding(CAN) and conventional DC plasma nitriding(CPN) methods,respectively.The micro-topography,phase composition and cross-sectional microhardness distribution of two nitriding layers were studied comparatively.The sliding wear resistance of the nitriding layers was examined by a ball-on-disk test against Si3N4 balls.The results indicated that the surface roughness Ra of the CAN layer was about 1 order less than that of the CPN layer.In addition,the CAN surfaces possessed significantly greater wear resistance than the CPN layer at higher loads,and increased the wear resistance of Ti6Al4V alloy by about 2 orders due to the higher loading bearing ability,higher rate of TiN phase,greater surface microhardness and bigger microhardness improving depth.This is because the double glow discharge effect in CAN strengthened the density of the active nitrogen atoms and the nitriding efficiency.Moreover,the ion bombardment effect on the surface of the nitriding titanium alloy was reduced obviously.
基金supported by grants from the National Nature Science Foundation of China and No.2006BAI04A05 from the Eleventh Five-Year Program of the National Science and Technology Project (No.30772867)
文摘Researches have shown that cancer stem cells, regulated by the niche where they reside, are the roots of oncogenesis, relapse and metastasis. To date, very few treatments have targeted on cancer stem cells. The authors study that the regulated factors in the niche share the characteristics of yin-yang in the theory of traditional Chinese medicine, which has confirmed its therapeutic effects in the prevention and treatment of cancer. So the authors presume that the mechanisms of traditional Chinese medicine on the prevention and treatment of cancer may be related to the yin-yang balance of the niche of cancer stem cells.
基金the National Natural Science Foundation of China(51873037 and 51503038)。
文摘The cationic group distribution along the polymeric backbones of anion exchange membranes(AEMs)has significant influence on their microscopic morphology and anion conductivity.To develop high-performance AEMs for vanadium redox flow batteries(VRFBs),a series of poly(fluorenyl ether)samples bearing di-and tri-quaternary ammonium side chains with similar ion exchange capacities(IECs)were synthesized by grafting cationic alkyl chains with tertiary amine-containing poly(fluorenyl ether)precursors.The experimental results indicate that the introduction of the multi-cationic side chains facilitates the formation of micro-phase-separated morphologies and enhances anion conductivity.Moreover,the number of spacer atoms between the quaternary ammonium groups on the side chains affects the water uptake of the membranes,thus complicating the relationship between the density of cationic group distribution and anion conductivity.The poly(fluorenyl ether)s with dicationic side chains and six spacing atoms(DQA-PFE-C6)showed the highest anion conductivity.A VRFB assembled with DQA-PFE-C6 exhibited a maximum power density of 239.80 mW cm^−2 at 250 mA cm^−2,which is significantly higher than a VRFB assembled with Nafion 212.Therefore,side chain engineering is an effective chemical approach to enhance the properties of AEMs for VRFB applications.
文摘Although Yin-Yang Wu-Xing (Yin-Yang and Five-Elements, subsystems of human body) has been the theoretical basis of traditional Chinese medicine (TCM) for more than 5 000 years, it has been primarily analytical or empirical in nature without a formal scientific foundation. Based on bipolar set theory, an equilibrium/non-equilibrium computational model of Yin-Yang Wu-Xing is proposed. The Yin-Yang Wu-Xing dynamical systems are formulated so that equilibrium and non-equilibrium conditions can be established and proved. Computer simulations of equilibrium and non-equilibrium processes show that this new approach can provide diagnostic decision support in TCM. Thus, this equilibrium-based approach provides a unique scientific basis for future research in TCM, Qi (vital energy), QiGong, Meridians and Collaterals (acupuncture channels) and herbal treatment. On the other hand, it provides a basic Yin-Yang cellular network architecture for modem scientific research in genomics such that regulation mechanisms of the ubiquitous YY1 protein for cell processes can be explained.
基金supported by the Natural Science Foundation of Inner Mongolia Autonomous Region (2011ZD02)
文摘The different interactions between a chemosensor, 1-(naphthalen-2-yl)-3-(6-nitrobenzothiazol-2-yl)-thiourea (1), and F, acetate (AcO-), Cl-, and Br- anions have been investigated theoretically at the B3LYP/6-31+G(d,p) level with the basis set superposition error (BSSE) correction. It was found that the high selectivity of compound 1 for F- can be ascribed to the ability of the anion to deprotonate the N-H fragment of the host sensor, while the chemosensor also has a strong affinity for AcO- by virtue of the formation of a hydrogen-bonded complex. Intramolecular charge transfer (ICT) causes the colorimetric signaling of compound 1 after interaction with F-/AcO. A study of substituent effects suggested that the O/NH- and O/S-substituted derivatives are also expected to be promising candidates for chromogenic F3AcO chemosensors.