Early drinking is considered to result in making tolerant of alcohol consumption and a higher prevalence of alcohol related disorders in the later. We focused generational impacts on drinking rate among high school st...Early drinking is considered to result in making tolerant of alcohol consumption and a higher prevalence of alcohol related disorders in the later. We focused generational impacts on drinking rate among high school students based on multiple nationwide data. The surveys were nationwide, cross-sectional random sampling surveys given every 4 years from the Japanese Youth Tobacco and Alcohol Surveys, 1996 to 2008. Participants were male 53,925 high school students from 7th grade to 11th grade. We divided to the three follow-up groups every 4 years from 1996 to 2004 for male junior high school students in 7th grades and the end periods were 4 years later in 11th grades. Outcome measures in this study were life time drinking, current drinking within 30 days and weekly drinking. All drinking rates decreased each at 7th and at 11th grade. The increments in these drinking rates from 7th grade to 11th grade in males decreased gradually in recent follow-up groups. Generational impacts should be considered by using follow-up groups to study drinking behaviors among students.展开更多
Blood alcohol concentration (BAC) differs greatly among individuals, even when people of the same sex and age drink alcohol under the same drinking conditions. In this study, we investigated the main factors involved ...Blood alcohol concentration (BAC) differs greatly among individuals, even when people of the same sex and age drink alcohol under the same drinking conditions. In this study, we investigated the main factors involved in the internal reg-ulation of individual differences in BAC, focusing on the alcohol dehydrogenase 1B (ADH1B) genotype, blood acetal-dehyde concentration (BAcH), amount of habitual alcohol consumption, pharmacokinetic parameters of BAC, distribution volume of ethanol (Vd), and gastric emptying rate (GER) under the same drinking conditions. Twenty healthy Japanese males aged between 40 and 59 years old and having the aldehyde dehydrogenase 2 (ALDH2) genotype of ALDH 2*1/*2 were recruited for this study. The subjects were given 0.32 g ethanol/kg body weight in the form of commercially available beer (5%, v/v). The results showed that BAC-max differed greatly among individuals with a more than two-fold variation. When the BAC-time curve was compared among ADH1B genotypes (ADH1B*1/*1, *1/*2, and *2/*2), there were no differences in BAC among the genotypes. Although BAcH, monthly alcohol consumption, elimination rate of blood ethanol (β value) and ethanol disappearance rate from the body (EDR) can affect BAC, all of them had no correlations with BAC-max. However, Vd (liter/kg), ΔPlasma glucose concentration (ΔPGC = PGC30 min ? PGC0 min) and the serum concentration of gastric inhibitory polypeptide (GIP) did correlate with BAC-max. Model 2 in multiple linear regression analysis showed the optimal model for Vd and GIP with positive correlations with BAC-max. As GIP and ΔPGC are both reflected by gastric emptying rate (GER), we concluded that the individual differences in BAC after moderate drinking are mainly regulated by GER together with Vd. These findings demonstrate that together with body water content, the gastrointestinal tract plays an important role in the regulation of individual differences in BAC, involving first pass metabolism of ethanol.展开更多
BACKGROUND Rectal carcinoma(RC),one of the most common malignancies globally,presents an increasing incidence and mortality year by year,especially among young people,which seriously affects the prognosis and quality ...BACKGROUND Rectal carcinoma(RC),one of the most common malignancies globally,presents an increasing incidence and mortality year by year,especially among young people,which seriously affects the prognosis and quality of life of patients.At present,dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)parameters and serum carbohydrate antigen 19-9(CA19-9)and CA125 Levels have been used in clinical practice to evaluate the T stage and differentiation of RC.However,the accuracy of these evaluation modalities still needs further research.This study explores the application and value of these methods in evaluating the T stage and differentiation degree of RC.AIM To analyze the diagnostic performance of DCE-MRI parameters combined with serum tumor markers(TMs)in assessing pathological processes and prognosis of RC patients.METHODS A retrospective analysis was performed on 104 RC patients treated at Yantai Yuhuangding Hospital from May 2018 to January 2022.Patients were categorized into stages T1,T2,T3,and T4,depending on their T stage and differentiation degree.In addition,they were assigned to low(L group)and moderate-high differentiation(M+H group)groups based on their differentiation degree.The levels of DCE-MRI parameters and serum CA19-9 and CA125 in different groups of patients were compared.In addition,the value of DCE-MRI parameters[volume transfer constant(Ktrans),rate constant(Kep),and extravascular extracellular volume fraction(Ve)in assessing the differentiation and T staging of RC patients was discussed.Furthermore,the usefulness of DCE-MRI parameters combined with serum CA19-9 and CA125 Levels in the evaluation of RC differentiation and T staging was analyzed.RESULTS Ktrans,Ve,CA19-9 and CA125 were higher in the high-stage group and L group than in the low-stage group and M+H Group,respectively(P<0.05).The areas under the curve(AUCs)of the Ktran and Ve parameters were 0.638 and 0.694 in the diagnosis of high and low stages,respectively,and 0.672 and 0.725 in diagnosing moderate-high and low differentiation,respectively.The AUC of DCE-MRI parameters(Ktrans+Ve)in the diagnosis of high and low stages was 0.742,and the AUC in diagnosing moderate-high and low differentiation was 0.769.The AUCs of CA19-9 and CA-125 were 0.773 and 0.802 in the diagnosis of high and low stages,respectively,and 0.834 and 0.796 in diagnosing moderate-high and low differentiation,respectively.Then,we combined DCE-MRI(Ktrans+Ve)parameters with CA19-9 and CA-125 and found that the AUC of DCE-MRI parameters plus serum TMs was 0.836 in the diagnosis of high and low stages and 0.946 in the diagnosis of moderate-high and low differentiation.According to the Delong test,the AUC of DCE-MRI parameters plus serum TMs increased significantly compared with serum TMs alone in the diagnosis of T stage and differentiation degree(P<0.001).CONCLUSION The levels of the DCE-MRI parameters Ktrans and Ve and the serum TMs CA19-9 and CA125 all increase with increasing T stage and decreasing differentiation degree of RC and can be used as indices to evaluate the differentiation degree of RC in clinical practice.Moreover,the combined evaluation of the above indices has a better effect and more obvious clinical value,providing important guiding importance for clinical condition judgment and treatment selection.展开更多
Steel 20Mn23AlV is a type of high aluminum steel with a very low ladle free-opening rate. The aluminum composition of 20Mn23AlV ranges from 1.6% to 2.45% ,which is significantly higher than other types of steel. Accor...Steel 20Mn23AlV is a type of high aluminum steel with a very low ladle free-opening rate. The aluminum composition of 20Mn23AlV ranges from 1.6% to 2.45% ,which is significantly higher than other types of steel. According to the real condition of 40 t ladle in steel-making plant of Baosteel Special Steel Company, previous works show that the key factors affecting the ladle free-opening rate of high aluminum steel in continuous casting are:sand material, accessories baking, ladle nozzle cleaning, the process and amount of adding sand, and the rate of argon stirring during refining. Therefore, improving the ladle filler sand quality, baking all of the raw materials, controlling the addition of ladle filler sand, cleaning the ladle nozzle, and optimizing argon stirring during the refining process can resolve the problem of a low ladle free-opening rate of high aluminum steel caused by the long ladle time of liquid steel.展开更多
Incorporating rate and state friction laws, stability of linearly stable (i.e., with stiffness greater than the critical value) spring-slider systems subjected to triggering perturbations was analyzed under variable...Incorporating rate and state friction laws, stability of linearly stable (i.e., with stiffness greater than the critical value) spring-slider systems subjected to triggering perturbations was analyzed under variable normal stress condition, and comparison was made between our results and that of fixed normal stress cases revealed in previous studies. For systems associated with the slip law, the critical mag- nitude of rate steps for triggering unstable slips are found to have a similar pattern to the fixed normal stress case, and the critical velocity steps scale with a/(b - a) when k = kcr for both cases. The rate-step boundaries for the variable normal stress cases are revealed to be lower than the fixed normal stress case by 7 %-16 % for a relatively large ct = 0.56 with (b - a)/a ranging from 0.25 to 1, indicating easier triggering under the variable normal stress condition with rate steps. The difference between fixed and variable normal stress cases decreases when the α value is smaller. In the same slip- law-type systems, critical displacements to trigger instability are revealed to be little affected by the variable normal stress condition. When k 〉 kcr(V,), a spring-slider system with the slowness law is much more stable than with the slip law,suggesting that the slowness law fits experimental data better when a single state variable is adopted. In stick-slip motions, the variable normal stress case has larger stress drops than the constant normal stress case. The variable normal stress has little effect on the range of slip velocity in systems associated with the slowness law, whereas systems associated with the slip law have a slowest slip velocity immensely smaller than the fixed normal stress case, by ~ 10 orders of magnitude.展开更多
The bactericidal effect on the representative type of Gram-negative Escherichia coli(E.coli) and Gram-positive Bacillus subtilis in drinking water was investigated in this paper by using dielectric barrier discharge...The bactericidal effect on the representative type of Gram-negative Escherichia coli(E.coli) and Gram-positive Bacillus subtilis in drinking water was investigated in this paper by using dielectric barrier discharge(DBD) advanced oxidation technology.The sterilizing rates under different conditions of reaction time t,input voltage V,p H value,and initial concentration of bacteria C_0 were investigated to figure out the optimum sterilization conditions.Our observations and comparisons of cell morphology alteration by scanning electron microscopy and transmission electron microscopy revealed the sterilization mechanisms.The results showed that the sterilizing rate increased obviously with the extension of reaction time t and the rise of input voltage V.The optimal sterilization effect was achieved when the p H value was 7.1.As the initial concentration of bacteria rose,the sterilizing rate decreased.When the input voltage was 2.2 k V and the initial concentration of bacteria was relatively low,the sterilizing rate almost reached 100% after a certain treatment time in neutral aqueous solution.The reasons for the great damage of cell structure and the killing of bacteria are the oxidation of O_3,OH and the accumulation of active species produced by DBD.The article provides a certain theoretical and experimental basis for DBD application in water pollution treatment.展开更多
The reformation of (Bi,Pb)-2223 from the liquid or melt is very important for a melting process of (Bi,Pb)-2223 tape. By combination of quenching experiment with X-ray diffraction (XRD) analysis, the effect of cooling...The reformation of (Bi,Pb)-2223 from the liquid or melt is very important for a melting process of (Bi,Pb)-2223 tape. By combination of quenching experiment with X-ray diffraction (XRD) analysis, the effect of cooling rate on the evolution of three superconducting phases in the (Bi,Pb)-2223 core of Ag-sheathed tape was investigated. The results show that (Bi,Pb)-2223 reformation from the melt seems to experience different routes during slowly cooling at different rates. One is that (Bi,Pb)-2223 phase reformed directly from the melt, and no Bi-2212 participate in this process. The other is that (Bi,Pb)-2223 is converted from the intermediate product, Bi-2212, which formed from the melt during the first cooling stage. Due to the inherent sluggish formation kinetics of (Bi,Pb)-2223 from Bi-2212, only partial (Bi,Pb)-2223 can finally be reformed with the second route.展开更多
The true stress-sWain relationships of Ti-5A1-2Sn-2Zr-4Mo-4Cr(TC17) alloy with a wide range of strain rates were investigated by tmiaxial quasi-static and dynamic compression tests, respectively. Quasi- static compr...The true stress-sWain relationships of Ti-5A1-2Sn-2Zr-4Mo-4Cr(TC17) alloy with a wide range of strain rates were investigated by tmiaxial quasi-static and dynamic compression tests, respectively. Quasi- static compression tests were carried out with Instron 8874 test machine, while dynamic compression tests were performed with the split Hopkinson pressure bar (SHPB) which was installed with heating device and synchro- assembly system. The dynamic mechanical behaviors tests of TC17 were carded out from room temperature to 800 ℃ at intervals of 200 ℃ and at high sWain rates (5 500-1 9200 s-l). The stress-strain curves considering temperature-sWain rate coupling actions were obtained. The Johnson-Cook constitutive model was developed through data fitting of the stress-sWain curves. The material constants in the developed constitutive model can be determined using isothermal and adiabatic stress-strain curves at different strain rates. The Johnson-Cook constitutive model provided satisfied prediction of the plastic flow stress for TC17 alloy.展开更多
This paper derives new and exact closed-form expressions for the average symbol error rate(SER) of square M-ary quadrature amplitude modulation(M-QAM) in wireless communication systems over theα-μfading channels sub...This paper derives new and exact closed-form expressions for the average symbol error rate(SER) of square M-ary quadrature amplitude modulation(M-QAM) in wireless communication systems over theα-μfading channels subject to an additive non-Gaussian noise. The obtained expressions take into account static and mobile wireless receivers. In addition, a closed-form expression for the outage probability in mobile networks is obtained. Please note that all derived expressions in this paper a valid for integer and non-integer values of the fading parameters. Analytical results are presented to study the impact of noise shaping parameter, severity of fading, and mobility on the average SER. Monte-Carlo simulations results are also provided to validate the accuracy of the analytical results.展开更多
Malus hupehensis (Pamp.) Rehd. is a widely cultivated rootstock in China. We studied the effect of three NO3-/NH4+ ratios (100/0, 50/50, and 0/100, molar basis) at total nitrogen (N) concentration of 8 mmoL L-1...Malus hupehensis (Pamp.) Rehd. is a widely cultivated rootstock in China. We studied the effect of three NO3-/NH4+ ratios (100/0, 50/50, and 0/100, molar basis) at total nitrogen (N) concentration of 8 mmoL L-1 in a nutrient solution on M. hupehensis seedlings. Plant biomass, NO3- and NH4+concentrafion, chlorophyll con- tent, respiratory rate, and cellular structure were investi- gated. M. hupehensis seedlings at the NO3-/NH4+ ratio of 50/50 had the highest level of fresh weight, dry weight, shoot length, and chlorophyll (a, b, and a + b) content, but the lowest respiration rate in the leavesand roots. In addition, thickness and numbers of palisade and spongy tissue cells of the leaves were greater with this treatment than with other treatments. At the NO3-/NH4+ ratio of 100/0, the leaves and roots had higher NO3- concentration and lower NH4+ concentration. However, the opposite trend occurred at the NO3-/NH4+ ratio of 0/100. Chloro- phyll (a, b, and a + b) content was lowest at the NO3-/NH4+ ratio of 100/0 than at the other ratios. At the NO3-/ NH4+ ratio of 0/100, oxygen (02) consumption increased in the leaves and roots, and irregular epidermis and cortex cells were observed in the root apical meristematic and mature region. Our results indicated that the NO3-INH4+ ratio at 50/50 was suitable for growth of M. hupehensis seedling to achieve the highest biomass production and efficiency.展开更多
Based upon broad-band CCD observation data of comet Hale-Bopp obtained by a 60cm telescope at Xinglong Station of Beijing Astronomical Observatory during March-August, 1996, the photometric results of comet Hale-Bopp ...Based upon broad-band CCD observation data of comet Hale-Bopp obtained by a 60cm telescope at Xinglong Station of Beijing Astronomical Observatory during March-August, 1996, the photometric results of comet Hale-Bopp are reported. Using the photometric results, the dust production rate, radius and mass of nucleus of comet Hale-Bopp are estimated as follows: dM/dt~1.5×10 5 kgs -1, R n~35.5km, and M n~5.65×10 16kg.展开更多
The effect of strain rate on plasticity has been Investigat-ed for three metallic materials with dynamic tension tech-nique. A phenomenon of high strain induced plasticity -increasing was found for tested materials. T...The effect of strain rate on plasticity has been Investigat-ed for three metallic materials with dynamic tension tech-nique. A phenomenon of high strain induced plasticity -increasing was found for tested materials. The elongation of quenched 30CrMnSiNi2A is 14. 5% under 40 m/s loading rate which is more than two times of the 7 % un-der 0. 5 mm/min. This typic high strain rate induced plasticity - Increasing phenomenon is associated with adiabatic heating, strain twinning and suppression of strain - induced - phase transformation.展开更多
In this paper, ultrasonic (20 kHz) fatigue tests were performed on specimens of a high-strength steel in very high cycle fatigue (VHCF) regime. Experimental results showed that for most tested specimens failed in ...In this paper, ultrasonic (20 kHz) fatigue tests were performed on specimens of a high-strength steel in very high cycle fatigue (VHCF) regime. Experimental results showed that for most tested specimens failed in a VHCF regime, a fatigue crack originated from the interior of specimen with a fish-eye pattern, which contained a fine granular area (FGA) centered by an inclusion as the crack origin. Then, a two-parameter model is proposed to predict the fatigue life of high-strength steels with fish-eye mode failure in a VHCF regime, which takes into account the inclusion size and the FGA size. The model was verified by the data of present experiments and those in the literature. Furthermore, an analytic formula was obtained for estimating the equivalent crack growth rate within the FGA. The results also indicated that the stress intensity factor range at the front of the FGA varies within a small range, which is irrespective of stress amplitude and fatigue life.展开更多
文摘Early drinking is considered to result in making tolerant of alcohol consumption and a higher prevalence of alcohol related disorders in the later. We focused generational impacts on drinking rate among high school students based on multiple nationwide data. The surveys were nationwide, cross-sectional random sampling surveys given every 4 years from the Japanese Youth Tobacco and Alcohol Surveys, 1996 to 2008. Participants were male 53,925 high school students from 7th grade to 11th grade. We divided to the three follow-up groups every 4 years from 1996 to 2004 for male junior high school students in 7th grades and the end periods were 4 years later in 11th grades. Outcome measures in this study were life time drinking, current drinking within 30 days and weekly drinking. All drinking rates decreased each at 7th and at 11th grade. The increments in these drinking rates from 7th grade to 11th grade in males decreased gradually in recent follow-up groups. Generational impacts should be considered by using follow-up groups to study drinking behaviors among students.
文摘Blood alcohol concentration (BAC) differs greatly among individuals, even when people of the same sex and age drink alcohol under the same drinking conditions. In this study, we investigated the main factors involved in the internal reg-ulation of individual differences in BAC, focusing on the alcohol dehydrogenase 1B (ADH1B) genotype, blood acetal-dehyde concentration (BAcH), amount of habitual alcohol consumption, pharmacokinetic parameters of BAC, distribution volume of ethanol (Vd), and gastric emptying rate (GER) under the same drinking conditions. Twenty healthy Japanese males aged between 40 and 59 years old and having the aldehyde dehydrogenase 2 (ALDH2) genotype of ALDH 2*1/*2 were recruited for this study. The subjects were given 0.32 g ethanol/kg body weight in the form of commercially available beer (5%, v/v). The results showed that BAC-max differed greatly among individuals with a more than two-fold variation. When the BAC-time curve was compared among ADH1B genotypes (ADH1B*1/*1, *1/*2, and *2/*2), there were no differences in BAC among the genotypes. Although BAcH, monthly alcohol consumption, elimination rate of blood ethanol (β value) and ethanol disappearance rate from the body (EDR) can affect BAC, all of them had no correlations with BAC-max. However, Vd (liter/kg), ΔPlasma glucose concentration (ΔPGC = PGC30 min ? PGC0 min) and the serum concentration of gastric inhibitory polypeptide (GIP) did correlate with BAC-max. Model 2 in multiple linear regression analysis showed the optimal model for Vd and GIP with positive correlations with BAC-max. As GIP and ΔPGC are both reflected by gastric emptying rate (GER), we concluded that the individual differences in BAC after moderate drinking are mainly regulated by GER together with Vd. These findings demonstrate that together with body water content, the gastrointestinal tract plays an important role in the regulation of individual differences in BAC, involving first pass metabolism of ethanol.
文摘BACKGROUND Rectal carcinoma(RC),one of the most common malignancies globally,presents an increasing incidence and mortality year by year,especially among young people,which seriously affects the prognosis and quality of life of patients.At present,dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)parameters and serum carbohydrate antigen 19-9(CA19-9)and CA125 Levels have been used in clinical practice to evaluate the T stage and differentiation of RC.However,the accuracy of these evaluation modalities still needs further research.This study explores the application and value of these methods in evaluating the T stage and differentiation degree of RC.AIM To analyze the diagnostic performance of DCE-MRI parameters combined with serum tumor markers(TMs)in assessing pathological processes and prognosis of RC patients.METHODS A retrospective analysis was performed on 104 RC patients treated at Yantai Yuhuangding Hospital from May 2018 to January 2022.Patients were categorized into stages T1,T2,T3,and T4,depending on their T stage and differentiation degree.In addition,they were assigned to low(L group)and moderate-high differentiation(M+H group)groups based on their differentiation degree.The levels of DCE-MRI parameters and serum CA19-9 and CA125 in different groups of patients were compared.In addition,the value of DCE-MRI parameters[volume transfer constant(Ktrans),rate constant(Kep),and extravascular extracellular volume fraction(Ve)in assessing the differentiation and T staging of RC patients was discussed.Furthermore,the usefulness of DCE-MRI parameters combined with serum CA19-9 and CA125 Levels in the evaluation of RC differentiation and T staging was analyzed.RESULTS Ktrans,Ve,CA19-9 and CA125 were higher in the high-stage group and L group than in the low-stage group and M+H Group,respectively(P<0.05).The areas under the curve(AUCs)of the Ktran and Ve parameters were 0.638 and 0.694 in the diagnosis of high and low stages,respectively,and 0.672 and 0.725 in diagnosing moderate-high and low differentiation,respectively.The AUC of DCE-MRI parameters(Ktrans+Ve)in the diagnosis of high and low stages was 0.742,and the AUC in diagnosing moderate-high and low differentiation was 0.769.The AUCs of CA19-9 and CA-125 were 0.773 and 0.802 in the diagnosis of high and low stages,respectively,and 0.834 and 0.796 in diagnosing moderate-high and low differentiation,respectively.Then,we combined DCE-MRI(Ktrans+Ve)parameters with CA19-9 and CA-125 and found that the AUC of DCE-MRI parameters plus serum TMs was 0.836 in the diagnosis of high and low stages and 0.946 in the diagnosis of moderate-high and low differentiation.According to the Delong test,the AUC of DCE-MRI parameters plus serum TMs increased significantly compared with serum TMs alone in the diagnosis of T stage and differentiation degree(P<0.001).CONCLUSION The levels of the DCE-MRI parameters Ktrans and Ve and the serum TMs CA19-9 and CA125 all increase with increasing T stage and decreasing differentiation degree of RC and can be used as indices to evaluate the differentiation degree of RC in clinical practice.Moreover,the combined evaluation of the above indices has a better effect and more obvious clinical value,providing important guiding importance for clinical condition judgment and treatment selection.
文摘Steel 20Mn23AlV is a type of high aluminum steel with a very low ladle free-opening rate. The aluminum composition of 20Mn23AlV ranges from 1.6% to 2.45% ,which is significantly higher than other types of steel. According to the real condition of 40 t ladle in steel-making plant of Baosteel Special Steel Company, previous works show that the key factors affecting the ladle free-opening rate of high aluminum steel in continuous casting are:sand material, accessories baking, ladle nozzle cleaning, the process and amount of adding sand, and the rate of argon stirring during refining. Therefore, improving the ladle filler sand quality, baking all of the raw materials, controlling the addition of ladle filler sand, cleaning the ladle nozzle, and optimizing argon stirring during the refining process can resolve the problem of a low ladle free-opening rate of high aluminum steel caused by the long ladle time of liquid steel.
基金supported by the National Natural Science Foundation of China under Grant Nos.40574080 and 41274186
文摘Incorporating rate and state friction laws, stability of linearly stable (i.e., with stiffness greater than the critical value) spring-slider systems subjected to triggering perturbations was analyzed under variable normal stress condition, and comparison was made between our results and that of fixed normal stress cases revealed in previous studies. For systems associated with the slip law, the critical mag- nitude of rate steps for triggering unstable slips are found to have a similar pattern to the fixed normal stress case, and the critical velocity steps scale with a/(b - a) when k = kcr for both cases. The rate-step boundaries for the variable normal stress cases are revealed to be lower than the fixed normal stress case by 7 %-16 % for a relatively large ct = 0.56 with (b - a)/a ranging from 0.25 to 1, indicating easier triggering under the variable normal stress condition with rate steps. The difference between fixed and variable normal stress cases decreases when the α value is smaller. In the same slip- law-type systems, critical displacements to trigger instability are revealed to be little affected by the variable normal stress condition. When k 〉 kcr(V,), a spring-slider system with the slowness law is much more stable than with the slip law,suggesting that the slowness law fits experimental data better when a single state variable is adopted. In stick-slip motions, the variable normal stress case has larger stress drops than the constant normal stress case. The variable normal stress has little effect on the range of slip velocity in systems associated with the slowness law, whereas systems associated with the slip law have a slowest slip velocity immensely smaller than the fixed normal stress case, by ~ 10 orders of magnitude.
基金supported by the Science and Technology Support Project Plan and Social Development of Jiangsu Province,China(No.BE2011732)the Science and Technology Support Project Plan and Social Development of Zhenjiang,Jiangsu Province,China(No.SH2012013)
文摘The bactericidal effect on the representative type of Gram-negative Escherichia coli(E.coli) and Gram-positive Bacillus subtilis in drinking water was investigated in this paper by using dielectric barrier discharge(DBD) advanced oxidation technology.The sterilizing rates under different conditions of reaction time t,input voltage V,p H value,and initial concentration of bacteria C_0 were investigated to figure out the optimum sterilization conditions.Our observations and comparisons of cell morphology alteration by scanning electron microscopy and transmission electron microscopy revealed the sterilization mechanisms.The results showed that the sterilizing rate increased obviously with the extension of reaction time t and the rise of input voltage V.The optimal sterilization effect was achieved when the p H value was 7.1.As the initial concentration of bacteria rose,the sterilizing rate decreased.When the input voltage was 2.2 k V and the initial concentration of bacteria was relatively low,the sterilizing rate almost reached 100% after a certain treatment time in neutral aqueous solution.The reasons for the great damage of cell structure and the killing of bacteria are the oxidation of O_3,OH and the accumulation of active species produced by DBD.The article provides a certain theoretical and experimental basis for DBD application in water pollution treatment.
文摘The reformation of (Bi,Pb)-2223 from the liquid or melt is very important for a melting process of (Bi,Pb)-2223 tape. By combination of quenching experiment with X-ray diffraction (XRD) analysis, the effect of cooling rate on the evolution of three superconducting phases in the (Bi,Pb)-2223 core of Ag-sheathed tape was investigated. The results show that (Bi,Pb)-2223 reformation from the melt seems to experience different routes during slowly cooling at different rates. One is that (Bi,Pb)-2223 phase reformed directly from the melt, and no Bi-2212 participate in this process. The other is that (Bi,Pb)-2223 is converted from the intermediate product, Bi-2212, which formed from the melt during the first cooling stage. Due to the inherent sluggish formation kinetics of (Bi,Pb)-2223 from Bi-2212, only partial (Bi,Pb)-2223 can finally be reformed with the second route.
基金Funded by the National Basic Research Program of China(No.2009CB724401)the Major Science and Technology Program of High-end CNC Machine Tools and Basic Manufacturing Equipment(No.2012ZX04003-041)
文摘The true stress-sWain relationships of Ti-5A1-2Sn-2Zr-4Mo-4Cr(TC17) alloy with a wide range of strain rates were investigated by tmiaxial quasi-static and dynamic compression tests, respectively. Quasi- static compression tests were carried out with Instron 8874 test machine, while dynamic compression tests were performed with the split Hopkinson pressure bar (SHPB) which was installed with heating device and synchro- assembly system. The dynamic mechanical behaviors tests of TC17 were carded out from room temperature to 800 ℃ at intervals of 200 ℃ and at high sWain rates (5 500-1 9200 s-l). The stress-strain curves considering temperature-sWain rate coupling actions were obtained. The Johnson-Cook constitutive model was developed through data fitting of the stress-sWain curves. The material constants in the developed constitutive model can be determined using isothermal and adiabatic stress-strain curves at different strain rates. The Johnson-Cook constitutive model provided satisfied prediction of the plastic flow stress for TC17 alloy.
基金the support of SNCS Research Center and the Deanship of Scientific Research at the University of Tabukfinancial and inkind support for the project no. S-1438-0161
文摘This paper derives new and exact closed-form expressions for the average symbol error rate(SER) of square M-ary quadrature amplitude modulation(M-QAM) in wireless communication systems over theα-μfading channels subject to an additive non-Gaussian noise. The obtained expressions take into account static and mobile wireless receivers. In addition, a closed-form expression for the outage probability in mobile networks is obtained. Please note that all derived expressions in this paper a valid for integer and non-integer values of the fading parameters. Analytical results are presented to study the impact of noise shaping parameter, severity of fading, and mobility on the average SER. Monte-Carlo simulations results are also provided to validate the accuracy of the analytical results.
基金supported by the Agricultural Comprehensive Development Project of Hebei Province(No.2012ACDPHP01)
文摘Malus hupehensis (Pamp.) Rehd. is a widely cultivated rootstock in China. We studied the effect of three NO3-/NH4+ ratios (100/0, 50/50, and 0/100, molar basis) at total nitrogen (N) concentration of 8 mmoL L-1 in a nutrient solution on M. hupehensis seedlings. Plant biomass, NO3- and NH4+concentrafion, chlorophyll con- tent, respiratory rate, and cellular structure were investi- gated. M. hupehensis seedlings at the NO3-/NH4+ ratio of 50/50 had the highest level of fresh weight, dry weight, shoot length, and chlorophyll (a, b, and a + b) content, but the lowest respiration rate in the leavesand roots. In addition, thickness and numbers of palisade and spongy tissue cells of the leaves were greater with this treatment than with other treatments. At the NO3-/NH4+ ratio of 100/0, the leaves and roots had higher NO3- concentration and lower NH4+ concentration. However, the opposite trend occurred at the NO3-/NH4+ ratio of 0/100. Chloro- phyll (a, b, and a + b) content was lowest at the NO3-/NH4+ ratio of 100/0 than at the other ratios. At the NO3-/ NH4+ ratio of 0/100, oxygen (02) consumption increased in the leaves and roots, and irregular epidermis and cortex cells were observed in the root apical meristematic and mature region. Our results indicated that the NO3-INH4+ ratio at 50/50 was suitable for growth of M. hupehensis seedling to achieve the highest biomass production and efficiency.
文摘Based upon broad-band CCD observation data of comet Hale-Bopp obtained by a 60cm telescope at Xinglong Station of Beijing Astronomical Observatory during March-August, 1996, the photometric results of comet Hale-Bopp are reported. Using the photometric results, the dust production rate, radius and mass of nucleus of comet Hale-Bopp are estimated as follows: dM/dt~1.5×10 5 kgs -1, R n~35.5km, and M n~5.65×10 16kg.
文摘The effect of strain rate on plasticity has been Investigat-ed for three metallic materials with dynamic tension tech-nique. A phenomenon of high strain induced plasticity -increasing was found for tested materials. The elongation of quenched 30CrMnSiNi2A is 14. 5% under 40 m/s loading rate which is more than two times of the 7 % un-der 0. 5 mm/min. This typic high strain rate induced plasticity - Increasing phenomenon is associated with adiabatic heating, strain twinning and suppression of strain - induced - phase transformation.
基金supported by the National Basic Research Program of China (Grant 2012CB937500)the National Natural Science Foundations of China (Grants 11172304 and 11202210)
文摘In this paper, ultrasonic (20 kHz) fatigue tests were performed on specimens of a high-strength steel in very high cycle fatigue (VHCF) regime. Experimental results showed that for most tested specimens failed in a VHCF regime, a fatigue crack originated from the interior of specimen with a fish-eye pattern, which contained a fine granular area (FGA) centered by an inclusion as the crack origin. Then, a two-parameter model is proposed to predict the fatigue life of high-strength steels with fish-eye mode failure in a VHCF regime, which takes into account the inclusion size and the FGA size. The model was verified by the data of present experiments and those in the literature. Furthermore, an analytic formula was obtained for estimating the equivalent crack growth rate within the FGA. The results also indicated that the stress intensity factor range at the front of the FGA varies within a small range, which is irrespective of stress amplitude and fatigue life.