Basing on the DFT calculations we propose the new theoretical model which describes both the surface tension σ of the short chain n-alkanes at their normal boiling points and their reaction rate constants with hydrox...Basing on the DFT calculations we propose the new theoretical model which describes both the surface tension σ of the short chain n-alkanes at their normal boiling points and their reaction rate constants with hydroxyl radicals OH<span style="white-space:nowrap;">•</span> (at 297 ± 2 K) on the basis of their molecular orbital electronic characteristics. It has been shown that intermolecular dispersion attraction within the surface liquid monolayer of these compounds, as well as their reaction rate constants k with OH<span style="white-space:nowrap;">•</span> radicals are determined by the energies <em>E<sub>orb</sub></em> of the specific occupied molecular orbitals which are the same in the determination of both the above physico-chemical characteristics of the studied n-alkanes. The received regression equations confirm the theoretically found dependences between the quantities of σ and k and the module |<em>E<sub>orb</sub></em>|. For the compounds under study this fact indicates the key role of their electronic structure particularities in determination of both the physical (surface tension) and the chemical (reaction rate constants) properties.展开更多
[Objectives] To explore the effects of Danqu capsules(the prescription of Lei Zhongyi, the master of traditional Chinese medicine for the syndrome of intermingling of phlegm and static blood of coronary heart disease)...[Objectives] To explore the effects of Danqu capsules(the prescription of Lei Zhongyi, the master of traditional Chinese medicine for the syndrome of intermingling of phlegm and static blood of coronary heart disease) on arterial blood pressure, heart rate and myocardial tension time index in rats. [Methods] A total of 50 SD rats, weighing(300±20) g, were randomly and evenly divided into Danqu capsule observation groups(low, middle and high-dose groups) and control groups(saline group and captopril group). Under anesthesia, the rats in each group were administered with 0.6, 1.2 and 2.4 g/kg of Danqu capsule suspension, 1 mL/100 g of saline and 10 mg/kg of captopril, respectively through duodena, and their systolic blood pressure, diastolic blood pressure, mean arterial pressure, pulse pressure difference and heart rate were measured and recorded by RM6240 multi-channel physiological signal acquisition and processing system before administration, 10, 20, 30, 40, 50, 60, 90 and 120 min after the administration, respectively, and the myocardial tension time index was calculated. [Results] Compared with the saline group, the systolic, diastolic and mean pressure reduced 10, 20, 30, 40, 50, 60, 90 and 120 min after the administration, and the pulse pressure difference did not change significantly in the Danqu capsule groups(low, middle and high-dose groups), and the heart rate slowed down and the myocardial tension time index reduced in the high-dose Danqu capsule group. Compared with the captopril group, the Danqu capsule groups showed similar blood pressure-reducing effect. [Conclusions]Danqu capsules have obvious effect of lowering blood pressure and myocardial tension time index. High-dose Danqu capsules has the effect of slowing down the heart rate. The blood pressure-lowering effect of Danqu capsules shows a dose-dependent manner. Clinically, they can be used in patients with coronary heart diseases and hypertension, suggesting that they should be used with caution in patients with hypotension.展开更多
The major objective of this research was to discuss the effects of loading rate on the flexural-tension properties and uniaxial compressive strength of micro-surfacing mixture using three-point bending test and uniaxi...The major objective of this research was to discuss the effects of loading rate on the flexural-tension properties and uniaxial compressive strength of micro-surfacing mixture using three-point bending test and uniaxial compressive test respectively. As a preventive maintenance surface treatment on asphalt pavement, micro-surfacing was formed on the basis of the ISSA recommendation of an optimum micro-surfacing design. Tests were conducted over a wide range of temperature to investigate the difference of properties from low loading rate to a relatively high loading rate. Three-point bending test was used to study the flexural strength, strain and modulus of micro-surfacing mixture, and uniaxial compressive test was carried out to obtain the relationship between strength and the loading rate as well as temperature. The experimental results showed that flexural strength at high loading rate was larger than that at low loading rate. The flexural strength difference between low and high loading rate enlarged when the temperature rose. The flexural strain at high loading rate increased compared with results of the low loading rate. Results of the flexural modulus revealed that micro-surfacing mixture exhibited better anti-cracking characteristic at low temperature when given a relatively low loading rate. Results of uniaxial compressive test revealed that the strength difference of micro-surfacing among different loading rates increased with the increase of temperature. The logarithm relationship between the strength and loading rate over a wide range of temperature was obtained to compare the experimental and predicted values, which resulting in a reasonable consistency.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
WEDM is used in machining conductive materials where it is required to obtained complicated and intricate shapes with high accuracy.Various applications are in the field of automobile,medical industries,aerospace etc....WEDM is used in machining conductive materials where it is required to obtained complicated and intricate shapes with high accuracy.Various applications are in the field of automobile,medical industries,aerospace etc.WEDM is an economical machining option with short product development cycle.Surface roughness,kerf width,Material removal rate,Recast layer hardness and surface microhardness in WEDM are most important responses.In this paper,effect of varied Wire tension on SR,KW,MRR,RCL hardness and surface microhardness on AISI 304 have been investigated.Pulse on time,pulse off time,current and dielectric fluid are taken as fixed parameter.Results show that Wire tension influences the SR,MRR and Surface microhardness and has no effect on kerf width in case of Stainless steel304.展开更多
文摘Basing on the DFT calculations we propose the new theoretical model which describes both the surface tension σ of the short chain n-alkanes at their normal boiling points and their reaction rate constants with hydroxyl radicals OH<span style="white-space:nowrap;">•</span> (at 297 ± 2 K) on the basis of their molecular orbital electronic characteristics. It has been shown that intermolecular dispersion attraction within the surface liquid monolayer of these compounds, as well as their reaction rate constants k with OH<span style="white-space:nowrap;">•</span> radicals are determined by the energies <em>E<sub>orb</sub></em> of the specific occupied molecular orbitals which are the same in the determination of both the above physico-chemical characteristics of the studied n-alkanes. The received regression equations confirm the theoretically found dependences between the quantities of σ and k and the module |<em>E<sub>orb</sub></em>|. For the compounds under study this fact indicates the key role of their electronic structure particularities in determination of both the physical (surface tension) and the chemical (reaction rate constants) properties.
基金Supported by Science and Technology Coordination Innovation Project in Shaanxi Province(2016TZC-S-14-3)
文摘[Objectives] To explore the effects of Danqu capsules(the prescription of Lei Zhongyi, the master of traditional Chinese medicine for the syndrome of intermingling of phlegm and static blood of coronary heart disease) on arterial blood pressure, heart rate and myocardial tension time index in rats. [Methods] A total of 50 SD rats, weighing(300±20) g, were randomly and evenly divided into Danqu capsule observation groups(low, middle and high-dose groups) and control groups(saline group and captopril group). Under anesthesia, the rats in each group were administered with 0.6, 1.2 and 2.4 g/kg of Danqu capsule suspension, 1 mL/100 g of saline and 10 mg/kg of captopril, respectively through duodena, and their systolic blood pressure, diastolic blood pressure, mean arterial pressure, pulse pressure difference and heart rate were measured and recorded by RM6240 multi-channel physiological signal acquisition and processing system before administration, 10, 20, 30, 40, 50, 60, 90 and 120 min after the administration, respectively, and the myocardial tension time index was calculated. [Results] Compared with the saline group, the systolic, diastolic and mean pressure reduced 10, 20, 30, 40, 50, 60, 90 and 120 min after the administration, and the pulse pressure difference did not change significantly in the Danqu capsule groups(low, middle and high-dose groups), and the heart rate slowed down and the myocardial tension time index reduced in the high-dose Danqu capsule group. Compared with the captopril group, the Danqu capsule groups showed similar blood pressure-reducing effect. [Conclusions]Danqu capsules have obvious effect of lowering blood pressure and myocardial tension time index. High-dose Danqu capsules has the effect of slowing down the heart rate. The blood pressure-lowering effect of Danqu capsules shows a dose-dependent manner. Clinically, they can be used in patients with coronary heart diseases and hypertension, suggesting that they should be used with caution in patients with hypotension.
文摘The major objective of this research was to discuss the effects of loading rate on the flexural-tension properties and uniaxial compressive strength of micro-surfacing mixture using three-point bending test and uniaxial compressive test respectively. As a preventive maintenance surface treatment on asphalt pavement, micro-surfacing was formed on the basis of the ISSA recommendation of an optimum micro-surfacing design. Tests were conducted over a wide range of temperature to investigate the difference of properties from low loading rate to a relatively high loading rate. Three-point bending test was used to study the flexural strength, strain and modulus of micro-surfacing mixture, and uniaxial compressive test was carried out to obtain the relationship between strength and the loading rate as well as temperature. The experimental results showed that flexural strength at high loading rate was larger than that at low loading rate. The flexural strength difference between low and high loading rate enlarged when the temperature rose. The flexural strain at high loading rate increased compared with results of the low loading rate. Results of the flexural modulus revealed that micro-surfacing mixture exhibited better anti-cracking characteristic at low temperature when given a relatively low loading rate. Results of uniaxial compressive test revealed that the strength difference of micro-surfacing among different loading rates increased with the increase of temperature. The logarithm relationship between the strength and loading rate over a wide range of temperature was obtained to compare the experimental and predicted values, which resulting in a reasonable consistency.
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.
文摘WEDM is used in machining conductive materials where it is required to obtained complicated and intricate shapes with high accuracy.Various applications are in the field of automobile,medical industries,aerospace etc.WEDM is an economical machining option with short product development cycle.Surface roughness,kerf width,Material removal rate,Recast layer hardness and surface microhardness in WEDM are most important responses.In this paper,effect of varied Wire tension on SR,KW,MRR,RCL hardness and surface microhardness on AISI 304 have been investigated.Pulse on time,pulse off time,current and dielectric fluid are taken as fixed parameter.Results show that Wire tension influences the SR,MRR and Surface microhardness and has no effect on kerf width in case of Stainless steel304.
