Aim To study the most stable pH value of endomorphin-1 solution and toestimate the shelf-life of EM-1 solution. Methods The content of EM-1 in its solution was determinedby HPLC, and stability was studied by accelerat...Aim To study the most stable pH value of endomorphin-1 solution and toestimate the shelf-life of EM-1 solution. Methods The content of EM-1 in its solution was determinedby HPLC, and stability was studied by accelerated tests. Results The most stable pH value of EM-1solution was observed. By the accelerated tests we obtained the Arrhe-nius relationship and thepharmacokinetic parameters. Conclusion The most stable pH value of EM-1 solution is 4.5 -4.8. Thet_(1/2)(25℃) is 45 d.展开更多
Following the study on effects of different root temperature treatments on growth and stomata of tomato plants under high temperature in summer, the influence of different root temperature treatments on microstructure...Following the study on effects of different root temperature treatments on growth and stomata of tomato plants under high temperature in summer, the influence of different root temperature treatments on microstructure of tomato leaves was studied in depth in this paper. The tomato plants were cultured with circulating nutrient solutions. Under three different root temperature treatments [（23±1）, （28±1）, （33±1）℃], the microstructure of tomato leaves were observed and measured with paraffin section method. The results showed that with the increase of root temperature, the thickness, palisade tissue thickness, spongy tissue thickness of tomato leaves all decreased, but the epidermis thickness and palisade tissue thickness to spongy tissue thickness ratio increased. Therefore, increased root temperature led to drought stress to tomato plants, and in order to adapt to the hot and drought environment, tomato plants changed their structural characteristics.展开更多
Nanosized FeCo- and FeCu-codoped ZnO particles were synthesized by rheological phase reaction-precursor method and the thermal decomposition of oxalate precursors was studied by thermogravimetry and differential therm...Nanosized FeCo- and FeCu-codoped ZnO particles were synthesized by rheological phase reaction-precursor method and the thermal decomposition of oxalate precursors was studied by thermogravimetry and differential thermal analysis in air atmosphere. X-ray analysis revealed that the FeCo- and FeCu-codoped ZnO crystallize in a wurtzite structure. Further characterization by HRTEM showed that no FeCo, FeCu clusters and other secondary phases were found in the samples. X-ray photoelectron spectroscopy and absorption spectra results indicated that Fe and Cu were mainly likely to have nominal Fe3＋ and Cu＋ and Co successfully incorporated into the wurtzite configurations, 2＋ lattice at the Zn2＋ sites. Curie temperature above room temperatures was observed from the FeCo- and FeCu-codoped ZnO nanoparticles. The origin of the observed ferromagnetism in the FeCo- and FeCu-codoped ZnO nanoparticles can be explained by Ruderman-Kittel-Kasuya-Yosida-type exchange mediated under the conduction carriers and the double-exchange-like interaction, respectively.展开更多
It is extremely important to study and understand the deformation behavior and strength characteristics of rocks under thermal-mechanical （TM） coupling effects. Failure behavior and strength characteristics of Pingd...It is extremely important to study and understand the deformation behavior and strength characteristics of rocks under thermal-mechanical （TM） coupling effects. Failure behavior and strength characteristics of Pingdingshan sandstone were investigated at room temperatures up to 300℃ in an internally heated apparatus and tensile load through meso-scale laboratory experiments in this work. 33 experiments have successfully been conducted for Pingdingshan sandstone. Experimental results indicated that the tensile strength increased slowly with temperatures from 25℃ to 100℃, and then sharply jumped from 100℃ to 150℃, and finally decreased slightly with temperatures from 150℃ to 300℃. And about 150℃ is the threshold temperature of strength and thermal cracking. At low temperatures （25℃-150℃）, sandstone strength is determined by relatively weak clay cement. However, at higher temperatures （150℃-300℃）, because of the strength enhancement of clay cement, sandstone strength is controlled by both mineral particles and clay cement. The effects of cement clay, micro-cracks closing, and thermal cracking were the possible reasons for our detailed analysis. In addition, the typical fracture position maps and nominal stress-strain curves indicated that the temperature had strong effects on the failure mechanism of sandstone. The fractograph implied that the dominant fracture mechanism tended to transform from brittle at low temperatures to ductile at high temperatures.展开更多
文摘Aim To study the most stable pH value of endomorphin-1 solution and toestimate the shelf-life of EM-1 solution. Methods The content of EM-1 in its solution was determinedby HPLC, and stability was studied by accelerated tests. Results The most stable pH value of EM-1solution was observed. By the accelerated tests we obtained the Arrhe-nius relationship and thepharmacokinetic parameters. Conclusion The most stable pH value of EM-1 solution is 4.5 -4.8. Thet_(1/2)(25℃) is 45 d.
文摘Following the study on effects of different root temperature treatments on growth and stomata of tomato plants under high temperature in summer, the influence of different root temperature treatments on microstructure of tomato leaves was studied in depth in this paper. The tomato plants were cultured with circulating nutrient solutions. Under three different root temperature treatments [（23±1）, （28±1）, （33±1）℃], the microstructure of tomato leaves were observed and measured with paraffin section method. The results showed that with the increase of root temperature, the thickness, palisade tissue thickness, spongy tissue thickness of tomato leaves all decreased, but the epidermis thickness and palisade tissue thickness to spongy tissue thickness ratio increased. Therefore, increased root temperature led to drought stress to tomato plants, and in order to adapt to the hot and drought environment, tomato plants changed their structural characteristics.
基金Acknowledgment： This work was supported by the National Nature Science Foundation of China （No. 20071026）. The authors thank professor ZHANG X. D and Dr. SUN Z. M. for helpful works on measuring the magnetic properties.
文摘Nanosized FeCo- and FeCu-codoped ZnO particles were synthesized by rheological phase reaction-precursor method and the thermal decomposition of oxalate precursors was studied by thermogravimetry and differential thermal analysis in air atmosphere. X-ray analysis revealed that the FeCo- and FeCu-codoped ZnO crystallize in a wurtzite structure. Further characterization by HRTEM showed that no FeCo, FeCu clusters and other secondary phases were found in the samples. X-ray photoelectron spectroscopy and absorption spectra results indicated that Fe and Cu were mainly likely to have nominal Fe3＋ and Cu＋ and Co successfully incorporated into the wurtzite configurations, 2＋ lattice at the Zn2＋ sites. Curie temperature above room temperatures was observed from the FeCo- and FeCu-codoped ZnO nanoparticles. The origin of the observed ferromagnetism in the FeCo- and FeCu-codoped ZnO nanoparticles can be explained by Ruderman-Kittel-Kasuya-Yosida-type exchange mediated under the conduction carriers and the double-exchange-like interaction, respectively.
基金supported by the National Natural Science Foundation of China(Grant No.11102225)the Special Funds for Major State Basic Research Project(Grant Nos. 2010CB732002 and 2011CB201201)+2 种基金the National Excellent Doctoral Dissertation of China(Grant No.201030)the Beijing Nova Program (Grant No.2010B062)the New Century Excellent Talents in University(Grant No.NCET-09-0726)
文摘It is extremely important to study and understand the deformation behavior and strength characteristics of rocks under thermal-mechanical （TM） coupling effects. Failure behavior and strength characteristics of Pingdingshan sandstone were investigated at room temperatures up to 300℃ in an internally heated apparatus and tensile load through meso-scale laboratory experiments in this work. 33 experiments have successfully been conducted for Pingdingshan sandstone. Experimental results indicated that the tensile strength increased slowly with temperatures from 25℃ to 100℃, and then sharply jumped from 100℃ to 150℃, and finally decreased slightly with temperatures from 150℃ to 300℃. And about 150℃ is the threshold temperature of strength and thermal cracking. At low temperatures （25℃-150℃）, sandstone strength is determined by relatively weak clay cement. However, at higher temperatures （150℃-300℃）, because of the strength enhancement of clay cement, sandstone strength is controlled by both mineral particles and clay cement. The effects of cement clay, micro-cracks closing, and thermal cracking were the possible reasons for our detailed analysis. In addition, the typical fracture position maps and nominal stress-strain curves indicated that the temperature had strong effects on the failure mechanism of sandstone. The fractograph implied that the dominant fracture mechanism tended to transform from brittle at low temperatures to ductile at high temperatures.
