Molecular self-assembly is extremely important in many fields, but the characterization of their corresponding intermolecular interactions is still lacking. The C-H stretching Raman band can reflect the hydrophobic in...Molecular self-assembly is extremely important in many fields, but the characterization of their corresponding intermolecular interactions is still lacking. The C-H stretching Raman band can reflect the hydrophobic interactions during the self-assembly process of sodium dodecyl sulfate （SDS） in aqueous solutions. However, the Raman spectra in this region are seriously overlapped by the OH stretching band of water. In this work, vertically polarized Raman spectra were used to improve the detection sensitivity of spectra of C-H region for the first time. The spectral results showed that the first critical micelle concentration and the second critical micelle concentration of SDS in water were 8.5 and 69 mmol/L, respectively, which were consistent with the results given by surface tension measurements. Because of the high sensitivity of vertically polarized Raman spectra, the critical micelle concentration of SDS in a relatively high concentration of salt solution could be obtained in our experiment. The two critical concentrations of SDS in 100 mmol/L NaCl solution were recorded to be 1.8 and 16.5 mmol/L, respectively. Through comparing the spectra and surface tension of SDS in water and in NaCl solution, the self-assembly process in bulk phase and at interface were discussed. The interactions among salt ions, SDS and water molecules were also analyzed. These results demonstrated the vertically polarized Raman spectra could be employed to study the self-assembly process of SDS in water.展开更多
In this paper, operation characteristic of condensate polishing system is studied during startup, based on generator blowdown limit, given limit ion concentration in condensate during condenser leakage. Further give c...In this paper, operation characteristic of condensate polishing system is studied during startup, based on generator blowdown limit, given limit ion concentration in condensate during condenser leakage. Further give conclusion about condensate polishing system configuration and operation requirement： full flow condensate polishing system （CPS） is necessary to the units cooled by sea water, and it is better that one or two series put in service during normal operation other than all of them in hot standby. While continuous condensate tube leakage is 256 L/h, the units cooled by fresh water will be shutdown immediately, for this level leakage, whichever condensate polishing system capacity is 50% （30%） or 100%, action level 2 will be preformed, so 50% （30%） is enough for fresh water cooled units.展开更多
The purpose of this study is to use magnetic field of 50/60 Hz up to 0.2 mT for energy source. This paper focuses on magnetic energy harvesting from electrical appliances which can be also used for power consumption m...The purpose of this study is to use magnetic field of 50/60 Hz up to 0.2 mT for energy source. This paper focuses on magnetic energy harvesting from electrical appliances which can be also used for power consumption monitoring. The magnetic energy harvesting device consists of an energy harvesting module, Cockcroft-Walton circuit and storage capacitor. First of all, typical magnetic fields around several electrical appliances are investigated. In order to harvest 10 mJ energy, the shape of magnetic flux concentration flange in energy harvesting module and number of steps in Cockcroft-Walton circuit are considered. From experimental results, magnetic energy harvesting of 17 mJ from a refrigerator is successfully demonstrated.展开更多
A combination of cascade aeration and biofiltration systems is one of the available ecological treatments to reduce the concentration of pollutants in grey water and resolve the problem of acute water crisis supply in...A combination of cascade aeration and biofiltration systems is one of the available ecological treatments to reduce the concentration of pollutants in grey water and resolve the problem of acute water crisis supply in Iraq. An experimental constructed grey water treatment system has been installed at AI-Mustansiriya University, College of Engineering during the period from January to December 2012. The performance of the treatment schemes has been evaluated by monitoring the quality of the raw grey water and effluent on these samples which are： pH, COD （chemical oxygen demand）, TSS （total suspended solids）, TDS （total dissolved solids）, PO43 （phosphates）, NO32 （nitrates）, NO （nitrites）, oils ＆ grease, NH3-N （ammonia-nitrogen） and some anions and cations. The average removal rate of COD was more than 60% that of NH3-N, NO3-N, NO2-N, TDS and TSS that were 55%-89%, 59%-74%, 79%-98%, 17%-52% and 51%-87%, respectively. Also the results indicate that the removal efficiency of ions concentrations such as Ca2＋, Mg2＋, Na＋, K＋ were 78%-96%, 73%-97%, 14%-47% and 44%-64%, respectively, while for cations such as SO42, Cl and PO43-, the removal efficiencies were 33%-79%, 27%-61% and 81%-99%, respectively. Finally oils ＆ grease was 79%-88%.展开更多
The pump-probe technique is an effective method to investigate ultrafast dynamics. And it is widely used in fundamental and application fields of Physics, Chemistry and Biology. The dynamics of bulk GaAs was investiga...The pump-probe technique is an effective method to investigate ultrafast dynamics. And it is widely used in fundamental and application fields of Physics, Chemistry and Biology. The dynamics of bulk GaAs was investigated by femtosecond laser. By changing the area of pump spot, different laser fluences were obtained to excite electron from valence states to conduction states. And it was found that the amplitude of reflectivity change is different. When the carrier density N is 1.44×10^18/cm^3, the change of refraction index is about Dnc=-3.33×10^-5. And when N is0. 36×10^10/cm^3, the change is -2.0×10^-5.展开更多
A differential carbon monoxide(CO) concentration sensing device using a self-fabricated spherical mirror(e.g.light-collector) and a multi-pass gas-chamber is presented in this paper.Single-source dual-channel detectio...A differential carbon monoxide(CO) concentration sensing device using a self-fabricated spherical mirror(e.g.light-collector) and a multi-pass gas-chamber is presented in this paper.Single-source dual-channel detection method is adopted to suppress the interferences from light source,optical path and environmental changes.Detection principle of the device is described,and both the optical part and the electrical part are developed.Experiments are carried out to evaluate the sensing performance on CO concentration.The results indicate that at 1.013×10~5 Pa and 298 K,the limit of detection(LoD) is about 11.5 mg/m^3 with an absorption length of 40 cm.As the gas concentration gets larger than115 mg/m^3(1.013×10~5 Pa,298 K),the relative detection error falls into the range of-1.7%—+1.9%.Based on 12 h long-term measurement on the 115 mg/m^3 and 1 150 mg/m^3 CO samples,the maximum detection errors are about0.9%and 5.5%,respectively.Due to the low cost and competitive characteristics,the proposed device shows potential applications in CO detection in the circumstances of coal-mine production and environmental protection.展开更多
Over the past 60 years, the air concentration in water has been considered as a control index of cavitation erosion reduction and widely used in the designs of hydraulic structures. However, the mechanism of air entra...Over the past 60 years, the air concentration in water has been considered as a control index of cavitation erosion reduction and widely used in the designs of hydraulic structures. However, the mechanism of air entrainment against cavitation erosion has been paid good attention to. In the present work, the effect of air bubble size on cavitation erosion reduction was experimentally investigated. A device with micron-scale orifice diameters(10, 20 and 50 μm in size) was specially designed to introduce air bubbles into water. The experiments about the effect of air bubble size were conducted by means of a vibratory apparatus, including the behavior of formation and movement for single air bubble, the characteristics of cavitation erosion reduction at different air entrainment conditions. The findings demonstrate that high air concentration has significant effects on cavitation erosion reduction.But, a notable problem was that the size of air bubbles is of outstanding effect on cavitation erosion reduction. Small air bubbles support to alleviate cavitation erosion, even at same air concentration.展开更多
The free flow on the step surfaces has received much attention for its representative body type,flow structure,water-air two phase flow,cavitation,and many complex issues.The experiments about the time-averaged pressu...The free flow on the step surfaces has received much attention for its representative body type,flow structure,water-air two phase flow,cavitation,and many complex issues.The experiments about the time-averaged pressure and aeration concentration distribution on the step surface show that the vertical plane of steps will inevitably experience negative pressure,which must rely on adequate aeration concentration to avoid cavitation damage.However,the self-aerated flow at the head section has a relatively low aeration concentration,and the concentration of the entire steps decreases with the increasing of weir head,the minimum appears in the vicinity of the corner,and the location is close to the minimum pressure.Thus,it is necessary to set aerator in the upstream end of the step surfaces to avoid cavitation damage.展开更多
基金This work is supported by the National Natural Science Foundation of China （No.21473171 and No.21573208）, the Pundamental Research Funds for the Central Universities （No.JB160508）, and the Huashan Mountain Scholar Program.
文摘Molecular self-assembly is extremely important in many fields, but the characterization of their corresponding intermolecular interactions is still lacking. The C-H stretching Raman band can reflect the hydrophobic interactions during the self-assembly process of sodium dodecyl sulfate （SDS） in aqueous solutions. However, the Raman spectra in this region are seriously overlapped by the OH stretching band of water. In this work, vertically polarized Raman spectra were used to improve the detection sensitivity of spectra of C-H region for the first time. The spectral results showed that the first critical micelle concentration and the second critical micelle concentration of SDS in water were 8.5 and 69 mmol/L, respectively, which were consistent with the results given by surface tension measurements. Because of the high sensitivity of vertically polarized Raman spectra, the critical micelle concentration of SDS in a relatively high concentration of salt solution could be obtained in our experiment. The two critical concentrations of SDS in 100 mmol/L NaCl solution were recorded to be 1.8 and 16.5 mmol/L, respectively. Through comparing the spectra and surface tension of SDS in water and in NaCl solution, the self-assembly process in bulk phase and at interface were discussed. The interactions among salt ions, SDS and water molecules were also analyzed. These results demonstrated the vertically polarized Raman spectra could be employed to study the self-assembly process of SDS in water.
文摘In this paper, operation characteristic of condensate polishing system is studied during startup, based on generator blowdown limit, given limit ion concentration in condensate during condenser leakage. Further give conclusion about condensate polishing system configuration and operation requirement： full flow condensate polishing system （CPS） is necessary to the units cooled by sea water, and it is better that one or two series put in service during normal operation other than all of them in hot standby. While continuous condensate tube leakage is 256 L/h, the units cooled by fresh water will be shutdown immediately, for this level leakage, whichever condensate polishing system capacity is 50% （30%） or 100%, action level 2 will be preformed, so 50% （30%） is enough for fresh water cooled units.
文摘The purpose of this study is to use magnetic field of 50/60 Hz up to 0.2 mT for energy source. This paper focuses on magnetic energy harvesting from electrical appliances which can be also used for power consumption monitoring. The magnetic energy harvesting device consists of an energy harvesting module, Cockcroft-Walton circuit and storage capacitor. First of all, typical magnetic fields around several electrical appliances are investigated. In order to harvest 10 mJ energy, the shape of magnetic flux concentration flange in energy harvesting module and number of steps in Cockcroft-Walton circuit are considered. From experimental results, magnetic energy harvesting of 17 mJ from a refrigerator is successfully demonstrated.
文摘A combination of cascade aeration and biofiltration systems is one of the available ecological treatments to reduce the concentration of pollutants in grey water and resolve the problem of acute water crisis supply in Iraq. An experimental constructed grey water treatment system has been installed at AI-Mustansiriya University, College of Engineering during the period from January to December 2012. The performance of the treatment schemes has been evaluated by monitoring the quality of the raw grey water and effluent on these samples which are： pH, COD （chemical oxygen demand）, TSS （total suspended solids）, TDS （total dissolved solids）, PO43 （phosphates）, NO32 （nitrates）, NO （nitrites）, oils ＆ grease, NH3-N （ammonia-nitrogen） and some anions and cations. The average removal rate of COD was more than 60% that of NH3-N, NO3-N, NO2-N, TDS and TSS that were 55%-89%, 59%-74%, 79%-98%, 17%-52% and 51%-87%, respectively. Also the results indicate that the removal efficiency of ions concentrations such as Ca2＋, Mg2＋, Na＋, K＋ were 78%-96%, 73%-97%, 14%-47% and 44%-64%, respectively, while for cations such as SO42, Cl and PO43-, the removal efficiencies were 33%-79%, 27%-61% and 81%-99%, respectively. Finally oils ＆ grease was 79%-88%.
文摘The pump-probe technique is an effective method to investigate ultrafast dynamics. And it is widely used in fundamental and application fields of Physics, Chemistry and Biology. The dynamics of bulk GaAs was investigated by femtosecond laser. By changing the area of pump spot, different laser fluences were obtained to excite electron from valence states to conduction states. And it was found that the amplitude of reflectivity change is different. When the carrier density N is 1.44×10^18/cm^3, the change of refraction index is about Dnc=-3.33×10^-5. And when N is0. 36×10^10/cm^3, the change is -2.0×10^-5.
基金supported in part by the National Key Technology R&D Program of China(Nos.2013BAK06B04 and 2014BAD08B03)the National Natural Science Foundation of China(Nos.61307124 and 11404129)+2 种基金the Science and Technology Department of Jilin Province of China(Nos.20120707 and 20140307014SF)the Changchun Municipal Science and Technology Bureau(Nos.11GH01 and 14KG022)the State Key Laboratory of Integrated Optoelectronics,Jilin University(No.IOSKL2012ZZ12)
文摘A differential carbon monoxide(CO) concentration sensing device using a self-fabricated spherical mirror(e.g.light-collector) and a multi-pass gas-chamber is presented in this paper.Single-source dual-channel detection method is adopted to suppress the interferences from light source,optical path and environmental changes.Detection principle of the device is described,and both the optical part and the electrical part are developed.Experiments are carried out to evaluate the sensing performance on CO concentration.The results indicate that at 1.013×10~5 Pa and 298 K,the limit of detection(LoD) is about 11.5 mg/m^3 with an absorption length of 40 cm.As the gas concentration gets larger than115 mg/m^3(1.013×10~5 Pa,298 K),the relative detection error falls into the range of-1.7%—+1.9%.Based on 12 h long-term measurement on the 115 mg/m^3 and 1 150 mg/m^3 CO samples,the maximum detection errors are about0.9%and 5.5%,respectively.Due to the low cost and competitive characteristics,the proposed device shows potential applications in CO detection in the circumstances of coal-mine production and environmental protection.
基金supported by the National Natural Science Foundation of China(Grant No.51409187)the Fundamental Research Funds for the Central Universities(Grant No.2016B09914)
文摘Over the past 60 years, the air concentration in water has been considered as a control index of cavitation erosion reduction and widely used in the designs of hydraulic structures. However, the mechanism of air entrainment against cavitation erosion has been paid good attention to. In the present work, the effect of air bubble size on cavitation erosion reduction was experimentally investigated. A device with micron-scale orifice diameters(10, 20 and 50 μm in size) was specially designed to introduce air bubbles into water. The experiments about the effect of air bubble size were conducted by means of a vibratory apparatus, including the behavior of formation and movement for single air bubble, the characteristics of cavitation erosion reduction at different air entrainment conditions. The findings demonstrate that high air concentration has significant effects on cavitation erosion reduction.But, a notable problem was that the size of air bubbles is of outstanding effect on cavitation erosion reduction. Small air bubbles support to alleviate cavitation erosion, even at same air concentration.
基金The National Basic Research Program of China("973"Project)(Grant No.2013CB035905)The National Natural Science Foundation of China(Grant No.51179114)
文摘The free flow on the step surfaces has received much attention for its representative body type,flow structure,water-air two phase flow,cavitation,and many complex issues.The experiments about the time-averaged pressure and aeration concentration distribution on the step surface show that the vertical plane of steps will inevitably experience negative pressure,which must rely on adequate aeration concentration to avoid cavitation damage.However,the self-aerated flow at the head section has a relatively low aeration concentration,and the concentration of the entire steps decreases with the increasing of weir head,the minimum appears in the vicinity of the corner,and the location is close to the minimum pressure.Thus,it is necessary to set aerator in the upstream end of the step surfaces to avoid cavitation damage.
