Background: In recent years, Burkina Faso has faced increasing insecurity and terrorist attacks. The police, gendarmerie, and justice services are very often in demand to carry out criminal investigations, which are s...Background: In recent years, Burkina Faso has faced increasing insecurity and terrorist attacks. The police, gendarmerie, and justice services are very often in demand to carry out criminal investigations, which are slowed down or incomplete due to the absence of DNA analysis on biological samples from crime scenes and on apprehended suspects. The purpose of this study was to evaluate the contribution of DNA analysis to the resolution of criminal cases in Burkina Faso. Methodology: This study was carried out from June 2019 to July 2020. Three (03) crimes were investigated, and DNA analysis was performed on biological samples from the crime scene, suspects, and victims using the AmpFlSTR® identifiler® Direct kit on the ABI 3130 Genetic Analyzer. Results: In the explosion case, the alleles found in the victim were the same as those identified in the blood trace from the crime scene. In the armed robbery case, there was a perfect match between the DNA profile of the blood trail and that of suspect 2 for all 15 STRs analyzed. In the murder case, the DNA profile of the murdered man’s son and the DNA profile of the biological trace were identical. Conclusion: The DNA analyses carried out in criminal cases have identified the perpetrators of the crimes. Their guilt or innocence will be confirmed by the investigators during the interrogations and hearings.展开更多
The editor regrets that they inadvertently pasted the wrong figure during the production stage.The correct Fig.7 should be as below:The editor would like to apologise for any inconvenience caused.
The growth of computing power in data centers(DCs)leads to an increase in energy consumption and noise pollution of air cooling systems.Chip-level cooling with high-efficiency coolant is one of the promising methods t...The growth of computing power in data centers(DCs)leads to an increase in energy consumption and noise pollution of air cooling systems.Chip-level cooling with high-efficiency coolant is one of the promising methods to address the cooling challenge for high-power devices in DCs.Hybrid nanofluid(HNF)has the advantages of high thermal conductivity and good rheological properties.This study summarizes the numerical investigations of HNFs in mini/micro heat sinks,including the numerical methods,hydrothermal characteristics,and enhanced heat transfer technologies.The innovations of this paper include:(1)the characteristics,applicable conditions,and scenarios of each theoretical method and numerical method are clarified;(2)the molecular dynamics(MD)simulation can reveal the synergy effect,micro motion,and agglomeration morphology of different nanoparticles.Machine learning(ML)presents a feasiblemethod for parameter prediction,which provides the opportunity for the intelligent regulation of the thermal performance of HNFs;(3)the HNFs flowboiling and the synergy of passive and active technologies may further improve the overall efficiency of liquid cooling systems in DCs.This review provides valuable insights and references for exploring the multi-phase flow and heat transport mechanisms of HNFs,and promoting the practical application of HNFs in chip-level liquid cooling in DCs.展开更多
Ground penetrating radar （GPR） attribute technology has been applied to many aspects in recent years but there are very few examples in the field of archaeology. Especially how can we extract effective attributes fr...Ground penetrating radar （GPR） attribute technology has been applied to many aspects in recent years but there are very few examples in the field of archaeology. Especially how can we extract effective attributes from the two- or three-dimensional radar data so that we can map and describe numerous archaeological targets in a large cultural site？ In this paper, we applied GPR attribute technology to investigate the ancient Nanzhao castle-site in Tengchong, Yunnan Province. In order to get better archaeological target （the ancient wall, the ancient kiln site, and the ancient tomb） analysis and description, we collated the GPR data by collected standardization and then put them to the seismic data processing and interpretation workstation. The data was processed, including a variety of GPR attribute extraction, analysis, and optimization and combined with the archaeological drilling data. We choose the RMS Amplitude, Average Peak Amplitude, Instantaneous Phase, and Maximum Peak Time to interpret three archaeological targets. By comparative analysis, we have clarified that we should use different attributes to interpret different archaeological targets and the results of attribute analysis after horizon tracking is much better than the results based on a time slice.展开更多
In order to carry out the comprehensive reform of the professional master’s degree training mode of clinical pharmacy, we carried out interviews among 91 persons on the professional master’s degree of clinical pharm...In order to carry out the comprehensive reform of the professional master’s degree training mode of clinical pharmacy, we carried out interviews among 91 persons on the professional master’s degree of clinical pharmacy in Peking University School of Pharmaceutical Sciences and collected extensive feedback. We preliminaries explore the mode of Doctor of Pharmacy（Pharm. D.） Education, laying the foundation for Doctor’s education of professional clinical pharmacy in China. We conducted investigations and interviews among 91 clinical pharmacists and students of Peking University School of Pharmaceutical Sciences on the training of professional master’s degree and Pharm. D. education mode, which includes 67 postgraduates and 24 clinical pharmacists. Respondents put forward the problems of training mode and corresponding suggestions and opinions from different aspects during the investigation and interview. The results mainly divide into four aspects： curriculum setting, clinical practice, assessme nt system and teaching resources. Respondents put forward effective feedback on the above four aspects, which are beneficial to the comprehensive reform of the training mode of professional master degree in clinical pharmacy and preliminary exploration of Pharm. D. Education in China.展开更多
Careful and thorough incident investigations and pre-job safety analyses completed by knowledgeable and competent individuals can significantly reduce workplace incidents. Working parties must act together to make the...Careful and thorough incident investigations and pre-job safety analyses completed by knowledgeable and competent individuals can significantly reduce workplace incidents. Working parties must act together to make these safety tools effective. To get the staff units to work together in a co-ordinated manner, they must be shown the value of their work in preventing accidents. Examples of actual accidents investigated during the author's 18 years as a mine inspector in Saskatchewan are discussed within the context of pre-job safety analyses. The causes of the accidents are explored with close reference to how pre-job safety analyses could have prevented their occurrence.展开更多
Perovskite-type oxides of LaMnO3 were synthesized by means of the sol-gel method, in the presence of citric acid as gelling agent. The precursors used were Mn（NO3）2·H2O, La2O3, and NaOH,mixed in the stoichiomet...Perovskite-type oxides of LaMnO3 were synthesized by means of the sol-gel method, in the presence of citric acid as gelling agent. The precursors used were Mn（NO3）2·H2O, La2O3, and NaOH,mixed in the stoichiometric ratio to obtain perovskite materials. The obtained gel was heat-treated at 400, 600 and 800 ℃ respectively, for 6 h. X-ray diffraction and FT-IR spectroscopy were used to analyze the phase transformation as a function of temperature, and the Rietveld refinement was used in order to characterize the materials obtained structurally. The average crystallite size of the products was calculated from XRD data and the average particle size was measured from the TEM micrographs. At 600 ℃, the synthesized compound is well-crystallized, showcases a perovskite structure（Pm-3m space group）, and exhibits uniform and homogeneous hexagonally-shaped particles, with sizes in the 20-50 nm range.Complex impedance measurements in the 20-2 × 10^6 Hz frequency range were carried out at different temperatures（26-115 ℃）, and the electrical conduction mechanism is discussed.展开更多
In order to reveal combustion characteristics of H_2/air mixture in a micro-combustor with and without bluff body, the effects of inlet velocities, equivalence ratios and bluff body's blockage ratios on the temper...In order to reveal combustion characteristics of H_2/air mixture in a micro-combustor with and without bluff body, the effects of inlet velocities, equivalence ratios and bluff body's blockage ratios on the temperature field, pressure of the combustor wall, combustion efficiency and blow-off limit were investigated. The numerical results indicate that the sudden expansion plate micro combustor with bluff body could enhance the turbulent disturbance of the mixed gas in the combustion chamber and the combustion condition is improved. Moreover, a low-speed and high temperature recirculation region was formed between the sudden expansion step and the bluff body so that the high and uniform wall temperature(>1000 K) could be gotten. As a result, it could strengthen the mixing process, prolong the residence time of gas, control the flame position effectively and widen the operation range by the synergistic effect of the bluff body and steps. When the blockage ratio ranged from 0.3 to 0.6, it could be found that the bluff body could play a stabilizing effect and expand combustion blow burning limit, and combustion efficiency firstly was increased with the inlet velocity and equivalence ratio, and then was decreased.展开更多
AIM:To ascertain the pattern of investigations at first contact in uveitic patients and evaluate compliance to treatment.METHODS:An observational study comprised of 201 uveitic patients presenting for the first time t...AIM:To ascertain the pattern of investigations at first contact in uveitic patients and evaluate compliance to treatment.METHODS:An observational study comprised of 201 uveitic patients presenting for the first time to our centre from January 2019 to June 2020.Detailed information regarding systemic investigations undertaken by specialists at the time of first contact and the cost of these investigations were reviewed on the first visit to our centre.Compliance with the treatment was determined and reasons behind non-compliance were evaluated on the first follow-up in patients who had no improvement in clinical signs and symptoms.RESULTS:The mean age of the study group was 35.35±14.1y and gender composition was 59.7%males and 40.3%females.Anterior uveitis was observed in 45.3%of patients,intermediate uveitis in 31.8%of patients,posterior uveitis in 14.9%of patients and panuveitis in 8.0%of patients.Association with a systemic disease was evident in 17.9%of patients.When compared with standard guidelines and uveitis patterns,systemic investigations were identified to be relevant only in 38.3%of patients.Non-compliance to treatment was documented in 22.4%of patients.Common reasons for non-compliance were inadequate counselling by the treating physician about treatment in 26.7%of patients and a busy schedule at work/school in 22.2%of patients.CONCLUSION:Significant number of investigations performed at first contact is found to be contrary to standard guidelines and are not contributory to the care.About a quarter of patients in this study are found to be non-compliant with the treatment.Compliance is more challenging to achieve in school-going children and working adults.The availability of comprehensive,periodically updated,evidence-based guidelines on the role of investigations and the use of trained counsellors may help to channelize proper evaluation and improve compliance to treatment,respectively,in patients with uveitis.展开更多
The electronic structures of PF and PF＋ are calculated with the high-level configuration interaction method. To improve the precision of calculations, the spin-orbit coupling effect, the scalar relativistic effect, a...The electronic structures of PF and PF＋ are calculated with the high-level configuration interaction method. To improve the precision of calculations, the spin-orbit coupling effect, the scalar relativistic effect, and the Davidson correction（q-Q） are also considered. The spectroscopic parameters of bound states are derived by the electronic structures of PF and PF＋, which are in good accordance with the measurements. The transition dipole moments of spin-allowed transitions are evaluated, and the radiative lifetimes of several A S states of PF and PF＋ are obtained.展开更多
Aluminum/steel electric transition joints (ETJs) are used in aluminum reduction cell for the purpose of welding aluminum rod and steel bracket components. Solid state welding process used for joining aluminum and stee...Aluminum/steel electric transition joints (ETJs) are used in aluminum reduction cell for the purpose of welding aluminum rod and steel bracket components. Solid state welding process used for joining aluminum and steel at the electric transition joints have the drawbacks of cracking and separation at the interface surfaces. Cracking and separation at the electric transition joints are caused by the stress singularities that developed due to the mismatch in thermal and mechanical properties of each material. To overcome the drawback of electric transition joints, aluminum/steel functionally graded may be used as electric transition joints or proposed. Therefore manufacturing and investigation of aluminum/steel functionally graded materials fabricated by powder metallurgy process were carried out through the current work. Different samples with different layers of aluminum/steel functionally graded materials were compacted using steel die and punch at the same compacted pressure and sintered temperature. After investigating the different samples of aluminum/steel functionally graded materials under different fabrication conditions, the suitable fabrication regime was determined with the aid of microscopic observations.展开更多
Crystal structure predictions of Pb0.5Ba0.5 Ti03 alloys under different pressures are performed based on the parti- cle swarming optimization algorithm. The predicted stable ground-state and high-pressure phases are t...Crystal structure predictions of Pb0.5Ba0.5 Ti03 alloys under different pressures are performed based on the parti- cle swarming optimization algorithm. The predicted stable ground-state and high-pressure phases are tetragonal ferroelectric （I4mm） and cubic para-electric （Fm3m）, respectively, whose structural details have not been re- ported. The pressure-induced colossal enhancements in piezoelectric response are associated with the mechanical and dynamical instabilities instead of polarization rotation. The band gap of the tetragonM phase is indirect and that of the cubic phase is always direct. As pressure increases, the alloy displays the similar band-gap behaviors to PbTiO3, while different from BaTiO5, which is attributed to the different orbital contributions to the valence bands. Our calculated results are in good agreement with the available data.展开更多
Iron ions were used as probes to explore the structural and magnetic properties of 70TeO2'25B2O3' 5SrF2 vitreous matrix. The distribution of Fe3+ ions on different structural aggregates was revealed by means ...Iron ions were used as probes to explore the structural and magnetic properties of 70TeO2'25B2O3' 5SrF2 vitreous matrix. The distribution of Fe3+ ions on different structural aggregates was revealed by means of EPR, as depending on Fe2O3 concentration. Strongly distorted octahedral sites were detected for the isolated paramagnetic ions, and also clusters of Fe ions especially at high Fe2O3 content of samples. Magnetic susceptibility measurements evidenced both dipoledipole and superexchange type interactions involving iron ions. Mixed valence states of iron ions were also detected展开更多
Described here are the fabrication and characterization of carbon fiber cylinder ultramicroelectrodes with cylinder length of less than 100 am, total tip diameter of several hundreds nanometers. The electrodes have be...Described here are the fabrication and characterization of carbon fiber cylinder ultramicroelectrodes with cylinder length of less than 100 am, total tip diameter of several hundreds nanometers. The electrodes have been fabricated by direct etching of carbon fiber using an ion beam thinner. Optical microscopy, scanning electron microscopy (SEM), cyclic voltammetry have been employed to characterize those electrodes. The experimental results obtained indicate the electrodes can be used for in vivo detection of neurotransmitters such as dopamine, 5—hydroxytryptamine in a single cell.展开更多
The effects of pressure on phonon modes of ferroeleetrie tetragonal P4mm and paraelectric cubic Pm3m PbTiOa are systematically investigated by using first-principles simulations. The pressure-induced tetragonal-to-cub...The effects of pressure on phonon modes of ferroeleetrie tetragonal P4mm and paraelectric cubic Pm3m PbTiOa are systematically investigated by using first-principles simulations. The pressure-induced tetragonal-to-cubie and subsequent cubic-to-tetragonal phase transitions are the second-order transitions, which are different from the phase transitions induced by temperature [Phys. Rev. Lett. 25 （1970） 167]. As pressure increases, the lowest A1 and E modes of the tetragonal phase become softer and converge to the F1u mode of the cubic phase. As pressure further increases, the lowest Flu mode first hardens and then softens again, and finally diverges into A1 and E modes. The behaviors of optical phonon modes confirm the ferroelectric-to-paraelectric-to-ferroeleetric phase transitions.展开更多
The question of possible teleconnections between the middle latitude general circulation and the Indian south-west monsoon was investigated in this paper. Within the framework of a simple model it was shown that there...The question of possible teleconnections between the middle latitude general circulation and the Indian south-west monsoon was investigated in this paper. Within the framework of a simple model it was shown that there can exist such an interaction via the ultra-long Rossby waves.展开更多
Sea surface electric field observations off the coast from Goa (15°25'N, 73°47'E) to Madras (13°04'N, 80°15'E) around Sri Lanka, in a distance range 25-135 km from coast, during 9-2...Sea surface electric field observations off the coast from Goa (15°25'N, 73°47'E) to Madras (13°04'N, 80°15'E) around Sri Lanka, in a distance range 25-135 km from coast, during 9-20 May 1983 were taken. In this paper we have examined the diurnal variation of electric field in the Arabian Sea, Indian Ocean and Bay of Bengal regions covered during the cruise of the research ship ORV Gaveshani. An aspect of electric field dependence on coastal distance and Aitken Nuclei concentration has also been studied. An attempt to examine the latitude dependence of field was also made. Results obtained in the above studies are presented and compared with those obtained elsewhere.展开更多
A comprehensive Ground Penetration Radar (GPR) investigations and hazard assessment for the rehabilitation and strengthening of Habib Sakakini’s Palace in Cairo is presented herein, which is considered one of the mos...A comprehensive Ground Penetration Radar (GPR) investigations and hazard assessment for the rehabilitation and strengthening of Habib Sakakini’s Palace in Cairo is presented herein, which is considered one of the most significant architectural heritage sites in Egypt. The palace located on an ancient water pond at the eastern side of Egyptian gulf besiding Sultan Bebris Al-Bondoqdary mosque is a place also called “Prince Qraja al-Turkumany pond”. That pond had been filled down by Habib Sakakini at 1892 to construct his famous palace in 1897. The integrated geophysical survey of the palace allowed the identification of several targets of potential archaeological and geotechnical engineering interest buried in fill and silty clay in the depth range between 100 - 700 cm. the methodological development focused on Multi-Fold (MF) Ground Penetrating Radar (GPR) imaging and subsurface characterization based on integrated velocity and attenuation analysis. Eight hundred sqm of Ground penetration Radar (GPR) profiling have been conducted to monitor the subsurface conditions. 600 meters are made in the surrounding area of the Palace and 200 sqm at the basement. The aim is to monitor the soil conditions beneath and around the Palace and to identify potential geological discontinuities, or the presence of faults and cavities. A suitable single and dual antenna are used (500 - 100 MHZ) is used to penetrate the desired depth of 7 meters (ASTM D6432). The GPR is used also detect the water table. At the building basement the GPR is used to identify the foundation thickness and soil-basement interface. As well as the inspection of cracks in some supporting columns, piers and masonry walls. The GPR also was used to investigate the floors and ceilings conditions and structural mapping. The results were validated by the geotechnical and structural surveys. All these results together with the seismic hazard analysis will be used for the complete analysis of the palace in the framework of the rehabilitation and strengthening works foreseen in a second stage.展开更多
A new type of saddle field ion gun has been developed in our laboratories, and it can emit ions and a large proportion of energetic neutrals.The ion gun has been used in the neutral and ion impact radiation （NIIR） s...A new type of saddle field ion gun has been developed in our laboratories, and it can emit ions and a large proportion of energetic neutrals.The ion gun has been used in the neutral and ion impact radiation （NIIR） spectrometer to decrease the effect of charge accumulation on the surfaces of specimens. Some metals, including aluminium, copper and nickel and their oxides had been analysed by NIIR. By comparing the intensities of the spectral lines of the above metals and their oxides the intensification effect due to oxidation had been found. The ratio of intensities between Al I（3962（?）） for Al<sub>2</sub>O<sub>3</sub> and Al I （3962（?）） for Al is 120, so the effect can be seen clearly from the above experimental results. The mechanism of the intensification effect has been discussed in the paper.展开更多
This study reveals the most known barriers to successful marine safety investigations important role of effective marine accident investigation in the improvement of the maritime safety through prevention similar casu...This study reveals the most known barriers to successful marine safety investigations important role of effective marine accident investigation in the improvement of the maritime safety through prevention similar casualties from occurring in the future and explores the legal obligations of all parties under different international maritime conventions and codes.Since marine safety investigations results and recommendations are important for the maritime safety,so this paper determines,the shortage of application of the international regulations adopted by IMO related to maritime safety,and the shortage of legal measures to support safety at sea and protection or reduce marine pollution.This paper also aims to improve special measures for procedures of marine accident investigation and highlights the importance of identifying the liability and effective recommendations.展开更多
文摘Background: In recent years, Burkina Faso has faced increasing insecurity and terrorist attacks. The police, gendarmerie, and justice services are very often in demand to carry out criminal investigations, which are slowed down or incomplete due to the absence of DNA analysis on biological samples from crime scenes and on apprehended suspects. The purpose of this study was to evaluate the contribution of DNA analysis to the resolution of criminal cases in Burkina Faso. Methodology: This study was carried out from June 2019 to July 2020. Three (03) crimes were investigated, and DNA analysis was performed on biological samples from the crime scene, suspects, and victims using the AmpFlSTR® identifiler® Direct kit on the ABI 3130 Genetic Analyzer. Results: In the explosion case, the alleles found in the victim were the same as those identified in the blood trace from the crime scene. In the armed robbery case, there was a perfect match between the DNA profile of the blood trail and that of suspect 2 for all 15 STRs analyzed. In the murder case, the DNA profile of the murdered man’s son and the DNA profile of the biological trace were identical. Conclusion: The DNA analyses carried out in criminal cases have identified the perpetrators of the crimes. Their guilt or innocence will be confirmed by the investigators during the interrogations and hearings.
文摘The editor regrets that they inadvertently pasted the wrong figure during the production stage.The correct Fig.7 should be as below:The editor would like to apologise for any inconvenience caused.
基金funded by the Science and Technology Project of Tianjin(No.24YDTPJC00680)the National Natural Science Foundation of China(No.52406191).
文摘The growth of computing power in data centers(DCs)leads to an increase in energy consumption and noise pollution of air cooling systems.Chip-level cooling with high-efficiency coolant is one of the promising methods to address the cooling challenge for high-power devices in DCs.Hybrid nanofluid(HNF)has the advantages of high thermal conductivity and good rheological properties.This study summarizes the numerical investigations of HNFs in mini/micro heat sinks,including the numerical methods,hydrothermal characteristics,and enhanced heat transfer technologies.The innovations of this paper include:(1)the characteristics,applicable conditions,and scenarios of each theoretical method and numerical method are clarified;(2)the molecular dynamics(MD)simulation can reveal the synergy effect,micro motion,and agglomeration morphology of different nanoparticles.Machine learning(ML)presents a feasiblemethod for parameter prediction,which provides the opportunity for the intelligent regulation of the thermal performance of HNFs;(3)the HNFs flowboiling and the synergy of passive and active technologies may further improve the overall efficiency of liquid cooling systems in DCs.This review provides valuable insights and references for exploring the multi-phase flow and heat transport mechanisms of HNFs,and promoting the practical application of HNFs in chip-level liquid cooling in DCs.
基金sponsored by the National Natural Science Foundation of China(Grant No.41176167)the Projects of Cultural Heritage Protection,Zhejiang Province(Grant No.2010001 and No.2011008)
文摘Ground penetrating radar （GPR） attribute technology has been applied to many aspects in recent years but there are very few examples in the field of archaeology. Especially how can we extract effective attributes from the two- or three-dimensional radar data so that we can map and describe numerous archaeological targets in a large cultural site？ In this paper, we applied GPR attribute technology to investigate the ancient Nanzhao castle-site in Tengchong, Yunnan Province. In order to get better archaeological target （the ancient wall, the ancient kiln site, and the ancient tomb） analysis and description, we collated the GPR data by collected standardization and then put them to the seismic data processing and interpretation workstation. The data was processed, including a variety of GPR attribute extraction, analysis, and optimization and combined with the archaeological drilling data. We choose the RMS Amplitude, Average Peak Amplitude, Instantaneous Phase, and Maximum Peak Time to interpret three archaeological targets. By comparative analysis, we have clarified that we should use different attributes to interpret different archaeological targets and the results of attribute analysis after horizon tracking is much better than the results based on a time slice.
文摘In order to carry out the comprehensive reform of the professional master’s degree training mode of clinical pharmacy, we carried out interviews among 91 persons on the professional master’s degree of clinical pharmacy in Peking University School of Pharmaceutical Sciences and collected extensive feedback. We preliminaries explore the mode of Doctor of Pharmacy（Pharm. D.） Education, laying the foundation for Doctor’s education of professional clinical pharmacy in China. We conducted investigations and interviews among 91 clinical pharmacists and students of Peking University School of Pharmaceutical Sciences on the training of professional master’s degree and Pharm. D. education mode, which includes 67 postgraduates and 24 clinical pharmacists. Respondents put forward the problems of training mode and corresponding suggestions and opinions from different aspects during the investigation and interview. The results mainly divide into four aspects： curriculum setting, clinical practice, assessme nt system and teaching resources. Respondents put forward effective feedback on the above four aspects, which are beneficial to the comprehensive reform of the training mode of professional master degree in clinical pharmacy and preliminary exploration of Pharm. D. Education in China.
文摘Careful and thorough incident investigations and pre-job safety analyses completed by knowledgeable and competent individuals can significantly reduce workplace incidents. Working parties must act together to make these safety tools effective. To get the staff units to work together in a co-ordinated manner, they must be shown the value of their work in preventing accidents. Examples of actual accidents investigated during the author's 18 years as a mine inspector in Saskatchewan are discussed within the context of pre-job safety analyses. The causes of the accidents are explored with close reference to how pre-job safety analyses could have prevented their occurrence.
基金Project supported by the Experimental Demonstrative Project 48PED/2017-Executive Unit for Financing Higher Education,Research,Development and Innovation(UEFISCDI)
文摘Perovskite-type oxides of LaMnO3 were synthesized by means of the sol-gel method, in the presence of citric acid as gelling agent. The precursors used were Mn（NO3）2·H2O, La2O3, and NaOH,mixed in the stoichiometric ratio to obtain perovskite materials. The obtained gel was heat-treated at 400, 600 and 800 ℃ respectively, for 6 h. X-ray diffraction and FT-IR spectroscopy were used to analyze the phase transformation as a function of temperature, and the Rietveld refinement was used in order to characterize the materials obtained structurally. The average crystallite size of the products was calculated from XRD data and the average particle size was measured from the TEM micrographs. At 600 ℃, the synthesized compound is well-crystallized, showcases a perovskite structure（Pm-3m space group）, and exhibits uniform and homogeneous hexagonally-shaped particles, with sizes in the 20-50 nm range.Complex impedance measurements in the 20-2 × 10^6 Hz frequency range were carried out at different temperatures（26-115 ℃）, and the electrical conduction mechanism is discussed.
基金Project(51176045)supported by the National Natural Science Foundation of ChinaProject(201208430262)supported by the National Studying Abroad Foundation of China
文摘In order to reveal combustion characteristics of H_2/air mixture in a micro-combustor with and without bluff body, the effects of inlet velocities, equivalence ratios and bluff body's blockage ratios on the temperature field, pressure of the combustor wall, combustion efficiency and blow-off limit were investigated. The numerical results indicate that the sudden expansion plate micro combustor with bluff body could enhance the turbulent disturbance of the mixed gas in the combustion chamber and the combustion condition is improved. Moreover, a low-speed and high temperature recirculation region was formed between the sudden expansion step and the bluff body so that the high and uniform wall temperature(>1000 K) could be gotten. As a result, it could strengthen the mixing process, prolong the residence time of gas, control the flame position effectively and widen the operation range by the synergistic effect of the bluff body and steps. When the blockage ratio ranged from 0.3 to 0.6, it could be found that the bluff body could play a stabilizing effect and expand combustion blow burning limit, and combustion efficiency firstly was increased with the inlet velocity and equivalence ratio, and then was decreased.
文摘AIM:To ascertain the pattern of investigations at first contact in uveitic patients and evaluate compliance to treatment.METHODS:An observational study comprised of 201 uveitic patients presenting for the first time to our centre from January 2019 to June 2020.Detailed information regarding systemic investigations undertaken by specialists at the time of first contact and the cost of these investigations were reviewed on the first visit to our centre.Compliance with the treatment was determined and reasons behind non-compliance were evaluated on the first follow-up in patients who had no improvement in clinical signs and symptoms.RESULTS:The mean age of the study group was 35.35±14.1y and gender composition was 59.7%males and 40.3%females.Anterior uveitis was observed in 45.3%of patients,intermediate uveitis in 31.8%of patients,posterior uveitis in 14.9%of patients and panuveitis in 8.0%of patients.Association with a systemic disease was evident in 17.9%of patients.When compared with standard guidelines and uveitis patterns,systemic investigations were identified to be relevant only in 38.3%of patients.Non-compliance to treatment was documented in 22.4%of patients.Common reasons for non-compliance were inadequate counselling by the treating physician about treatment in 26.7%of patients and a busy schedule at work/school in 22.2%of patients.CONCLUSION:Significant number of investigations performed at first contact is found to be contrary to standard guidelines and are not contributory to the care.About a quarter of patients in this study are found to be non-compliant with the treatment.Compliance is more challenging to achieve in school-going children and working adults.The availability of comprehensive,periodically updated,evidence-based guidelines on the role of investigations and the use of trained counsellors may help to channelize proper evaluation and improve compliance to treatment,respectively,in patients with uveitis.
基金Supported by the National Natural Science Foundation of China under Grant No 11404180the Natural Science Foundation of Heilongjiang Province under Grant Nos F201335,A2015010,and A2015011the Postdoctoral Scientific Research Developmental Fund of Heilongjiang Province under Grant No LBH-Q14159
文摘The electronic structures of PF and PF＋ are calculated with the high-level configuration interaction method. To improve the precision of calculations, the spin-orbit coupling effect, the scalar relativistic effect, and the Davidson correction（q-Q） are also considered. The spectroscopic parameters of bound states are derived by the electronic structures of PF and PF＋, which are in good accordance with the measurements. The transition dipole moments of spin-allowed transitions are evaluated, and the radiative lifetimes of several A S states of PF and PF＋ are obtained.
文摘Aluminum/steel electric transition joints (ETJs) are used in aluminum reduction cell for the purpose of welding aluminum rod and steel bracket components. Solid state welding process used for joining aluminum and steel at the electric transition joints have the drawbacks of cracking and separation at the interface surfaces. Cracking and separation at the electric transition joints are caused by the stress singularities that developed due to the mismatch in thermal and mechanical properties of each material. To overcome the drawback of electric transition joints, aluminum/steel functionally graded may be used as electric transition joints or proposed. Therefore manufacturing and investigation of aluminum/steel functionally graded materials fabricated by powder metallurgy process were carried out through the current work. Different samples with different layers of aluminum/steel functionally graded materials were compacted using steel die and punch at the same compacted pressure and sintered temperature. After investigating the different samples of aluminum/steel functionally graded materials under different fabrication conditions, the suitable fabrication regime was determined with the aid of microscopic observations.
基金Supported by the Fundamental Research Funds for the Central Universities under Grant No 2013QNA38
文摘Crystal structure predictions of Pb0.5Ba0.5 Ti03 alloys under different pressures are performed based on the parti- cle swarming optimization algorithm. The predicted stable ground-state and high-pressure phases are tetragonal ferroelectric （I4mm） and cubic para-electric （Fm3m）, respectively, whose structural details have not been re- ported. The pressure-induced colossal enhancements in piezoelectric response are associated with the mechanical and dynamical instabilities instead of polarization rotation. The band gap of the tetragonM phase is indirect and that of the cubic phase is always direct. As pressure increases, the alloy displays the similar band-gap behaviors to PbTiO3, while different from BaTiO5, which is attributed to the different orbital contributions to the valence bands. Our calculated results are in good agreement with the available data.
文摘Iron ions were used as probes to explore the structural and magnetic properties of 70TeO2'25B2O3' 5SrF2 vitreous matrix. The distribution of Fe3+ ions on different structural aggregates was revealed by means of EPR, as depending on Fe2O3 concentration. Strongly distorted octahedral sites were detected for the isolated paramagnetic ions, and also clusters of Fe ions especially at high Fe2O3 content of samples. Magnetic susceptibility measurements evidenced both dipoledipole and superexchange type interactions involving iron ions. Mixed valence states of iron ions were also detected
基金This project was supported by the National Science Foundation of China and Doctoral Programme from State Education Commission Foundation of China
文摘Described here are the fabrication and characterization of carbon fiber cylinder ultramicroelectrodes with cylinder length of less than 100 am, total tip diameter of several hundreds nanometers. The electrodes have been fabricated by direct etching of carbon fiber using an ion beam thinner. Optical microscopy, scanning electron microscopy (SEM), cyclic voltammetry have been employed to characterize those electrodes. The experimental results obtained indicate the electrodes can be used for in vivo detection of neurotransmitters such as dopamine, 5—hydroxytryptamine in a single cell.
基金Supported by the Fundamental Research Funds for the Central Universities under Grant No 2013RC19
文摘The effects of pressure on phonon modes of ferroeleetrie tetragonal P4mm and paraelectric cubic Pm3m PbTiOa are systematically investigated by using first-principles simulations. The pressure-induced tetragonal-to-cubie and subsequent cubic-to-tetragonal phase transitions are the second-order transitions, which are different from the phase transitions induced by temperature [Phys. Rev. Lett. 25 （1970） 167]. As pressure increases, the lowest A1 and E modes of the tetragonal phase become softer and converge to the F1u mode of the cubic phase. As pressure further increases, the lowest Flu mode first hardens and then softens again, and finally diverges into A1 and E modes. The behaviors of optical phonon modes confirm the ferroelectric-to-paraelectric-to-ferroeleetric phase transitions.
文摘The question of possible teleconnections between the middle latitude general circulation and the Indian south-west monsoon was investigated in this paper. Within the framework of a simple model it was shown that there can exist such an interaction via the ultra-long Rossby waves.
文摘Sea surface electric field observations off the coast from Goa (15°25'N, 73°47'E) to Madras (13°04'N, 80°15'E) around Sri Lanka, in a distance range 25-135 km from coast, during 9-20 May 1983 were taken. In this paper we have examined the diurnal variation of electric field in the Arabian Sea, Indian Ocean and Bay of Bengal regions covered during the cruise of the research ship ORV Gaveshani. An aspect of electric field dependence on coastal distance and Aitken Nuclei concentration has also been studied. An attempt to examine the latitude dependence of field was also made. Results obtained in the above studies are presented and compared with those obtained elsewhere.
文摘A comprehensive Ground Penetration Radar (GPR) investigations and hazard assessment for the rehabilitation and strengthening of Habib Sakakini’s Palace in Cairo is presented herein, which is considered one of the most significant architectural heritage sites in Egypt. The palace located on an ancient water pond at the eastern side of Egyptian gulf besiding Sultan Bebris Al-Bondoqdary mosque is a place also called “Prince Qraja al-Turkumany pond”. That pond had been filled down by Habib Sakakini at 1892 to construct his famous palace in 1897. The integrated geophysical survey of the palace allowed the identification of several targets of potential archaeological and geotechnical engineering interest buried in fill and silty clay in the depth range between 100 - 700 cm. the methodological development focused on Multi-Fold (MF) Ground Penetrating Radar (GPR) imaging and subsurface characterization based on integrated velocity and attenuation analysis. Eight hundred sqm of Ground penetration Radar (GPR) profiling have been conducted to monitor the subsurface conditions. 600 meters are made in the surrounding area of the Palace and 200 sqm at the basement. The aim is to monitor the soil conditions beneath and around the Palace and to identify potential geological discontinuities, or the presence of faults and cavities. A suitable single and dual antenna are used (500 - 100 MHZ) is used to penetrate the desired depth of 7 meters (ASTM D6432). The GPR is used also detect the water table. At the building basement the GPR is used to identify the foundation thickness and soil-basement interface. As well as the inspection of cracks in some supporting columns, piers and masonry walls. The GPR also was used to investigate the floors and ceilings conditions and structural mapping. The results were validated by the geotechnical and structural surveys. All these results together with the seismic hazard analysis will be used for the complete analysis of the palace in the framework of the rehabilitation and strengthening works foreseen in a second stage.
文摘A new type of saddle field ion gun has been developed in our laboratories, and it can emit ions and a large proportion of energetic neutrals.The ion gun has been used in the neutral and ion impact radiation （NIIR） spectrometer to decrease the effect of charge accumulation on the surfaces of specimens. Some metals, including aluminium, copper and nickel and their oxides had been analysed by NIIR. By comparing the intensities of the spectral lines of the above metals and their oxides the intensification effect due to oxidation had been found. The ratio of intensities between Al I（3962（?）） for Al<sub>2</sub>O<sub>3</sub> and Al I （3962（?）） for Al is 120, so the effect can be seen clearly from the above experimental results. The mechanism of the intensification effect has been discussed in the paper.
文摘This study reveals the most known barriers to successful marine safety investigations important role of effective marine accident investigation in the improvement of the maritime safety through prevention similar casualties from occurring in the future and explores the legal obligations of all parties under different international maritime conventions and codes.Since marine safety investigations results and recommendations are important for the maritime safety,so this paper determines,the shortage of application of the international regulations adopted by IMO related to maritime safety,and the shortage of legal measures to support safety at sea and protection or reduce marine pollution.This paper also aims to improve special measures for procedures of marine accident investigation and highlights the importance of identifying the liability and effective recommendations.
