Currently, air pollution in Beijing has become a complex problem with two types of source pollutants： coal smoke and photochemical smog. Furthermore the maximum hourly mean concentration of O3 increases continuously,...Currently, air pollution in Beijing has become a complex problem with two types of source pollutants： coal smoke and photochemical smog. Furthermore the maximum hourly mean concentration of O3 increases continuously, especially in the summer. In order to simulate the photochemical reaction, develop an air quality simulation model and further improve the air quality of Beijing, a precisely temperature-controlled, indoor, smog chamber facility was designed and constructed at Tsinghua University. Characterization experiments have been carried out to acquire the basic parameters of the smog chamber, such as the wall loss rates of NO2, NO, O3, C3H6 and particulate matter （PM）, the intensity of ultraviolet （UV） light in the chamber, the reactivity of the purified air and the reproducibility of the experimental results. The results indicate that the facility performs up to specifications, and can meet the demands required for simulating the photochemical reaction. The effect of high primary contaminated PM on the formation of ozone and secondary organic aerosol （SOA） is under investigation.展开更多
Objective: To construct a cDNA library from human liver tissue with chronic hepatitis B and check its quality for investigating the expression level of liver tissue infected by hepatitis B virus. This will then be use...Objective: To construct a cDNA library from human liver tissue with chronic hepatitis B and check its quality for investigating the expression level of liver tissue infected by hepatitis B virus. This will then be used to find the relevant genes and interesting proteins associated with the development of hepatitis B. Methods: The total RNA from liver tissue with chronic hepa- titis B was extracted and the mRNA was purified using TRIZOL method. Switching mechanism at 5′ end of the RNA transcript (SMART) technique and CDS III/3′ primer were used for first-strand cDNA synthesis. Long distance polymerase chain reaction (LD PCR) was then used to synthesize the double-strand cDNA that was then digested by Sfi I and fractionated by CHROMA SPIN-400 column. The longer than 0.4 kb cDNAs were collected and ligated to λTriplEx2 vector. Then λ phage packaging reaction and library amplification were performed. The qualities of both unamplified and amplified cDNA libraries were strictly checked by conventional titer determination. Fourteen plaques were randomly picked and tested using PCR with universal primers derived from the sequence flanking the vector. Results: The titers of unamplifed and amplified libraries were 1.94×106 pfu/ml and 1.49×109 pfu/ml respectively. The percentages of recombinants from both libraries were 98.15% in unamplified library and 98.76% in amplified library. The lengths of the inserts were 1.23 kb in average, 1?2 kb in 64.29%, and 0.5?1.0 kb in 35.71%. Conclusion: A high quality cDNA library from human liver tissue with chronic hepatitis B was successfully constructed.展开更多
Clays are a constituent of the earth. As a result, the discovery and traditional use of clays in construction and pottery worldwide dates back to antiquity. Guinea has several deposits of clay minerals whose chemical ...Clays are a constituent of the earth. As a result, the discovery and traditional use of clays in construction and pottery worldwide dates back to antiquity. Guinea has several deposits of clay minerals whose chemical and mineralogical compositions have been little studied. Despite lacking of scientific data on these clay minerals, they are used today in pottery and habitat construction. As a step towards promoting the use of clay materials in Guinea, we conducted a study of the physicochemical and mineralogical properties of three natural clays from Kakan in the Republic of Guinea (AKKB, AKKE, AKKO) used in habitat construction. The aims of this work were to better understand their properties, but above all to be able to act on them to improve and broaden their applications, which until now have been limited to construction. These clays were studied by X-ray diffraction (XRD), X-ray fluorescence spectrometry (XRF), moisture content (%W), laser granulometry, Atterberg limits, specific surface area, infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis and differential thermal analysis (TGA/DTA). These analyses revealed that the main clay minerals present in our samples are kaolinite, illite and, montmorillonite, with the addition of impurities, the most abundant of which is quartz.展开更多
The character of Shylock in the Merchant of Venice is both intriguing and compelling. Hateful and greedy as he is on the onehand, yet suffered and pathetic on the other. Shakespeare is quite considerate in creating th...The character of Shylock in the Merchant of Venice is both intriguing and compelling. Hateful and greedy as he is on the onehand, yet suffered and pathetic on the other. Shakespeare is quite considerate in creating the character. This paper explores the possibili-ties behind Shakespeare, contradictory construction of Shylock.展开更多
El-Ashmonein is a significant archaeological site with different buildings from various eras. Between the villages of El-Idara and El-Ashmonein are there mains of Hermopolis, one of the ancient Egyptian metropolis cap...El-Ashmonein is a significant archaeological site with different buildings from various eras. Between the villages of El-Idara and El-Ashmonein are there mains of Hermopolis, one of the ancient Egyptian metropolis capitals of the fifteenth century of Upper Egypt, called the hare. The buildings in this archaeological site are exposed to many causes of destruction and damage. The remaining structures and granite free standing columns in this area are suffered from plenty of geo-environmental and geotechnical problems. The main objectives of this study are 1) to assess the current state of preservation of this important archaeological site, especially the basilica church with its free standing huge columns, 2) to analyze the different actions which cause the destruction of the archaeological site, in particular the old flash floods and earthquakes, and 3) to identify the geochemical and engineering properties of the construction materials of the granitic columns and other limestone structures of the basilica church by using different kind of sophisticated analytical and diagnostic tools and methods. The multi-criteria analysis allowed the integration of several elements for mapping the vulnerable zones. Results revealed that about 80% of the study area was exposed to high and medium old floods vulnerability because of the vicinity to the Nile River. The structural and non-structural measures recommended in this research will help the decision makers and planners to effectively develop strategies for future site management, intervention retrofitting and rehabilitation of this unique archaeological site.展开更多
Despite the gradual professionalization of the construction sector as well as the abundance of sand mining sites offered by the North Kivu, Democratic Republic of Congo Region, ignorance of materials by local builders...Despite the gradual professionalization of the construction sector as well as the abundance of sand mining sites offered by the North Kivu, Democratic Republic of Congo Region, ignorance of materials by local builders persists. This is the case of quarries extracting river sand used to make concrete and mortar. However, the dosages of the various constituents are most often chosen on the basis of experience without any prior characterization of this material. This paper presents a comprehensive review of the characterization of river sand for its use in concrete in DRC. The origin and global use of river sand in construction are presented in percentage terms to highlight the importance of river sand as a construction material. The physical properties of river sand, including particle size distribution, bulk density, absolute density, and cleanliness are discussed in detail. The paper examines the effect of variations in river sand properties on concrete behavior, including density and compressive strength. Overall, this paper emphasizes the need to properly characterize river sand before using it in construction to ensure durable, high-quality structures. This will avoid the problems that are observed in particular a bad behavior of the coating on the walls;cracks and crumbling of the beams, lintels, posts and even the ruin of the structures.展开更多
The aim of this study is to contribute to the mastery of the physical characteristics of lateritic soils in order to improve their use for the manufacture of Compressed Stabilized Earth Bricks (CSEB) in the province o...The aim of this study is to contribute to the mastery of the physical characteristics of lateritic soils in order to improve their use for the manufacture of Compressed Stabilized Earth Bricks (CSEB) in the province of North Kivu in the Democratic Republic of Congo (DRC). The study of the physical characteristics of lateritic soils was carried out. Samples were subjected to experimental identification tests on the physical characteristics (water content, density characteristics, particle size distribution and consistency). The results of the laboratory analysis of soil samples show that the water content varies between 5.4% and 36.99%. The density of the solid grains has an arithmetic mean of 2.5 g/cm</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">. The apparent density varies from 0.83 to 1.35 g/cm</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">. As for the dry density, it is in the range of 0.61 to 1.25 g/cm</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">. These relatively low densities indicate that the material studied ha</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> a significant degree of deformability. From the particle size analysis, it appears that the material studied contain</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> an important fraction of fine particles. According to the consistency study, the soils studied are plastic clay as Ap class according to the Central Laboratory for Roads and Bridges (CLRB) geotechnical classification system. The particle size curves of the studied samples are within the preferential range of good soils for the manufacture of CSEB. The points representing the studied samples are within the preferential plasticity range of good soils for the manufacture of CSEB. From the above parameters, it appears that the studied material is well adapted for the manufacture of the Compressed Stabilized Earth Bricks</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">.展开更多
针对未充分考虑气象因子交互作用、模型非线性表达能力存在局限性等问题,基于复合因子构造提出一种结合科尔莫戈洛夫-阿诺德网络(Kolmogorov-Arnold network,KAN)与双向长短期记忆(bidirectional long short-term memory,BiLSTM)网络的...针对未充分考虑气象因子交互作用、模型非线性表达能力存在局限性等问题,基于复合因子构造提出一种结合科尔莫戈洛夫-阿诺德网络(Kolmogorov-Arnold network,KAN)与双向长短期记忆(bidirectional long short-term memory,BiLSTM)网络的电力负荷预测方法。首先,通过高斯混合模型(Gaussian mixture model,GMM)将有相似特征的用电负荷曲线归类。其次,提出复合因子构造策略,通过皮尔逊相关性分析量化气象因子与负荷的线性关联度,筛选关键气象变量并构造交互项,充分挖掘气象因素间潜在交互作用,结合最大信息系数(maximal information coefficient,MIC)进一步提取非线性依赖特征。最后,针对传统BiLSTM模型全连接层对高维非线性特征学习能力受限的问题,引入KAN替代全连接层,利用其非线性映射能力,构建KAN-BiLSTM混合预测模型。基于某地区实际数据进行算例分析,实验结果表明,在春秋日、夏季常温日、夏季高温日、冬季日4类不同负荷模式下所提方法均具有较高的预测准确率和普适性,可为多气象耦合场景下的电力负荷精准预测提供一种可行的解决方案。展开更多
文摘Currently, air pollution in Beijing has become a complex problem with two types of source pollutants： coal smoke and photochemical smog. Furthermore the maximum hourly mean concentration of O3 increases continuously, especially in the summer. In order to simulate the photochemical reaction, develop an air quality simulation model and further improve the air quality of Beijing, a precisely temperature-controlled, indoor, smog chamber facility was designed and constructed at Tsinghua University. Characterization experiments have been carried out to acquire the basic parameters of the smog chamber, such as the wall loss rates of NO2, NO, O3, C3H6 and particulate matter （PM）, the intensity of ultraviolet （UV） light in the chamber, the reactivity of the purified air and the reproducibility of the experimental results. The results indicate that the facility performs up to specifications, and can meet the demands required for simulating the photochemical reaction. The effect of high primary contaminated PM on the formation of ozone and secondary organic aerosol （SOA） is under investigation.
基金Project (No. 30371270) supported by the National Natural Science Foundation of China
文摘Objective: To construct a cDNA library from human liver tissue with chronic hepatitis B and check its quality for investigating the expression level of liver tissue infected by hepatitis B virus. This will then be used to find the relevant genes and interesting proteins associated with the development of hepatitis B. Methods: The total RNA from liver tissue with chronic hepa- titis B was extracted and the mRNA was purified using TRIZOL method. Switching mechanism at 5′ end of the RNA transcript (SMART) technique and CDS III/3′ primer were used for first-strand cDNA synthesis. Long distance polymerase chain reaction (LD PCR) was then used to synthesize the double-strand cDNA that was then digested by Sfi I and fractionated by CHROMA SPIN-400 column. The longer than 0.4 kb cDNAs were collected and ligated to λTriplEx2 vector. Then λ phage packaging reaction and library amplification were performed. The qualities of both unamplified and amplified cDNA libraries were strictly checked by conventional titer determination. Fourteen plaques were randomly picked and tested using PCR with universal primers derived from the sequence flanking the vector. Results: The titers of unamplifed and amplified libraries were 1.94×106 pfu/ml and 1.49×109 pfu/ml respectively. The percentages of recombinants from both libraries were 98.15% in unamplified library and 98.76% in amplified library. The lengths of the inserts were 1.23 kb in average, 1?2 kb in 64.29%, and 0.5?1.0 kb in 35.71%. Conclusion: A high quality cDNA library from human liver tissue with chronic hepatitis B was successfully constructed.
文摘Clays are a constituent of the earth. As a result, the discovery and traditional use of clays in construction and pottery worldwide dates back to antiquity. Guinea has several deposits of clay minerals whose chemical and mineralogical compositions have been little studied. Despite lacking of scientific data on these clay minerals, they are used today in pottery and habitat construction. As a step towards promoting the use of clay materials in Guinea, we conducted a study of the physicochemical and mineralogical properties of three natural clays from Kakan in the Republic of Guinea (AKKB, AKKE, AKKO) used in habitat construction. The aims of this work were to better understand their properties, but above all to be able to act on them to improve and broaden their applications, which until now have been limited to construction. These clays were studied by X-ray diffraction (XRD), X-ray fluorescence spectrometry (XRF), moisture content (%W), laser granulometry, Atterberg limits, specific surface area, infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis and differential thermal analysis (TGA/DTA). These analyses revealed that the main clay minerals present in our samples are kaolinite, illite and, montmorillonite, with the addition of impurities, the most abundant of which is quartz.
文摘The character of Shylock in the Merchant of Venice is both intriguing and compelling. Hateful and greedy as he is on the onehand, yet suffered and pathetic on the other. Shakespeare is quite considerate in creating the character. This paper explores the possibili-ties behind Shakespeare, contradictory construction of Shylock.
文摘El-Ashmonein is a significant archaeological site with different buildings from various eras. Between the villages of El-Idara and El-Ashmonein are there mains of Hermopolis, one of the ancient Egyptian metropolis capitals of the fifteenth century of Upper Egypt, called the hare. The buildings in this archaeological site are exposed to many causes of destruction and damage. The remaining structures and granite free standing columns in this area are suffered from plenty of geo-environmental and geotechnical problems. The main objectives of this study are 1) to assess the current state of preservation of this important archaeological site, especially the basilica church with its free standing huge columns, 2) to analyze the different actions which cause the destruction of the archaeological site, in particular the old flash floods and earthquakes, and 3) to identify the geochemical and engineering properties of the construction materials of the granitic columns and other limestone structures of the basilica church by using different kind of sophisticated analytical and diagnostic tools and methods. The multi-criteria analysis allowed the integration of several elements for mapping the vulnerable zones. Results revealed that about 80% of the study area was exposed to high and medium old floods vulnerability because of the vicinity to the Nile River. The structural and non-structural measures recommended in this research will help the decision makers and planners to effectively develop strategies for future site management, intervention retrofitting and rehabilitation of this unique archaeological site.
文摘Despite the gradual professionalization of the construction sector as well as the abundance of sand mining sites offered by the North Kivu, Democratic Republic of Congo Region, ignorance of materials by local builders persists. This is the case of quarries extracting river sand used to make concrete and mortar. However, the dosages of the various constituents are most often chosen on the basis of experience without any prior characterization of this material. This paper presents a comprehensive review of the characterization of river sand for its use in concrete in DRC. The origin and global use of river sand in construction are presented in percentage terms to highlight the importance of river sand as a construction material. The physical properties of river sand, including particle size distribution, bulk density, absolute density, and cleanliness are discussed in detail. The paper examines the effect of variations in river sand properties on concrete behavior, including density and compressive strength. Overall, this paper emphasizes the need to properly characterize river sand before using it in construction to ensure durable, high-quality structures. This will avoid the problems that are observed in particular a bad behavior of the coating on the walls;cracks and crumbling of the beams, lintels, posts and even the ruin of the structures.
文摘The aim of this study is to contribute to the mastery of the physical characteristics of lateritic soils in order to improve their use for the manufacture of Compressed Stabilized Earth Bricks (CSEB) in the province of North Kivu in the Democratic Republic of Congo (DRC). The study of the physical characteristics of lateritic soils was carried out. Samples were subjected to experimental identification tests on the physical characteristics (water content, density characteristics, particle size distribution and consistency). The results of the laboratory analysis of soil samples show that the water content varies between 5.4% and 36.99%. The density of the solid grains has an arithmetic mean of 2.5 g/cm</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">. The apparent density varies from 0.83 to 1.35 g/cm</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">. As for the dry density, it is in the range of 0.61 to 1.25 g/cm</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">. These relatively low densities indicate that the material studied ha</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> a significant degree of deformability. From the particle size analysis, it appears that the material studied contain</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> an important fraction of fine particles. According to the consistency study, the soils studied are plastic clay as Ap class according to the Central Laboratory for Roads and Bridges (CLRB) geotechnical classification system. The particle size curves of the studied samples are within the preferential range of good soils for the manufacture of CSEB. The points representing the studied samples are within the preferential plasticity range of good soils for the manufacture of CSEB. From the above parameters, it appears that the studied material is well adapted for the manufacture of the Compressed Stabilized Earth Bricks</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">.
文摘针对未充分考虑气象因子交互作用、模型非线性表达能力存在局限性等问题,基于复合因子构造提出一种结合科尔莫戈洛夫-阿诺德网络(Kolmogorov-Arnold network,KAN)与双向长短期记忆(bidirectional long short-term memory,BiLSTM)网络的电力负荷预测方法。首先,通过高斯混合模型(Gaussian mixture model,GMM)将有相似特征的用电负荷曲线归类。其次,提出复合因子构造策略,通过皮尔逊相关性分析量化气象因子与负荷的线性关联度,筛选关键气象变量并构造交互项,充分挖掘气象因素间潜在交互作用,结合最大信息系数(maximal information coefficient,MIC)进一步提取非线性依赖特征。最后,针对传统BiLSTM模型全连接层对高维非线性特征学习能力受限的问题,引入KAN替代全连接层,利用其非线性映射能力,构建KAN-BiLSTM混合预测模型。基于某地区实际数据进行算例分析,实验结果表明,在春秋日、夏季常温日、夏季高温日、冬季日4类不同负荷模式下所提方法均具有较高的预测准确率和普适性,可为多气象耦合场景下的电力负荷精准预测提供一种可行的解决方案。
