One hundred and fifty years ago, Charles Darwin’s on the Origin of Species explained the evolution of species through evolution by natural selection. To date, there is no simple piece of evidence demonstrating this c...One hundred and fifty years ago, Charles Darwin’s on the Origin of Species explained the evolution of species through evolution by natural selection. To date, there is no simple piece of evidence demonstrating this concept across species. Chargaff’s first parity rule states that comple-mentary base pairs are in equal proportion across DNA strands. Chargaff’s second parity rule, in-consistently followed across species, states that the base pairs are in equal proportion within DNA strands [G ≈ C, T ≈ A and (G + A) ≈ (C + T)]. Using genomic libraries, we analyzed the extent to which DNA samples followed Chargaff’s second parity rule. In organelle DNA, nucleotide rela-tionships were heteroskedastic. After classifying organelles into chloroplasts and mitochondria, and then into plant, vertebrate, and invertebrate I and II mitochondria, nucleotide relationships were expressed by linear regression lines. All regression lines based on nuclear and organelle DNA crossed at the same point. This is a simple demonstration of a common ancestor across species.展开更多
A significant fraction of the conventional oil reserves globally is in carbonate formations which contain a substantial amount of residual oil. Since primary and secondary recovery methods fail to yield above 20%-40%o...A significant fraction of the conventional oil reserves globally is in carbonate formations which contain a substantial amount of residual oil. Since primary and secondary recovery methods fail to yield above 20%-40%of original oil in place from these reserves, the need for enhanced oil recovery（EOR） techniques for incremental oil recovery has become imperative. With the challenges presented by the highly heterogeneous carbonate rocks,evaluation of tertiary-stage recovery techniques including chemical EOR（c EOR） has been a high priority for researchers and oil producers. In this review, the latest developments in the surfactant-based c EOR techniques applied in carbonate formations are discussed, contemplating the future direction of existing methodologies. In connection with this, the characteristics of heterogeneous carbonate reservoirs are outlined. Detailed discussion on surfactant-led oil recovery mechanisms and related processes, such as wettability alteration, interfacial tension reduction, microemulsion phase behavior, surfactant adsorption and mitigation, and foams and their applications is presented. Laboratory experiments, as well as field study data obtained using several surfactants, are also included.This extensive discussion on the subject aims to help researchers and professionals in the field to understand the current situation and plan future enterprises accordingly.展开更多
基于Wed of Science(WOS)和中国知网(CNKI)中1990—2023年数据库,采用文献计量学方法对有关酿酒葡萄及葡萄酒产地溯源的相关文献进行可视化分析。结果显示,研究葡萄酒产地溯源领域的国家主要有意大利225篇、西班牙209篇、法国148篇,国际...基于Wed of Science(WOS)和中国知网(CNKI)中1990—2023年数据库,采用文献计量学方法对有关酿酒葡萄及葡萄酒产地溯源的相关文献进行可视化分析。结果显示,研究葡萄酒产地溯源领域的国家主要有意大利225篇、西班牙209篇、法国148篇,国际上French National Research Institute for Agriculture,Food,and the Environment(INRAE)是目前葡萄酒溯源领域内的核心单位。国内机构的发文量均较少,且机构间合作较少。研究热点主要聚焦于“葡萄酒”、“模式识别”、“同位素”、“溯源”等关键词,目前葡萄酒通过矿物元素、品种、电子舌、指纹图谱、同位素、理化指标等更为丰富的指标进行产地鉴别。展开更多
针对混流装配线工序加工资源需求多样、工艺复杂、装配工期长等问题,采用Petri网和改进遗传算法对该问题进行优化求解。建立混流装配线赋时库所Petri网(timed place Petri net, TPPN)调度模型,基于模型激发序列,采用基于工序的编码方式...针对混流装配线工序加工资源需求多样、工艺复杂、装配工期长等问题,采用Petri网和改进遗传算法对该问题进行优化求解。建立混流装配线赋时库所Petri网(timed place Petri net, TPPN)调度模型,基于模型激发序列,采用基于工序的编码方式进行染色体编码;采用精英保留策略选择优异个体,改进遗传算法的交叉、变异操作,用改进后的遗传算法求解混流装配线调度问题。通过对比案例及实例数据计算结果验证了方案的有效性。展开更多
目的探讨中药材不同产地鉴别技术的研究现状和发展趋势,为中药材产地研究拓展思路。方法以“中药”“产地”“鉴别”等为关键字,在中国知网、维普网、PubMed、Web of Science等数据库中查询近10年发表的相关研究论文,并以“不同产地”...目的探讨中药材不同产地鉴别技术的研究现状和发展趋势,为中药材产地研究拓展思路。方法以“中药”“产地”“鉴别”等为关键字,在中国知网、维普网、PubMed、Web of Science等数据库中查询近10年发表的相关研究论文,并以“不同产地”和“鉴别技术”为主旨进行文献综述。结果中药材的不同产地鉴别技术包括性状与显微鉴别、理化鉴别、指纹图谱技术、DNA分子标记鉴别、生物效价评价和结合计算机算法的人工智能鉴别技术等多种方法,其中经验鉴别、显微鉴别和一般理化鉴别等传统鉴别方法简便易行,但依赖经验、专属性差;光谱法、指纹图谱、DNA标记技术等方法用于中药材产地鉴别克服了以上缺点,准确可靠、操作简便;结合计算机算法的人工智能鉴别技术更加准确高效,极大地降低了人工和时间成本,将成为未来发展的重要方向。结论中药材的不同产地鉴别存在一定的难度和不确定性,可以结合多种方法进行综合鉴别,发挥每种鉴别方法的优势,以确保结果的准确性。未来,中药材鉴别将更加智能化和自动化,利用人工智能、机器学习等技术可以提高鉴别效率和准确性。展开更多
文摘One hundred and fifty years ago, Charles Darwin’s on the Origin of Species explained the evolution of species through evolution by natural selection. To date, there is no simple piece of evidence demonstrating this concept across species. Chargaff’s first parity rule states that comple-mentary base pairs are in equal proportion across DNA strands. Chargaff’s second parity rule, in-consistently followed across species, states that the base pairs are in equal proportion within DNA strands [G ≈ C, T ≈ A and (G + A) ≈ (C + T)]. Using genomic libraries, we analyzed the extent to which DNA samples followed Chargaff’s second parity rule. In organelle DNA, nucleotide rela-tionships were heteroskedastic. After classifying organelles into chloroplasts and mitochondria, and then into plant, vertebrate, and invertebrate I and II mitochondria, nucleotide relationships were expressed by linear regression lines. All regression lines based on nuclear and organelle DNA crossed at the same point. This is a simple demonstration of a common ancestor across species.
文摘A significant fraction of the conventional oil reserves globally is in carbonate formations which contain a substantial amount of residual oil. Since primary and secondary recovery methods fail to yield above 20%-40%of original oil in place from these reserves, the need for enhanced oil recovery（EOR） techniques for incremental oil recovery has become imperative. With the challenges presented by the highly heterogeneous carbonate rocks,evaluation of tertiary-stage recovery techniques including chemical EOR（c EOR） has been a high priority for researchers and oil producers. In this review, the latest developments in the surfactant-based c EOR techniques applied in carbonate formations are discussed, contemplating the future direction of existing methodologies. In connection with this, the characteristics of heterogeneous carbonate reservoirs are outlined. Detailed discussion on surfactant-led oil recovery mechanisms and related processes, such as wettability alteration, interfacial tension reduction, microemulsion phase behavior, surfactant adsorption and mitigation, and foams and their applications is presented. Laboratory experiments, as well as field study data obtained using several surfactants, are also included.This extensive discussion on the subject aims to help researchers and professionals in the field to understand the current situation and plan future enterprises accordingly.
文摘基于Wed of Science(WOS)和中国知网(CNKI)中1990—2023年数据库,采用文献计量学方法对有关酿酒葡萄及葡萄酒产地溯源的相关文献进行可视化分析。结果显示,研究葡萄酒产地溯源领域的国家主要有意大利225篇、西班牙209篇、法国148篇,国际上French National Research Institute for Agriculture,Food,and the Environment(INRAE)是目前葡萄酒溯源领域内的核心单位。国内机构的发文量均较少,且机构间合作较少。研究热点主要聚焦于“葡萄酒”、“模式识别”、“同位素”、“溯源”等关键词,目前葡萄酒通过矿物元素、品种、电子舌、指纹图谱、同位素、理化指标等更为丰富的指标进行产地鉴别。
文摘针对混流装配线工序加工资源需求多样、工艺复杂、装配工期长等问题,采用Petri网和改进遗传算法对该问题进行优化求解。建立混流装配线赋时库所Petri网(timed place Petri net, TPPN)调度模型,基于模型激发序列,采用基于工序的编码方式进行染色体编码;采用精英保留策略选择优异个体,改进遗传算法的交叉、变异操作,用改进后的遗传算法求解混流装配线调度问题。通过对比案例及实例数据计算结果验证了方案的有效性。
文摘目的探讨中药材不同产地鉴别技术的研究现状和发展趋势,为中药材产地研究拓展思路。方法以“中药”“产地”“鉴别”等为关键字,在中国知网、维普网、PubMed、Web of Science等数据库中查询近10年发表的相关研究论文,并以“不同产地”和“鉴别技术”为主旨进行文献综述。结果中药材的不同产地鉴别技术包括性状与显微鉴别、理化鉴别、指纹图谱技术、DNA分子标记鉴别、生物效价评价和结合计算机算法的人工智能鉴别技术等多种方法,其中经验鉴别、显微鉴别和一般理化鉴别等传统鉴别方法简便易行,但依赖经验、专属性差;光谱法、指纹图谱、DNA标记技术等方法用于中药材产地鉴别克服了以上缺点,准确可靠、操作简便;结合计算机算法的人工智能鉴别技术更加准确高效,极大地降低了人工和时间成本,将成为未来发展的重要方向。结论中药材的不同产地鉴别存在一定的难度和不确定性,可以结合多种方法进行综合鉴别,发挥每种鉴别方法的优势,以确保结果的准确性。未来,中药材鉴别将更加智能化和自动化,利用人工智能、机器学习等技术可以提高鉴别效率和准确性。
