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
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。
