将Q235碳钢样品挂于不同海域(青岛和三亚)的不同腐蚀区带(潮差区和全浸区),在不同的时间点(90,180和270 d)取出,就腐蚀形貌、腐蚀速率、腐蚀产物成分进行分析,并采用传统平板分离和16S r DNA序列分析技术对腐蚀产物层中的微生物进行分...将Q235碳钢样品挂于不同海域(青岛和三亚)的不同腐蚀区带(潮差区和全浸区),在不同的时间点(90,180和270 d)取出,就腐蚀形貌、腐蚀速率、腐蚀产物成分进行分析,并采用传统平板分离和16S r DNA序列分析技术对腐蚀产物层中的微生物进行分离、纯化和培养。结果表明,Q235碳钢在不同海域不同腐蚀区带的腐蚀速率不同,且潮差区的腐蚀速率总是大于全浸区的;不同腐蚀区带腐蚀产物的内外层成分存在差别,外层含有Fe3O4,α-Fe OOH和γ-Fe OOH等,内层主要是Fe3O4,而不同海域形成的腐蚀产物成分差别不明显。不同时空下不同腐蚀区带Q235碳钢挂片腐蚀产物层中的细菌群落结构复杂且存在差异,主要包括硫酸盐还原菌、铁细菌和好氧/兼性厌氧菌等;在相同时空条件下,全浸区的细菌种类和数量均高于潮差区的,且更容易检测到硫酸盐还原菌的存在;好氧/兼性厌氧菌种类丰富,以弧菌属、芽孢杆菌属和假交替单胞菌属为优势菌。展开更多
It is well known that the use of Helmholtz decomposition theorem for static vector fields , when applied to the time dependent vector fields , which represent the electromagnetic field, allows us to obtain instan...It is well known that the use of Helmholtz decomposition theorem for static vector fields , when applied to the time dependent vector fields , which represent the electromagnetic field, allows us to obtain instantaneous-like solutions all along . For this reason, some people thought (see e.g. [1] and references therein) that the Helmholtz theorem cannot be applied to time dependent vector fields and some modification is wanted in order to get the retarded solutions. However, the use of the Helmholtz theorem for static vector fields is correct even for time dependent vector fields (see, e.g. [2]), so a relation between the solutions was required, in such a way that a retarded solution can be transformed in an instantaneous one, and conversely. On this paper we want to suggest, following most of the time the mathematical formalism of Woodside in [3], that: 1) there are many Helmholtz decompositions, all equally consistent, 2) each one is naturally related to a space-time structure, 3) when we use the Helmholtz decomposition for the electromagnetic potentials it is equivalent to a gauge transformation, 4) there is a natural methodological criterion for choosing the gauge according to the structure postulated for a global space-time, 5) the Helmholtz decomposition is the manifestation at the level of the fields that a gauge is involved. So, when we relate the retarded solution to the instantaneous one what we do is to change the gauge and the space-time. And, if the Helmholtz decompositions are related to a space-time structure, and are equivalent to gauge transformations, each gauge transformation is natural for a specific space-time. In this way, a Helmholtz decomposition for Euclidean space is equivalent to the Coulomb gauge and a Helmholtz decomposition for the Minkowski space is equivalent to the Lorenz gauge. This leads us to consider that the theories defined by different gauges may be mathematically equivalent, because they can be related by means of a gauge transformation, but they are not empirically equiv展开更多
We analyze some physical concepts only using natural numbers. We assume a dis-crete space. Physical variables such as speed and momentum are considered as result of the sum of discrete contributions. Such discrete con...We analyze some physical concepts only using natural numbers. We assume a dis-crete space. Physical variables such as speed and momentum are considered as result of the sum of discrete contributions. Such discrete contributions can be calculated with natural numbers only. Elementary algebra is used in the analysis of physical subjects.展开更多
文摘It is well known that the use of Helmholtz decomposition theorem for static vector fields , when applied to the time dependent vector fields , which represent the electromagnetic field, allows us to obtain instantaneous-like solutions all along . For this reason, some people thought (see e.g. [1] and references therein) that the Helmholtz theorem cannot be applied to time dependent vector fields and some modification is wanted in order to get the retarded solutions. However, the use of the Helmholtz theorem for static vector fields is correct even for time dependent vector fields (see, e.g. [2]), so a relation between the solutions was required, in such a way that a retarded solution can be transformed in an instantaneous one, and conversely. On this paper we want to suggest, following most of the time the mathematical formalism of Woodside in [3], that: 1) there are many Helmholtz decompositions, all equally consistent, 2) each one is naturally related to a space-time structure, 3) when we use the Helmholtz decomposition for the electromagnetic potentials it is equivalent to a gauge transformation, 4) there is a natural methodological criterion for choosing the gauge according to the structure postulated for a global space-time, 5) the Helmholtz decomposition is the manifestation at the level of the fields that a gauge is involved. So, when we relate the retarded solution to the instantaneous one what we do is to change the gauge and the space-time. And, if the Helmholtz decompositions are related to a space-time structure, and are equivalent to gauge transformations, each gauge transformation is natural for a specific space-time. In this way, a Helmholtz decomposition for Euclidean space is equivalent to the Coulomb gauge and a Helmholtz decomposition for the Minkowski space is equivalent to the Lorenz gauge. This leads us to consider that the theories defined by different gauges may be mathematically equivalent, because they can be related by means of a gauge transformation, but they are not empirically equiv
文摘We analyze some physical concepts only using natural numbers. We assume a dis-crete space. Physical variables such as speed and momentum are considered as result of the sum of discrete contributions. Such discrete contributions can be calculated with natural numbers only. Elementary algebra is used in the analysis of physical subjects.
