Magnetic field effect on the growth of metal silicate tubes -magnetically induced chiral structure-

我们已经发现了一个novel phenomenon that freestanding metal silicate tube growing from metal saltpowders such as fecl_2 and cocl_2 immersed in water sodium silicate forms a twisted（chiral or helical）结构。In the growing process of metal silicate tubesaqueous solution of metal salts is delivered through the tubes and emitted at the growing ends. Wehave given experimental proofs on the Lorentz force exerting on anions in the metal salt解决方案与helical structure的相关。However，why the Lorents force exerts on anions unsolved because the flow of the metal salt solution isparallel to applied magnetic field.我们已经提供了following model in order to explain thereason:Among ions included in the metal salt solution, metal ions are trapped in metal silicate membranes，while anions are emitted outward and could have a motion component perpendicular to the magneticfield. The Lorentz force would exert on such macroscopic flow of anions and generate vertexwhich would twist the tube before the solidification. In order to confirm this model，we have developed an In -situ监测系统under magnetic fields. In a gradient field of B=2.2T和B·dB/dx=46 T^2/m，vortex flow was observed around a growing end of a cobalt silicate tube from a cocl_2 powder in10wt.% water sodium silicate. In the experiments，我们也有通知，the growing ends of two horns. Further detailedinvestigation has revealed that the helical structure of the metal silicate tubes is double helixformed by twining of the two horns, It is the first time in our knowledge that the double helix likeDNA is observed in the formation of inorganic membranes。

We have found a novel phenomenon that freestanding metal silicate tube growing from metal salt powders such as FeCl_2 and CoCl_2 immersed in water solution of sodium silicate forms a twisted (chiral or helical) structure. In the growing process of metal silicate tubes, aqueous solution of metal salts is delivered through the tubes and emitted at the growing ends. We have given experimental proofs on that the Lorentz force exerting on anions in the metal salt solution is related to the formation of the helical structure. However, why the Lorents force exerts on anions was unresolved because the flow of the metal salt solution is parallel to applied magnetic field. We have proposed the following model in order to explain the reason : Among ions included in the metal salt solution, metal ions are trapped in metal silicate membranes, while anions are emitted outward and could have a motion component perpendicular to the magnetic field. The Lorentz force would exert on such macroscopic flow of anions and generate vertex, which would twist the tube before the solidification. In order to confirm this model, we have developed an in-situ observation system under magnetic fields. In a gradient field of B=2.2 T and B・dB/dx=46 T^2/m, vortex flow was observed around a growing end of a cobalt silicate tube from a CoCl_2 powder in 10wt.% water solution of sodium silicate. In the experiments, we have also noticed that the growing ends often take shape of two horns. Further detailed investigation has revealed that the helical structure of the metal silicate tubes is double helix formed by twining of the two horns. It is the first time in our knowledge that the double helix like DNA is observed in the formation of inorganic membranes.