The single vortex in the FFLO state

In this Letter, we study the generalized Ginzburg-Landau (GL) functional near the tricritical temperature, and obtain the vortex solution of the FFLO state. Furthermore, we investigate the structure of the vortex and find that the vortices shrink when the Zeeman effect is weaken or temperature is lowered. (C) 2010 Elsevier B.V. All rights reserved.

Mo掺杂对高纯Ce_(1-x)Nd_xO_(2-x/2)(x=0.10,0.15)体系烧结温度及晶界电性能的影响

用柠檬酸硝酸盐法制备高纯Ce1-xNdxO2-x/2(x=0.10,0.15)固溶体,加入摩尔分数为5%的Mo,研究了Mo掺杂对烧结温度、结构及电性能的影响.通过X射线衍射、电感偶合等离子体和场发射扫描电镜等手段对氧化物进行了结构表征,采用交流阻抗谱测试其电性能.柠檬酸硝酸盐法制备的前驱体经1450℃烧结24 h得到致密度大于96%的陶瓷材料;加入5%Mo,在1250℃下烧结8 h即可达到理想的致密度(>95%).加入Mo在烧结过程中可加快晶界迁移,促进晶粒生长,显著提高了晶界电导率.在600℃时Ce0.85Nd0.15O1.925的晶界电导率为2.56 S/m,加入Mo后材料的电导率增加到5.62 S/m.

Sensitisation identification of stainless steel to intergranular stress corrosion cracking by atomic force microscopy

A new technique was developed for characterisation of stainless steel to intergramilar stress corrosion cracking by atomic force microscopy. The technique proved to be effective in sensitisation identification of AISI 304 stainless steel and might be promising in sensitisation identification of other stainless steels. (c) 2007 Elsevier B.V. All rights reserved.

地质规律约束下的波阻抗反演

Impedance inversion is very important in seismic technology. It is based on seismic profile. Good inversion result is derived from high quality seismic profile, which is formed using high resolution imaging resolution. High-resolution process demands that signal/noise ratio is high. It is very important for seismic inversion to improve signal/noise ratio. the main idea is that the physical parameter (wave impedance), which describes the stratigraphy directly, is achieved from seismic data expressing structural style indirectly. The solution of impedance inversion technology, which is based on convolution model, is arbitrary. It is a good way to apply the priori information as the restricted condition in inversion. An updated impedance inversion technology is presented which overcome the flaw of traditional model and highlight the influence of structure. Considering impedance inversion restricted by sedimentary model, layer filling style and congruence relation, the impedance model is built. So the impedance inversion restricted by geological rule could be realized. there are some innovations in this dissertation: 1. The best migration aperture is achieved from the included angle of time surface of diffracted wave and reflected wave. Restricted by structural model, the dip of time surface of reflected wave and diffracted wave is given. 2. The conventional method of FXY forcasting noise is updated, and the signal/noise ratio is improved. 3. Considering the characteristic of probability distribution of seismic data and geological events fully, an object function is constructed using the theory of Bayes estimation as the criterion. The mathematics is used here to describe the content of practice theory. 4. Considering the influence of structure, the seismic profile is interpreted to build the model of structure. A series of structure model is built. So as the impedance model. The high frequency of inversion is controlled by the geological rule. 5. Conjugate gradient method is selected to improve resolving process for it fit the demands of geophysics, and the efficiency of algorithm is enhanced. As the geological information is used fully, the result of impedance inversion is reasonable and complex reservoir could be forecasted further perfectly.

碳硅钙石的矿物学特征、晶体结构和晶体化学

碳硅钙石—Ca_7[Si_6O_(18)] [CO_3]·2H_2O是钙的碳酸盐硅酸盐矿物的第三个成员(Pluth and Smith, 1973)。前人曾做过某些碳硅钙石的一般矿物学研究(McConnell, 1955; Murdoch, 1955和曹正民等，1987)。Pluth和Smith (1973)利用X射线四园衍射仪进行结构测定，但未能确定其空间群，给出的结果是I2/m或Im。与此相关，他们未能确定该矿物结构中CO_3的有序或无序；对Ca的配位亦不明了。另外，前人对Ca的碳酸盐硅酸盐矿物未作系统比较。1972年在安徽省濉溪县邹楼铁矿床的钻钆岩芯中也发现了碳硅钙石。作者对该地碳硅钙石样品进行了矿物学、晶体结构和晶体化学研究。作者对采自安徽的碳硅钙品进行了一系列矿物学研究后发现，本文碳硅钙石的一般矿物学特征和前人研究结果基本相同。这说明：（1）本文样品确为碳硅钙石；（2）不同产地和产状的碳硅钙石的矿物学特征相同，由此进一步反映该矿物具有极苛刻的生成条件。作者发现前人对碳硅钙石X射线粉晶衍射线条的指标化有不少错误或不足，并予以纠正。通过晶体结构测定与修正，作用确认碳硅钙石的空间群应为Cm。结构中CO_3有序。它属于等腰三角形几何构型；并呈“受压”迹象。该结构中SiO_4四面体连成稳定的Si_6O_(18)六元环。碳硅钙石结构中水以结晶小的形式存在。该结构中存在氢键。该结构中共有四种Ca的配位多面体；Cal的配位数为8，Ca2, Ca3和Ca4配位数为6。Ca－0多面体相互以复杂的共棱方式连接成层。层间夹有CO_3, Si_6O_(18)和H_2O。Ca-0多面体畸变程度不同。碳硅钙石的晶体化学式应表示为Ca~([8])Ca~([6])_6[Si~([4])_6O_(18)] [C~([3])O_3]·2H_2O。作者发现，可以用配位中心原子（或离子）的键价和讨论配位多面体的结构畸变；并证明对于中心原子（或离子）、配位原子（或离子）、配位数及R（平均键长）均相同的几个配位多面体，畸变程度越强，中心原子（或离子）的键价和越大。此外，作者认识到，离子键和共价键的判别在键价和上也有所体现。根据晶体结构信息，作者对碳硅钙石的某些矿物学特征进行了满意的解释，从而使两者得到相互印证。通过认真全面的比较，作者发现碳硅钙石及其类似古物——Ca的碳酸盐硅酸盐矿物是复杂多样的。除去具有相同或相近的元素组成和地质产状外，它们几乎不再有共同点。碳硅钙石均产自火成岩和沉积岩的接触带。它的结晶温压范围是非常狭窄的。这也正是碳硅钙石等矿物在自然界比较罕见的重要原因。本文碳硅钙石结晶于较晚期的低温热液阶段；并且直接结晶于溶液环境。