A study on 3-D velocity structure of crust and upper mantle in Sichuan -Yunnan region, China

Based on the first arrival P and S data of 4 625 regional earthquakes recorded at 174 stations dispersed in the Yunnan and Sichuan Provinces, the 3-D velocity structure of crust and upper mantle in the region is determined, incorporating with previous deep geophysical data. In the upper crust, a positive anomaly velocity zone exists in the Sichuan basin, whereas a negative anomaly velocity zone exists in the western Sichuan plateau. The boundary between the positive and negative anomaly zones is the Longmenshan fault zone. The images of lower crust and upper mantle in the Longmenshan fault, Xianshuihe fault, Honghe fault and others show the characteristic of tectonic boundary, indicating that the faults likely penetrate the Moho discontinuity. The negative velocity anomalies at the depth of 50 km in the Tengchong volcanic area and the Panxi tectonic zone appear to be associated with the temperature and composition variations in the upper mantle. The overall features of the crustal and the upper mantle structures in the SichuanYunnan region are the lower average velocity in both crust and uppermost mantle, the large crustal thickness variations, and the existence of high conductivity layer in the crust or/and upper mantle, and higher geothermal value. All these features are closely related to the collision between the India and the Asia plates. The crustal velocity in the SichuanYunnan rhombic block generally shows normal value or positive anomaly, while the negative anomaly exists in the area along the large strike-slip faults as the block boundary. It is conducive to the crustal block side-pressing out along the faults. In the major seismic zones, the seismicity is relative to the negative anomaly velocity. Most strong earthquakes occurred in the upper-mid crust with positive anomaly or normal velocity, where the negative anomaly zone generally exists below.

Synthesis and Crystal Structure of a Novel Three-dimensional Manganese(Ⅱ) Coordination Polymer:[Mn(pdc)]_n (pdc=Pyridine-2,4-dicarboxylate)

A novel manganese（H） coordination polymer [Mn（pdc）]n （pdc = pyridine-2,4- dicarboxylate） has been synthesized under hydrothermal conditions. The crystal is of monoclinic, space group P211n with a = 6.506（4）, b = 9.392（6）, c = 11.217（7） A, β = 105.650（12）°, V= 660.0（7）A3, Z = 4, Mr = 220.04, Dc = 2.215 g/cm3,μ = 1.971 mm-1, F（000） = 436, Rint = 0.0345, R = 0.0360 and wR = 0.0778 for 1259 observed reflections with I 〉 2σ（I）. In the structure, the Mn（Ⅱ） atom is coordinated in a distorted octahedral arrangement by one pyridine N and five carboxylate O atoms from five pdc ligands, each of which coordinates to five Mn atoms to propagate a three-dimensional layered framework.

Three-Dimensional Dynamic Based Borrowing Scheme for Wireless Cellular Networks

Mobility metrics of wireless networks such as link availability, number of neighboring nodes, link duration, link state, and link stability make it difficult to provide a node with quality of services guarantee. In previous research on Quality of Service (QoS) for cellular networks especially for handling handoff connections, the design was based on a flat 2D hexagon cells. However, in reality Base Station antenna coverage is in a 3D space and there exists a blind spot;the area which is just above and bellow the radiated antenna. In this paper we introduce the concept of Blind Spot (BS) in which there is no signals to initiate a call or accepting a handoff one. In BS, the signal power equal zero. Even if there is enough bandwidth to initiate or accept a handoff call, it will be blocked or dropped respectively. We present an implementation of Static Borrowing Scheme (SBS) and we extend the dynamic-rate based borrowing scheme [1] into 3-Dimentional structure and call it 3-Dimensional Dynamic Based Borrowing Scheme (3D DBBS). The proposed new technique for resource sharing is to ensure the continuity for both originating and handoff connections in 3-D cellular networks based on Dynamic-Based Borrowing Scheme (3D BBS). This technique aims to minimize the blocking probability of the originating calls by minimizing the dropping probability of the handoff requests and maximizing the channel utilization. The results revealed that 3D DBBS outperformed the static based schemes by 5% on average even when the blind spot of the base station antenna is taken into consideration. When moving to a 3D space, the results of the simulation showed the 3D DBBS outperformed the static scheme by 2% on average. As a result, considering nodes in a 3D space will have better QoS guarantee as the blocking and dropping probabilities are decreased. Thus, the bandwidth utilization is increased.

前驱体制备对三维通孔不锈钢泡沫性能的影响

研究前驱体中浆料浸入量与不锈钢粉末粒径对具有三维通孔网状结构不锈钢泡沫制品的开孔率和抗弯强度的影响。研究发现:随前驱体中浆料浸入量的增加,泡沫制品的抗弯强度逐渐提高,开孔率有所降低;而随着粉末粒径的减小,泡沫制品的抗弯强度显著增大,其开孔率呈轻微降低的趋势。当将44μm的316L不锈钢粉末与添加剂配成料浆浸入20ppi的聚氨酯海绵中,制成浸入量0.5 g/cm3的前驱体,然后在(1 260±2)℃时烧结30 min,可制得孔径大小为1mm左右、具有良好三维通孔结构的不锈钢泡沫,该泡沫的开孔率为81.2%,抗弯强度为51.72 MPa。

烧结制度对三维通孔不锈钢泡沫性能影响

研究了烧结制度对具有三维通孔网状结构泡沫不锈钢的线收缩率、开孔孔隙度、抗弯强度的影响。研究发现:随着烧结温度的升高和保温时间的延长,烧结制品的线收缩率增大,开孔孔隙度减小;随着烧结温度的升高,烧结制品抗弯强度先是增大,然后有所降低,保温时间的延长有利于提高抗弯强度,但影响没有烧结温度强烈。前驱体在1 260℃温度下烧结30min,可制得孔径大小为1mm左右、具有良好三维通孔结构的不锈钢泡沫,该泡沫的开孔孔隙度为81.2%,抗弯强度为51.72MPa。

三维通孔网状结构不锈钢泡沫的前驱体制备

研究了具有三维通孔网状结构不锈钢泡沫的前驱体制备工艺。研究发现，将含不锈钢粉末与添加剂A的料浆灌入经预处理过的海绵中制成前驱体、然后再对前驱体实施烧结的工艺可制备出三维通孔性良好的不锈钢泡沫；海绵的预处理可保证料浆在海绵中的均匀分布；当料浆中的添加剂A与固含分别控制在9％～13％与52％-75％时，所得泡沫体的孔筋粗细均匀，且其三维通孔性良好；不锈钢粉末的粒度及前驱体中的料浆负载量对不锈钢泡沫抗弯强度与开孔率有较大的影响。