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951.
对模糊综合评判方法提出一种新的评分法-模糊评分法,它可适用于单级或多级模糊综 合评判. 相似文献
952.
针对中国南方最重要的砂岩型铀成矿区带——滇西腾冲地块新生代盆地群,目前正在实施的新一轮调查已取得显著进展。尤其是在龙川江盆地南部钻探发现新的工业矿体,为成矿机制研究和探索勘查方向提供了宝贵素材。鉴于滇西成矿带特殊的"构造-赋铀岩相-成矿驱动"特征,开展矿体铀赋存状态研究,对于追溯铀源区、重建叠加成矿过程、建立找矿标志和矿床开发利用都具有重要意义,但相关报道鲜见。本文利用ICP-MS、电子探针定量分析和高分辨扫描电镜等手段,对龙川江盆地南部团田地区最新钻获的矿体岩心开展铀赋存状态分析。结果表明,该地区铀矿物以铀石为主,存在铀钍石、独居石等含铀矿物。铀矿物主要以微细粒侵染状赋存于填隙物处、吸附于碎屑矿物表面,少数以铀石微粒集合体形式赋存于蚀变黑云母、石英等矿物颗粒的裂隙中。面扫描影像显示出矿化段铀元素与钍、稀土元素钇具有正相关的分布特征,指示龙川江盆地团田地区砂岩型铀矿体物源区岩石Th、稀土元素Y含量可能具有较高本底值,对于追索物源区具有一定指示意义。龙川江盆地铀源供给存在多源性、多期性可能。 相似文献
953.
陈锋 《苏州大学学报(医学版)》2011,27(1)
设R为含幺交换环,X,y(∪)spec(R).在本文中,我们引入了相对于X,Y的广义局部上同调,并研究了它与一般局部上同调的关系及它的消失性. 相似文献
954.
Xing Wei ZhongYing Xue AiMin Wu Xiang Wang XianYuan Li Fei Ye Jie Chen Meng Chen Bo Zhang ChengLu Lin Miao Zhang Xi Wang 《科学通报(英文版)》2011,56(4-5):444-448
In this paper, we investigated the dose window of forming a continuous buried oxide (BOX) layer by single implantation at the implantation energy of 200 keV. Then, an improved two-step implantation process with second implantation dose of 3×1015 cm?2 was developed to fabricate high quality separation by implanted oxygen (SIMOX) silicon on insulator (SOI) wafers. Compared with traditional single implantation, the implantation dose is reduced by 18.2%. In addition, the thickness and uniformity of the BOX layers were evaluated by spectroscopic ellipsometry. Defect-free top Si as well as atomic-scale sharp top Si/buried oxide interfaces were observed by transmission electron microscopy, indicating a high crystal quality and a perfect structure of the SOI fabricated by two step implantation. The top Si/BOX interface morphology of the SOI wafers fabricated by single or two-step implantation was also investigated by atomic force microscopy. 相似文献
955.
A dragonfly wing consists of membranes and both longitudinal and cross veins. We observed the microstructure cross-section at several locations in the dragonfly wing using environmental scanning electron microscopy (ESEM). The organic nature of the junction between the vein and the membrane was clearly identifiable. The membrane was divided into two layers, the upper epidermis and the lower epidermis. These layers extend around the sandwich structure vein, and combine with the adjacent membrane at a symmetrical location along the vein. Thus, we defined this as an organic junction between the vein and the membranes. The organic junction is able to form a tight corrugation angle, which dramatically increases both the warping rigidity and the strength of the wing, but not the torsional rigidity. The torsional deformation is primarily controlled by the microstructure of the longitudinal veins, and is based on the relative rotation angle between the epidermal layer and the inner layer of the vein that forms the zigzag section. 相似文献
956.
We present a theory of the multi-threshold second-order phase transition,and experimentally demonstrate the multi-threshold secondorder phase transition phenomenon.With carefully selected parameters,in an external cavity diode laser system,we observe secondorder phase transition with multiple(three or four) thresholds in the measured power-current-temperature three dimensional phase diagram.Such controlled death and revival of second-order phase transition sheds new insight into the nature of ubiquitous secondorder phase transition.Our theory and experiment show that the single threshold second-order phase transition is only a special case of the more general multi-threshold second-order phase transition,which is an even richer phenomenon. 相似文献
957.
Coordination polymers (or metal-organic frameworks, MOFs), as one of the essences of crystal engineering and coordination chemistry, have attracted considerable atten-tion from chemists, 相似文献
958.
Aquaporins are implicated in a wide variety of plant physiological processes, although the mechanisms involved in their regulation are not fully understood. To gain further insight into the regulatory factors involved in this process, we used a yeast two-hybrid system to screen for potential binding partners to the Arabidopsis tonoplast intrinsic protein (TIP) AtTIP1;1. This was the first protein identified to be associated with high water permeability in vacuolar membranes from Arabidopsis thaliana. Using ... 相似文献
959.
During the first leg of a Chinese research cruise to the Southeast Indian Ridge (SEIR) in 2007, we revisited the K-segment of the SEIR and observed a water column turbidity anomaly at a CTD cast station. This station was located ~400 m from a dredge site on a plume anomaly detected in 1996 by US scientists. The characteristics of the turbidity anomaly detected in our survey are different from those observed 11 years previously, implying that either the detected anomalies have distinct and different plume sources or the robustness of the plume has changed in the intervening time. In addition, turbidity anomalies were observed at two localities on the K-segment in a deep tow-yo profile. If these two anomalies are not connected, the plume incidence calculated would be about 0.28, larger than the predicted value of 0.25 for a 65 mm/a spreading rate. This increase in plume incidence on the K-segment seems to be related to the influence of the St. Paul-Amsterdam hotspot, located about 300 km to the northwest. 相似文献
960.