Influence of prolonged optic flow stimuli on spontaneous activities of cat PMLS neurons

Changes in neuronal spontaneous activities after prolonged optic flow stimulation (using the three basic flow modes: translation, radiation and rotation) were investigated by extracellular single-unit recording in cortical area PMLS of the cat. The results showed that the evoked responses decreased with the prolongation of visual stimuli,and the spontaneous activities usually dropped to a lower level after the stimuli were withdrawn. Generally, the reduction in spontaneous activities was larger after adaptation in the preferred direction than in the non-preferred direction.This difference was much pronounced to translation stimuli,but relatively insignificant to radiation and rotation. These points suggest that non-specific fatigue may act as the key factor in adaptation to simple translation, while some kinds of more complicated, direction-specific mechanism may be involved in adaptation to the complex optic flow patterns. In addition, PMLS may play an important role in perception and adaptation to complex motion and the relevant motion after-effects.     

关于缓增广义函数的结构定理

本文在不涉及空间 D■及其对偶空间 D■性质的基础上,用简明的泛函分析方法证明缓增广义函数的结构定理.     

甘肃永登碱性熔岩中残留单斜辉石特征

对甘肃永登石灰沟－带分布的变白榴石响岩，辉石白榴岩，暗色粗面岩中的残留单斜辉石的产出条件，光学性质，化学成分进行了研究，确定上述各类岩石中残留的单斜辉石属于含钛普通辉石。化学成分主要是由ＣａＭｇＳｉ２Ｏ６约为８０．００％，ＣａＦｅＳｉ２Ｏ６约为１３．９６％，ＮａＦｅＳｉ２Ｏ６约为３％，ＣａＴｉＡｌ２Ｏ６约为３％，同时还含有少量的ＣａＡｌＳｉＡｌＯ６分子及Ｍｎ等组分。ＴｉＯ２的含量在０．６５％～１．     

四川盆地中部丘陵的土壤侵蚀特征

四川盆地中部的丘陵,是我国土壤侵蚀和水土流失最严重的地区之一。本文分析了川中丘陵土壤侵蚀的特征及影响因素,探讨了土壤侵蚀与水土流失的关系,以及该地区泥沙输移比的时间变化。笔者认为,川中丘陵的土壤侵蚀与泥沙外移是不同步的,沟谷的运移能力对侵蚀物质的外运极为重要。所以,对丘间沟谷的系统研究可为川中丘陵的水土保持工作提供基础的科学依据。     

一种诊断外周神经系统疾病的专家系统

采用人工智能技术，提取专家经验，构成推理规则和诊断知识库，并与数据库管理系统相集成，形成诊断专家系统。应用实践表明，在已测试的５１病例中，其诊断准确率达到９６％。     

人造卫星相对论摄动运动方程的解

本文应用平均根数法求得了人造卫星在地球形状摄动下,相对论摄动运动方程的二阶长期摄动和一阶长周期摄动的解.     

基于粗糙集与神经网络的机场气象新型预测模型

针对民用机场多因素气象预测问题的复杂性,提出了一种基于粗糙集—RBF神经网络模型.该模型利用粗糙集理论约简气象影响因素,提取关键因素作为网络的输入,简化了网络结构.实例验证,该模型的学习训练速度和预测精度远优于传统的RBF神经网络模型.     

Discovery and implications of the high-pressure pelitic granulite from the Jiaobei massif

The high pressure pelitic granulite with peak assemblage of garnet kyanite ternary feldspar muscovite rutile was discovered in Qixia area in the Precambrian Jiaobei massif, where high pressure basic granulites are widely distributed. The metamorphic peak conditions for the pelitic granulite were calculated as T=800-840℃ and P=1.0-1.25 GPa on the basis of P-T pseudosection. The post peak P-T path is characterized first by an isothermal decompression (ITD) pattern and then by an isobaric cooling (IBC) pattern, indicating a geodynamic process related to thinning of thickened continental crust.     

珍珠层作为骨修复材料的研究进展简

寻找和研制理想的骨修复材料一直是生物材料研究的热点之一。珍珠层作为生物骨替代材料,其优势在于含有具有诱导成骨作用的有机成分、合适的降解性能以及与人骨组织接近的力学性能。本文综述了珍珠层的结构、无机成分、有机成分、细胞相容性和生物降解性,这些研究结果表明,珍珠层具有很好的生物相容性。同时还分析了珍珠层作为骨修复材料存在的问题,展望了珍珠层作为骨修复材料应用的前景。