简介:AbstractThe petrous apex is a difficult to reach surgical area due to its deep position in the skull base and many vital surrounding structures. Petrous apex pathology ranges from extradural cholesterol granulomas, cholesteatomas, asymmetric pneumatization, and osteomyelitis to intradural meningiomas and schwannomas. Certain lesions, such as cholesterol granulomas, can be managed with drainage while neoplastic lesions must be completely resected. Surgical options use open, endoscopic, and combined techniques and are categorized into anterior, lateral, and posterior approaches. The choice of approach is determined by the nature of the pathology and location relative to vital structures and extension into surrounding structures and requires thorough preoperative evaluation and discussion of surgical goals with the patient. The purpose of this state-of-the-art review is to discuss the most commonly used surgical approaches to the petrous apex, and the anatomy on which these approaches are based.
简介:作为为一张PC类型纤维接头结束脸的最重要的几何参数之一,顶偏移量能贡献高插入损失和高背思考读物。为参数的一个新奇测量方法,接头旋转--方法,被建议。与方法,一张普通接头结束脸的顶偏移量被测量。结果与由北国3000纤维接头结束脸干涉仪测量了那相比。二结果之间的差别是1.8m,这被发现。同时,顶上的相关错误资源的影响在旋转下面抵消测量--方法和顶核心方法分别地被分析,并且二个错误方程被导出。分析结果看那,与顶核心方法相比轴在以内并且在对它的旋转引起的主要飞机垂直的指示的二另外的亚tilts是否不比原来的轴大倾斜角度,最大。测量错误然后将被至少22.5%与旋转减少--方法。方法的有实行可能被实验证实。
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简介:为评价农业政策与环境拓展APEX模型在淮河中上游坡面尺度的适宜性,将其应用于淮河中上游的3个径流小区,在采用傅里叶幅度灵敏度检验扩展法进行灵敏度分析的基础上,利用蒙特卡罗模拟结合多目标函数技术自动校正模型,并使用1982—1986年日径流和产沙数据实测值与模拟值评价模型适宜性。结果表明:湿度条件2下的径流曲线数初始值(CN2)、损耗系数(CNIC)、水土保持措施因子(PEC)以及最大径流率-降雨能量调整因子(APM)对产沙模拟影响较大,CN2和CNIC对地表径流模拟影响较大;在模型校正阶段,径流和产沙日平均模拟值的百分误差绝对值(APE)小于20%,纳希-苏特克利夫有效系数(EF)和R2分别大于0.45和0.55;在模型验证阶段,径流和产沙日平均模拟值的APE小于25%,EF和R2分别大于0.4和0.5。这说明APEX模型适用于淮河中上游坡面尺度,可用于评价该地区不同土地管理措施下的水土流失。