Busse „Phase Angle Thermography for depth resolved defect characterization”,

Abstract Optically excited Lockin-Thermography is a non-contact NDE-method which found many applications. However, the depth information about thermal boundaries (i.e. defects) which is included in the resulting phase angle images has not been extracted rigorously till now. This paper shows one way to derive from phase angle values depth resolved information on thermal boundaries and perform single-sided thermal wave profilometry

Decay time analysis in pulse thermography

Pulse Thermography is being used since several years for rapid detection of subsurface defects. This method is well suited for industrial applications because no physical contact to the test object is needed. Within a short measurement time robust results are obtained. Besides phase evaluation the decay time of surface temperature can be analyzed. In this paper the idea was to investigate the temperature half-life period of each surface point. The sample is assumed to be composed of small elements having the same surface area but different lengths. In a simple model, heat propagation in between these elements is neglected (local one dimensional model). Only changes in mass, heat capacity, and volume are considered. If the material has homogeneous thermal properties, the length (e.g. thickness) has a strong impact on the cooling down process. The concept takes the decay time for each element as a parameter for imaging

Kohärente Strahlquelle für die optische Freiraumkommunikation auf der Basis von hybrid integrierten Diodenlasern und Halbleiterlaser-Verstärkern : Abschlussbericht

[no abstract available

A Contemporary Clinico-Anatomical Guide to Craniovertebral Junction Surgery

Background Surgical treatment of ventral and ventrolateral lesions of the craniocervical junction are among the most challenging neurosurgical pathologies to treat. Three surgical techniques, the far lateral approach (and its variations), the anterolateral approach, and the endoscopic far medial approach can be used to approach and resect lesions in this area. Objective The aim of the study is to examine the surgical anatomy of three skull base approaches to the craniocervical junction and review surgical cases to better understand the indications and possible complications for each of these approaches. Methods Cadaveric dissections with standard microsurgical and endoscopic instruments were performed for each of the three surgical approaches, and key steps and surgically relevant anatomy were documented. Six patients with appropriate pre-, post-, and intraoperative imaging and video documentation are presented and discussed accordingly. Results Based on our institutional experience, all three approaches can be utilized to safely and effectively approach a wide variety of neoplastic and vascular pathology. Unique anatomical characteristics, lesion morphology and size, and tumor biology should all be considered when determining the optimal approach. Conclusion Preoperative assessment of surgical corridors with 3D illustrations helps to define the best surgical corridor. 360 degree knowledge of the anatomy of craniovertebral junction allows safe surgical approach and treatment of ventral and ventrolateral located lesions using one of the three approaches. Keywords craniocervical junction - far lateral approach - far medial approach - anterolateral approac