The problem of dynamic interactions between an orientation control law and pure pursuit guidance law for dive plane response of underwater vehicles is analyzed. A complete stability analysis is performed in order to e...
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The problem of dynamic interactions between an orientation control law and pure pursuit guidance law for dive plane response of underwater vehicles is analyzed. A complete stability analysis is performed in order to evaluate regions of stable vehicle operations. It is shown that loss of stability can occur in either a static or dynamic way. In the first, a linearly increasing path deviation is observed, whereas in the second the loss of stability is accompanied by the generation of self-sustained oscillatory motions around the commanded path. Nonlinear analysis reveals the occurrence of both static and Poincare-Andronov-Hopf bifurcations. Numerical experiments support the analytic predictions of the bifurcation analysis.
This paper discusses a new suspension and guidance configuration for a high-speed, electrodynamic suspension (EDS) maglev system. The configuration can also be used to develop an electromagnetic guideway directional s...
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This paper discusses a new suspension and guidance configuration for a high-speed, electrodynamic suspension (EDS) maglev system. The configuration can also be used to develop an electromagnetic guideway directional switch. The performance of the system is predicted using the dynamic circuit model. General expressions of the magnetic forces based on the harmonic approximation are obtained. The principle of the electromagnetic guideway directional switch for the EDS maglev system is discussed.
A simple framework to define generalized true proportional navigation (GTPN) guidance laws is presented. It is shown that this framework subsumes many of the generalizations presented in the earlier literature. The ca...
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A simple framework to define generalized true proportional navigation (GTPN) guidance laws is presented. It is shown that this framework subsumes many of the generalizations presented in the earlier literature. The capture regions of a number of GTPN guidance laws are obtained through a rigorous qualitative analysis. The method of analysis is simpler and lends itself directly to an easy geometrical interpretation. A considerable amount of misinterpretation in the previous results, arising out of certain basic misconceptions, are corrected here. It is shown that a logical application of the guidance philosophy, through a minor modification of GTPN to take into account the direction of rotation of the line-of-sight (LOS), contributes substantially to the expansion of the capture region in the relative velocity space. In particular, it is shown that the capture region also extends to the negative closing velocity region, thus making the modified GTPN almost comparable, so far as the domain of capturability of guidance laws is concerned, to the pure proportional navigation (PPN) guidance law. A number of new results on the exact bounds on the capture region are derived and illustrated through examples.
As the alignment of the tunnel is not straight in the horizontal plane or in the vertical plane, the lining had to be designed to follow the curves. The Paper explains how it was possible to use only twelve positions ...
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As the alignment of the tunnel is not straight in the horizontal plane or in the vertical plane, the lining had to be designed to follow the curves. The Paper explains how it was possible to use only twelve positions to align the segments. The laser and computer guidance method is described and the importance of mix design and placement of lining segment mortar emphasized. The methods used to solve problems raised by interaction between tunnels, reinforcement of segments, nature of gaskets and bolting are examined.
The results of ultrasound (US)-guided renal parenchymal cutting needle biopsies in 101 consecutive patients were reviewed. The biopsies were done with the automated Biopty device mounted with a 2.0-mm needle. One or 2...
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The results of ultrasound (US)-guided renal parenchymal cutting needle biopsies in 101 consecutive patients were reviewed. The biopsies were done with the automated Biopty device mounted with a 2.0-mm needle. One or 2 needle passes yielded sufficient material for histologic analysis in 94% (95/101). Three or more passes were required in 6% (6/101) to. obtain an adequate specimen. Mesangioproliferative glomerulonephritis, IgA-nephropathy, nephrosclerosis, diabetic nephropathy, secondary amyroidosis, lupus nephritis, minimal change glomeruronephritis and interstitial nephritis accounted for 79% of the final histologic diagnoses. The high quality and quantity of the tissue specimens yielded a definitive histologic diagnosis in renal parenchymal diseases of unknown etiology. Four major complications occurred, but no deaths or loss of kidney function were recorded. US proved useful as a guide to suitable biopsy site and in the detection of clinically significant complications. Prebiopsy screening of coagulation variables did not seem to prevent complications. Special attention should be paid to postbiopsy clinical observation.
The neural cell adhesion molecule (N-CAM) is an integral membrane glycoprotein which mediates the adhesion of neurons to neurons and to other types of cells. During development, the N-CAM molecule is converted from a ...
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The neural cell adhesion molecule (N-CAM) is an integral membrane glycoprotein which mediates the adhesion of neurons to neurons and to other types of cells. During development, the N-CAM molecule is converted from a microheterogenous, highly sialylated, embryonic form (200-230 kDa) to several distinct, less sialylated but more adhesive, adult forms (120, 140 and 180 kDa). Monoclonal antibodies to epitopes of N-CAM (designated 5A5, 12F8, 5B8, 12F11 and 14E6) were used to investigate the spatial and temporal distribution of these neural cell adhesion molecules during the development of the corticospinal tract (CST) in rat spinal cord, from postnatal day 1 (P1) until adulthood. The light microscopical observations indicate that the embryonic form of N-CAM (200-230 kDa) recognized by 5A5 and 12F8 antibodies, respectively, is probably involved in the process of initial ingrowth of pioneer CST-fibers into the ventralmost part of the dorsal funiculus. The adult forms of N-CAM (120, 140, 180 kDa) recognized by 5B8, 12F11, and 14E6 antibodies, respectively, are present during later stages of CST white matter ingrowth and probably involved in fasciculation of the later arriving CST axons. During the period of CST target innervation (P4-P21), a gradual shift from embryonic (200-230 kDa) to adult (120, 140 and 180 kDa) forms of N-CAM occurs in spinal white matter and in the spinal gray matter adjacent to the ventral most part of the dorsal funiculus. The presence of embryonic N-CAM (200 kDa), with its low adhesive capacity in the CST outgrowth area may allow the CST axons to branch. If this branching is no longer desirable, only the higher affinity forms of N-CAM (120, 140 and 180 kDa) are expressed. The absence of N-CAM on CST target interneurons in the base of the dorsal horn and intermediate spinal gray matter strongly suggest that N-CAM is not involved in CST synapse formation. Together, these results suggest that various forms of N-CAM are involved in CST spinal white mat
The local microenvironment of tissue cells has a profound influence on cell behaviour such as cell shape, guidance of movement, and so on. One approach to understanding this phenomenon, which is being applied by a num...
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The local microenvironment of tissue cells has a profound influence on cell behaviour such as cell shape, guidance of movement, and so on. One approach to understanding this phenomenon, which is being applied by a number of groups, is to model possible cues using microfabrication technology. Such techniques have been used to examine the behaviour of a number of cell types. The responses of fibroblasts, epithelial cells and neurones have been determined on a variety of micropatterned surfaces. Conventional photolithographic techniques and laser holography have been employed to define topographic patterns with feature sizes ranging from 25 mu m to 130 nm. Photolithography, combined with silanization of glass, has been used to chemically pattern surfaces;this results in differentially adhesive surfaces that mimic possible in vivo cues. The determination of the response of various cell types to these various surfaces has provided detailed information on the biological mechanisms controlling cell behaviour, and on aspects of tissue responses to implanted artificial devices;it has also illustrated the potential for technology utilizing immobilized cellular patterns.
Researchers at the University of California at Santa Barbara are devel-oping a personal guidance system that could someday enable visually im-paired travelers to navigate unfamiliar territory without assistance. "
Researchers at the University of California at Santa Barbara are devel-oping a personal guidance system that could someday enable visually im-paired travelers to navigate unfamiliar territory without assistance. "
The results of ultrasound (US)-guided renal parenchymal cutting needle biopsies in 101 consecutive patients were reviewed. The biopsies were done with the automated Biopty device mounted with a 2.0-mm needle. One or 2...
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The results of ultrasound (US)-guided renal parenchymal cutting needle biopsies in 101 consecutive patients were reviewed. The biopsies were done with the automated Biopty device mounted with a 2.0-mm needle. One or 2 needle passes yielded sufficient material for histologic analysis in 94% (95/101). Three or more passes were required in 6% (6/101) to obtain an adequate specimen. Mesangioproliferative glomerulonephritis, IgA-nephropathy, nephrosclerosis, diabetic nephropathy, secondary amyloidosis, lupus nephritis, minimal change glomerulonephritis and interstitial nephritis accounted for 79% of the final histologic diagnoses. The high quality and quantity of the tissue specimens yielded a definitive histologic diagnosis in renal parenchymal diseases of unknown etiology. Four major complications occurred, but no deaths or loss of kidney function were recorded. US proved useful as a guide to suitable biopsy site and in the detection of clinically significant complications. Prebiopsy screening of coagulation variables did not seem to prevent complications. Special attention should be paid to post-biopsy clinical observation.
学校辅导的概念辅导(guidance)是一种专业,目的在助人自助,它随着时代的变迁而不断发展与完善,但其基本原则保持不变。这些原则是:①关心人格发展;②以个人为重心;③强调合作而不用强迫;④尊重个人自由、尊严与价值;⑤是持续的教育。一般提到辅导,多半指的是学校中的进行的辅导工作,根据夏尔与史东(*** and ***)的分析,随着历史事件的变迁,学校辅导的概念,也有所嬗演,每一个概念都有它的社会背景,各有其独到的眼光和重点。学校辅导发展至今,七十多年来,有十二个模式出现。这十二种理论模式,在学校辅导实施中虽偶见到,但都找不到一个纯碎的理论架构,事实上,学校中的辅导实施很少受到单一理论的指导。
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