Scientific teaching quality evaluation system and the effective operation mechanism have a positive meaning for promoting teaching reform. Teachers’ specialization is the core of education, and is the starting point ...Scientific teaching quality evaluation system and the effective operation mechanism have a positive meaning for promoting teaching reform. Teachers’ specialization is the core of education, and is the starting point and end-result of education reform. Teachers’ professional development has three kinds of orientation rational orientation, reflection-evaluation orientation, and ecological orientation. Some new research suggests that re? ection-evaluation orientation is the best way to improve teachers’ professional abilities. At present, reflective teacher education has become worldwide trend. Compared with experiential teaching, reflective teaching is a sort of positive tool which is used to help teachers conduct their active and professional work. The main purpose of reflective teaching is to allow teachers to reffect on their own work and self-evaluation, and improve their methodology, eventually improve teaching methods and promote student learning. Nevertheless, there are many problems in the teaching quality evaluation system in the aspects of concept, subject, standard, organization, etc. Therefore, we have to reffect and reconstruct the teaching quality evaluation system in colleges and universities.展开更多
The randomized controlled trial (RCT) as applied to medicine started in the mid last century(1) and is now deemed as the most rigorous scientific method for evaluating the clinical effectiveness of medical interve...The randomized controlled trial (RCT) as applied to medicine started in the mid last century(1) and is now deemed as the most rigorous scientific method for evaluating the clinical effectiveness of medical interventions. The earliest RCTs in Chinese medicine (CM) appeared in the early 1980s. In the past 30 years, RCT was seen to have gradually infiltrated into and have been accepted reluctantly by CM.展开更多
High cement bond quality is required to keep an oil well from hydraulic commu- nication between zones. In the cement bond evaluation, the ultrasonic echo method is widely used for its capability of channeling azimuth ...High cement bond quality is required to keep an oil well from hydraulic commu- nication between zones. In the cement bond evaluation, the ultrasonic echo method is widely used for its capability of channeling azimuth detection. Full waveforms reflected from the cased hole are simulated for different bonding conditions by the generalized transfer matrix method. Because of the high acoustic impedance of casing, the amplitudes of the reflected waves from the cement and the formation are small and cannot easily be used to evaluate the cementing condition. The wave that can propagate into the cement and the formation through the casing concentrates closely on the casing resonant frequency. To reduce the amplitude of the reflected wave from the casing inner surface and highlight the part of the reflected wave which carries the cementing quality information, the reflected full wave is filtered according to the casing resonant frequency. There are several wave packets in the filtered waveform. When the amplitude of the second wave packet is low, the cement bonds well with the casing, otherwise poorly. A low amplitude third wave packet is an indication of a good bond of the cement with the formation, otherwise poor. To reveal the sensitivity of the reflection wave amplitudes to the incident angle, reflected full waveform is modeled when an acoustic beam with finite width is incident on the casing. It is shown that the bond evaluation method based on filtered wave packets is valid for incident angle less than 5 degrees.展开更多
文摘Scientific teaching quality evaluation system and the effective operation mechanism have a positive meaning for promoting teaching reform. Teachers’ specialization is the core of education, and is the starting point and end-result of education reform. Teachers’ professional development has three kinds of orientation rational orientation, reflection-evaluation orientation, and ecological orientation. Some new research suggests that re? ection-evaluation orientation is the best way to improve teachers’ professional abilities. At present, reflective teacher education has become worldwide trend. Compared with experiential teaching, reflective teaching is a sort of positive tool which is used to help teachers conduct their active and professional work. The main purpose of reflective teaching is to allow teachers to reffect on their own work and self-evaluation, and improve their methodology, eventually improve teaching methods and promote student learning. Nevertheless, there are many problems in the teaching quality evaluation system in the aspects of concept, subject, standard, organization, etc. Therefore, we have to reffect and reconstruct the teaching quality evaluation system in colleges and universities.
文摘The randomized controlled trial (RCT) as applied to medicine started in the mid last century(1) and is now deemed as the most rigorous scientific method for evaluating the clinical effectiveness of medical interventions. The earliest RCTs in Chinese medicine (CM) appeared in the early 1980s. In the past 30 years, RCT was seen to have gradually infiltrated into and have been accepted reluctantly by CM.
基金supported by the National Natural Science Foundation of China(41174110,41204092)
文摘High cement bond quality is required to keep an oil well from hydraulic commu- nication between zones. In the cement bond evaluation, the ultrasonic echo method is widely used for its capability of channeling azimuth detection. Full waveforms reflected from the cased hole are simulated for different bonding conditions by the generalized transfer matrix method. Because of the high acoustic impedance of casing, the amplitudes of the reflected waves from the cement and the formation are small and cannot easily be used to evaluate the cementing condition. The wave that can propagate into the cement and the formation through the casing concentrates closely on the casing resonant frequency. To reduce the amplitude of the reflected wave from the casing inner surface and highlight the part of the reflected wave which carries the cementing quality information, the reflected full wave is filtered according to the casing resonant frequency. There are several wave packets in the filtered waveform. When the amplitude of the second wave packet is low, the cement bonds well with the casing, otherwise poorly. A low amplitude third wave packet is an indication of a good bond of the cement with the formation, otherwise poor. To reveal the sensitivity of the reflection wave amplitudes to the incident angle, reflected full waveform is modeled when an acoustic beam with finite width is incident on the casing. It is shown that the bond evaluation method based on filtered wave packets is valid for incident angle less than 5 degrees.