雨课堂与腾讯课堂联用的“有机化学”线上教学设计与实践*

基于智慧教学工具“雨课堂”为主和“腾讯课堂”为辅的双平台联用组合,将“雨课堂”优秀的教学互动和全周期记录学习活动表现的功能与“腾讯课堂”网络直播高峰期画面卡顿少、师生可以语音互动的优点结合起来,充分发挥“以学生为中心”的教学理念,探讨了有机化学课程的线上教学设计,并在教学班级中进行了广泛实践。实践证明,“雨课堂”直播为主和“腾讯课堂”为辅的双平台联用教学模式能保证教学质量、激发学生的学习兴趣和提高学生的学习效果。     

Ways in which engaging with someone else’s reasoning is productive

Classrooms which involve students in mathematical discourse are becoming ever more prominent for the simple reason that they have been shown to support student learning and affinity for content. While support for outcomes has been shown, less is known about how or why such strategies benefit students. In this paper, we report on one such finding: namely that when students engage with another’s reasoning, as necessitated by interactive conversation, it supports their own conceptual growth and change. This qualitative analysis of 10 university students provides insight into what engaging with another’s reasoning entails and suggests that higher levels of engagement support higher levels of conceptual growth. We conclude with implications for instructional practice and future research.     

通过教学过程和互动设计保障在线教学的效果

Based on the analysis of the courses and the investigation of students' online learning needs, an online teaching mode of "Tencent Classroom" and "Rain Classroom" with "split screen" is designed. This mode is used for the online teaching of "Foundation of Innovation and Entrepreneurship" and "Chemical Instrumentation and Automation". After two months of teaching practice, the teaching and learning were reflected and summarized, aiming to improve the performance of online teaching.     

Simultaneous determination of nitrite and nitrate in dew, rain, snow and lake water samples by ion-pair high-performance liquid chromatography

A simple, fast, sensitive and accurate reversed-phase ion-pair HPLC method for simultaneous determination of nitrite and nitrate in atmospheric liquids and lake waters has been developed. Separations were accomplished in less than 10 min using a reversed-phase C₁₈ column (150 mm × 2.00 mm i.d., 5 μm particle size) with a mobile phase containing 83% 3.0 mM ion-interaction reagent tetrabutylammonium hydroxide (TBA-OH) and 2.0 mM sodium phosphate buffer at pH 3.9 and 17% acetonitrile (flow rate, 0.4 mL/min). UV light absorption responses at 205 nm were linear over a wide concentration range from 100 μg/mL to the detection limits of 10 μg/L for nitrite and 5 μg/L nitrate. Quantitation was carried out by the peak area method. The relative standard deviation for the analysis of nitrite and nitrate was less than 3.0%. This method was applied for the simultaneous determination of nitrite and nitrate in dew, rain, snow and lake water samples collected in southeast Massachusetts. Nitrate was found being present at 4.79-5.99 μg/mL in dew, 1.20-2.63 μg/mL in rain, 0.32-0.60 μg/mL in snow and 0.12-0.23 μg/mL in lake water. Nitrite was only a minor species in dew (0.62-0.83 μg/mL), rain (<0.005-0.14 μg/mL), snow (0.021-0.032 μg/mL) and lake water (0.12-0.16 μg/mL). High levels of nitrite and nitrate observed in dew water droplets may constitute an important source of hydroxyl radicals in the sunny early morning.     

Three-phase coupled modelling research on rain–wind induced vibration of stay cable based on lubrication theory

Cables of cable-stayed bridges may vibrate with large amplitude under wind and rain, which is known as rain–wind induced vibration (RWIV). According to the pervious researches, the formations and oscillations of rivulets on stay cable surface play important roles in RWIV. In this paper, four different 2D models are presented based on lubrication theory, and the best way of simulating RWIV through lubrication theory is confirmed by the comparisons of rivulet motions and cable vibration responses between these four models and pervious researches. On this basis, the relations among rivulet motions, cable aerodynamic forces and vibration responses are investigated to reveal the mechanism of RWIV. Numerical simulation results show that when RWIV occurs, the periodic oscillations of rivulets around cable lead to the periodic fluctuations of cable lift and drag, whose frequencies are almost equal and close to cable natural frequency. Under the periodically fluctuant lift and drag, cable vibrates with large amplitude in across-wind and along-wind directions, which may further enhance the circumferential oscillations of rivulets conversely. These confirm the conclusion that the resonance between rivulets and cable oscillation may be one of the main reasons for RWIV.     

Study on the role of rivulet in rain–wind-induced cable vibration through wind tunnel testing

Rain–wind-induced vibration (RWIV) of stay cables has become a concern in bridge engineering over the past decades. The excitation mechanism of RWIV remains unclear. Many researchers believe that the upper rivulet is crucial to RWIV. However, experimental study on rivulet is challenging and limited. The current study designs and tests a cable model of 160 mm in diameter in an open jet wind tunnel. The upper rivulet movement and cable vibration are simultaneously measured. The importance of the upper rivulet in RWIV is directly demonstrated by alternately controlling the upper and lower rivulets. The characteristics of the upper rivulet movement and the effects of this movement on RWIV are investigated in detail. The experiment shows that the rivulet–cable system is coupled, which causes the cable and upper rivulet to vibrate at different amplitudes under the same wind speed. The upper rivulet harmonic movement changes the wind loading on the cable, causing the harmonic vibration of the cable, which in turn exerts a harmonic inertia force on the rivulet. A large vibration of the coupled system then develops.     

Arguing About the Effectiveness of Assessments for the Classroom

Approaches to test score use and test purpose lack the well-developed methodological guidelines and established sources of evidence available for intended score interpretation. We argue in this paper that this lack fails to reflect the ultimate purpose of a test score—to help solve an important problem faced by intended test users. We explore the treatment of intended test purpose and test score use under the chain of assumption/inferences perspective identified within an argument-based approach to validity. Next, we revisit the notion of test score use and argue that, at least for classroom assessments based on complex constructs, such as learning progressions in math and science, test score use can be more effectively conceptualized as part of a potential solution to solving a problem, or “job-to-be-done.”. We argue for shifting from the definition of validity to the concept of effectiveness. Finally, we illustrate an argument- based approach to test score effectiveness by contrasting effectiveness arguments for interim assessments based on a conventional test blueprint or a test blueprint augmented with learning progressions.     

基于"互联网+"生物化学新教学模式的建立

The rapid development of internet technology has made the access to knowledge more convenient and diverse, which is both an opportunity and a challenge for traditional teaching methods. By analyzing and comparing the characteristics of four advanced teaching methods and techniques, and addressing the specific curriculum features and students' situation, a new mixed teaching model was constructed by Traditional Classroom Teaching Model (TCTM), Small Private Online Course (SPOC) and Flipping Classroom Model (FCM). The proportion of the three teaching methods was about 50%:35%:15%, respectively. By striving to combine their strengths and develop students' learning and reasoning ability gradually, the proposed mode achieved a satisfactory teaching effect.     

在无机化学教学中培养学生的创新思维

根据无机化学授课对象的特点,结合无机化学教学心得,分别以水的电化学稳定窗口、配位化学的发展史及铝离子浓度的测定为例,讲述了科学研究、化学史、实践与教学内容相结合对提高教学效果、培养学生创新思维的作用。     

有机化学在线课堂教学实践探索

The spring semester of 2020 is affected by the new coronary pneumonia epidemic, which prevents the normal classroom teaching of universities in China. Nankai University actively responds to the request of "Suspended classes but not stop teaching and learning" proposed by the Ministry of Education. The online teaching software such as "Rain Classroom" and "Tencent Meeting" are used to provide online teaching to undergraduate students. This article takes organic chemistry teaching as an example and introduces the implementation process and effectiveness of online teaching. According to the particularity of online teaching, teachers must change the teaching mode to ensure the teaching work carried out effectively.