- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Introducing Manganese-Doped Lead Halide Perovskite Quantum Dots: A Simple Synthesis Illustrating Optoelectronic Properties of Semiconductors
摘要： Quantum dots (QDs) are considered useful for demonstrating quantum phenomena in undergraduate laboratories due to their monodisperse size and excellent optical properties. Although doping has an increasingly important role in QD fabrication in the semiconductor field, it has rarely been discussed in the context of the undergraduate laboratory. In this work, a simple synthesis and characterization method for Mn-doped CsPbCl3 QDs for an upper-level undergraduate inorganic chemistry laboratory is reported. The Mn-doped CsPbCl3 system benefits from a simplified synthesis and straightforward characterization. This experiment introduces QD research to students and offers opportunities for instructors to discuss many important concepts in inorganic chemistry, such as energy band theory, particle-in-a-box model, electron paramagnetic resonance, ligand field theory, and nanochemistry.
关键词： Inorganic Chemistry,Crystal Field/Ligand Field Theory,EPR/ESR Spectroscopy,Upper-Division Undergraduate,Hands-On Learning/Manipulatives,Laboratory Instruction,Nanotechnology
更新于2025-11-20 15:33:11
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Identifying the Optimal 3D Display Technology for Hands-On Virtual Experiential Learning: A Comparison Study
摘要： The purpose of this study was to test different 3D display technologies in a hands-on virtual experiential learning environment (VELE) and determine the optimal 3D display technology. A conceptual framework was firstly proposed to explain the mechanism of how VR display features affect virtual experiential learning. Then, a single-factor within-subject experimental design was adopted for testing. The within-subject factor was three types of 3D display technology: fully immersive virtual reality (VR) mode [VR head-mounted display (HMD)], partially immersive VR mode (3D projection), and augmented reality (AR) mode (AR HMD). The dependent variables were visual comfort, interaction experience, learning experience, and outcome. A virtual math learning environment was established, and the aforementioned display technologies were tested in two hands-on virtual experiential learning scenarios. Results showed that different display technologies significantly affected users’ visual comfort, interaction experience, learning experience, and outcome in experiential learning (ps < 0.05). User ratings on these aspects for the VR HMD were significantly higher than those for the 3D projection and AR HMD. Thus, the VR HMD contributes to a best viewing experience and learning experience in terms of hands-on virtual experiential learning in the scenarios tested. Whether the study results still hold reliably in terms of more complex learning activities and long-term learning needs to be further studied.
关键词： visual comfort,Experiential learning,augmented reality,hands-on learning,virtual reality
更新于2025-09-23 15:21:01
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Raman spectroscopy coupled with ambient ionization mass spectrometry: A forensic laboratory investigation into rapid and simple dual instrumental analysis techniques
摘要： We present a laboratory experiment, developed around a pair of instrumental analysis techniques, Raman spectroscopy and ambient ionization mass spectrometry (MS), conducted by senior chemistry undergraduate students for bulk analysis of over-the-counter drugs using benchtop versions of the two instruments, as well as trace analysis of illicit drugs utilizing the corresponding portable instruments. The identification and confirmation of seized drugs is a routine operation in forensic laboratories that can be simplified using these two instrumental techniques in tandem. Bulk samples are readily analyzed using conventional Raman spectroscopy followed by paper cone spray ionization (PCSI) MS, while trace analysis is allowed by a simple single-substrate dual-analyzer method using surface enhanced Raman spectroscopy (SERS) from paper followed by paper spray ionization (PSI) MS. The introduction of these novel strategies to the students exposed them to potential career paths in forensic science by means of a hands-on experience that provided fundamental knowledge about this set of analytical methods, including intercomparisons of their performance, as well as practical issues like costs, regulations and databases. The use of portable instrumentation represents an additional learning experience for the students, considering that it is cutting-edge technology that is just now being transferred from academic to industrial labs and that it allows a valuable discussion of the advantages and disadvantages of bringing the laboratory to the field.
关键词： Mass spectrometry,Hands-on learning,Forensic analysis,Drugs of abuse,Paper cone spray ionization,Paper spray ionization,Paper surface enhanced Raman spectroscopy,Raman spectroscopy,Ambient ionization,Laboratory instruction
更新于2025-09-23 15:21:01
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Simple Acid Vapor Method for Production of HCl and DCl Gas for IR Spectroscopy
摘要： We report here a method that utilizes the vapor pressure of HCl(g) above a concentrated HCl(aq) solution as an extremely simple and safe method to produce small amounts of HCl vapor in an IR gas cell. This vapor pressure approach can also be used to produce DCl(g) by introducing a few drops of concentrated DCl(aq) into the gas cell.
关键词： Physical Chemistry,Laboratory Instruction,IR Spectroscopy,Upper-Division Undergraduate,Hands-On Learning/Manipulatives
更新于2025-09-23 15:21:01
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Identification of Proteins Using Four Methods of Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry
摘要： An upper-division undergraduate- or graduate-level laboratory experiment, challenging students to identify bovine serum albumin, equine myoglobin, bovine calmodulin, and bovine cytochrome c, uses four methods of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS): linear positive, in-source decay, peptide mass fingerprint, and postsource decay. Individual hands-on experience with each method is provided in a three week experiment. The importance of sequencing proteins/peptides when identifying proteomic targets using MALDI-TOF MS is emphasized.
关键词： Mass Spectrometry,Hands-On Learning/Manipulatives,Upper-Division Undergraduate,Laboratory Instruction,Graduate Education/Research,Bioanalytical Chemistry,Biotechnology,Analytical Chemistry,Biochemistry
更新于2025-09-19 17:13:59
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Detecting and Quantifying Microplastics in Bottled Water using Fluorescence Microscopy: A New Experiment for Instrumental Analysis and Environmental Chemistry Courses
摘要： Microplastics (MPs) are small plastic particles (<5 mm in size) that are ubiquitous in the environment and have even been detected in bottled water. In this laboratory experiment, suited for instrumental or environmental chemistry classes, students detect and quantify MPs in bottled water by filtering and staining them with Nile red dye prior to utilizing fluorescence microscopy. Instrumental concepts in fluorescence spectroscopy are reinforced as students build a low-cost fluorescence microscope and use it to collect images of the fluorescing MPs for counting purposes and assessing morphology. The exercise introduces students to MP pollution, an emerging field of chemical research, and motivates and engages them helping to form connections beyond the classroom. Each group detected MPs in their bottled water, and many were surprised by how many they found. Overall, the hands-on experiment received positive feedback from students, and postexperiment assessments showed marked improvement in their understanding of the principles of fluorescence and of the growing problem of MP pollution.
关键词： Analytical Chemistry,Upper-Division Undergraduate,Collaborative/Cooperative Learning,Water/Water Chemistry,Instrumental Methods,Environmental Chemistry,Hands-On Learning/Manipulatives
更新于2025-09-12 10:27:22
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Exploring the Gel State: Optical Determination of Gelation Times and Transport Properties of Gels with an Inexpensive 3D-Printed Spectrophotometer
摘要： The study of gels and their properties is a compelling topic both technologically and scienti?cally, and should therefore be emphasized in chemistry and material science syllabuses. In the present laboratory experiment, we propose two experiences, aimed at introducing gelation and gel transport properties using silica gels made from sodium silicate and sodium citrate bu?er. In particular, gelation times are used to teach kinetics and optical properties to ?rst and second year General Chemistry students. Gelation times are determined by measuring the increment in scattering intensity with a 3D-printed spectrophotometer. The gel transport properties are presented to further exemplify Fickian and non-Fickian behavior through ionic dyes di?using in gels. A qualitative description is obtained from charge interactions, and a quantitative description utilizing the di?usion coe?cient is achieved by analyzing absorbance pro?les. These tasks were designed to encourage students to work with unusual topics in a holistic way, approaching new materials, properties, and DIY equipment. Blueprints for the spectrophotometer, resources for instructors, and a detailed students’ guide are provided together with a short report model to promote critical discussion of the observations.
关键词： Transport Properties,Physical Chemistry,Materials Science,Second-Year Undergraduate,Hands-On Learning/Manipulatives,First-Year Undergraduate/General
更新于2025-09-09 09:28:46
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A Simple Synthetic Approach To Prepare Silver Elongated Nanostructures: From Nanorods to Nanowires
摘要： A procedure for one-pot preparation and characterization of silver 1D nanostructures is described. The main advantages of this synthetic approach are the simplicity and reproducibility, where the size of the final product can be controlled just by changing the reaction time. This experiment is designed as a laboratory introduction to colloidal chemistry for undergraduate and graduate students; they can appreciate the role of the different reagents in a relatively complex reaction and understand the relation between the morphology of a metal at the nanoscale and some macroscopic properties, such as its visible absorption spectrum (i.e., color).
关键词： Nanotechnology,Synthesis,Second-Year Undergraduate,UV?Vis Spectroscopy,Physical Chemistry,Laboratory Instruction,Hands-On Learning/Manipulatives,First-Year Undergraduate/General,Metals,Colloids
更新于2025-09-04 15:30:14
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Process Analytical Technology for Online Monitoring of Organic Reactions by Mass Spectrometry and UV–Vis Spectroscopy
摘要： Process analytical technologies (PATs) are used in the pharmaceutical and other industries to monitor chemical processes in real-time with analytical instrumentation. Each PAT analyzer brings its own advantages and disadvantages to the process, and multiplexing PAT analyzers can be advantageous as they can provide confirmatory measurements and increase the overall confidence of the analysis. In a pedagogical setting, online reaction monitoring enables the instructor to explain the fundamentals of instrumental techniques while highlighting pertinent real-world applications. Here we present a teaching laboratory exercise in which students monitor an amide bond formation reaction by flow UV?vis spectroscopy and by mass spectrometric analysis. The coupling of these two specific instruments allows students to investigate two instruments in one laboratory exercise, to explore the fundamentals behind each, and to contemplate the advantages and disadvantages of these instrumental methods. The coupling of the two instruments was aided by 3D printing which allowed students to explore how rapid prototyping can enable the development of innovative procedures.
关键词： Organic Chemistry,Mass Spectrometry,UV?Vis Spectroscopy,Laboratory Instruction,Instrumental Methods,Hands-On Learning/Manipulatives,Upper-Division Undergraduate,Analytical Chemistry,Reactions
更新于2025-09-04 15:30:14