52,577 research outputs found
Measuring and analyzing German and Spanish customer satisfaction of using the iPhone 4S Mobile Cloud service
No full textThis paper presents the customer satisfaction analysis for measuring popularity in the Mobile Cloud, which is an emerging area in the Cloud and Big Data Computing. Organizational Sustainability Modeling (OSM) is the proposed method used in this research. The twelve-month of German and Spanish consumer data are used for the analysis to investigate the return and risk status associated with the ratings of customer satisfaction in the iPhone 4S Mobile Cloud services. Results show that there is a decline in the satisfaction ratings in Germany and Spain due to economic downturn and competitions in the market, which support our hypothesis. Key outputs have been explained and they confirm that all analysis and interpretations fulfill the criteria for OSM. The use of statistical and visualization method proposed by OSM can expose unexploited data and allows the stakeholders to understand the status of return and risk of their Cloud strategies easier than the use of other data analysis
[[alternative]]A Study of Program Planning for the Teacher-Chang College of Psychology
No full text[[abstract]]A Study of Program Planning for the Teacher-Chang College of Psychology
Ya-Yen Chang
Abstract
The purpose of this study was to understand the program planning practices of the College of Psychology and tried to plan an ideal program finally. The qualitative study approach and the questionnaire investigation were adopted to examine the Teacher-Chang College of Psychology program. The program planners were interviewed concerning their beliefs of the program goals, the curriculum design of the programs and their evaluation procedures. Through interviews and questionnaire investigations the findings are as follows:
1. People didn’t know the Teacher-Chang College of Psychology very well.
2. The recruiting of lecturers were mainly inner teachers. The groups and workshops were their main curriculum style. The curriculum contents were almost about self-growth and human relationship. The problem of curriculum design was that the Teacher-Chang College of Psychology didn’t have steady lecturer recruit.
3. The Teacher-Chang College of Psychology didn’t have enough program planners and program planners didn’t have enough ability. However there was a discrepancy between the head of Teacher-Chang and other centers.
4. There were not concrete marketing strategy and experts. Marketing strategy is to use old-fashioned media.
5. The main evaluation was quantitative and interview, while qualitative evaluation and whole program evaluation were being neglected.
Key words: Program planning, Teacher-Chang, adult education,
College of Psychology
Xinjiang (China), folk dancing of Uyghurs
No full textFolk-dance of UighursImage is part of research conducted by Chang Chih-Yi for the article: Land Utilization and Settlement Possibilities in Sinkiang
Author(s): Chang Chih-Yi
Source: Geographical Review, Vol. 39, No. 1 (Jan., 1949), pp. 57-75
Published by: American Geographical Society
Stable URL: http://www.jstor.org/stable/211157http://www.jstor.org/stable/211157Grayscal
Asian Pacific Islander Desi Awareness Month Keynote Lecture with Dr. Gordon H. Chang hosted by the APIDA Commission
No full textDr. Gordon H. Chang will speak on the history of anti-Asian violence in America on April 27, 2023, at 1:00 EDT for one hour. Dr. Chang recently stepped down as the Senior Associate Vice Provost for Under Graduate Education at Stanford and is a professor of history. He is also the Olive H. Palmer Professor in Humanities at Stanford University. He is the author of nine books, primarily on U.S. China relations and the Asian-American experience
Mauriesia Chang, 2010, gen. nov.
No full textMauriesia gen. nov. Diagnosis: Differs from the other genera of Glomeridae in the following combination of characters. Mediumsized Glomeridae with all four palps of gnathochilarium subequal in length. Organ of Tőmősváry suboval, short. Antennae with four normal apical cones. Collum with two transverse striae. Thoracic shield with a small hyposchism field and numerous transverse striae, of which several crossing the dorsum. Colour pattern vivid. Tegument smooth and shining, devoid of pilosity. Male pygidium with a median lobule at caudal margin. Male leg 17 with a high outer coxal lobe and a 4 -segmented, somewhat reduced telopodite. Male leg 18 with an ogival, or arcuated, syncoxite notch and a 4 -segmented, less strongly reduced telopodite. Male leg 19 (telopod) unusually stout, prefemur especially short (Figs 10 and 11); syncoxite horns high, central lobe present; prefemur medially with a membranous sac and a strong seta near its base on caudal face; femur with a peculiar, long, basal, mediad directed apophysis (a) and a very conspicuous, strongly sclerotized, distal finger (f) on caudal face, as well as with a setose bulge (s) medially; tibia with a smaller but evident, likewise strongly sclerotized, distal finger (p) caudolaterally; tarsus with a strong seta apically. Type species: Mauriesia splendida sp. nov. Name: Honours Jean-Paul Mauriès, the globally renowned specialist in Diplopoda and the author of the modern classification of the Glomerida.Published as part of Chang, Hsueh-Wen, 2010, Pill-millipedes (Glomerida, Diplopoda) in Taiwan, pp. 1-20 in Zootaxa 2477 on page 2, DOI: 10.5281/zenodo.19531
Nien Chang
No full textNien Chang (January 28, 1915 – November 2, 2009) was a Chinese author who recounted her harrowing experiences of the Cultural Revolution in her memoir Life and Death in Shanghai.https://nsuworks.nova.edu/nsudigital_forums/1070/thumbnail.jp
Covalent organic framework-supported Zn single atom catalyst for highly efficient N-formylation of amines with CO2 under mild conditions
No full textTransformation of CO2 into value-added chemicals with efficient and recyclable catalyst is an effective way to reduce carbon emissions. It is valuable to develop an efficient catalyst that can promote the N-formylation reaction under mild conditions with a high activity and excellent recyclability. Single atom catalysts (SACs) possess ultimate atom utilization efficiency and outstanding catalytic performance. Herein, we synthesize Zn SACs (Zn-TpPa) anchored on a COF (TpPa-1) using a facile solution method. Catalyzed by Zn-TpPa, CO2 and N-methylamine are transformed into N-methylformanilide under mild reaction conditions with a TOF of 17,155 h−1, which is the highest among all reported recyclable Zn-based catalysts. Zn-TpPa can also catalyze N-formylation of many other amines with excellent yields. The higher reactivity was attributable to the well-dispersed Zn active sites on COF and outstanding adsorption of CO2 owing to high surface area of COF. Our research provides a facile method for constructing SACs as well as an effective pathway for CO2 transformation and environmental protection.
Graphical abstract
Zn Single atom catalysts anchored on COF (TpPa-1) are prepared in a facile method and characterized. Zn-TpPa promotes N-formylation of N-methylaniline with CO2 and phenylsilane under mild conditions with the highest TOF among all reported recyclable Zn-catalysts. Besides, Zn-TpPa can catalyze N-formylation of many other amines with excellent yields. The work provides a facile method for constructing SACs.
Download : Download high-res image (217KB)
Download : Download full-size image
Introduction
Carbon dioxide (CO2), known as the main factor for green-house effect, has stimulated much effort to develop efficient technologies and methods for decreasing the CO2 level in the atmosphere. [[1], [2], [3], [4], [5]] As CO2 is a non-toxic, abundant, renewable C1 building block, easily available and environmentally benign feedstock, in view of green and sustainable chemistry, designing recyclable catalysts for the transformation of CO2 into value-added chemicals has recently emerged as an attractive route. [[6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23]] One interesting route to fix CO2 is synthesis of formamides through N-formylation of amines using CO2 in the presence of reducing agent. Many catalysts were reported to promote this reaction. [10,16,[24], [25], [26], [27], [28], [29], [30]] However, those reported N-formylation catalysis either have a limited turnover frequency (TOF) [21,[31], [32], [33], [34], [35], [36]] or require harsh conditions, such as high reaction temperatures (>60 °C) [7,15,21,25,34,[36], [37], [38]] or high CO2 pressure (>1 Mpa) [6,7,[13], [14], [15],21,32,33,[37], [38], [39], [40]] and poor recyclability [35]. It is highly desirable to develop an efficient catalyst that can promote the N-formylation reaction under mild conditions with a high TOF and excellent recyclability.
Single-atom catalysts (SACs), containing single metal atoms anchored on solid supports, represent the utmost utilization of metallic catalysts and thus maximize catalytic reactivity. [[41], [42], [43], [44], [45]] Several fabrication processes for SACs have been reported [46], including atomic layer deposition, [47] wet chemistry [48], MOF derivative [49], potential cycling [50], acid leaching [51] and photodeposition [52]. However, they usually either require harsh conditions, such as high temperature, high pressure, acids or complicated reaction procedures. Considering the large-scale production in future industrialization, a simple and efficient way to achieve SACs is more favorable. An appropriate support is critical to interact strongly with isolated atoms, and thus prevents the movement and aggregation of isolated atoms [[53], [54], [55]], creating stable, finely dispersed active sites.
Covalent organic frameworks (COFs) represent an important type of covalent porous materials with high surface area and well-defined structures. [56,57] The periodic and permanent porosity endow COFs an excellent substrate for SACs [58]. The bottom-up synthesis using different building blocks endows COFs with tunable skeleton structure, pore size, and topology schemes [53,59,60]. With the bottom-up synthesis of COFs followed by post-metalation, it offers unprecedented opportunities for constructing SACs with well-defined catalytic centers in high metal loading [61].
Herein, we demostrate Zn single atom catalyts can be prepared on COF (TpPa-1) with high loading amount by facile dropwise adding Zn2+ solution into TpPa-1 suspension (Scheme 1) [62,63]. Catalyzed by Zn-TpPa, N-methylformanilide is produced by reacting N-methylaniline with CO2 and hydrosilanes under mild reaction conditions (1 bar CO2 pressure at room temperature) in 3 h with a TOF of 17,155 h−1, which is the highest among reported recyclable Zn-based catalysts. Besides, Zn-TpPa could catalyze N-formylation of many other amines with excellent yields. Our research provides a simple yet efficient method for constructing SACs as well as provides an effective and sustainable pathway for CO2 transformation and environmental protection.
Section snippets
Materials and characterizations
1,3,5-triformylphloroglucinol (Tp) and p-phenylenediamine (Pa-1) were purchased from Shanghai Macklin Biochemical Co. Ltd. N-methylaniline, aniline, p-toluidine, N-methyl-p-toluidine, 4-methoxy-N-methylaniline, 4-bromo-N-methylaniline, N-methylcyclohexylamine, diethylamine, pyrrolidine, morpholine, 1,2,3,4-Tetrahydro-1-methylquinoline, and phenylsilane were obtained from J&K Scientific Ltd. N, N-dimethylformamide, acetonitrile mesitylene, dioxane and methanol were obtained from Aladdin
Characterization of materials
We synthesized single atom catalysts Zn-TpPa by adding the aqueous Zn salt solution into TpPa-1 suspension (Scheme 1), which was synthesized according to the method as previously reported. [62,63] The composition of TpPa-1 and Zn-TpPa was assessed with X-ray photoelectron spectroscopy. The peaks at 1020 eV and 1045 eV in Zn 2p XPS (Fig. S1d) spectrum indicated the presence of Zn element in Zn-TpPa. Besides, the Zn loading in the Zn-TpPa reached 0.5 wt%, as determined by inductively coupled
Conclusion
In conclusion, Zn single atom catalyst on COF with high loading were facially prepared. Zn-TpPa showed excellent catalyst activity, selectivity and recyclability for N-formation under mild condition with CO2 and phenysilane. It showed the highest TOF normalized to single Zn sites as 17,155 h−1 among all reported Zn-based catalysts. Importantly, Zn-TpPa showed the highest TOF among all reported catalysts which promoted N-formylation of N-methylaniline with CO2 and hydrosilanes with good
CRediT authorship contribution statement
Qiang Cao: Investigation, Conceptualization, Writing - original draft. Long-Long Zhang: Data curation. Chang Zhou: Resources. Jing-Hui He: Supervision, Writing - review & editing, Funding acquisition. Antonio Marcomini: Writing - review & editing. Jian-Mei Lu: Resources, Writing - review & editing, Supervision, Funding acquisition.
Declaration of Competing Interest
The authors report no declarations of interest.
Acknowledgements
We gratefully acknowledge the financial support provided by National Natural Science Foundation of China (21978185, 21938006, 21776190), the National Key R&D Program of China (2020YFC1818401, 2017YFC0210906), Basic Research Project of Leading Technology in Jiangsu Province (BK20202012), Suzhou Science and Technology Bureau Project (SYG201935) and the project supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
Global Media Ideas - Infinite Pathways to Creative Succes - Tim Chang - Part One.mp4
No full textDuring the X Media Lab: Global Media Ideas summit in June 2011 media and technology writer Brad Howarth conducted interviews with industry experts for Creativeinnovation. This video is part one of Brad Howarth's interview with Tim Chang about his role as Partner at Norwest Venture Partners (Palo Alto). Tim focuses on investments in mobile, gaming, digital media, and also leads Norwest Venture Partners's investment practice in China and Asia-Pacific. Tim shares tips on how to get an introduction to a Venture Capital; the elements of a good pitch and follow-up. And what he looks at when considering a deal - The 3Ts: Team, Traction, Tier 1 co-investors
Long-lived metastable state and hysteresis in the binding of acetylcholine to Torpedo californica acetylcholine receptor
No full textChang HW, Bock E, Neumann E. Long-lived metastable state and hysteresis in the binding of acetylcholine to Torpedo californica acetylcholine receptor. Biochemistry. 1984;23(20):4546-4556
- …
