scholarly journals Internal OH− induced cascade quenching of upconversion luminescence in NaYF4:Yb/Er nanocrystals

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Yansong Feng ◽  
Zhi Li ◽  
Qiqing Li ◽  
Jun Yuan ◽  
Langping Tu ◽  
...  
Keyword(s):  
Large Range ◽  
Model Simulation ◽  
Upconversion Luminescence ◽  
Dynamical Process ◽  
Spectroscopy Study ◽  
Factors Affecting ◽  
Before And After ◽  
Microscopic Interactions ◽  
Surface Ligand ◽  
Emission Quenching

AbstractInternal hydroxyl impurity is known as one of the main detrimental factors affecting the upconversion (UC) efficiency of upconversion luminescence (UCL) nanomaterials. Different from surface/ligand-related emission quenching which can be effectively diminished by, e.g., core/shell structure, internal hydroxyl is easy to be introduced in synthesis but difficult to be quantified and controlled. Therefore, it becomes an obstacle to fully understand the relevant UC mechanism and improve UC efficiency of nanomaterials. Here we report a progress in quantifying and large-range adjustment of the internal hydroxyl impurity in NaYF4 nanocrystals. By combining the spectroscopy study and model simulation, we have quantitatively unraveled the microscopic interactions underlying UCL quenching between internal hydroxyl and the sensitizers and activators, respectively. Furthermore, the internal hydroxyl-involved UC dynamical process is interpreted with a vivid concept of “Survivor effect,” i.e., the shorter the migration path of an excited state, the larger the possibility of its surviving from hydroxyl-induced quenching. Apart from the consistent experimental results, this concept can be further evidenced by Monte Carlo simulation, which monitors the variation of energy migration step distribution before and after the hydroxyl introduction. The new quantitative insights shall promote the construction of highly efficient UC materials.

An Empirical Investigation of Factors Affecting Stock Prices in Vietnam

2014 ◽  
pp. 74-89 ◽  
Author(s):  
Vinh Vo Xuan
Keyword(s):  
Exchange Rates ◽  
Crude Oil ◽  
Foreign Exchange ◽  
Stock Prices ◽  
Global Financial Crisis ◽  
Oil Prices ◽  
Foreign Exchange Rates ◽  
Factors Affecting ◽  
Crude Oil Prices ◽  
Before And After

This paper investigates factors affecting Vietnam’s stock prices including US stock prices, foreign exchange rates, gold prices and crude oil prices. Using the daily data from 2005 to 2012, the results indicate that Vietnam’s stock prices are influenced by crude oil prices. In addition, Vietnam’s stock prices are also affected significantly by US stock prices, and foreign exchange rates over the period before the 2008 Global Financial Crisis. There is evidence that Vietnam’s stock prices are highly correlated with US stock prices, foreign exchange rates and gold prices for the same period. Furthermore, Vietnam’s stock prices were cointegrated with US stock prices both before and after the crisis, and with foreign exchange rates, gold prices and crude oil prices only during and after the crisis.

Factors Affecting Eyelid Crease Formation Before and After Silicone Frontalis Suspension for Adult-Onset Myogenic Ptosis

2015 ◽  
Vol 31 (3) ◽  
pp. 227-232 ◽  
Author(s):  
Richard C. Allen ◽  
Esther S. Hong ◽  
M. Bridget Zimmerman ◽  
Leslie A. Morrison ◽  
Jeffrey A. Nerad ◽  
...  
Keyword(s):  
Adult Onset ◽  
Factors Affecting ◽  
Before And After ◽  
Frontalis Suspension

scholarly journals Tensile Testing with Cyclic Strain Holding to Analyze Dynamic Recrystallization of Pure Lead

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Mayu Muramatsu ◽  
Motomichi Koyama ◽  
Ikumu Watanabe
Keyword(s):  
Dynamic Recrystallization ◽  
Tensile Testing ◽  
Cyclic Strain ◽  
Tensile Tests ◽  
Pure Lead ◽  
Factors Affecting ◽  
Before And After ◽  
Dynamic Recrystallization Behavior ◽  
The Difference ◽  
Strain Responses

We analyzed the dynamic recrystallization of pure lead by tensile testing with cyclic strain holding at room temperature. The specimens were held at an identical strain and subsequently reloaded, providing the strength before and after the strain holding process. The difference in strength enables factors affecting dynamic recrystallization behavior to be analyzed through mechanical testing. For instance, the effects of strain rate on dynamic recrystallization were analyzed by comparing the results obtained from tensile tests with and without strain holding. This experimental technique demonstrated some parts of contribution of elastic strain, dynamic recovery, dynamic recrystallization, and necking to stress-strain responses.

scholarly journals USAGE OF YOU TUBE- BASED VIDEOS IN LEARNING DAILY ENGLISH CONVERSATION FOR CHILDREN AT ASRAMA YATIM MIZAN AMANAH, SALIHARA, PASAR MINGGU, SOUTH JAKARTA

Pujangga ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 48
Author(s):  
Evi Jovita Putri ◽  
Gilang Ilham Agustinus ◽  
Intan Kusuma Wardhani
Keyword(s):  
Language Learning ◽  
Test Score ◽  
Qualitative Method ◽  
Influential Factors ◽  
Learning Activities ◽  
Factors Affecting ◽  
Before And After ◽  
Post Test ◽  
Learning English ◽  
Descriptive Qualitative

ABSTRACT This research aims to analyze the effectiveness of YouTube-based videos as a media in learning daily English conversation for children and to identify factors affecting learning daily English conversation for children by using YouTube-based videos as a media. To obtain the aims, this research uses six children whose ages vary from ten to twelve years old lived in Asrama Yatim Mizan Amanah located at Jalan Salihara, Pasar Minggu, South Jakarta as the source of data. Descriptive qualitative method is applied as the research design. In collecting data, the researchers gather the result of learning activities in pre-tests, treatments, and post-tests. Meanwhile, in analyzing the data, the researchers compare the children’s pre-test score with their post-test score to see the development of learning which show their competence before and after being treated. in this case, the research is focused on two topics, Greeting and Introduction in English. The children are introduced some expressions of greeting and introduction in English children by using YouTube-based videos, then some roleplays or conversation containing expressions of greeting and introduction are shown to the children by watching together YouTube-based videos. The last, the children are asked to recognize and practice the expression of greeting and introduction in English. The result shows that the usage of YouTube based video as a media in learning daily English conversation for children is considered effective. Four out of six children are able to memorize new expressions of both greeting and introduction in English, whereas the two other children remains stagnant after learning using YouTube based videos. It is found that there are factors that affect learning English for children by using this media, they are; personality, motivation and attitude, intelligent, learners’ belief, and personality. The most influential factors affecting learning are motivation and attitude. The successful children have these factors stronger rather than the stagnant children. Based on the result, the effectiveness in learning English using YouTube-based videos will be stronger if it is supported by an interactive and conducive learning atmosphere. The learning atmosphere should be considered to achieve a stronger speaking English proficiency. Key words: YouTube based-videos, language learning, daily English conversation ABSTRAK Penelitian ini ditujukan untuk menganalisis keefektifan penggunaan video berbasis YouTube sebagai media dalam belajar percakapan bahasa Inggris sehari-hari pada anak-anak dan untuk mengidentifikasi faktor yang mempengaruhi pembelajaran percakapan bahasa Inggris sehari-hari pada anak-anak yang menggunakan video berbasis YouTube. Untuk mencapai tujuan tersebut, penelitian ini menjadikan enam orang anak berumur sepuluh hingga dua belas tahun yang tinggal di Asrama Yatim Mizan Amanah Jalan Salihara, Pasar Minggu, Jakarta Selatan sebagai sumber data. Penelitian ini menggunakan metode descriptive qualitative. Disini, proses pengumpulan data meliputi pengumpulan hasil pre-tests, treatment, dan post-test. Sementara itu, proses analisis data dilakukan dengan cara membandingkan skor pre-test dengan skor post-test pembelajar untuk melihat perkembangan pembelajaran yang menunjukkan perkembangan anak-anak sebelum dan sesudah pembelajaran. Penelitian difokuskan pada dua topik pembelajaran yaitu sapaan dan perkenalan bahasa Inggris. Dalam hal ini anak-anak diajak mengenal ekspresi sapaan dan perkenalan dalam Bahasa Inggris melalui video yang ada pada YouTube. Kemudian menonton beberapa simulasi dari perilaku menyapa dan berkenalan dalam Bahasa Inggris juga melalui video You-Tube. Pada tahap terakhir, para pembelajar ini diminta untuk berlatih mengingat dan mempraktekkan ungkapan sapaan dan perkenalan dalam Bahasa Inggris Hasil penelitian menunjukkan bahwa penggunaan video berbasis YouTube sebagai media belajar percakapan bahasa Inggris sehari-hari adalah efektif. Empat dari 6 anak mampu mengingat kosakata sapaan dan perkenalan yang baru secara signifikan setelah belajar menggunakan media video berbasis You Tube, meskipun ada 2 anak yang tidak mengalami peningkatan. Ada beberapa faktor yang memengaruhi pembelajaran pada anak-anak tersebut diantaranya kepribadian, motivasi dan sikap, kecerdasan, dan keyakinan. Faktor yang paling berpengaruh pada pembelajaran adalah motivasi dan sikap. Anak-anak yang mengalami peningkatan belajar yang pesat memiliki faktor motivasi dan sikap yang lebih kuat dibanding anak-anak yang tidak mengalami peningkatan. Berdasarkan hasil tersebut, keefektifan dalam belajar percakapan Bahasa Inggris sehari-hari menggunakan video YouTube menjadi lebih besar jika didukung oleh atmosfer belajar yang interaktif dan kondusif. Hal ini mesti diperhatikan guna mencapai kemampuan Bahasa Inggris lisan yang lebih baik. Kata Kunci: Video YouTube, Pembelajaran Bahasa, Percakapan dasar dalam Bahasa Inggris.

scholarly journals Lidar observation and model simulation of a volcanic-ash-induced cirrus cloud during the Eyjafjallajökull eruption

2012 ◽  
Vol 12 (6) ◽  
pp. 15675-15707 ◽  
Author(s):  
C. Rolf ◽  
M. Krämer ◽  
C. Schiller ◽  
M. Hildebrandt ◽  
M. Riese
Keyword(s):  
Volcanic Ash ◽  
Model Simulation ◽  
Cirrus Cloud ◽  
Backward Trajectories ◽  
Microphysical Properties ◽  
Ice Nuclei ◽  
A Value ◽  
Lidar Measurements ◽  
Before And After ◽  
Western Germany

Abstract. Heterogeneous ice formation induced by volcanic ash from the Eyjafjallajökull volcano eruption in April 2010 is investigated based on the combination of a cirrus cloud observed with a backscatter lidar over Jülich (Western Germany) and model simulations along backward trajectories. The microphysical properties of the cirrus cloud could only be represented by the microphysical model under the assumption of an enhanced number of efficient ice nuclei originating from the volcanic eruption. The ice nuclei (IN) concentration determined by lidar measurements directly before and after cirrus cloud occurrence implies a value of around 0.1 cm−3 (in comparison clean IN conditions: 0.01 cm−3). This leads to a cirrus cloud with rather small ice crystals having a mean radius of 12 μm and a modification of the ice particle number (0.08 cm−3 instead of 3 × 10−4 cm−3 under clean IN conditions). The effectiveness of ice nuclei was estimated by the use of the microphysical model and the backward trajectories based on ECMWF data, establishing a freezing threshold of around 105% relative humidity with respect to ice in a temperature range from −45 to −55 °C. Only with these highly efficient ice nuclei was it possible for the cirrus cloud to be formed in a slightly supersaturated environment.

scholarly journals Impacts of Government and Household Expenditure on Human Development Index

JEJAK ◽  
2017 ◽  
Vol 10 (2) ◽  
pp. 412-428
Author(s):  
Niken Sulistyowati ◽  
Bonar Marulitua Sinaga ◽  
Novindra Novindra
Keyword(s):  
Human Development ◽  
Human Development Index ◽  
Model Simulation ◽  
Government Expenditure ◽  
Estimation Method ◽  
Structural Equations ◽  
Simultaneous Equations ◽  
Factors Affecting ◽  
Development Index ◽  
Central Java

The objective of this reseach are to: (1) analyze the factors affecting human development index and household expenditures for health, education and others, (2) predict the impacts of government expenditure policy in the field of education, health, and infrastructure on human development index in Central Java. The model was built using econometric approach in the form of a system of simultaneous equations, including five blocks i.e. government's revenue, expenditures, input, output, and performance. The system of simultaneous equations consisted of 26 equations (19 structural equations and 7 identity equations). The estimation method used Two Stage Least Squares with SYSLIN procedure. Prediction simulation used the stepwise Autoregressive method. The model simulation used Newton's method and SIMNLIN procedure. The results of policy simulation concludes that the combination of the increase in government expenditure for education and infrastructure lead to better performance in increasing income per capita, disposable income and HDI compared to the combination of the policy of the increase in government expenditure for education and in both municipalities and district, but municipalities receive greatest impact compared to the district.

Factors affecting post‐relocation adaptation in a case of an entire plant relocation

2002 ◽  
Vol 17 (2) ◽  
pp. 80-94 ◽  
Author(s):  
Moshe Krausz ◽  
Aharon Bizman ◽  
Shaul Fox
Keyword(s):  
Organizational Change ◽  
Work Satisfaction ◽  
Emotional Reactions ◽  
Adaptation Measures ◽  
Factors Affecting ◽  
Family Issue ◽  
Entire Plant ◽  
Before And After ◽  
Plant Relocation

Pre‐relocation measures as well as measures collected subsequent to it were used to predict employees’ post‐relocation adaptation in a case where an entire plant relocated its premises. The distance between the old and the new site did not require home relocation, with the result that the change was deemed less of a “family issue” than an essentially work and organizational change. The sample consisted of 176 employees, for whom matched before and after questionnaires were available. Pre‐relocation measures included demographics, justification of management’s decision to relocate, and positive and negative emotional reactions to the move. In addition, measures of perceived changes were taken after the move. The three post‐relocation adaptation measures were work satisfaction, loyalty to the organization, and relocation satisfaction. Findings are discussed in the light of previous findings, although most of that research dealt with individual as opposed to plant relocation, and of very few studies dealing with post‐relocation variables.

Yucatec Land and Labor before and after Spanish Incursions

2020 ◽  
pp. 210-223
Author(s):  
Adolfo Iván Batún Alpuche ◽  
Patricia A. McAnany ◽  
Maia Dedrick
Keyword(s):  
Private Property ◽  
Large Range ◽  
Post Colonial ◽  
High Productivity ◽  
Intensive Production ◽  
Cozumel Island ◽  
Western Concept ◽  
Before And After

Yucatec land and labor arrangements before and after Spanish incursions are examined for ruptures and continuities. The Western concept of private property is found to ring hollow in a landscape in which intersecting spheres of authority (including those of supernaturals) guide protocols of access and extraction. Furthermore, no simple dichotomy between pre- and post-colonial can explain the range of land arrangements and networks of labor that existed across Yucatán. Through the input of labor or as a consequence of geomorphology, a patchwork of high-productivity micro-environments can be found across Yucatán and on Cozumel Island. Cultivation and/or extraction at these resource-intensive production zones encompassed a large range of labor arrangements and interdependencies during Pre-Columbian times. In general, land and labor are conceptualized as suspended within relationships of shifting authority. In reference to both land labor, authors break with the construct of “control over” and embrace the phrase “authority to,” which recognizes the role of negotiation and the inclusion of supernatural forces perceived to have played a structuring role in the disposition of land and labor.

scholarly journals Survival of Young Greater Snow Geese (Chen Caerulescens Atlantica) During Fall Migration

The Auk ◽  
2005 ◽  
Vol 122 (2) ◽  
pp. 479-496 ◽  
Author(s):  
Stéphane Menu ◽  
Gilles Gauthier ◽  
Austin Reed
Keyword(s):  
Body Mass ◽  
High Arctic ◽  
Climatic Conditions ◽  
Factors Affecting ◽  
Chen Caerulescens ◽  
Migratory Flight ◽  
Snow Geese ◽  
Before And After ◽  
Chen Caerulescens Atlantica ◽  
Similar Survival

Abstract The many hazards that await birds along their migratory routes may negatively affect their survival, especially among newly fledged young. We estimated survival of young Greater Snow Geese (Chen caerulescens atlantica) during fall migration from the High Arctic to temperate areas and examined factors affecting their survival over a five-year period, using two approaches. First, each year (1993–1997), we banded fledglings and adults in mid-August, just before their departure from Bylot Island in the High Arctic (Nunavut, Canada), and again at an important staging area 3,000 km to the south at the Cap Tourmente National Wildlife Area (Québec, Canada) in October; recovery data from those two banding periods allowed estimation of survival during fall migration. Second, we visually determined brood size of neck-banded females before and after the main portion of the migratory flight, to estimate survival of young. The two approaches yielded similar survival estimates and showed the same interannual variation, thus suggesting that estimates were reliable. Mortality of young shortly after fledging and during the fall migration was high, compared with that of adults (monthly survival 0.662 in young vs. 0.989 in adults). However, mortality of young after migration was similar to that of adults (monthly survival 0.969 in young vs. 0.972 in adults). Migration survival of young varied considerably among annual cohorts (range of 0.119–0.707 over five years), and most of the mortality appeared to be natural. Survival was especially low in years when (1) temperatures at time of fledging and start of migration were low (i.e. near or below freezing), (2) mean body mass of goslings near fledging was low, or (3) mean fledging date was late. Our results suggest that migration survival of young is affected by a combination of several factors (climatic conditions, body mass, and fledging date) and that survival is reduced when one of those factors intervenes.

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