Hydrogen-induced properties and functionalities in organic-inorganic hybrid materials

Thesis (Ph. D. in Science)--University of Tsukuba, (A), no. 3392, 2004.3.25Includes bibliographical reference

Risks of Chest X-ray Examination for Students

Chest X-ray (CXR) examination is considered essential for health checkups of students;thus, it is important to objectively assess the CXR for a better understanding of the appropriate X-ray exposure dose, and the risks such an examination entails. Accordingly, we performed a multi-institutional study regarding students' CXR exposure, during a 6year-period from 2002 (partially including 2001) to 2007, with the collaboration of national, municipal, and private universities and colleges in Japan. A glass badge was worn by the students at the time of CXR screening examination. These glass badges were collected, and their X-ray exposure doses were measured. The results indicated a tendency of decreasing exposure dose over the 6 years, though the difference was not significant. In a comparison of the chest X-ray systems within institutions (own X-ray equipmentinside systems) with those outside the institution (mobile X-ray equipmentoutside systems), the average exposure dose with the outside systems exceeded that of the inside systems. Both inside and outside systems included a few X-ray machines with which the exposure was more than 1mSv. Based on these facts, individuals in charge of student health checkups should be aware of the exposure dose of each chest fluorographic system at their institution.</p

Origin of the visible-light response of nickel(II) oxide cluster surface modified titanium(IV) dioxide

A number of NiO clusters have been formed on TiO2 (anatase/rutile = 4/1 w/w, P-25, Degussa) in a highly dispersed state (NiO/TiO2) by the chemisorption-calcination cycle technique. The NiO/TiO2 causes high visible-light activities for the degradations of 2-naphthol and p-cresol exceeding those of FeOx/TiO2 (Tada et al. Angew. Chem., Int. Ed. 2011, 50, 3501-3505). The main purpose of this study is to clarify the origin at an electronic level by the density functional simulation for NiO, Ni2O2, Ni3O3, and Ni4O4 clusters supported on TiO2 rutile (110) and anatase (001) surfaces. The clusters adsorb strongly on both rutile and anatase with adsorption energies ranging from -3.18 to -6.15 eV, creating new interfacial bonds between the clusters and both surfaces. On rutile, intermetallic Ni-Ti bonds facilitate stronger binding compared with anatase. The electronic structure shows that the top of the valence bands (VBs) of rutile and anatase arises from electronic states on the NiO cluster. On the other hand, the conduction band of rutile is from the Ti 3d states, whereas NiO cluster levels are generated near the conduction band minimum of anatase. This is in contrast to the SnO2/rutile TiO2 system, where the density of states near the conduction band minimum increases with the VB unmodified. In the NiO/TiO2 system, the band gaps of both rutile and anatase are narrowed by up to 0.8 eV compared with pristine TiO2, which pushes the photoactivity into the visible region. In view of the calculated electronic structure, we have attributed the enhanced photocataltyic activity both to the charge separation due to the excitation from the Ni 3d surface sub-band to the TiO2 conduction band and the action of the NiO species as a mediator for the electron transfer from the TiO2 conduction band to O-2

The use of Lecturer Based Supportive Tools (LBST) as Data Provider for Indonesian Lecturer Administrative Problems

Recently, Indonesia has more than 3.000 Higher Education Institutions, 300.000 lecturers, and 7.8 million higher education students. To handle those numerous stakeholders, Directorate General Higher Education Indonesia Government (DGHEI - as the regulator of higher education institutions) has been developed several websites as Information Systems (IS). The developed information system was used to manage information that attached on the stakeholders entities. Those information entities were projected for open public data access. In other hand, the Information Systems that offered by DGHEI are not only single information system. But also several information system that not integrated yet become single portal. Moreover, DGHEI regulates lecturers to upload their entities such as portfolios and other supporting documents developed IS's. However, this will be cause a time consuming, repetition activities and data redundant. Those problems are called administrative problems. In the meantime, our current development Lecturer Based Supportive Tool (LBST) has been developed as lecturer assistance to enrich learning materials on limited bandwidth condition. This paper discusses the use of LBST as Data Provider to solve the administrative problems that has been occurred in Indonesia higher education environments. Instead of uploading into DGHEI information systems, lecturers eager to use LBST as an alternative systems that offered by DGHEI. As a result, LBST could be driven into data provider that provides information that needed by DGHEI or other data customers

Developing Moodle Plugin for Creating Learning Content with Another REST Function Call

The Moodle REST function calls enables third party applications having access to the Moodle database's through Moodle web services and REST (Representational state transfer) protocols. The access could be as learning content creation. According to Moodle architecture, the learning content creation, need to be placed on Moodle section tables. This is shown, a third party application should make or use the Moodle section when making a course. The 'section' is the most essential component on Moodle. Because, the 'section' contain documents, assignments, quiz for learners. However, some Moodle REST function calls, such as creating the "section" on Moodle courses, have not been implemented in the Moodle system, yet. And for our current development applications, it need to have an access to create complete learning content on section tables. With developing Moodle plugins, possibly create learning content in the Moodle sections, but needed Moodle REST function call to access developed plugin. Therefore, we propose solutions that developed a Moodle plugin to create learning content and solve an unprovided Moodle REST function call by developed another Moodle REST function call. This paper presents our current development to enable creation of learning content from third party application, using the developed Moodle plugin. As a result, with the developed Moodle plugin, success to create learning content on Moodle LMS, and developed another Moodle REST function call

Tin oxide-surface modified anatase titanium(IV) dioxide with enhanced UV-light photocatalytic activity

[Sn(acac)(2)]Cl-2 is chemisorbed on the surfaces of anatase TiO2 via ion-exchange between the complex ions and H+ released from the surface Ti-OH groups without liberation of the acetylacetonate ligand (Sn(acac)(2)/TiO2). The post-heating at 873 K in air forms tin oxide species on the TiO2 surface in a highly dispersed state on a molecular scale ((SnO2)(m)/TiO2). A low level of this p block metal oxide surface modification (similar to 0.007 Sn ions nm(-2)) accelerates the UV-light-activities for the liquid- and gas-phase reactions, whereas in contrast to the surface modification with d block metal oxides such as FeOx and NiO, no visible-light response is induced. Electrochemical measurements and first principles density functional theory (DFT) calculations for (SnO2)(m)/TiO2 model clusters (m = 1, 2) indicate that the bulk (TiO2)-to-surface interfacial electron transfer (BS-IET) enhances charge separation and the following electron transfer to O-2 to increase the photocatalytic activity

Loading effect in copper(II) oxide cluster-surface-modified titanium(IV) oxide on visible- and UV-light activities

Cu(acac)2 is chemisorbed on TiO2 particles [P-25 (anatase/rutile = 4/1 w/w), Degussa] via coordination by surface Ti–OH groups without elimination of the acac ligand. Post-heating of the Cu(acac)2-adsorbed TiO2 at 773 K yields molecular scale copper(II) oxide clusters on the surface (CuO/TiO2). The copper loading amount (Γ/Cu ions nm–2) is controlled in a wide range by the Cu(acac)2 concentration and the chemisorption–calcination cycle number. Valence band (VB) X-ray photoelectron and photoluminescence spectroscopy indicated that the VB maximum of TiO2 rises up with increasing Γ, while vacant midgap levels are generated. The surface modification gives rise to visible-light activity and concomitant significant increase in UV-light activity for the degradation of 2-naphthol and p-cresol. Prolonging irradiation time leads to the decomposition to CO2, which increases in proportion to irradiation time. The photocatalytic activity strongly depends on the loading, Γ, with an optimum value of Γ for the photocatalytic activity. Electrochemical measurements suggest that the surface CuO clusters promote the reduction of adsorbed O2. First principles density functional theory simulations clearly show that, at Γ 1, the VB maximum rises and the unoccupied Cu 3d levels move to the conduction band minimum of TiO2. These results suggest that visible-light excitation of CuO/TiO2 causes the bulk-to-surface interfacial electron transfer at low coverage and the surface-to-bulk interfacial electron transfer at high coverage. We conclude that the surface CuO clusters enhance the separation of photogenerated charge carriers by the interfacial electron transfer and the subsequent reduction of adsorbed O2 to achieve the compatibility of high levels of visible and UV-light activities

Synchronizing learning material on Moodle and lecture based supportive tool: The REST based approach

A lecturer's role are the important part for the success of any eLearning platform, include Moodle LMS. Because only lecturers that enrich learning materials. Unfortunately, Indonesia still faces the bandwidth gap that made difficulties to use Moodle as a daily basis. Moreover, it will become complex when lecturer decide to install it on a local machine. This paper presents supportive tool that not only for enrich learning materials in offline conditions with easy initiation steps, but also synchronize it on remote LMS using Moodle RE ST web service in order to share learning material in limited bandwidth