Novel Cs2HfCl6 Crystal Scintillator: Recent Progress and Perspectives

Recent progress in Cs2HfCl6 (CHC) crystal production achieved within the last five years is presented. Various aspects have been analyzed, including the chemical purity of raw materials, purification methods, optimization of the growth and thermal conditions, crystal characterization, defect structure, and internal radioactive background. Large volume, crack-free, and high quality CHC crystals with an ultimate scintillating performance were produced as a result of such extensive research and development (R & D) program. For example, the CHC crystal sample with dimensions ∅23 × 30 mm3 demonstrates energy resolution of 3.2% FWHM at 662 keV, the relative light output at the level of 30,000 ph/MeV and excellent linearity down to 20 keV. Additionally, this material exhibits excellent pulse shape discrimination ability and low internal background of less than 1 Bq/kg. Furthermore, attempts to produce a high quality CHC crystal resulted in research on this material optimization by constitution of either alkali ions (Cs to Tl), or main element (Hf to Zr), or halogen ions (Cl to Br, I, or their mixture in different ratio), as well as doping with various active ions (Te4+, Ce3+, Eu3+, etc.). This leads to a range of new established scintillating materials, such as Tl2HfCl6, Tl2ZrCl6, Cs2HfCl4Br2, Cs2HfCl3Br3, Cs2ZrCl6, and Cs2HfI6. To exploit the whole potential of these compounds, detailed studies of the material’s fundamental properties, and understanding of the variety of the luminescence mechanisms are required. This will help to understand the origin of the high light yield and possible paths to further extend it. Perspectives of CHC crystals and related materials as detectors for rare nuclear processes are also discussed.

Download Full-text

TECHNOLOGICAL ASPECTS OF HIGH QUALITY RAW MATERIAL OBTAINING FOR PECTIN PRODUCTION

Vestnik of the Russian agricultural science ◽

10.30850/vrsn/2019/6/47-50 ◽

1970 ◽

pp. 47-50

Author(s):

I. A. Ilina ◽

I. A. Machneva ◽

E. S. Bakun

Keyword(s):

Raw Materials ◽

Thermal Characteristics ◽

Environmental Safety ◽

Raw Material ◽

High Quality ◽

Temperature Conductivity ◽

Drying Temperature ◽

Plant Raw Materials ◽

Gel Forming Ability

The article is devoted to the study of the chemical composition, physical and thermal-pfysical characteristics of damp apple pomaces and the identifying patterns of influence of drying temperature the functional composition and gel-forming ability of pectin. The research is aimed at obtaining initial data for the subsequent calculation of the main technological, hydro-mechanical, thermal, structural and economic characteristics of devices for drying the plant raw materials, ensuring the environmental safety and high quality of pectin-containing raw materials, the reducing heat and energy costs. As a result of the study of the thermal characteristics of apple pomaces, the critical points (temperature conductivity – 16.5 x 10-8 m2/s, thermal conductivity – 0.28 W/m K, heat capacity – 1627 j/(kg K)) at a humidity of 56 % are determined, which characterizing the transition from the extraction of weakly bound moisture to the extraction of moisture with strong bonds (colloidal, adsorption). It was found that the pomaces obtained from apples of late ripening have a higher content of solids (21-23 %), soluble pectin and protopectin (2.5-4.5 %). Dried pomaces obtained from apple varieties of late ripening contain up to 25 % pectin, which allow us to recommend them as a source of raw materials for the production of pectin. The optimum modes of preliminary washing of raw materials are offered, allowing to the remove the ballast substances as much as possible. It is established that when the drying temperature increases, the destructive processes are catalyzed: the strength of the pectin jelly and the uronide component and the degree of pectin esterification are reduced. The optimum drying temperature of damp apple pomaces is 80 0C, at which the quality of pectin extracted from the dried raw materials is maintained as much as possible. It is shown that the most effective for the pectin production is a fraction with a particle size of 3-5 mm, which allow us to extract up to 71 % of pectin from raw materials.

Download Full-text

Synthesis of high quality 2D carbide MXene flakes using a highly purified MAX precursor for ink applications

Nanoscale Advances ◽

10.1039/d0na00398k ◽

2021 ◽

Author(s):

Shi-Hyun Seok ◽

Seungjun Choo ◽

Jinsung Kwak ◽

Hyejin Ju ◽

Ju-Hyoung Han ◽

...

Keyword(s):

Raw Materials ◽

High Quality ◽

Max Phases ◽

Painting Process ◽

Manufacturing Techniques

A method of pelletizing raw materials was used to tackle unwarranted variations in MXene products depending on the parent MAX phases, manufacturing techniques, and preparation parameters, enabling a direct painting process on various surfaces for ink applications.

Download Full-text

Recent progress of high-quality GaN substrates by HVPE method

10.1117/12.2257202 ◽

2017 ◽

Cited By ~ 15

Author(s):

Hajime Fujikura ◽

Takehiro Yoshida ◽

Masatomo Shibata ◽

Yohei Otoki

Keyword(s):

Recent Progress ◽

High Quality

Download Full-text

Preparation of Hydroxyapatite/Chitosan Biological Coatings on Carbon/Carbon Composites

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.434-435.502 ◽

2010 ◽

Vol 434-435 ◽

pp. 502-505

Author(s):

Ying Hua Li ◽

Li Yun Cao ◽

Jian Feng Huang ◽

Xie Rong Zeng

Keyword(s):

Heat Treatment ◽

Electrophoretic Deposition ◽

Isopropyl Alcohol ◽

Raw Materials ◽

Composite Coatings ◽

Thermal Conditions ◽

Hydrothermal Condition ◽

Subsequent Heat Treatment ◽

Carbon Composites ◽

Deposition Voltage

Hydroxyapatite/Chitosan (HAp/CS) bio-coatings were prepared on the surface of carbon/ carbon (C/C) composites by hydrothermal electrophoretic deposition, using sonochemical process resulted HAp nanoparticles, isopropyl alcohol and chitosan as raw materials. The influences of hydro- thermal conditions and deposition voltage on the microstructures and morphologies of the as-prepared coatings were investigated. It was shown that homogenous and dense HAp/CS coatings on C/C composites are obtained by hydrothermal electrophoretic deposition. With the increase of deposition voltage, density and homogeneity of the as-prepared HAp/CS composite coatings are well improved. Due to the growth of HAp nanoparticles in the hydrothermal condition, the subsequent heat treatment of the HAp/CS coatings is not needed.

Download Full-text

The Preparation of High Quality CIS Films by Spraying Citrate-Capped Cu11In9 Alloy Nanoparticles Ink and RTP Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.787.382 ◽

2013 ◽

Vol 787 ◽

pp. 382-387

Author(s):

Li Zhou ◽

Yuan Kui Ding ◽

Pai Feng Luo

Keyword(s):

Raw Materials ◽

Low Cost ◽

Chalcopyrite Structure ◽

Alloy Nanoparticles ◽

System Research ◽

Spherical Nanoparticles ◽

Particle Agglomeration ◽

Energy Band Gap ◽

High Quality ◽

Selenization Process

A facile low-cost non-vacuum process for fabrication of high quality CuInSe2(CIS) films is described, which indicates a promising way for the application in thin film solar cells. First, citrate-capped Cu11In9alloy nanoparticles are synthesized by hot-injection method after a system research on the different reaction time and Cu-In ratio of the raw materials. From the TEM and XRD results, we can see that uniform spherical nanoparticles with dominant Cu11In9phase and less particle-to-particle agglomeration are successfully achieved in this study. Then, employing spray and RTP selenization process, high quality CIS films with dense and big grains are obtained, which show the single chalcopyrite structure and the preferred (112) orientation. An energy band gap about 1.01 eV is measured through the absorption spectroscopy measurement in our work.

Download Full-text

Toward the total synthesis of lophotoxin — New methodologies and synthetic strategies

Canadian Journal of Chemistry ◽

10.1139/v06-073 ◽

2006 ◽

Vol 84 (10) ◽

pp. 1226-1241 ◽

Cited By ~ 14

Author(s):

Peter Wipf ◽

Michel Grenon

Keyword(s):

Transition Metal ◽

Total Synthesis ◽

Recent Progress ◽

Furan Ring ◽

Addition Reaction ◽

Thermal Conditions ◽

Preliminary Results ◽

Keto Esters ◽

New Methodologies ◽

Metal Catalyzed

Our recent progress toward the synthesis of the furanocembranolide lophotoxin (1) is disclosed. Strategies for the stereoselective incorporation of the C13 stereocenter by a catalytic desymmetrization of a cyclic meso-anhydride, as well as a novel 1,6-addition reaction of organocuprates to unsaturated [1,3]dioxin-4-ones are discussed. Preliminary results on the development of a rhodium-catalyzed asymmetric 1,6-addition reaction are also mentioned. Finally, modifications of a previously reported transition-metal-catalyzed cyclization reaction involving α-propargyl β-keto esters allow furan ring formation either under thermal conditions or by microwave irradiation.Key words: 1,6-addition, organocuprates, catalytic desymmetrization, furan cyclization, microwave.

Download Full-text

Synthesis of Low Viscosity Polydimethylsiloxane Using Low Grade of Octamethylcyclotetrasiloxane

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1028.365 ◽

2021 ◽

Vol 1028 ◽

pp. 365-370

Author(s):

Diba G Auliya ◽

Soni Setiadji ◽

Zulfi Mofa Agasa ◽

Fitrilawati ◽

Norman Syakir ◽

...

Keyword(s):

Ring Opening ◽

Raw Materials ◽

Vitreoretinal Surgery ◽

Production Costs ◽

Low Grade ◽

High Grade ◽

High Quality ◽

Low Viscosity ◽

Polymerization Method

Polydimethylsiloxane (PDMS) has been widely used as a vitreous humour substitution in vitreoretinal surgery. Due to its limited availability and increasing domestic needs, the price of PDMS in Indonesia became very expensive. Previously, we reported the synthesized of PDMS from a high grade of monomer of 98% of Octamethylcyclotetrasiloxane (D4) and found that all PDMS samples produced high quality samples similar to that of commercial one. However, by considering the ease of obtaining raw materials and also the production costs, the synthesis of PDMS using monomer which easy to be found in Indonesia and low production costs is needed to be developed. Here, we reported the synthesis of PDMS using low grade of 96% of D4 in order to produce high quality of PDMS with low viscosity that can be used for vitreous humous substitution in vitreoretinal surgery. PDMS samples with low viscosity value of 0.94-1.35 Pa.s have been successfully synthesized from low grade of D4 and MM using ring-opening polymerization method. The yields of PDMS resulted in this research were in the range between 67.27% and 76.26%. From FTIR spectroscopy, it is found that all synthesized samples have structure and functional groups similar to PDMS using high grade of monomer of 98% Octamethylcyclotetrasiloxane (D4). From refractometer and surfgauge measurements, all samples have refractive index in the range of 1,4034-1,4040 and the value surface tension was 21 m.N/m.

Download Full-text

Research of pneumatic conveyor for overloading of fuel pellets

Energy and automation ◽

10.31548/energiya2021.06.088 ◽

2021 ◽

pp. 88-96

Author(s):

N. Spodyniuk ◽

◽

L. Horbachenko ◽

Keyword(s):

Key Words ◽

Agricultural Sector ◽

Raw Materials ◽

Agricultural Waste ◽

High Quality ◽

Fuel Pellets ◽

Energy Consuming ◽

Loading And Unloading

The constant development of the country's agricultural sector allows the production of biofuels, such as fuel pellets, from agricultural waste - straw, corn and sunflower husks. However, the transportation of fuel pellets is quite energy consuming. The process of loading and unloading, transportation over long distances requires complex mechanized equipment. The use of a pneumatic conveyor for grain reloading will allow to provide high-quality transportation of fuel pellets. The aim of the article was to investigate the operation of the pneumatic conveyor for overloading fuel pellets, to determine the optimal indicators that affect the productivity of the pneumatic conveyor. Since fuel pellets, as raw materials, are structurally similar to cereals, a study of the pneumatic grain conveyor PTZ-25 was conducted. The dependence of the productivity of the pneumatic conveyor on the lifting height h, m and the length of the pipelines L, m was obtained. The obtained results showed that by reducing the length of the pipelines by four times and the lifting height by half, the productivity of the pneumatic conveyor will increase by 1.15 times. Key words: fuel pellets, pneumatic conveyor, productivity

Download Full-text

Dependence of Scintillators Optical Properties on Intrinsic Structural Defects

MRS Proceedings ◽

10.1557/proc-348-247 ◽

1994 ◽

Vol 348 ◽

Cited By ~ 2

Author(s):

N.V. Kilassen

Keyword(s):

Plastic Deformation ◽

Optical Properties ◽

Crystal Growth ◽

Spectral Distribution ◽

Light Output ◽

Structural Defects ◽

High Quality ◽

Intrinsic Defects ◽

Distribution Kinetics ◽

Wide Range

ABSTRACTThe studies of the dependence of the optical properties of various scintillators on intrinsic structural defects have been reviewed. The greater part of the review is devoted to the defects introduced by plastic deformation. A wide range of variations in the light output, spectral distribution, kinetics and other properties has been observed. These defects can be induced during crystal growth, annealing, processing, etc. The proper regulation of the superstructure of intrinsic defects can ensure the production of high quality scintillators having required properties.

Download Full-text