Synthesis of nanocrystalline Cu2 – xSe at room temperature by γ-irradiation

2000 ◽  
Vol 78 (9) ◽  
pp. 1143-1146
Author(s):  
Zhengping Qiao ◽  
Yi Xie ◽  
Jianguang Xu ◽  
Xianming Liu ◽  
Yingjie Zhu ◽  
...  

Ten nm nonstoichiometric compound Cu2 – xSe was firstly synthesized at room temperature by γ-irradiation, using sodium selenosulfate as the selenium source. The influence of the coordination of copper ions and the pH value of the solutions on the formation of Cu2 – xSe has been studied. The Cu2 – xSe was prepared here for x = 0.13.Key words: copper selenide, nanocrystalline, γ-irradiation.


1977 ◽  
Vol 16 (01) ◽  
pp. 30-35 ◽  
Author(s):  
N. Agha ◽  
R. B. R. Persson

SummaryGelchromatography column scanning has been used to study the fractions of 99mTc-pertechnetate, 99mTcchelate and reduced hydrolyzed 99mTc in preparations of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn). The labelling yield of 99mTc-EDTA(Sn) chelate was as high as 90—95% when 100 μmol EDTA · H4 and 0.5 (Amol SnCl2 was incubated with 10 ml 99mTceluate for 30—60 min at room temperature. The study of the influence of the pH-value on the fraction of 99mTc-EDTA shows that pH 2.8—2.9 gave the best labelling yield. In a comparative study of the labelling kinetics of 99mTc-EDTA(Sn) and 99mTc- DTPA(Sn) at different temperatures (7, 22 and 37°C), no significant influence on the reduction step was found. The rate constant for complex formation, however, increased more rapidly with increased temperature for 99mTc-DTPA(Sn). At room temperature only a few minutes was required to achieve a high labelling yield with 99mTc-DTPA(Sn) whereas about 60 min was required for 99mTc-EDTA(Sn). Comparative biokinetic studies in rabbits showed that the maximum activity in kidneys is achieved after 12 min with 99mTc-EDTA(Sn) but already after 6 min with 99mTc-DTPA(Sn). The long-term disappearance of 99mTc-DTPA(Sn) from the kidneys is about five times faster than that for 99mTc-EDTA(Sn).



Author(s):  
Ignazio Blanco ◽  
Traian Zaharescu

AbstractA series of ethylene-propylene-diene-terpolymer (EPDM)/polyhedral oligomeric silsesquioxane (POSS) composites at different percentage of POSS were prepared and subjected to γ-irradiation. Both irradiated and non-irradiated EPDM and composites were investigated by the means of thermal analysis to verify if the presence of POSS molecules is able to reduce the oxidation level of free radicals generated during the degradation and to evaluate the effects of the irradiation. EPDM composites at 1, 3 and 5 mass% of POSS were thus degraded in a thermogravimetric (TG) balance in dynamic heating conditions (25–700 °C), in both inert and oxidative atmosphere by flowing nitrogen and air respectively. Thermal characterization was then completed by carrying out Differential Scanning Calorimetry (DSC) analysis from sub-ambient to better highlight the melting of the polymer and polymer composites occurring just above the room temperature. FTIR spectroscopy was also performed for the prepared samples to check the presence of the molecular filler in the composites and for the TG’s residue at 700 °C, in order to evaluate its nature. DSC and TGA parameters were detected and discussed to have information about the effect of the degradation’s environment, the effect of irradiation on polymer stabilization and the effect of POSS content in the polymer matrix.





2006 ◽  
Vol 84 (10) ◽  
pp. 1268-1272 ◽  
Author(s):  
Aaron W Amick ◽  
Keith S Griswold ◽  
Lawrence T Scott

An efficient gram scale synthesis of the previously unknown 4,7-di-tert-butylacenaphthenone (3b) is reported. The facile isomerization of epoxide 9b to ketone 3b occurs simply on stirring a solution of 9b with silica gel at room temperature. Aldol cyclotrimerization of 3b with titanium tetrachloride gives 2,5,8,11,14,17-hexa-tert-butylde cacyclene (1b) in 58% isolated yield. X-ray crystal structures have been obtained for the synthetic intermediates 4,7-di-tert-butylacenaphthene (2b) and 4,7-di-tert-butylacenaphthylene (8b).Key words: aromatic, decacyclene, hydrocarbon, nonalternant, polycyclic.



2015 ◽  
Vol 30 ◽  
pp. 48-55 ◽  
Author(s):  
S.S. Dhasade ◽  
J.V. Thombare ◽  
R.S. Gaikwad ◽  
S.V. Gaikwad ◽  
S.S. Kumbhare ◽  
...  


2021 ◽  
Vol 98 ◽  
pp. 14-18
Author(s):  
Thao Nguyen Thi ◽  
◽  
Nam Pham Ky ◽  
Ngoc Tran Vu Diem

Brass melting slag (20.38 wt.% Zn) was leached in sulfuric acid with concentration of (50 + 80) g/l H2SO4, leaching temperature of (30 + 60) °C for (30 + 120) min. The optimized conditions for 94.16% Zn extraction from brass melting slag were found as 70 g/l H2SO4, room temperature and 90 min. The leaching solution was purified by removal of Fe through Fe(OH)3 precipitation when adding ZnO to adjust pH value of 5. The solution was continuously cemented by Zn metal at 60 °C for 60 min to obtain Cu metal with high purity of 99 wt.% Cu. The purified solution with 37.64 g/l Zn was modified by Na2C03 to have pH value of about 6 and precipitation of ZnC03 (94.14 %).



2021 ◽  
Vol 37 (2) ◽  
pp. 302-307
Author(s):  
Abdulrahman G. Alhamzan

In this study date pits of two types of date-palm trees (Phoenix Dactylifera L.), in Saudi Arabia were used as bio-sorbents for heavy metals (e.g. lead and copper) from aqueous solutions. Investigation of equilibrium time and the effect of different concentrations of metals were performed. Adsorption capacity of bio-sorbents increased when increasing concentration of metal ions. Maximum adsorption capacity at room temperature of Sukary date pits was 17.53 mg g-1 and 9.86 mg g-1 for lead and copper ions, respectively. Whereas, Khlass date pits showed maximum adsorption capacity at 14.1 mg g-1 and 7.91 mg g-1 for lead and copper ions, respectively at room temperature. Equilibrium isotherm models, (Langmuir and Freundlich models), were used for analysis of equilibrium experimental results. these models describe the experimental data well.



2017 ◽  
Vol 21 (2) ◽  
pp. 63-72 ◽  
Author(s):  
Yunfeng Hu ◽  
Zengyu Wei ◽  
Yuanyuan Chen

AbstractIn this paper, the quality changes of fresh dumpling wrappers during storage were studied by measuring the changes of microbial growth, color, pH, texture, cooking property, moisture content and distribution of raw dumpling wrappers. The correlation of these indicators was analyzed. The results showed that the dumpling wrappers had generated lots of microorganisms during storage and the pH value decreased gradually. The dumpling wrappers had browning and the color became darker. The texture of the dumpling wrappers changed obviously. The original structure of raw dumpling wrappers were destroyed, the water distribution is uneven and migration to the surface. The apparent index of raw dumpling wrappers has a significant correlation with the internal change, which provides a certain guiding significance for maintaining the good quality of dumpling wrappers.



2020 ◽  
Vol 10 (03) ◽  
pp. 374-377
Author(s):  
Ibtihal Ismail Muhammad Al-Ani

The present study aimed to study the possibility of producing a drink that looks like grafted milk by using chickpeas and evaluate its physical, chemical, microbial, and sensory properties. The result showed the superiority of F treatment (soaking 100 grams of chickpeas at the refrigerator temperature 4ºC for 12 hours) over the rest seven treatments in extraction efficiency, which was 70%, while, it was 50.5% in H treatment (soaking 100 grams of chickpeas in the heated water at 60ºC for 30 minutes). The highest value of the product density was after water and flavorings addition in the D treatment (soaking 100 grams chickpeas in 0.05 soda solution at 60ºC for 30 minutes), and it was 0.97 g cm-3, compared with the lowest density 0.57 g cm-3 in A treatment (soaking 100 grams chickpeas in 0.05 soda solution at room temperature 25ºC for 12 hours). pH values were highest in A treatment compared with the other treatments, and its value was 7.66 in the 1st and 2nd day, after dissolving in a refrigerator at 4ºC, and then, for 5 minutes at room temperature 30ºC. The lowest value in the D treatment was 6.45 on the 1st day, and 6.87 on the 2nd day in the G treatment. On the 3rd day, the highest pH value was 7.13 in the D treatment, and the lowest value 6.79 was in the E treatment. pH highest value was 6.2 on the 4th day in A treatment. From the last results, it may be concluded that F treatment was the best in extraction efficiency, the final product density, and less total bacterial number, after dissolving for 5 days at refrigerator temperature 4ºC, and then, at room temperature 30ºC for 3 and 48 hours incubation. The best extraction volume and pH were in A treatment.



2020 ◽  
Vol 25 (1) ◽  
pp. 52
Author(s):  
Alston Millan

Nutmeg oleoresin microcapsule is the solid, liquid, and gas coating technology of the nutmeg fruit.  The purpose of this study was to know how mace nutmeg oleoresin microcapsules could preserve the broiler chicken meat at room temperature during 4 days of observation. The experimental design used was a Completely Randomized Design (CRD) consisting of 5 treatments with mace concentration of nutmeg microcapsules oleoresin (0, 50, 100, 150, and 200) ppm. The variables observed were water content, pH value, total microbes, and organoleptic properties (color, aroma, and texture). The results showed that mace nutmeg oleoresin microcapsules did not affect (p> 0.05)  water content and sensory properties of broiler chicken meat, but had a significant effect (p <0.05) on the pH value and total microbe at the same day of room temperature storage. Panel organoleptic test results on the level of preference for meat color, aroma, and texture of chicken meat were in the range score of 3 (somewhat like) to 4 (somewhat dislike). The treatments of nutmeg oleoresin did not affect (p> 0.05) on color, the aroma, and the texture of broiler chicken meat. This research shows that marinating using oleoresin microcapsules has not been effective as a preservative to broiler chicken meat at room temperature. Keywords: chicken meat, mace nutmeg oleoresin microcapsules



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