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Rabia Zafar,Seon Yeong Park,Chang Gyun Kim 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.5
Microplastics coexist with the chemical reactive oxygen species in natural waters, however, there is still a lack to elucidate the effect of these radicals on the microplastic surficial oxidation. In this study, the ozonation of polyethylene microplastics was carried out under varying ozone dosages ranging from 4 to 7 ㎎/min for 60, 120 and 180 min, where its ozone uptake was iodometrically compared and surficial modification was spectroscopically analyzed using FTIR and XPS. For that, the lowest ozone uptake was 16% at 4 ㎎/min ozone supplied for 60 min whereas the highest was observed of 44% at 7 ㎎/min ozone added for 180 min. Moreover, in the FTIR analysis, carbonyl (1,600-1,800 ㎝<SUP>-1</SUP>) and hydroxyl (3,200-3,600 ㎝<SUP>-1</SUP>) indices were improved more than 20% and 13% when they were ozonized at 7 mg/min for 180 min compared to 4 ㎎/min for 60 min, respectively. XPS also revealed that 7 ㎎/min of ozone supplied for 180 min provided the highest of oxygen functionalities, but while there was no significant change in C-C bond. It can be concluded that the surficial modification of PE including formation of oxygen functionalities could be more preferably influenced by the reaction time than ozone dosages.
Rabia Zafar,Seon Yeong Park,Chang Gyun Kim 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.3
This study examined the effects of ozonation and UV applied in series (O₃+UV) or simultaneously (UVO) under four different ozone dosages from 4 to 7 mg/min to understand the surface alterations on polyethylene microplastics in aquatic environments via the photochemical oxidation process. The plastic samples were analyzed by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and contact angle measurements. FTIR spectroscopy showed that the levels of carbonyl (ketone and esters) and vinyl groups increased gradually with increasing ozone dose injected; the highest was observed at 6 mg/min of ozone. On the other hand, the levels at 7 mg/min of ozone were slightly lower than those at 4 to 6 mg/min. This could be related to the deeper penetration into the crystalline bulk polymeric chain. The contact angle changed from 125.90˚ to the lowest value of 120.04˚ and 123.8˚ for O₃+UV and UVO, respectively. Furthermore, XPS showed that C-O was only presented in the 7 mg/min sample, whereas C-O, OH, C=O, and C-C=O remained for 4 to 6 mg/min. Overall, O₃+UV can oxidize the surface of the polyethylene microplastic particles more effectively than those of UVO, irrespective of the ozone dosages.
Edge version of harmonic index and harmonic polynomial of some classes of graphs
Rabia Nazir,Shoaib Sardar,Sohail Zafar,Zohaib Zahid 한국전산응용수학회 2016 Journal of applied mathematics & informatics Vol.34 No.5
In this paper we define the edge version of harmonic index and harmonic polynomial of a graph $G$. We computed explicit formulas for the edge version of harmonic index and harmonic polynomial of many well known classes of graphs.
EDGE VERSION OF HARMONIC INDEX AND HARMONIC POLYNOMIAL OF SOME CLASSES OF GRAPHS
NAZIR, RABIA,SARDAR, SHOAIB,ZAFAR, SOHAIL,ZAHID, ZOHAIB The Korean Society for Computational and Applied M 2016 Journal of applied mathematics & informatics Vol.34 No.5
In this paper we define the edge version of harmonic index and harmonic polynomial of a graph G. We computed explicit formulas for the edge version of harmonic index and harmonic polynomial of many well known classes of graphs.
Toxicity of seventeen insecticides to Camponotus sericeus (Hymenoptera: Formicidae)
Khan Hafiz Azhar Ali,Zafar Rabia,Nasir Iqra 한국응용곤충학회 2021 Journal of Asia-Pacific Entomology Vol.24 No.1
The success of chemical control depends on toxicity of insecticides against insect pests. Camponotus sericeus is an important urban pest with the ability to cause substantial damage to wooden structures, but there is a lack of information on toxicity of insecticides against C. sericeus. To determine the insecticide toxicity, workers of C. sericeus were exposed to 17 insecticides from different classes: carbamate (methomyl, bendiocarb), organo phosphate (chlorpyrifos, profenofos, temephos), pyrethroid (bifenthrin, deltamethrin, permethrin), neon icotinoid (acetamiprid, imidacloprid, thiamethoxam), avermectin (abamectin, emamectin), pyrrole (chlorfenapyr), phenylpyrazole (fipronil), and spinosyn (spinosad and spinetoram), via residual bioassay method. The LC 50 ranged from: 0.15 to 0.20 µg/vial for carbamates, 0.09 to 0.27 µg/vial for organophosphates, 0.09 to 0.44 µg/vial for pyrethroids, 0.02 to 0.67 µg/vial for neonicotinoids, 0.54 to 0.82 µg/vial for avermectins, 0.78 µg/vial for pyrrole, 0.62 µg/vial for phenylpyrazole, and 1.96 to 2.05 µg/vial for spinosyns. Overall, acetamiprid was the most toxic one among the tested insecticides followed by permethrin, temephos, profenofos, bendiocarb and methomyl, while spinosad and spinetoram were the least toxic insecticides. Considering the potential toxicity of different insecticides against C. sericeus, future studies could investigate the practical application of these insecticides in order to design an effective management plan.
uz Zaman, Maseeh,Fatima, Nosheen,Sajjad, Zafar,Zaman, Unaiza,Tahseen, Rabia,Zaman, Areeba Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.23
Positron emission tomography (PET) as the functional component of current hybrid imaging (like PET/CT or PET/MRI) seems to dominate the horizon of medical imaging in coming decades. $^{18}$Flourodeoxyglucose ($^{18}FDG$) is the most commonly used probe in oncology and also in cardiology and neurology around the globe. However, the major capital cost and exorbitant running expenditure of low to medium energy cyclotrons (about 20 MeV) and radiochemistry units are the seminal reasons of low number of cyclotrons but mushroom growth pattern of PET scanners. This fact and longer half-life of $^{18}F$ (110 minutes) have paved the path of a centralized model in which $^{18}FDG$ is produced by commercial PET radiopharmacies and the finished product (multi-dose vial with tungsten shielding) is dispensed to customers having only PET scanners. This indeed reduced the cost but has limitations of dependence upon timely arrival of daily shipments as delay caused by any reason results in cancellation or rescheduling of the PET procedures. In recent years, industry and academia have taken a step forward by producing low energy, table top cyclotrons with compact and automated radiochemistry units (Lab-on-Chip). This decentralized strategy enables the users to produce on-demand doses of PET probe themselves at reasonably low cost using an automated and user-friendly technology. This technological development would indeed provide a real impetus to the availability of complete set up of PET based molecular imaging at an affordable cost to the developing countries.