Mohammed Abdullah Issa

10 Questions 21 Answers 0 Followers

Questions related from Mohammed Abdullah Issa

Possible reason to change the color of carbon dots from greenish into blue after immobilization process?

Dear experts, Liquid carbon dots (CDs ) were synthesized with greenish color under UV-light. However, after mixing with PVA polymer, the color turned to blue with enhanced quantum yield (QY). what...

17 March 2020 5,468 4 View

Why to use acid or base for the development of fluorescent carbon dots?

Salam all. according to the reported work in the literature, some authors used strong acid (like refluxing with HNo3) in conjugation with carbon-based precursor, while others used base such as...

05 December 2019 5,617 3 View

Anyone can help me to explain this graph?

Based on response surface methodology (RSM) of the design experts software, two-dimension graph were obtained. The influence of two independent variables (X1X2) on the response (QY) is shown in...

06 May 2019 8,319 3 View

How to confirm the existence of carboxylic (-COOH) groups ?

Based on FTIR and XPs analysis, how to confirm that the obtained carbon dots (CDs) has (-COOH). In which form these groups can present in our material where C-C, C-N, O-H, C-H, C=O, C-O and C-O-C...

11 August 2018 5,670 6 View

Why to add buffer solution for the preparation of heavy metal ions?

According to the literatures, I noticed some of researchers used buffer solution for the preparation of heavy metal ions, whereas the others are not and they just used deionized water for the...

17 February 2018 500 3 View

Based on response surface methodology, what does it mean by getting lower predicted R-squared value than the adjusted R-squared?

Hi all. I'm working on the optimization process using central composite design (Design Experts software). The results showed that the model is significant but at the same time the predicted...

13 February 2018 7,667 9 View

Can we skip dialysis step to get fluorescent carbon dots during the synthesis process?

I'm working on nanotechnology right now. I read many articles, some of them use dialysis during their synthesis process where as the others find that filtration and centrifuge of the product is...

17 August 2017 3,272 3 View

Why carbon dots show both excitation-dependent/independent emission wavelength?

Based on selective luminescence study, The as-synthesized carbon nano dots (CDs) show both excitation-dependent/independent emission wavelength at one time. how can we explain that multiple behavior?

01 January 1970 4,952 7 View

Best country, in general, for postdoc nowadays?

Based on "quality of research" and "remuneration" which country should be chosen for postdoc study.

01 January 1970 5,098 10 View

Anyone knows the easiest method to calculate limit of detection (LOD) using excel?

Hi all. I got table in excel that involved the two following items: X-axis: concentration ranges. y-axis: values the obtained with respect to X-axis values. Now i need to calculate the linear...

01 January 1970 881 9 View