Comparison of Urea and Citric Acid Complexing Agents and Annealing Temperature Effect on the Structural Properties of <svg     style="vertical-align:-3.636pt;width:11.1125px;" id="M1" height="15.0125" version="1.1" viewBox="0 0 11.1125 15.0125" width="11.1125"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
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</svg>- and <svg     style="vertical-align:-0.216pt;width:14.1125px;" id="M2" height="10.725" version="1.1" viewBox="0 0 14.1125 10.725" width="14.1125"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
			<g transform="matrix(.022,-0,0,-.022,.062,10.4)"><path id="x1D736" d="M505 450h125l-163 -259q-1 -4 -1 -12q0 -19 1 -23q9 -98 41 -98q36 0 58 76l24 -7q-34 -139 -121 -139q-32 0 -57.5 24t-31.5 55q-72 -77 -181 -77q-73 0 -114 44t-41 124q0 118 79 210q79 93 197 93q51 0 86 -27t50 -71zM369 281q0 141 -62 141q-43 0 -95 -84
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</svg>-Alumina Nanoparticles Synthesized by Sol-Gel Method

<table>SEM image of Al<sub>2</sub>O<sub>3</sub> nanoparticles prepared by citric acid calcined at (a) 750°C and (b) 1250°C.</table>

Advances in Materials Science and Engineering

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Figure 4

Figure 4: Comparison of Urea and Citric Acid Complexing Agents and Annealing Temperature Effect on the Structural Properties of <svg     style="vertical-align:-3.636pt;width:11.1125px;" id="M1" height="15.0125" version="1.1" viewBox="0 0 11.1125 15.0125" width="11.1125"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
			<g transform="matrix(.022,-0,0,-.022,.062,10.412)"><path id="x1D738" d="M377 450h126l-264 -401q0 -75 -21 -153q-12 -44 -36 -71t-56 -27q-27 0 -42 18.5t-15 42.5q0 34 30 89q9 16 32 50q21 31 29 46q13 91 13 208q0 45 -11 94q-11 47 -34 47q-38 0 -61 -81h-23q40 150 121 150q46 0 65 -34.5t19 -99.5q0 -54 -7 -125z" /></g>

		
	
</svg>- and <svg     style="vertical-align:-0.216pt;width:14.1125px;" id="M2" height="10.725" version="1.1" viewBox="0 0 14.1125 10.725" width="14.1125"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
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q-52 -82 -52 -195q0 -50 15 -83t42 -33q35 0 79 57q43 58 67 121q6 35 6 76z" /></g>

		
	
</svg>-Alumina Nanoparticles Synthesized by Sol-Gel Method 

Figure 4 | Comparison of Urea and Citric Acid Complexing Agents and Annealing Temperature Effect on the Structural Properties of 
	
		
			

		
	
- and 
	
		
			

		
	
-Alumina Nanoparticles Synthesized by Sol-Gel Method 

Advances in Materials Science and Engineering

Comparison of Urea and Citric Acid Complexing Agents and Annealing Temperature Effect on the Structural Properties of - and -Alumina Nanoparticles Synthesized by Sol-Gel Method

Figure 4