The publishing and editorial teams would like to thank the following, for their invaluable service as 2021 reviewers for this journal. We are very grateful for the contributions made. With their help, the journal has been able to publish such high-quality articles:

• A, Vivek Anand
• Abbasi Moshaei, Alireza
• Aghaabbasloo, Mohammad
• Agrawal, Saurabh
• Ai, Yue
• Akhtar, Jamil
• Alboul, Lyuba
• Alghannam, Essa
• Ali, Badar
• Armada, Manuel
• Au, Chi Kit
• Avila, Luis
• Aw, Kean
• Aydin, Muhammet
• Bai, Deju
• Bai, Long
• Bai, Shaoping
• Banka, Asif Ali
• Bayram, Atilla
• Będkowski, Janusz
• Belaidi, Hadjira
• Bi, Yunbo
• Bi, Zhuming
• Bijalwan, Vishwanath
• Billingsley, John
• Bingol, Mustafa Can
• Birglen, Lionel
• Biswal, Priyaranjan
• Bolmsjö, Gunnar
• Bonnin, Patrick
• Bruzzone, Luca
• Cai, Chengtao
• Cai, Mingxue
• Cai, Yunfei
• Çakir, Mustafa
• Cao, Hongli
• Cao, Yanlong
• Capi, Genci
• Carvalho De Souza, João Pedro
• Caurin, Glauco
• Chand, Praneel
• Charaf, Hassan
• Charoo, M S 
• Chaudhary, Gopal
• Chen, Fei
• Chen, Guangqing
• Chen, Haofeng
• Chen, Heping
• Chen, Hua
• Chen, Shengyong
• Chen, Wenliang
• Chen, Xizhang
• Chen, Yang
• Chen, Yinglong
• Cheng, Qiang
• Cheraghpour Samavati, Farzad
• Chi, Xing
• Chiddarwar, Shital
• Choi, Hyouk Ryeol
• Chu, Wenmin
• Cong, Ming
• Crowder, Richard
• Cukla, Anselmo Rafael
• Cunha, Alexandre
• Dachang, ZHU
• Das, Harish
• Dash, Anjan
• De Saxe, Christopher
• Deniz, Cengiz
• Derby, Stephen
• Diaz-Cacho Medina, Miguel
• Díaz, Carlos
• Dillmann, Rüdiger
• Do, Yongtae
• Doh, Nakju
• Dong, Jianwei
• Dong, Mingjie
• Du, Guanglong
• Du, Ruilong
• Duan, Q.
• Ehsani-Seresht, Abbas
• Ertugrul, Seniz
• Fang, Bin
• Fei, Fang
• Feng, Shaochuan
• Fernandez, Roemi
• Foglia, Mario
• G Nair, Vishnu
• Gaikwad, Lokpriya 
• Gan, Zhan
• Gani, Khalid
• Gao,  Hongbo
• Gao, Xueshan
• Gao, Yongzhuo
• Gil, Arturo
• Gimenez, Antonio
• González Crespo, Rubén
• Gothandaraman, Rajkumar
• Gu, Zengdao
• Gulzar, Ovais
• Gulzar, Saqib 
• Gulzar, Syed Mudasir
• Guo, Fayong
• Guo, Hao
• Guo, Shuai
• Guo, Yingjie
• Gupta, Arun
• Habib, Maki
• Haleem, Abid
• Han, Yali
• He, Baiyan
• He, Bin
• He, Lei
• He, Ye
• Hernando, Miguel
• Hong, Lei
• Horikawa, Oswaldo
• Hsieh, Sheng-Jen
• Hua, Changchun
• Huang, Haoqian
• Huang, Jun
• Huang, Wenkai
• Huang, Xiaochen
• Hugel, Vincent
• Huo, Jianwen
• Huo, Liguo
• Jain, Arpit
• Jain, Tushar
• Jannif, Nayzel
• Javaid, Mohd
• Jha, Abhishek
• Jha, Alok
• Jian, Fang
• Jiang, Daogeng
• Jiang, Wei
• Jiang, Wei
• Jiangtao, Qi
• Jin, Xiao
• Ju, Feng
• Ju, Zhaojie
• Jun, Changhyun
• Jun, Cheng
• Jun, Huang
• Kardan, Iman
• Kashyap, Abhishek
• Kataria, Ravinder
• Kexin, Ding
• Khan, Shahbaz
• Khan, Umer
• Khan, Waseem
• Kim, Heon-Hui
• Klemm, Victor
• Koli, Abdul
• Kuang, Jianghua
• Kubota, Naoyuki
• Kucuk, Serdar
• Kumar, Atul 
• Kumar, Dinesh
• Kumar, Narendra 
• Kurtser, Polina
• Kwok, Ngaiming
• Lambert, Jason Michel
• Le, Vu
• Leng, Yuquan
• Li, Changyang
• Li, Chenggang
• Li, Enbo
• Li, Guoyuan
• Li, Hengyu
• Li, Jian
• Li, Jiehao
• Li, Junye
• Li, Longqiu
• Li, Qiang
• Li, Qingmei
• Li, Ruifeng
• Li, Shuai
• Li, Tao
• Li, Wenhang
• Li, Wenshuo
• Li, Yongyao
• Li, Yuanhong
• Li, Zhenhui
• Liang, Xifeng
• Lima Ii, Eduardo
• Lin, Ruihao
• Lin, Sheng
• Lindner, Lars
• Liu, Dong
• Liu, Gangfeng
• Liu, Guangjun
• Liu, Ji-Xin
• Liu, Jie
• Liu, Lei
• Liu, Louis Kp
• Liu, Quan
• Liu, Tianliang
• Liu, Xiaoguang
• Liu, Zhi-Wei
• Liyan, Zhang
• Long, Derek
• Lourenço, Bernardo
• Lu, Huimin
• Lu, Xiaolong
• Luo, Yan 
• Ma, Tian-Lei
• Mandru, Dan
• Mao, Yan
• Mashayekhi, Ahmad
• Mcbryan, Katherine
• Mendes, Nuno
• Mercorelli, Paolo
• Mianowski, Krzysztof
• Mir, Faizan Ul Haq
• Mohan, Santhakumar 
• Mohanty, Chinmaya Prasad 
• Mohanty, Prases
• Molfino, Rezia
• Mondal, Amit
• Monteiro, Sergio
• Moon, Seungbin
• Munoz-Hernandez, German Ardul
• Muscato, Giovanni
• Muthuswamy, Sreekumar
• Nabulsi, Samir 
• Nassirharand, Amir
• Nayak, Ankit
• Nearchou, Andreas
• Neto, Pedro
• Nguyen, Cat Ho
• Nguyen, Nhan
• Ni, Mao
• Niu, Jie
• Nokhbe Foghahayee, Hoda
• Ogbemhe, John
• Ouelmokhtar, Hand
• Ozkan, Metin
• Pan, Hongtao
• Panda, Jyoti
• Pandey, Anish
• Pandey, Krishna Kant
• Pang, Zaixiang
• Park, Eunil
• Patle, Dr. Bhumeshwar Kujilal 
• Pawar, Vaibhav
• Phan Bui, Khoi
• Piardi, Luis
• Pires, J. Norberto
• Pucedji, Kristof
• Pushparaj, Ashok
• Qian, Meng
• Qian, Yan
• Qiao, Guifang
• Qiao, Xiaoguang
• Qin, Wenlong
• Qiu, Jing
• Qu, Jiadi
• R, Hari Krishnan
• Rab, Shanay
• Raj, Manish
• Raj, Sudhan
• Ramanathan, Kuppan Chetty
• Ramasamy, Sudhakar
• Rengifo, Carlos
• Rios-Cabrera, Reyes
• Rubio, Francisco
• Sahu, Dr. Chinmaya 
• Sarkar, Soumic
• Sayahkarajy, Mostafa
• Semwal, Dr. Vijay Bhaskar 
• Semwal, Vijay Bhaskar
• Shao, Ke
• Shao, Ziyan
• Sharma , G V S S
• Sharma, Kamal
• Sharma, Nitin
• Sharma, Rajiv Kumar
• Shen, Yantao
• Shen, Zhipeng
• Shi, Haoran
• Shi, Hu
• Shirwalkar, Varsha
• Shrivastava, Yogesh
• Singh, Dr. Jasveer
• Singh, Ravi Pratap
• Singh, Sanjeev 
• Skrzypczynski, Piotr
• Song, Guangming
• Song, Yuntao
• Soria, Alberto
• Soyguder, Servet
• Stefano, Mauro
• Stopforth, Riaan
• Su, Shijian
• Sudheer, A P
• Suhaib, Mohd.
• Sziebig, Gabor
• Tambuskar, Dhanraj
• Tan, Guo
• Tao, Guanghong
• Tong, Jinwu
• Trang, Thanhtrung
• Tsintotas, Konstantinos A.
• Türkeş, Erol
• Ul Haq, Mir Irfan
• Uppada, Sudhakar 
• Wan, Weiwei
• Wang, Guifei
• Wang, Hao
• Wang, Hong-Qiang
• Wang, Hongrui
• Wang, Wei
• Wang, Wen
• Wang, Wendong
• Wang, Yaoyao
• Wei, Wang
• Wei, Xiaoyong
• Wen, Haiying
• Wen, Shuhuan
• Wu, Chuanyu
• Wu, Gupan
• Wu, Jun
• Wu, Qingcong
• Wu, Shaobo
• Wu, Xin
• Xia, Xiaowei
• Xiang, Chaoqun
• Xianjin, Xu
• Xiao, Juliang
• Xie, Biyun
• Xie, Ou
• Xing, Guanyu
• Xiong, Ya
• Xiu, Lei
• Xu, Jinting
• Xu, Kai
• Xu, Li
• Xu, Wenfu
• Xue, Zhao
• Yadav, Dr. Poonam
• Yan, Qiang
• Yan, Yu
• Yang, Chenguang
• Yang, Huayong
• Yang, Wei
• Yang, Yang
• Yang, Yuxiang
• Yao, Yan-An
• Yeon, Suyong
• Yeshmukhametov, Azamat
• Yılmaz, Cüneyt
• Yuan, Jing
• Yun, Chao
• Zarafshan, Payam
• Zeng, Fanyu
• Zhang, Chunyan
• Zhang, He
• Zhang, Hui
• Zhang, Jianhua
• Zhang, Tao
• Zhang, Tie
• Zhang, Xiaoqin
• Zhang, Xinbin
• Zhao, Shoubo
• Zhao, Yanzheng
• Zheng, Tianjiang
• Zhong, Jun
• Zhou, Huaidong
• Zhu, Hongbo
• Zhu, Wei Dong
• Zhu, Yanghui
• 李, 论