Study of single photon echo detection technology in underwater target ranging

2005 ◽  
Author(s):  
Xiao Lin Sui ◽  
Zheng Yu Zhang ◽  
Xiao Long Zhang ◽  
Fei Xuan ◽  
Ming Yu ◽  
...  
2018 ◽  
Vol 39 (1) ◽  
pp. 130-133
Author(s):  
Gao Wei ◽  
Ma Shiwei ◽  
Duan Yuanyuan

2013 ◽  
Vol 734-737 ◽  
pp. 3075-3078 ◽  
Author(s):  
Zhong Liu ◽  
Ke Li ◽  
Bing Yan

The attack from small speedboat and underwater robot is becoming more and more serious. And most powerful countries have installed underwater surveillance systems to protect port, ship, seashore depository and anchorage. The detection technology of underwater target is the most important technology in the process of surveillance. In order to take good advantage of the target’s geometry characteristic and classification function of SVM(Support Vector Machine), an algorithm for imaging sonar target detection based on geometry characteristic and SVM is proposed in the paper. The experiment results are presented and show that this algorithm is in high detection rate under complex underwater circumstance.


Author(s):  
Wangshuai Xu ◽  
Shaowei Zhen ◽  
Hailiang Xiong ◽  
Bingqing Zhao ◽  
Ziyi Liu ◽  
...  

1988 ◽  
Vol 13 (4) ◽  
pp. 318 ◽  
Author(s):  
Koos Duppen ◽  
Douwe A. Wiersma

Science ◽  
1978 ◽  
Vol 202 (4368) ◽  
pp. 645-648 ◽  
Author(s):  
A. Feng ◽  
J. Simmons ◽  
S. Kick

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4940
Author(s):  
Yanjuan Wang ◽  
Junsheng Wang ◽  
Chen Zhou ◽  
Gege Ding ◽  
Mengmeng Chen ◽  
...  

There are a huge number, and abundant types, of microalgae in the ocean; and most of them have various values in many fields, such as food, medicine, energy, feed, etc. Therefore, how to identify and separation of microalgae cells quickly and effectively is a prerequisite for the microalgae research and utilization. Herein, we propose a microfluidic system that comprised microalgae cell separation, treatment and viability characterization. Specifically, the microfluidic separation function is based on the principle of deterministic lateral displacement (DLD), which can separate various microalgae species rapidly by their different sizes. Moreover, a concentration gradient generator is designed in this system to automatically produce gradient concentrations of chemical reagents to optimize the chemical treatment of samples. Finally, a single photon counter was used to evaluate the viability of treated microalgae based on laser-induced fluorescence from the intracellular chlorophyll of microalgae. To the best of our knowledge, this is the first laboratory prototype system combining DLD separation, concentration gradient generator and chlorophyll fluorescence detection technology for fast analysis and treatment of microalgae using marine samples. This study may inspire other novel applications of micro-analytical devices for utilization of microalgae resources, marine ecological environment protection and ship ballast water management.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
You-Zhi Ma ◽  
Ming Jin ◽  
Duo-Lun Chen ◽  
Zong-Quan Zhou ◽  
Chuan-Feng Li ◽  
...  

AbstractPhoton echo is a fundamental tool for the manipulation of electromagnetic fields. Unavoidable spontaneous emission noise is generated in this process due to the strong rephasing pulse, which limits the achievable signal-to-noise ratio and represents a fundamental obstacle towards their applications in the quantum regime. Here we propose a noiseless photon-echo protocol based on a four-level atomic system. We implement this protocol in a Eu3+:Y2SiO5 crystal to serve as an optical quantum memory. A storage fidelity of 0.952 ± 0.018 is obtained for time-bin qubits encoded with single-photon-level coherent pulses, which is far beyond the maximal fidelity achievable using the classical measure-and-prepare strategy. In this work, the demonstrated noiseless photon-echo quantum memory features spin-wave storage, easy operation and high storage fidelity, which should be easily extended to other physical systems.


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