This study investigates inductively coupled transmission technology using seawater and underwater anchor chains as the transmission medium for real-time data transfer from underwater measurement instruments.Because of...This study investigates inductively coupled transmission technology using seawater and underwater anchor chains as the transmission medium for real-time data transfer from underwater measurement instruments.Because of the physical properties of seawater,challenges,such as frequency selective fading and multipath effect,limit long-distance current signal transmission.Conventional modulation techniques,such as amplitude shift keying(ASK)and differential phase shift keying(DPSK),are constrained by low bandwidth utilization and high bit error rates(BER).To address these issues,we optimize the seawater channel model using data from the National Oceanographic Data Center and previous measurements,analyzing the relationship between seawater conductivity,depth,and signal frequency.We constructed an experimental platform using a six-winding manganese-zinc ferrite ring based on an inductive coupling model for data transmission.A steel cable is anchored at both ends of a seawater bucket through two rings,exposing the cable core to establish a closed loop in seawater.An orthogonal frequency division multiplexing(OFDM)algorithm is used to improve transmission performance by distributing data across multiple subcarriers,effectively mitigating multipath fading and frequency selective fading.Compared with ASK and DPSK,this method significantly reduces the BER and improves the channel capacity,exhibiting robustness in underwater communication.Finally,in our study,a mathematical model of the underwater multipath channel for distances of 300,1000,and 2000 m is established,showing an improvement in channel capacity of approximately 2.5 bps/Hz based on the OFDM algorithm.This advancement is essential for enhancing the performance of underwater signal transmission and supporting its practical application.展开更多
To address the current issues with the conventional slide gate system utilized in the steel teeming process,a unique electromagnetic induction controlled automated steel teeming(EICAST)technology has been developed.Co...To address the current issues with the conventional slide gate system utilized in the steel teeming process,a unique electromagnetic induction controlled automated steel teeming(EICAST)technology has been developed.Cooling means of spiral coil in this technology is directly related to its service life.Firstly,heat transfer processes of air cooling and spray cooling were compared and analyzed.Secondly,the impacts of water temperature,water flow rate and air flow rate were examined in order to maximize the spray cooling effect.To maintain coil temperature at a low value consistently throughout the entire thermal cycle process of the ladle,a combined cooling mode was finally employed.Numerical simulation was applied to examine the coil temperature variation with different cooling systems and characteristics.Before coil operation,spray cooling is said to be more effective.By controlling the water flow rate and air flow rate,the spray cooling effect is enhanced.However,water temperature has little or no impact when using spray cooling.Air cooling during the secondary refining process and spray cooling prior to coil operation are combined to further lower coil temperature.When the direction of the spray cooling is from bottom to top,the coil temperature is lowered below 165℃.A practical induction coil cooling plan was provided for the EICAST technology’s production process.展开更多
基金supported by grants from the National Natural Science Foundation of China(No.62071329)the National Science Foundation of Tianjin(No.23JCZDJC00440)the Key Areas R&D Programs of Guangdong Province(No.2020B1111020001).
文摘This study investigates inductively coupled transmission technology using seawater and underwater anchor chains as the transmission medium for real-time data transfer from underwater measurement instruments.Because of the physical properties of seawater,challenges,such as frequency selective fading and multipath effect,limit long-distance current signal transmission.Conventional modulation techniques,such as amplitude shift keying(ASK)and differential phase shift keying(DPSK),are constrained by low bandwidth utilization and high bit error rates(BER).To address these issues,we optimize the seawater channel model using data from the National Oceanographic Data Center and previous measurements,analyzing the relationship between seawater conductivity,depth,and signal frequency.We constructed an experimental platform using a six-winding manganese-zinc ferrite ring based on an inductive coupling model for data transmission.A steel cable is anchored at both ends of a seawater bucket through two rings,exposing the cable core to establish a closed loop in seawater.An orthogonal frequency division multiplexing(OFDM)algorithm is used to improve transmission performance by distributing data across multiple subcarriers,effectively mitigating multipath fading and frequency selective fading.Compared with ASK and DPSK,this method significantly reduces the BER and improves the channel capacity,exhibiting robustness in underwater communication.Finally,in our study,a mathematical model of the underwater multipath channel for distances of 300,1000,and 2000 m is established,showing an improvement in channel capacity of approximately 2.5 bps/Hz based on the OFDM algorithm.This advancement is essential for enhancing the performance of underwater signal transmission and supporting its practical application.
基金supported by the Startup Foundation of Shenyang Agriculture University(No.X2023050)the Fundamental Research Funds for the Central Universities(No.N2209006)the National Natural Science Foundation of China(No.U22A20173).
文摘To address the current issues with the conventional slide gate system utilized in the steel teeming process,a unique electromagnetic induction controlled automated steel teeming(EICAST)technology has been developed.Cooling means of spiral coil in this technology is directly related to its service life.Firstly,heat transfer processes of air cooling and spray cooling were compared and analyzed.Secondly,the impacts of water temperature,water flow rate and air flow rate were examined in order to maximize the spray cooling effect.To maintain coil temperature at a low value consistently throughout the entire thermal cycle process of the ladle,a combined cooling mode was finally employed.Numerical simulation was applied to examine the coil temperature variation with different cooling systems and characteristics.Before coil operation,spray cooling is said to be more effective.By controlling the water flow rate and air flow rate,the spray cooling effect is enhanced.However,water temperature has little or no impact when using spray cooling.Air cooling during the secondary refining process and spray cooling prior to coil operation are combined to further lower coil temperature.When the direction of the spray cooling is from bottom to top,the coil temperature is lowered below 165℃.A practical induction coil cooling plan was provided for the EICAST technology’s production process.
