Terahertz(THz)communication has been envisioned as a key enabling technology for sixthgeneration(6G).In this paper,we present an extensive THz channel measurement campaign for 6G wireless communications from 220 GHz t...Terahertz(THz)communication has been envisioned as a key enabling technology for sixthgeneration(6G).In this paper,we present an extensive THz channel measurement campaign for 6G wireless communications from 220 GHz to 330 GHz.Furthermore,the path loss is analyzed and modeled by using two single-frequency path loss models and a multiplefrequencies path loss model.It is found that at most frequency points,the measured path loss is larger than that in the free space.But at around 310 GHz,the propagation attenuation is relatively weaker compared to that in the free space.Also,the frequency dependence of path loss is observed and the frequency exponent of the multiple-frequencies path loss model is 2.1.Moreover,the cellular performance of THz communication systems is investigated by using the obtained path loss model.Simulation results indicate that the current inter-site distance(ISD)for the indoor scenario is too small for THz communications.Furthermore,the tremendous capacity gain can be obtained by using THz bands compared to using microwave bands and millimeter wave bands.Generally,this work can give an insight into the design and optimization of THz communication systems for 6G.展开更多
Heterotrophic cultivation has been proved to be an effective and industrially scalable route for the economical production of Chlorella biomass.Nevertheless,the low protein content of heterotrophic Chlorella biomass h...Heterotrophic cultivation has been proved to be an effective and industrially scalable route for the economical production of Chlorella biomass.Nevertheless,the low protein content of heterotrophic Chlorella biomass hinders its utilization as a superior protein source.In this study,the influences of various C/N ratios on cell growth and protein production were evaluated for a previously isolated protein-rich alga Chlorella sorokiniana CMBB276.The results indicated that a high C/N ratio was favorable for cell growth,whereas a low C/N ratio was advantageous for protein synthesis.A proposed two-stage nitrogen supply strategy by shifting the C/N ratio from 18 to 6 was found to be capable of simultaneously improve the protein content and yield of C.sorokiniana CMBB276,achieving the maximum protein content of 58.6% of dry cell weight(DCW)and a final protein yield of 87.0 g L^(−1),respectively.We further verified that the fast accumulated ammonium in C.sorokiniana CMBB276 cultivated with the switched C/N ratio contributed to the remarkable enhancement of protein content,while concurrently causing cytotoxicity.Moreover,under high ammonium stress,while maintaining a high protein content,C.sorokiniana CMBB276 persisted in growing with a decreased level of cellular reactive oxygen species(ROS)and cell membrane damage through exogenous addition of acetate,which lays the foundation for further improvement of protein production by applying the two-stage nitrogen supply strategy in combination with acetate addition.展开更多
基金supported by the National Science Fund for Distinguished Young Scholars(No.61925102)the National Key R&D Program of China(No.2020YFB1805002)the Key Project of State Key Lab of Networking and Switching Technology(No.NST20180105).
文摘Terahertz(THz)communication has been envisioned as a key enabling technology for sixthgeneration(6G).In this paper,we present an extensive THz channel measurement campaign for 6G wireless communications from 220 GHz to 330 GHz.Furthermore,the path loss is analyzed and modeled by using two single-frequency path loss models and a multiplefrequencies path loss model.It is found that at most frequency points,the measured path loss is larger than that in the free space.But at around 310 GHz,the propagation attenuation is relatively weaker compared to that in the free space.Also,the frequency dependence of path loss is observed and the frequency exponent of the multiple-frequencies path loss model is 2.1.Moreover,the cellular performance of THz communication systems is investigated by using the obtained path loss model.Simulation results indicate that the current inter-site distance(ISD)for the indoor scenario is too small for THz communications.Furthermore,the tremendous capacity gain can be obtained by using THz bands compared to using microwave bands and millimeter wave bands.Generally,this work can give an insight into the design and optimization of THz communication systems for 6G.
基金supported by grants from the Technology Innovation Center for Exploitation of Marine Biological Resources,Ministry of Natural Resources(TICMBR202401)National Key R&D Program of China(2018YFD0901500)Chinese Academy of Sciences(ZDRW-ZS-2017).
文摘Heterotrophic cultivation has been proved to be an effective and industrially scalable route for the economical production of Chlorella biomass.Nevertheless,the low protein content of heterotrophic Chlorella biomass hinders its utilization as a superior protein source.In this study,the influences of various C/N ratios on cell growth and protein production were evaluated for a previously isolated protein-rich alga Chlorella sorokiniana CMBB276.The results indicated that a high C/N ratio was favorable for cell growth,whereas a low C/N ratio was advantageous for protein synthesis.A proposed two-stage nitrogen supply strategy by shifting the C/N ratio from 18 to 6 was found to be capable of simultaneously improve the protein content and yield of C.sorokiniana CMBB276,achieving the maximum protein content of 58.6% of dry cell weight(DCW)and a final protein yield of 87.0 g L^(−1),respectively.We further verified that the fast accumulated ammonium in C.sorokiniana CMBB276 cultivated with the switched C/N ratio contributed to the remarkable enhancement of protein content,while concurrently causing cytotoxicity.Moreover,under high ammonium stress,while maintaining a high protein content,C.sorokiniana CMBB276 persisted in growing with a decreased level of cellular reactive oxygen species(ROS)and cell membrane damage through exogenous addition of acetate,which lays the foundation for further improvement of protein production by applying the two-stage nitrogen supply strategy in combination with acetate addition.
