Dwarf Water Lilies Nymphoides aquatica(J.F.Gmel)Kuntze have floating and submerged leaves.Some submerged aquatic vascular plants have a form of CAM(Crassulacean Acid Metabolism)called Submerged Aquatic Macrophyte(SAM)...Dwarf Water Lilies Nymphoides aquatica(J.F.Gmel)Kuntze have floating and submerged leaves.Some submerged aquatic vascular plants have a form of CAM(Crassulacean Acid Metabolism)called Submerged Aquatic Macrophyte(SAM)metabolism.Blue-diode based PAM technology was used to measure the Photosynthetic Oxygen Evolution Rate(POER:1O_(2)≡4e^(-)).Optimum Irradiance(E_(opt)),maximum POER(POER_(max))and quantum efficiency(α_(0))all vary on a diurnal cycle.The shape of the POER vs.E curves is different in seedling,submerged and surface leaves.Both E_(opt)and POER_(max)are very low in seedling leaves(E_(opt)≈104μmol photon m^(-2)s^(-1),PPFD;POER_(max)≈4.95µmol O_(2)g^(-1)Chl a s^(-1)),intermediate in mature submerged leaves(E_(opt)≈419µmol photon m^(-2)s^(-1)PPFD,POER_(max)≈38.1µmol O_(2)g^(-1)Chl a s^(-1))and very high in surface leaves(E_(opt)≈923µmol photon m^(-2)s^(-1)PPFD,POER_(max)≈76.1µmol O_(2)g^(-1)Chl a s^(-1)).Leaf titratable acid(C4 acid pool)is too small(≈20 to 50 mol H+m^(-3))to support substantial SAM metabolism.Gross daily photosynthesis of surface leaves is≈3.71 g C m^(-2)d^(-1)in full sun and as much as 1.4 gC m^(-2)d^(-1)in shaded submerged leaves.There is midday inhibition of photosynthesis.展开更多
The 4-level pulse amplitude modulation(PAM4)based on an 23 GHz ultrabroadband directly modulated laser(DML)was proposed.We have experimentally demonstrated that based on intensity modulation and direct detection(IMDD)...The 4-level pulse amplitude modulation(PAM4)based on an 23 GHz ultrabroadband directly modulated laser(DML)was proposed.We have experimentally demonstrated that based on intensity modulation and direct detection(IMDD)56 Gbps per wavelength PAM4 signals transferred over 35 km standard single mode fiber(SSMF)without any optical amplification and we have achieved the bit error rate(BER)of the PAM4 transmission was under 2.9×10–4 by using feed forward equalization(FFE).展开更多
Since the poor performance of orthogonal binary Pulse Position Modulation (PPM) compared with binary Pulse Amplitude Modulation (PAM), this paper presents a new modulation scheme named Pulse Width Modulation (PWM) for...Since the poor performance of orthogonal binary Pulse Position Modulation (PPM) compared with binary Pulse Amplitude Modulation (PAM), this paper presents a new modulation scheme named Pulse Width Modulation (PWM) for Impulse Radio Ultra-WideBand (IR-UWB) communication systems. This modulation scheme uses pulses with equal amplitude and different widths to carry different information. The receiver employs differences between similarity coefficients among these pulses to distinguish different information. Both theoretical analysis and simulation results verify that this novel scheme has a Signal to Noise Ratio (SNR) gain of about 1.75 dB compared with or- thogonal binary PPM, and has an SNR loss of about 1.4 dB compared with binary PAM. Although both the theoretical analysis and simulations are based on time-hopping multiple access, this modulation scheme can also be applied to other accessing techniques of UWB communication systems.展开更多
车载通信是高速串行器与解串器(serializer and deserializer,SerDes)技术应用的一个重要领域。针对复杂车载环境中链路高频衰减导致的符号间干扰在高阶调制方式下更为严重的问题,引入深度学习方法,设计一种基于Transformer编码器结构...车载通信是高速串行器与解串器(serializer and deserializer,SerDes)技术应用的一个重要领域。针对复杂车载环境中链路高频衰减导致的符号间干扰在高阶调制方式下更为严重的问题,引入深度学习方法,设计一种基于Transformer编码器结构的低复杂度信道均衡方案,以提高接收信号质量。该方案将输入序列转换为抽象的表示向量,然后利用编码器层提取表示向量的特征信息,最后全连接层根据特征信息对信号进行分类,从而实现高速SerDes信道均衡。实验结果表明:与传统自适应算法和全连接神经网络模型相比,所提方案能够有效降低高频衰减导致的信号失真,在计算复杂度降低19%和24%的情况下接收信噪比增益分别为1.8 dB和0.9 dB。通过在高速SerDes系统中应用所提信道均衡方案,可以提高信号传输质量以及增强系统的鲁棒性。展开更多
文摘Dwarf Water Lilies Nymphoides aquatica(J.F.Gmel)Kuntze have floating and submerged leaves.Some submerged aquatic vascular plants have a form of CAM(Crassulacean Acid Metabolism)called Submerged Aquatic Macrophyte(SAM)metabolism.Blue-diode based PAM technology was used to measure the Photosynthetic Oxygen Evolution Rate(POER:1O_(2)≡4e^(-)).Optimum Irradiance(E_(opt)),maximum POER(POER_(max))and quantum efficiency(α_(0))all vary on a diurnal cycle.The shape of the POER vs.E curves is different in seedling,submerged and surface leaves.Both E_(opt)and POER_(max)are very low in seedling leaves(E_(opt)≈104μmol photon m^(-2)s^(-1),PPFD;POER_(max)≈4.95µmol O_(2)g^(-1)Chl a s^(-1)),intermediate in mature submerged leaves(E_(opt)≈419µmol photon m^(-2)s^(-1)PPFD,POER_(max)≈38.1µmol O_(2)g^(-1)Chl a s^(-1))and very high in surface leaves(E_(opt)≈923µmol photon m^(-2)s^(-1)PPFD,POER_(max)≈76.1µmol O_(2)g^(-1)Chl a s^(-1)).Leaf titratable acid(C4 acid pool)is too small(≈20 to 50 mol H+m^(-3))to support substantial SAM metabolism.Gross daily photosynthesis of surface leaves is≈3.71 g C m^(-2)d^(-1)in full sun and as much as 1.4 gC m^(-2)d^(-1)in shaded submerged leaves.There is midday inhibition of photosynthesis.
基金supported by National Key Research and Development Program of China (No. 2018YFB2201101)the National Natural Science Foundation of China (Nos. 61635001 and 61575186)
文摘The 4-level pulse amplitude modulation(PAM4)based on an 23 GHz ultrabroadband directly modulated laser(DML)was proposed.We have experimentally demonstrated that based on intensity modulation and direct detection(IMDD)56 Gbps per wavelength PAM4 signals transferred over 35 km standard single mode fiber(SSMF)without any optical amplification and we have achieved the bit error rate(BER)of the PAM4 transmission was under 2.9×10–4 by using feed forward equalization(FFE).
文摘Since the poor performance of orthogonal binary Pulse Position Modulation (PPM) compared with binary Pulse Amplitude Modulation (PAM), this paper presents a new modulation scheme named Pulse Width Modulation (PWM) for Impulse Radio Ultra-WideBand (IR-UWB) communication systems. This modulation scheme uses pulses with equal amplitude and different widths to carry different information. The receiver employs differences between similarity coefficients among these pulses to distinguish different information. Both theoretical analysis and simulation results verify that this novel scheme has a Signal to Noise Ratio (SNR) gain of about 1.75 dB compared with or- thogonal binary PPM, and has an SNR loss of about 1.4 dB compared with binary PAM. Although both the theoretical analysis and simulations are based on time-hopping multiple access, this modulation scheme can also be applied to other accessing techniques of UWB communication systems.
文摘车载通信是高速串行器与解串器(serializer and deserializer,SerDes)技术应用的一个重要领域。针对复杂车载环境中链路高频衰减导致的符号间干扰在高阶调制方式下更为严重的问题,引入深度学习方法,设计一种基于Transformer编码器结构的低复杂度信道均衡方案,以提高接收信号质量。该方案将输入序列转换为抽象的表示向量,然后利用编码器层提取表示向量的特征信息,最后全连接层根据特征信息对信号进行分类,从而实现高速SerDes信道均衡。实验结果表明:与传统自适应算法和全连接神经网络模型相比,所提方案能够有效降低高频衰减导致的信号失真,在计算复杂度降低19%和24%的情况下接收信噪比增益分别为1.8 dB和0.9 dB。通过在高速SerDes系统中应用所提信道均衡方案,可以提高信号传输质量以及增强系统的鲁棒性。
