One-shot pre-equalization scheme based on frequency pilot tones for bandwidth-limited IM/DD DCI transmission.

O-band intensity modulation and direct detection (IM/DD) transmission offers a promising solution for high-speed data center interconnects (DCIs). Additionally, the introduction of bismuth-doped fiber amplifiers (BDFAs) results in less nonlinear impact and a higher link budget compared with semiconductor optical amplifiers (SOAs). However, with these key issues resolved, the system bandwidth limitation emerges as the next critical bottleneck for high-speed O-band DCI transmission that limits overall performance.

Digital mobile fronthaul scheme based on diff-delta-sigma modulation and OCT precoding.

In this Letter, we experimentally demonstrate digital mobile fronthaul (MFH) for 65536 quadrature amplitude modulation (65536-QAM) signals based on a diff-delta-sigma modulation (D-DSM) scheme with orthogonal circulant matrix transform (OCT) precoding. By combining the D-DSM scheme with OCT precoding, we successfully solved the problem of uneven distribution of in-band quantization noise (IBN) while bringing about a quantization SNR gain of about 1.5 dB.

Computational design of carboxylase for the synthesis of 4-hydroxyisophthalic acid from p-hydroxybenzoic acid by fixing CO.

Carbon dioxide (CO) emissions constitute the primary contribution to global climate change. Synthetic CO fixation represents an exceptionally appealing and sustainable method for carbon neutralization. Unlike the limitations of chemical catalysis, biological CO fixation displays high selectivity and the ability to operate under mild conditions.

High-order QAM NANF transmission utilizing MIMO equalizer integrated with low-complexity decision-directed carrier phase estimation.

We experimentally realized a high-speed nested anti-resonant nodeless fiber (NANF) transmission with the assistance of the polarization division multiplexing (PDM) and probabilistic shaping (PS) technology. In this system, a low-complexity multiple-input multiple-output (MIMO) real-valued equalizer (RVE) is integrated with decision-directed carrier phase estimation (DDCPE), which is robust against the IQ cross talk and a tiny phase disturbance between PS symbols. By using the proposed MIMO-RVEDDCPE, the 60-Gbaud PDM-PS-256QAM signal has been delivered through 2-km NANF satisfying the soft-decision forward error correction (SD-FEC) threshold.

Development of a Strategy for the Total Synthesis of Alkaloids via the Cyclobutenone-Based PET-Initiated Cationic Radical-Driven [2+2]/Retro-Mannich Reaction.

A novel strategy for the synthesis of alkaloids has been achieved via a photoredox-initiated [2+2]/retro-Mannich reaction of tryptamine-substituted enaminones as a key step. The developed chemistry has been applied to the construction of the core tetracycle of alkaloids (±)-aspidospermidine and (±)-limaspermidine.

SNR-enhanced signal delivery scheme with delta-sigma modulation in a four-mode fiber system.

This Letter proposes a scheme for optimizing the signal-to-noise ratio (SNR) of signal to improve the system performance by a 1 bit delta-sigma modulation (DSM) in a four-mode MDM system for mobile fronthaul. A 1 bit digitalized signal with an SNR of 60 dB from transmitter digital signal processing (Tx DSP) can be achieved. Based on this system, an experimental demonstration of the ultrahigh-order 1048576-QAM signal transmission over a 50 km strong-coupling few-mode fiber (FMF) is successfully realized.

A Highly Sensitive Model Based on Graph Neural Networks for Enzyme Key Catalytic Residue Prediction.

Determining the catalytic site of enzymes is a great help for understanding the relationship between protein sequence, structure, and function, which provides the basis and targets for designing, modifying, and enhancing enzyme activity. The unique local spatial configuration bound to the substrate at the active center of the enzyme determines the catalytic ability of enzymes and plays an important role in the catalytic site prediction. As a suitable tool, the graph neural network can better understand and identify the residue sites with unique local spatial configurations due to its remarkable ability to characterize the three-dimensional structural features of proteins.

Probabilistic shaping-based delta sigma modulation.

This Letter proposes a probabilistic shaping delta-sigma modulation technique. By performing delta-sigma modulation on the probability shaping signal at the transmitting end, under the same transmit power and the same net bit rate, the delta-sigma modulation signal based on probability shaping can obtain better anti-noise capability than the delta-sigma modulation signal only. Under the same information entropy conditions, the bit error rate performance of the PS-based 131072QAM signal modulated by delta-sigma modulation is better than that of the ordinary 65536QAM signal using the delta-sigma modulation scheme, and lower than that of soft decision-forward error correction (4 × 10).

Temperature errors in two-color pyrometry simultaneously considering reflection and combustion gas radiation.

Temperature measurements are ubiquitous in combustion systems. However, the accuracy of surface temperature measurements of critical components operating in a harsh combustion gases environment is greatly affected by reflection and combustion gas radiation. In this paper, an analytical two-color pyrometry model was used to quantitatively analyze the temperature errors caused by the combination of reflection and HO-CO-CO-N mixture radiation.

Effect of graphene on the mechanical and anisotropic thermal properties of Cu-Ta composites.

Strong interfacial bonding is the basic requirement for metal-graphene composites for higher thermo-mechanical properties. In the present work, a novel metal tantalum is introduced in the metal-graphene composites prepared by (ball-milling + molecular level mixing) followed by hot press sintering. SEM, transmission electron microscopy and high transmission electron microscopy are observed to check the interface area which shows the presence of tantalum carbide on the interface area which is formed during the sintering process.

Stereoselective Synthesis of Cyclohepta[b]indoles by Visible-Light-Induced [2+2]-Cycloaddition/retro-Mannich-type Reactions.

A novel method for the concise synthesis of cyclohepta[b]indoles in high yields was developed. The method involves a visible-light-induced, photocatalyzed [2+2]-cycloaddition/ retro-Mannich-type reaction of enaminones. Experimental and computational studies suggested that the reaction is a photoredox process initiated by single-electron oxidation of an enaminone moiety, which undergoes subsequent cyclobutane formation and rapidly fragmentation in a radical-cation state to form cyclohepta[b]indoles.

A novel doublet extreme learning machines for Delta 3D printer fault diagnosis using attitude sensor.

Extreme learning machine (ELM) has better operation efficiency in fault diagnosis. However, the recognition accuracy of ELM algorithm is actually affected by the activation function. Moreover, most of the testing dataset are coming from high precision and expensive sensors.

Generative Transfer Learning for Intelligent Fault Diagnosis of the Wind Turbine Gearbox.

Intelligent fault diagnosis algorithms based on machine learning and deep learning techniques have been widely used in industrial applications and have obtained much attention as well as achievements. In real industrial applications, working loads of machines are always changing. Hence, directly applying the traditional algorithms will cause significant degradation of performance with changing conditions.

Intelligent Fault Diagnosis of Delta 3D Printers Using Attitude Sensors Based on Support Vector Machines.

Health condition is a vital factor affecting printing quality for a 3D printer. In this work, an attitude monitoring approach is proposed to diagnose the fault of the delta 3D printer using support vector machines (SVM). An attitude sensor was mounted on the moving platform of the printer to monitor its 3-axial attitude angle, angular velocity, vibratory acceleration and magnetic field intensity.