Single Operation Research Articles

Electromagnetic compatibility study of trackside antenna array miniaturization in the subway tunnel

Abstract To improve the compatibility of the subway tunnel’s electromagnetic environment and reduce the radiation impact of trackside antennas on subway workers. This paper proposes a miniaturized dual-band trackside antenna array by using metamaterial units. Its operation bandwidth is 2.33 ∼ 2.56 GHz and 3.24 ∼ 3.45 GHz, which could simultaneously satisfy the signal cover demands of the communications-based train control (CBTC) and the civil 5G wireless communication system. The proposed miniaturized antenna array has a maximum gain of 14.4 dBi and a maximum channel capacity of 13.9 bps Hz−1 at a signal-to-noise ratio (SNR) of 20 dB, which can effectively improve the quality of wireless communication systems. The number of trackside antennas with a single operation frequency band is reduced, and the distance between the antennas is enlarged at the same time. Besides that, we analyze the radiation impact on the tunnel electromagnetic environment of the proposed trackside antenna array. In particular, the electromagnetic dose absorbed by the human model of a tunnel worker is quantized. The results show that the electric field strength in the tunnel reduces by 4.11% at least after antenna array miniaturization, and the specific absorption rate (SAR) absorbed by the worker model’s trunk, skull, brain, heart, and liver is reduced by a maximum of 19.02%, 33.16%, 28.27%, 41.75%, and 74.54%, respectively, further lowering the human electromagnetic exposure risk. Therefore, a miniaturized trackside antenna array could reduce the interference from other radiation sources in the tunnel while providing a new idea for electromagnetic protection for subway workers.

A facile and green procedure in preparing dibenzo-chromeno-phenazine-diones using an effectual and recyclable Brønsted acidic ionic liquid

First, a Brønsted acid ionic liquid (BAIL) in the role of a double acid-base called 1,3-n-propyl-bipyridinium bisulfonic acid-ditrifluoroacetate (PBPBSDT) was produced, and its skeleton was determined via TGA, mass, 13C NMR, 19F NMR, 1H NMR and FT-IR data. Further, it was successfully applied in the preparation of dibenzo-chromeno-phenazine-dione derivatives (1a-12a, 9–15 min, 90–98%) via one-pot multicomponent domino reaction among 2 mmol 2-hydroxynaphthalene-1,4-dione, 1 mmol benzene-1,2-diamine, and 1 mmol aldehydes under optimal conditions (5 mol% of PBPBSDT, solvent-free, 60 °C). The proper reproducibility of the PBPBSDT homogeneous catalyst (5 times), solvent-free medium, reasonable TON (Turnover Number) and TOF (Turnover Frequency) numbers, the non-metallic framework of the catalyst, and the formation of C-N, C = N, C-C, C = C, C-O bonds in a single operation are the distinct advantages of this protocol.

The Effectiveness of Triton Used With XP-3D Adaptive Files and Active Irrigation on Smear Layer Removal During Root Canal Preparation: A Qualitative Scanning Electron Microscopy (SEM) Study.

Standard irrigating protocols during root canal treatment call for the use of sodium hypochlorite during chemo-mechanical preparation, followed by final irrigation with ethylenediaminetetraacetic acid (EDTA). This study determined the effectiveness of a new irrigant, Triton (Brasseler, USA), on smear layer removal during root canal treatment compared to that of 5.25% sodium hypochlorite and CanalPro EDTA 17% (Coltene). Twenty-one extracted anterior teeth were prepared for root canal treatment. The teeth were divided into three groups: five teeth were used as control with saline as the irrigant, eight teeth with sodium hypochlorite and 17% EDTA as irrigants, and eight teeth with Triton as the irrigant. Root canal preparation was done using the XP-3D shaper and finisher files (Brasseler, USA) for all teeth with respective irrigants. A single operator performed all root canal treatment procedures. The teeth were prepared for scanning electron microscopy (SEM), and analysis was performed by a second investigator. The smear layer removal was qualitatively assessed to determine the effectiveness of irrigants. Smear layer removal was most effective for teeth irrigated with 5.25% sodium hypochlorite, followed by 17% EDTA (Group B). Teeth irrigated with Triton (Group A) showed a similar appearance to the hypochlorite/EDTA group but with isolated instances of inter-tubular debris. Sodium hypochlorite use followed by a final rinse with EDTA remains the gold standard for the removal of the smear layer created during canal instrumentation.

Point-to-multipoint beam-steering terahertz communications using a photonics-based leaky-wave transmit antenna

Abstract We report on the successful implementation of a photonic-based beam steering approach for point-to-multipoint terahertz (THz) communications. The frequency-agile radiation properties of a THz leaky-wave antenna connected to a photodiode are utilized in the remote transmitter for generating multiple individually steerable THz beams. The approach benefits from the ultra-wide frequency tunability of optical heterodyne systems for frequency-agile THz beam steering. Moreover, the approach allows to exploit high performance and mature optical modulation techniques for generating THz beams with a high data capacity. In the THz receiver, a carrier frequency insensitive envelope THz detector based upon a single Schottky-barrier diode is used. In detail, THz communications in the 300 GHz band (WR3.4) with a maximum steering angle up to 90° is reported. Experimentally, for single steerable THz beam operation, a record high data rate of 35 Gbit/s at a wireless distance of 30 cm is achieved using two-level pulse amplitude modulation. Also, longer wireless distances up to 110 cm with 5 Gbit/s are demonstrated. Furthermore, point-to-multipoint THz communications is reported using two individually steerable THz beams carrying 10 Gbit/s and 5 Gbit/s over 70 cm and 50 cm, respectively.

Cooperative game robust optimization control for wind-solar-shared energy storage integrated system based on dual-settlement mode and multiple uncertainties

Aiming at the problems of renewable energy output uncertainties and single scenario operation mode of energy storage systems, a cooperative game robust optimization control method for wind-solar-shared energy storage system based on dual-settlement mode of power market is proposed in this paper. A cooperative game-based energy management framework under dual settlement mode of electricity market is constructed, the profit relationship between shared energy storage under multiple application scenarios and renewable energy are extracted and the corresponding profit models are established. Considering the multiple uncertainties of renewable energy and electricity prices, combined with robust optimization theory, a multi-level two-stage robust optimization model is established to make optimal electricity trading decisions for renewable energy and shared energy storage. Additionally, the cooperative game robust optimization model is solved by i-C&CG algorithm. The effectiveness of proposed control method is verified through actual operating data of a certain power grid in China. The simulation results show that the cooperative game robust optimization model achieves the optimal operation of the wind-solar-shared energy storage system considering multiple uncertainties, which can improve the ability of the system to cope with the uncertainty risk and the reliability of the system.

Five-Component [2 + 2 + 1 + 1] Tandem Benzannulation Leading to Multifunctionalized Aromatic Amines.

An unprecedented five-component [2 + 2 + 1 + 1] benzannulation strategy for regioselective assembly of densely functionalized aromatic amines from two ynals, two malononitriles, and sodium sulfinates is established. The benzannulation protocol enables the efficient installation of five substituents on a benzene ring via the formation of multiple chemical bonds in a single operation, providing various multifunctionalized aromatic primary amines in moderate to good yields. Additionally, three-component [3 + 2 + 1] cycloaddition of malononitriles, ynals, and NH4SCN was also achieved to produce 2-amnopyridine derivatives with NH4SCN serving as an ammonia surrogate.

Design and Testing of an Offset Straw-Returning Machine for Green Manures in Orchards

In order to solve the problems of traditional orchard-specific green manure crushing and returning machines, such as the single operation effect, root system damage, unsustainable green manure growth, and low utilization rate, an offset crushing–furrowing–burying–straw-returning machine was designed for green manures in orchards. Based on quadratic regression combination experiments, the Discrete Element Method (EDEM) was used to construct a discrete element model simulating the deep furrowing and burying processes of the furrowing and soil-covering device, where the advance speed, plow-shaped furrowing blade rotation speed, and furrowing depth were considered as experimental factors and the coverage rate was taken as an evaluation index, and then simulation analyses were carried out to obtain experimental data; Design-Expert was used to perform ANOVA and RSM analyses, thus finding that its optimal working parameter portfolio consists of the advance speed of 42 m/min, the furrowing blade rotation speed of 300 r/min, and the furrowing depth of 190 mm, and that the coverage rate is 95.82% when this parameter portfolio is applied. Field experiments were conducted to validate the optimal parameter portfolio. The experimental results show that with an average coverage rate of 90.87% (4.95% away from the optimal value based on the simulation experiments on average), an average crushing length qualification rate of 91.24%, and an average root system damage rate of 5.6%, this device is applicable for its operation conditions. The development of this machine and the construction of its parameter model can provide a certain reference value for developing and optimizing related machines including green manure-returning machines.

Endoscopic Posterior Cervical Craniolateral Inclinatory Foraminotomy

Study Design: Case series. Objective: Endoscopic posterior cervical foraminotomy gains attention for cervical radiculopathy due to its feasibility, better outcomes, and lower complications than traditional approaches, enabling efficient multilevel decompression in a single operation while avoiding anterior cervical diskectomy and fusion–related issues. However, with multilevel decompression, the remnant lamina becomes thin and fragile. We propose craniolateral inclinatory foraminotomy to minimize bone removal during laminotomy, reducing the risk of iatrogenic or postoperative lamina fractures in tandem decompression. Materials and Methods: From 2021 to 2022, 8 consecutive patients underwent the procedure and were followed up for at least 6 months. The VAS, NDI, and MacNab scores were recorded for clinical recovery and patient satisfaction evaluations. Preoperative and postoperative CT scans were utilized to measure the lamina preservation percentage at each level. Results: The clinical outcomes improved significantly in every patient. No postoperative neck pain, segmental instability, or lamina fracture were observed. The mean lamina preservation percentages of C5, C6, C7, and all vertebrae were 68.8%, 73.22%, 71.86%, and 72.18%, respectively. Conclusions: Ongoing technical adjustments will accompany endoscopic technique development to decrease complications and enhance benefits. Our reported technique avoids extensive laminotomy in multilevel tandem decompression, aiming to prevent lamina fractures and anticipate a reduction in postoperative neck pain. Level of Evidence: Level IV.

A mcgyvering way to left bundle branch area pacing : using the treadmill test machine ECG system and modified V1 / V6 leads connected to the pacing system analyser for left bundle branch area pacing

Abstract Background Left bundle branch area pacing (LBBaP) is a novel pacing modality which provides physiological synchronisation of both the ventricles. However, its use and adoption requires the presence of a standardised electrophysiological (EP) system with 12 lead ECG to show left bundle branch area capture. Purpose The aim of the study was to assess the feasibility and outcomes of using the conventional treadmill test (TMT) machine 12 lead ECG system and modified V1 and V6 leads connected to the pacing system analyser (PSA) to demonstrate conduction system capture during left bundle branch area pacing (LBBaP). Methods LBBaP was attempted by a single operator in a mixed cohort of patients at peripheral hospitals lacking the standardised EP system. The presence of LBB area capture was tested with the aid of the 12 lead ECG system connected to the standard TMT machine (1). Conduction system capture was also assessed using modified V1 and V6 leads connected to the PSA for measurement of V6 left ventricular activation time (LVAT)(2) . The baseline clinical, procedural, pacing, electrocardiographic parameters, echocardiographic response (> 10% improvement in ejection fraction {EF}) and clinical response to LBBaP were assessed. Results LBBaP was attempted in 19 patients and was successful in 18 patients (94.7%). Patient characteristics include age 66.7 +/- 11.47 years, female 47.37%, male 52.63%, ischaemic cardiomyopathy 10.52% and non-ischaemic cardiomyopathy 5.26% .The mean baseline EF and QRS duration was 45%+/-14% and 130.18 +/-10.45 milliseconds(ms) respectively. LBBaP threshold was 0.59 +/-0.168 volts and R wave amplitude was 12+/-3.5 millimetres , which remained stable during the mean follow up of 15.9 +/-13.67 months. The mean fluoroscopic duration was 11.57 +/-2.58 minutes and procedural time was 108.78+/-29.20 minutes. LBBaP resulted in impressive narrowing of the QRS duration to 102.39 +/-10.55 ms (p<0.001) with LVAT of 68.94 +/-9.94 ms. LVEF improved in the patients with cardiomyopathy from 33.4 +/- 5.77 % to 48.2+/-12.37 % (p=0.028) .Clinical and echocardiographic response was noted in 87.5% of patients with cardiomyopathy. Conclusion The 12 lead ECG system with the standardised TMT machine in conjunction with the modified V1 and V6 leads connected to the PSA is a feasible alternative to the EP system to perform successful left bundle branch area pacing.ECG leads connected during LBBapClinical profile of patients

Echocaridographic assessment of pulmonary hypertension: improving the probability

Abstract Introduction Pulmonary hypertension (PH) is a cardio-pulmonary disorder characterised by raised pulmonary artery pressure (mPAP >20mmHg) leading to right ventricular failure, and death if left untreated. Transthoracic echocardiography (TTE) assessment of PH uses a probability-based approach, combining peak tricuspid regurgitant velocity with other supporting signs. We evaluated the latest ESC TTE PH guidelines in a real-world UK dataset and identified markers that may improve the sensitivity of the existing algorithm. Method Retrospective analysis of 447 patients referred for initial PH assessment. This was a select population of patients who underwent both TTE and right heart catheter (RHC) (mean time to RHC = 40±30 days). In addition to current TTE PH probability markers we analysed right ventricular free wall strain (RVFWS). Measurements were made by a single operator using Tomtec Arena 2020. Crosstabulation, ROC curve analysis and T-tests were used to compare variables between PH and no PH. Results Mean sample age was 64±15 yrs (61% female). 6.9% (n=4) of the no PH group had pulmonary mid-systolic notching, which may be due to pseudo-notching attributable to incomplete Doppler envelope. Sensitivity and specificity of current ESC TTE probability guidelines were 83%, and 65% respectively (95% C.I.). However, within the low probability group (i.e. those felt to be less likely to have PH) 62% (n=63) had confirmed PH at RHC (mPAP = 28±9). The addition of RVFWS as an additional marker to the existing supporting signs of PH (Table 1) resulted in an improvement of the sensitivity of the algorithm to 92% with a mild reduction in specificity (63%). The number of false negatives were reduced by 51%. Of these, the majority were in the low TTE probability group (n = 32). Conclusions Using current PH TTE probability algorithms classifies a significant proportion of those with PH as having a low TTE PH probability. The addition of RVFWS improves the sensitivity of the existing algorithm to 92% and reduces false negatives by 51%.

Clinical and diagnostic value of the novel algorithm for categorisation of neonatal interatrial communication; findings at follow-up in preschool children

Abstract Background and aim Differentiation between a patent foramen ovale (PFO) and an atrial septal defect (ASD) of the secundum type is challenging, particularly in newborns. A PFO is considered normal, often undergoes spontaneous closure and is rarely associated with complications. An ASDs on the other hand tend to remain patent and may lead to right sided volumen overload, atrial fibrillation, and stroke, often necessitating surgical repair. To determine the need for follow-up in newborns with interatrial communications (IACs), a clear diagnostic differentiation between ASD and PFO is essential. We recently developed an algorithm to facilitate differentation between ASD and PFO in newborns. In this study, we reassessed preschool children diagnosed according to this algorithm with an ASD or a PFO neonatally, to investigate potential differences in patentcy between the two IAC subtypes. Methods Children participating in a large, multicenter, prospective population study were enrolled for a follow-up echocardiogram if they had a PFO or an ASD detected at the neonatal echocardiogram. The recently developed algorithm classifies IACs into three subtypes of PFO and three subtypes of ASD. According to the algorithm an ASD was defined as a defect with a diameter ≥4 mm, a location in the inferior part of the septum, or if multiple communications were present. Children with neonatal IACs were included until reaching n=200 in each of the six groups of IAC subtypes, or all children in a group (n<200) were invited. A single operator, blinded to the neonatal IAC subtype, assessed the follow-up echocardiograms for patency of an IAC. Patent IACs were reclassified as ASD or PFO using the same algorithm. Results We included 904 children with IAC (median age 5.2 years [interquartile range 4.5-5.5], 54% female). Neonatally, ASDs were present in 292 newborns and PFOs in 612 newborns. The follow-up echocardiograms showed patency of the IAC in 62 of the children with a neonatal ASD (18.5%) and in 54 of the children with a neonatal PFO (10.1%), (OR 2.0 [95% CI 1.3;3.0], p-value<0.001). Overall, patency was sligtly more frequent in girls (15.1%) compared to boys (10.1%), (OR 1.6 [95% CI 1.0;2.4], p-value<0.05). The risk of having a patent IAC, that classified as an ASD at follow-up, was 7.5% in the group of children with a neonatal ASD, compared to 1.1% in the group with a neonatal PFO, (OR 7.0 [95% CI 2.9;19.7], p-value<0.0001), figure. Conclusions Newborns diagnosed according to the new IAC algorithm with an ASD were twice as likely to have a patent IAC at follow-up at five years of age compared to children diagnosed with a neonatal PFO. At follow-up, the risk of having a patent IAC, that was classified as an ASD, was very low for children with a neonatal PFO. These findings support the diagnostic and clinical value of the new IAC diagnostic algorithm to differentiate between neonates with IACs that may need follow-up.

Beat-to-beat measurement of R-wave peak time for left bundle branch area pacing: man versus machine using a novel automated algorithm

Abstract Background Assessment of stimulation spike to R-wave peak time (RWPT) in V6 and in aVL, and V6-V1 interpreak interval, may be used to evaluate presence of conduction system capture during left bundle branch area pacing (LBBAP). This is performed by manual measurements which is tedious and requires a skilled operator to limit variability in the measurements. Automatic beat-to-beat measurement of these intervals may streamline workflow during implantation, but such an algorithm has never been tested so far. Purpose To test the feasibility of performing beat-to-beat automatic measurement of RWPT using an algorithm designed to measure the interval between the stimulation spike and the peak positive voltage, and to compare the results with manual measurements. Methods ECG recordings from 50 patients (28% female, mean age 81.5 ± 9.0 years) undergoing LBBAP implantation were evaluated on a electrophysiology recording system by manually measuring RWPT in V6 and in aVL and the V6-V1 interpeak intervals . A single operator performed offline measurements on 10 consecutive beats in each patient. The same beats were subjected to the same measurements using an automatic algorithm after signal conditioning in a novel EP recording System. The correlation between manual and automatic measurements was calculated. Variability of the measurements (evaluated by standard deviation) in the 10 consecutive beats was also compared. Results Of the 500 beats measured, 3 were excluded due to obvious morphological differences affecting the interval measurement (e.g. due to fusion beats). The algorithm was unable to make a measurement in V6 in 20 beats and manual assessment of aVL was not possible in one patient, meaning that 1461/1500 (97.4%) measurements were compared between the manual and automatic methods. The results are shown in the figure. There was excellent correlation between manual and automatic measurements, with lower variability using the latter method. Conclusion Beat-to-beat automatic measurement of RWPT is feasible and provides excellent correlation with manual measurements, with less variability in the values. This algorithm may streamline the measurements during implantation. However, prospective evaluation is required to confirm operation of the algorithm in the clinical setting to include challenges such as electrical noise.

Preferences for genetic interventions for SCA and Huntington’s disease: results of a discrete choice experiment among patients

BackgroundAlthough genetic interventions are on the horizon for some polyglutamine expansion diseases, such as subtypes of spinocerebellar ataxia (SCA) and Huntington’s disease (HD), the patients’ preferences regarding these new therapies are unclear. This study aims to get insight into what extent different characteristics of genetic interventions affect the preferences of patients with SCA and HD with regard to these interventions.MethodsManifest and premanifest patients with SCA or HD were recruited online by platforms of patient associations. The respondents conducted a questionnaire that included a discrete choice experiment (DCE). The experimental design included 24 choice sets, but these were divided into three blocks of eight to reduce the number of tasks per respondent. Each choice set included two alternative treatments and consisted of four attributes (mode and frequency of administration, chance of a beneficial effect, risks, and follow-up), each with three or four different levels. The forced choice-elicitation format was used. Data were analyzed by using a multinominal logistic regression model.ResultsResponses of 216 participants were collected. The mode and frequency of administration of a genetic intervention, as well as the chance of a beneficial effect both influence the choice for a genetic intervention. Respondents less prefer repeated lumbar punctures compared to a single operation. As expected, a higher beneficial effect of treatment was preferred. Risks and follow-up did not influence the choice for a genetic intervention.ConclusionsThe results can be used for the design and implementation of future genetic interventional trials as well as of patient-centered care pathways for rare movement disorders such as SCA and HD.

Iterative Function Allocation of Single Pilot Operations Based on Biclustering Method

The successful transition from a two-pilot to a single-pilot mode cannot solely rely on simply augmenting advanced automation in the cockpit. The degree of support provided by functions at different levels of automation varies, and introducing new functions simultaneously brings new demands for the single pilot, leading to imbalanced workload. To address these shortcomings and enhance the rationality of function allocation under workload constraints, this paper introduces an iterative function allocation method. Initially, the functions are categorized and classified into different levels of automation to obtain the initial function allocation scheme. Subsequently, a novel bicluster mining algorithm called K-Miner is proposed to identify elements requiring iterative design. As a case study, the multitask surface scenario in SPO is considered. By applying the proposed iterative design method, the task performance of the single pilot is improved, the workload of the single pilot is effectively reduced, and situational awareness is improved to a certain extent.

Multi Combustor Turbine Engine Acceleration Process Control Law Design

Abstract Focusing on the collaborative fuel supply and acceleration problem of multi combustor turbine engine, a variable geometry composite regulation acceleration control law design method based on the combination of compressor intermediate stage air bleed(CIB) and low-pressure turbine guide vanes(LTGV) is proposed. The multi combustor collaborative fuel supply law and variable geometry regulation law during acceleration process are obtained by Particle Swarm Optimization-Sequence Quadratic Program (PSO-SQP) optimization, and the composite regulation acceleration control strategy of dual/single combustion chamber idle acceleration process is explored. The multi combustor acceleration process simulation results indicate that the variable geometry composite regulation method can effectively alleviate the stability margin limitation of the compressor during the initial acceleration stage. Compared with conventional acceleration methods, the maximum relative reduction in acceleration time of our method reaches 26%; Enhancing the combustion exergy efficiency during the acceleration process can significantly improve the engine's acceleration performance.; For the acceleration process from single combustion chamber idle operation to normal operation of a dual combustion chamber, simultaneous fuel supply from both combustion chambers during acceleration has a shorter acceleration time. The research results of this paper can provide important references for the design of transition state control systems for multi combustor turbine engines.

Winding process of fibre-reinforced thermoplastic tubes with integrated tape production through in-situ roving impregnation and infrared consolidation

This paper introduces a novel method for producing fibre-reinforced thermoplastic tubes by integrating tape production and consolidation into a single operation. This innovation diverges from conventional methods by combining processes to reduce costs by using raw materials instead of organotapes, allowing customised material combinations and utilising residual heat from tape production. The new process uses carbon roving and molten low-viscosity PA6 granulates, processed through a new direct impregnation setup in siphon design. Key advancements include a high-speed impregnation module capable of up to 1 m/s with high-performance extruders, cost-effective infrared emitters for winding, and a powered consolidation unit with adjustable winding angles between ± 65° and ± 90°. Experiments demonstrate operational speeds of approximately 471 mm/min, with an optimal cross-winding speed of 354 mm/min due to the technical limitations of the laboratory extruder and IR emitter used. Based on the technical limitations of the current system, future improvements and methodological changes will be discussed.

MEMPERLUAS KEMAMPUAN ALAT PENCABUT SINGKONG: PENGEMBANGAN LEBIH LANJUT UNTUK KEBUTUHAN PETANI

This research builds upon the author's earlier work on the design of a cassava pulling tool. The aim is to develop a non-mechanical or minimally-powered tool that addresses farmer needs. The tool design incorporates Quality Function Deployment (QFD) to ensure user satisfaction. QFD is a method that integrates customer desires into technical requirements during the design phase, prior to production. Data analysis revealed key user desires: lightweight materials, affordability, the ability to pull multiple cassava stems simultaneously, durability, safety, and additional functionalities. House of Quality (HOQ) analysis identified the most crucial attribute (weight of importance: 30%) as the ability to pull multiple stems at once. This finding served as the primary basis for prototype development and technical characteristic definition. Subsequent prototype testing successfully uprooted cassava plants, demonstrating the tool's capability of pulling multiple stems in a single operation.

GDMol: Generative Double-Masking Self-Supervised Learning for Molecular Property Prediction.

Effective molecular feature representation is crucial for drug property prediction. Recent years have seen increased attention on graph neural networks (GNNs) that are pre-trained using self-supervised learning techniques, aiming to overcome the scarcity of labeled data in molecular property prediction. Traditional GNNs in self-supervised molecular property prediction typically perform a single masking operation on the nodes and edges of the input molecular graph, masking only local information and insufficient for thorough self-supervised training. Hence, we propose a model for molecular property prediction based on generative double-masking self-supervised learning, termed as GDMol. This integrates generative learning into the self-supervised learning framework for latent representation, and applies a second round of masking to these latent representations, enabling the model to better capture global information and semantic knowledge of the molecules for a richer, more informative representation, thereby achieving more accurate and robust molecular property prediction. Our experiments on 5 datasets demonstrated superior performance of GDMol in predicting molecular properties across different domains. Moreover, we used the masking operation to traverse through the gradient changes of each node, the magnitude and sign of which reflect the positive and negative contribution respectively of the local structure in the molecule to the prediction outcome. This in-depth interpretative analysis not only enhances the model's interpretability, but also provides more targeted insights and direction for optimizing drug molecules. In summary, this research offers novel insights on improving molecular property prediction tasks, and paves the way for further research on the application of generative learning and self-supervised learning in the field of chemistry.

Micro-extrusion foaming fabricating porous polyester elastomeric fiber for using in radiative cooling fabrics

Climate change has unleashed relentless global heatwaves, posing grave threats to the physical and mental well-being of outdoor laborers and the smooth functioning of society. Porous polymeric fibers exhibit promising potential in personal thermal management for wearable fabrics. Nevertheless, the absence of an environmentally friendly, cost-effective, and efficient method for producing the desired porous fibers remains a formidable challenge. Here, we introduce a pioneering micro-extrusion foaming technique for crafting elastic porous fibers endowed with dense longitudinally oriented cell morphologies, remarkable porosity of 69 % and elongation of 668 %. The technique enabled the continuous production of porous fibers exceeding 3000 m in length in a single operation, with fiber diameters controlled to approximately 0.25–0.55 mm. Fabrics woven from the elastic porous fiber offered a soft touch, proficiently reflecting more than 90.0 % of incident solar radiation and emitting 91.9 % of absorbed heat radiation, thereby achieving a theoretical radiant cooling power of 111.46 W/m2 on sunlit days. Leveraging the controllable and scalable attributes of micro-extrusion foaming, the porous fiber is primed for practical deployment and expansion into diverse wearable applications.

Design of Nanosecond Pulse Laser Diode Array Driver Circuit for LiDAR

The pulse laser emission circuit plays a crucial role as the emission unit of time-of-flight (TOF) LiDAR. This paper proposes a nanosecond-level pulse laser diode array drive circuit for LiDAR, primarily aimed at addressing the issue of high-speed scanning drive for the laser diode array at the emission end of solid-state LiDAR. Based on the single pulse laser diode drive circuit, this paper innovatively designs a circuit that includes modules such as a boost circuit, linear power supply, high-speed gate driver, GaN field-effect transistor, and pulse narrowing circuit, realizing an 8-channel laser diode array drive circuit. This circuit can achieve a pulse laser array drive with a single channel operating frequency of greater than 100 kHz, an output pulse width of less than 5 ns, a peak power greater than 75 W, and a channel switching time that does not exceed 1 μs. A field programmable gate array (FPGA) is used to control the operation of this circuit and perform a series of performance tests. Experimental results show that this circuit has a high repetition rate, large output power, a narrow pulse width, and fast switching speeds, making it highly suitable for use in the optical emission module of solid-state LiDAR.