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Direct optical probing of the antiferromagnetic order parameter in atomically thin samples is challenging, for example, via magneto-optical spectroscopy, due to the lack of net magnetization. Here, we report zigzag-antiferromagnetism (AFM) induced optical linear dichroism (LD) in layered transition-metal thiophosphate FePS3 down to the monolayer limit. The observed LD is giant despite having the optical wave vector parallel to the Neel vector. The LD is at least one order of magnitude larger than those reported in other antiferromagnetic systems, where the optical wave vector is orthogonal to the Neel vector. The large LD enables the probe of 60° orientated zigzag-AFM domains. The optical anisotropy in FePS3 originates from an electronic anisotropy associated with the zigzag direction of the AFM order and is independent of the spin-pointing direction. Our findings point to a new optical approach for the investigation and control of zigzag or stripe magnetic order in strongly correlated systems.

In many engineering practices with uncertainty, the non-probabilistic methods play an increasing important role. To overcome the limitation of traditional single-uncertainty modeling methods in handling coupled uncertain problems, this paper develops a more general hybrid uncertainty analysis framework. The non-probabilistic hybrid uncertainties are expressed as coupled fuzzy-interval variables, where the bounds of interval are interpreted as fuzzy sets instead of deterministic values. By means of the cut-set strategy and decomposition theorem in fuzzy set theory, the hybrid uncertain problem is transformed into a series of dual-interval problems. The conservative and radical extreme-value predictions in different variable subspaces are adopted to characterize the coupled uncertainty in output response. To further improve the computational efficiency of extreme-value prediction, an adaptive response surface model using radial basis function is proposed, where the potential global optimum points are introduced as the new sample points in the sequential sampling process. Finally, the effectiveness of the proposed method on dealing with non-probabilistic hybrid uncertainties is validated by two examples.

For the interaction between marine robots and divers in the underwater environment, a method of diver’s gesture recognition and segmentation is proposed. This method first uses the progressive growing training method to optimize the generative adversarial networks, generating high-resolution images with complex content. Then, we use the generative adversarial network model as a data augmentation method and generate high-resolution images. We make the masks of gestures in the new dataset and use the mask R-CNN algorithm for gesture recognition and gesture segmentation. The experimental results show that the generating data improves the accuracy of several object recognition algorithms but cannot completely replace the original data and the mean average precision of gesture recognition is 0.85. The visualization shows the validity and weakness of segmentation.

Heterobilayers of transition metal dichalcogenides (TMDCs) can form a moiré superlattice with flat minibands, which enables strong electron interaction and leads to various fascinating correlated states. These heterobilayers also host interlayer excitons in a type-II band alignment, in which optically excited electrons and holes reside on different layers but remain bound by the Coulomb interaction. Here we explore the unique setting of interlayer excitons interacting with strongly correlated electrons, and we show that the photoluminescence (PL) of interlayer excitons sensitively signals the onset of various correlated insulating states as the band filling is varied. When the system is in one of such states, the PL of interlayer excitons is relatively amplified at increased optical excitation power due to reduced mobility, and the valley polarization of interlayer excitons is enhanced. The moiré superlattice of the TMDC heterobilayer presents an exciting platform to engineer interlayer excitons through the periodic correlated electron states., Heterobilayers of transition metal dichalcogenides host moiré superlattices that give rise to strong electron interactions. Here, the authors study the photoluminescence from interlayer excitons in a WS2/WSe2 heterobilayer to reveal the onset of various correlated insulating states.

In this paper, quaternary oxide semiconductor was applied as sensing material for the fabrication of gas sensors. One-step solvothermal method was utilized to synthesize the sensing material. Various characterization methods including XRD, XPS, SEM, HRTEM were employed to analyze the composition and structure of the sensing material. Composite composed of CuInW2O8 and CuWO4 was successfully prepared at last characterized by XRD result. The SEM result revealed the structure of the sensing material: nanoparticles assembled spindle-like nanostructure with ~200 nm long axis and ~60 nm short axis. Sensor based on the spindle-like nanostructures was systemically tested to acquire the information about the sensing properties. The sensor exhibited responses to acetone at the operating temperatures from 190 to 275 °C. The results showed that the sensor was more sensitive to acetone compared with other gases at the optimal operating temperature of 210 °C. The response of the sensor was also tested under the relative humidity from 25 RH% to 95 RH% at the operating temperature of 210 °C. The response variation was only 13.9%, demonstrating that the sensor possessed strong anti-humidity ability. It was worth noting that the sensor showed acceptable long-term stability compared with other acetone sensors. The gas sensing mechanism was also discussed here. This work might provide ideas for the development of novel sensitive materials for the application of gas sensors.

Conductive polymer direct electroplating technology is one of the research hotspots in printed circuit board manufacturing. In this work, we designed a simple, efficient and environmental friendly chemical polymerization method to form a conductive polymer-based metal-mixed composite film where the polymer was polythiophene and the metals included copper and silver (PT-based Cu/Ag composite film). The work function of the PT-based Cu/Ag composite film decreased from 4.822 eV of pure PT to 4.638 eV, which serves as a seed layer to prepare conductive circuits by the additive process. The method without the metal etching and photolithography steps solves the problems of conventional subtractive processes for forming conductive patterns. Besides, the PT-based Cu/Ag composite film is able to increase the roughness of the substrate to improve the bonding force between the electroplated copper layer and the substrate. Moreover, due to the particularity of oxidation solution for preparing the PT-based Cu/Ag composite film, conductive lines and patterns can be selectively formed on insulating substrate with arbitrary shapes by the additive process.

Constant current controlled flyback converter is widely used in low power applications for its simple structure and low cost. In order to further improve the output power and the efficiency, active-clamp flyback converter with soft-switching technique is always used. To avoid the nonlinearity and temperature drift of opto-coupler in the feedback circuit, a constant current digital control method is proposed for a primary-side regulation active-clamp (PSRAC) flyback converter in this article. Soft-switching technique is realized in discontinuous conduction modulation mode with a modified active-clamp technique. To compensate the nonlinearity of the secondary diode current with primary-side regulation, a new output current estimation algorithm is put forward based on the charge balance principle. The output current is predicted from primary current and the auxiliary winding voltage, and constant output current control is realized with primary peak current control method. The cost is low as only one low speed digital-to-analog converter, three comparators and a digital controller are required. The proposed control scheme was verified by a field-programmable gate array controlled 5.4–10.8 V/1.80 A PSRAC flyback converter. The output current accuracy is within in 1.2% in different input and output condition and the peak efficiency is improved by 3.6% after active-clamp technique is used.

This paper presents the design for a new differential-dual-drive low-speed micro-feed mechanism. The ‘nut rotary ball screw pair’ is the main driving component of the mechanism. The screw and nut are each driven by a servo motor and these motors rotate in the same direction at a similar speed. The nonlinear factors such as friction and backlash can lead to unstable behaviours such as stick-slip and oscillation of the feed system. We use the Euler–Bernoulli beam elements, which have axial and torsional degrees of freedom, to describe the axial and torsional vibration of the ball screw, and use the spring-lumped parameter method to analyse other components of the feed system. An electromechanical coupling dynamic model with nonlinear factors of friction and clearance is established. Through simulation analysis and experiment, the difference in response of single-drive and differential-dual-drive systems under the influence of friction and clearance is studied. The results show that the nonlinear factors of friction and clearance have an influence on the feed speed of single-drive and differential-dual-drive system, but the low-speed micro-feed performance of the differential-dual-drive system is evidently better than that of the single-drive system. In the experiment, under the condition of screw single drive and differential dual drive, the critical crawling velocities of the table are measured. The experimental results are consistent with the simulation results, which verifies that the established models are reasonable. This lays a foundation for the design and research of the controller.

Under high concentrations, strong pressure, and low temperature, fluorophores usually exhibit the fluorescence quenching phenomenon. Of significance, the development of aggregation-induced emission (AIE) and pressure-induced emission (PIE) fluorophores has perfectly prevented fluorescence quenching under high concentrations and strong pressure. However, cooling-induced fluorescence quenching in water is still an urgent problem. In this paper, cooling-induced emission (CIE) enhancement based on a biperylene monoimide (BPMI) derivative, BPMI-18Lac, with a conjugated lactose-based glycodendrimer was developed. BPMI-18Lac, as a non-AIE molecule, exhibited the CIE phenomenon with a fluorescent intensity increasing 7-fold when the temperature decreased from 80 to −40 °C. The mechanism was due to the inhibition of the intramolecular electron interactions between the perylene monoimide moieties linked by the C–C single bond. In addition, BPMI-18Lac, as a multivalent glycodendrimer, showed selective fluorescence i...

Fault diagnosis of analog circuit is critical to improve safety and reliability in electrical systems and reduce losses. Traditional fault diagnosis methods of analog circuit usually rely on the hand design feature extractor and can not generalize well to other diagnosis domains. To address these issues, an end-to-end denoising autoencoder (EEDAE)-based fault diagnosis approach is proposed. The proposed approach includes denoising autoencoder (DAE) and a softmax classifier. The DAE is designed to automatically extract fault features from the raw time series signals without any signal processing techniques and diagnostic expertise, and then the softmax classifier is used to classify the fault mode of analog circuits. Specifically, we design a novel loss function by jointly minimizing reconstruction loss and classification loss to improve training efficiency. The proposed approach just has one training stage, in which the encoder, decoder, and classifier are trained simultaneously. The experimental results demonstrate that compared with traditional methods, the proposed method has higher accuracy and lower requirements on data.

The great threat and destructiveness brought by a rock burst make its prediction and prevention crucial in engineering. The rock burst hazard evaluation at project locations is an effective way of preventing rock burst since currently real-time prediction is not available. Since different control factors and discrimination conditions of rock burst were accepted by conventional risk determination methods, the rock burst risk determination in the same area may produce conflicting results. In this study, Naive Bayes statistical learning models based on different model prior distributions representing highly complicated nonlinear relationship between rock burst hazard and impact factors were built to evaluate the rock burst hazards. The results suggested that the Bayes statistical learning model based on a Gaussian prior has the strongest performance over four preset prior distributions. Combining the rock mechanics parameters measured in the laboratory and the stress data collected on the project sites, the proposed model was successfully employed to evaluate the kimberlite rock burst risk of a diamond mine in Canada. The Bayes statistical learning model exhibits its robustness and generalization in rock burst hazard evaluation, which can be generalized for similar engineering cases with enough supported data.

In this article, the AlGaN barrier fully removed recessed-gate normally off AlGaN/GaN high electron mobility transistors (HEMTs) with N2O plasma treatment are fabricated. The low speed and low damage etching is used in recessed-gate etching, the etching depth is about 26 nm with 0.4 nm remaining, and then, the remaining barrier layer is oxidized by N2O plasma treatment. In the terms of devices’ characteristics, the threshold voltage of the recessed-gate HEMT is +1.5 V, and the channel current of recessed-gate HEMTs at $V_{\mathrm {GS}} - V_{\mathrm {TH}} = 1.5$ V is about 110 mA/mm. Moreover, 14 mV/V of drain-induced barrier lowering (DIBL) and 70 mV/decade of subthreshold slope (SS) are achieved. More importantly, the fully recessed-gate HEMT shows the average breakdown electric field at $V_{G}= 0$ V of about 0.64 MV/cm, which is a very high value in the fully normally off recessed-gate HEMTs without metal insulator semiconductor (MIS) structure, which will be beneficial to the application of this device in the low power supply topology circuit.

This article develops a game-theoretic model to value the bidirectional option in a one-manufacturer and one-component-supplier system. The production process of the supplier is subject to random yield. The manufacturer contracts the supplier with bidirectional options to obtain components, and assembles them into end products to meet a stochastic demand. In addition, both firms can sell or/and buy the components on a spot market. First, the unique optimal order and production strategies of the decentralized system under bidirectional option contracts are derived. Second, resorting to numerical example and comparing the bidirectional option model with the call option model, we find that the manufacturer’s optimal firm and total order as well as expected profit under bidirectional options are larger than that of under call options, but the option quantity has the opposite tendency. The supplier’s optimal production quantity are larger under bidirectional options than that of under call options, but only when the option (exercise) price exceeds a certain value, the supplier’s expected profit under bidirectional options will be larger than that of under call options. Third, the coordination of the decentralized system under bidirectional option contracts is analyzed and a coordination mechanism with the contract is designed.

Gellan gum (GG) is often added to gelatin (GL) to improve the gel property. GG‐based or inulin (IL)‐based hydrogels were developed. Rigid and brittle gels or smooth and delicate gels were prepared with GG and IL, respectively. This study aimed to explore the properties and interaction mechanisms of the mixed‐gel system containing GL, GG, and IL, in which different ratios of GG‐IL (0.4%) (10:0, 8:2, 6:4, 5:5, 4:6, 2:8, and 0:10) were added to GL (6%). Texture profiles, rheological properties, water mobility, intermolecular forces, circular dichroism (CD) spectra, and microstructures were analyzed. The results showed that addition of GG‐IL could improve the hardness, chewiness, and cohesiveness of mixed‐gel, besides maintaining appropriate springiness. Water mobility of the mixed‐gel decreased while viscoelasticity increased upon the addition GG. At GG:IL = 2:8, the melting temperature of mixed‐gel was far higher than that of GL gel itself. The GL‐GG‐IL gel showed decrease in nonspecific bonding and increase in hydrogen bonding compared with the GL gel. CD spectra indicated the promotion of GL unfolding by GG, hence suggesting the binding of GG to GL; binding ability was better at GG:IL >5:5. Cryo‐SEM provided evidence for the formation of cross‐linked network within GL‐GG‐IL. Overall, we concluded that addition of GG‐IL to GL system would be most suitable for improving the properties of mixed‐gel. This finding may be potentially applicable in the further development of gel food products, such as meat jellies and gummy jellies., This study aimed to explore the properties and underlying interactions of a mixed‐gel system containing gelatin (GL), gellan gum (GG), and inulin (IL), with different ratios of GG‐IL (10:0, 8:2, 6:4, 5:5, 4:6, 2:8, and 0:10) added to GL. we concluded that addition of GG‐IL into GL system is the most feasible combination for improving the properties of mixed‐gel.

Elucidating the dynamic couplings of hydrogen bonds remains an important and challenging goal for spectroscopic studies of bulk systems, because their vibrational signatures are masked by the collective effects of the fluctuation of many hydrogen bonds. Here we utilize size-selected infrared spectroscopy based on a tunable vacuum ultraviolet free electron laser to unmask the vibrational signatures for the dynamic couplings in neutral trimethylamine-water and trimethylamine-methanol complexes, as microscopic models with only one single hydrogen bond holding two molecules. Surprisingly broad progression of OH stretching peaks with distinct intensity modulation over ∼700 cm-1 is observed for trimethylamine-water, while the dramatic reduction of this progression in the trimethylamine-methanol spectrum offers direct experimental evidence for the dynamic couplings. State-of-the-art quantum mechanical calculations reveal that such dynamic couplings are originated from strong Fermi resonance between the stretches of hydrogen-bonded OH and several motions of the solvent water/methanol, such as translation, rocking, and bending, which are significant in various solvated complexes commonly found in atmospheric and biological systems.

Spectroscopic characterization of clusters is crucial to understanding the structures and reaction mechanisms at the microscopic level, but it has been proven to be a grand challenge for neutral clusters because the absence of a charge makes it difficult for the size selection and detection. Infrared (IR) spectroscopy based on threshold photoionization using a tunable vacuum ultraviolet free electron laser (VUV-FEL) has recently been developed in the lab. The IR-VUV depletion and IR+VUV enhancement spectroscopic techniques open new avenues for size-selected IR spectroscopies of a large variety of neutral clusters without confinement (i.e., an ultraviolet chromophore, a messenger tag, or a host matrix). The spectroscopic principles have been demonstrated by investigations of some neutral water clusters and some metal carbonyls. Here, the spectroscopic principles and their applications for neutral clusters are reviewed.

Neutral titanium-metal carbonyl complexes with the chemical formula Ti(CO)n (n = 4-7) are produced in the gas phase by the reactions of titanium atoms with carbon monoxide in a pulsed laser vaporization-supersonic expansion source. Their infrared absorption spectra in the carbonyl stretching frequency region are measured by infrared plus vacuum ultraviolet (IR+VUV) two-color ionization spectroscopy based on a tunable VUV free electron laser. Infrared spectroscopy in conjunction with quantum chemical calculations confirm that all of these complexes have unexpected titanium ketenylidene OTiCCO(CO)n-2 structures. Bonding analysis indicates that the OTiCCO core structure can be described by the bonding interactions between a TiO+ cation in the doublet ground state and a doublet ground state of CCO-. The results reveal that the C-O bond breaking and C-C bond formation proceed efficiently in the reactions between laser-vaporized titanium atoms and carbon monoxide.

Photocatalytic reduction of CO2 into value-added chemical fuels is an appealing approach to address energy crisis and global warming. CsPbBr3 quantum dots (QDs) are good candidates for CO2 reduction because of their excellent photoelectric properties, including high molar extinction coefficient, low exciton binding energy, and defect tolerance. However, the pristine CsPbBr3 QDs generally have low photocatalytic performance mainly due to dominant charge recombination and lack of efficient catalytic sites for CO2 adsorption/activation. Herein, we report a new photocatalytic system, in which CsPbBr3 QDs are coupled with covalent triazine frameworks (CTFs) for visible-light-driven CO2 reduction. In this hybrid photocatalytic system, the robust triazine rings and periodical pore structures of CTFs promote the charge separation in CsPbBr3 and endow them with strong CO2 adsorption/activation capacity. The resulting photocatalytic system exhibits excellent photocatalytic activity towards CO2 reduction. This work presents a new photocatalytic system based on CTFs and perovskite QDs for visible-light-driven CO2 reduction, which highlights the potential of perovskite-based photocatalysts for solar fuel applications.

Train network control management system (TCMS) is an important part of the High-speed rail train. Because of the TCMS's complex and redundant structure, long-term operation environment, etc., breakdowns inevitably in the long-time running. Based on the historical fault data of the TCMS accumulated during their online service, the working principles, failure modes, and effects analysis of TCMS are researched and the dynamic fault tree (DFT) model of TCMS failure is built. Then, the dynamic fault tree model is transformed into the Bayesian network (BN) model, which can model the reliability of such types of systems. Finally, combining DFT with BN is used for fault probability estimation and reliability assessment. The results present that increasing the reliability of key modules for the TCMS would be of great help to High-speed rail train engineers in the fault diagnosis field.

The increasing penetration of renewable generation presents challenges for system frequency regulation due to short-term power fluctuations and system inertia reductions. This article presents a coordinated control strategy for frequency regulation in which inverter air-conditioning (IAC) units are used to perform primary frequency regulation (PFR) and fixed frequency air-conditioning (FFAC) units are used to perform secondary frequency regulation (SFR). In PFR, the regulation power is provided by adjusting the setpoints of the IAC units. A random number generation method is proposed to stochastically trigger IAC units based on the frequency deviation in real time. Furthermore, a recovery method is presented to stably restore the IAC units to their initial operating states after regulation. In SFR, a constant equivalent duty ratio method is raised to keep the regulation power stable over a long instruction interval. Based on this, the transforming time interval method is presented to determine the ON/OFF status of FFAC units to provide the required regulation power. Additionally, a recovery method for FFAC units is proposed to mitigate the power rebound after regulation. The proposed control strategy achieves an improved frequency regulation effect with fewer communication demands. Dynamic simulations in a six-machine two-area system and an isolated microgrid with wind power verify the effectiveness of the proposed control strategy.

The effect of charge on the dihydrogen storage capacity of Sc2–C6H6 has been investigated at B3LYP-D3/6-311G(d,p) level. The neutral system Sc2–C6H6 can store 8H2 with gravimetric density of 8.76 wt %, and one H2 dissociates and bonds atomically on the scandium atom. The adsorption of 8H2 on Sc2–C6H6 is energetically favorable below 155 K. The atom-centered density matrix propagation (ADMP) molecular dynamics simulations show that Sc2–C6H6 can adsorb 3H2 within 1000 fs at 300K. Compared with Sc2–C6H6, the charged systems can adsorb more hydrogen molecules with higher gravimetric density, and all the H2 are adsorbed in the molecular form. The gravimetric densities of Sc2–C6H6+ and Sc2–C6H62+ are 9.75 and 10.71 wt%. Moreover, the maximum adsorption of charged systems are favorable in wider temperature range. Most importantly, the ADMP-MD simulations indicate that Sc2–C6H62+ can adsorb 6 hydrogen molecules within 1000 fs at 300K. It can be found that the gravimetric density (6.72 wt%) of Sc2–C6H62+ still exceeds the target of US Department of Energy (DOE) under ambient conditions.

It has been a consensus that the exciton binding energies in two-dimensional (2D) Ruddlesden–Popper perovskites is closely correlated with the number of layers. However, the detailed recombination dynamics of excitons and free carriers in these 2D perovskites are still highly controversial. Using transient spectroscopic techniques, carrier dynamics of 2D Ruddlesden–Popper perovskites are investigated at both room and low temperatures. We confirmed that 2D perovskites of (BA)2PbI4, with the number of [PbX6]4− layers n = 1, exhibit clearly exciton characteristic properties. Meanwhile, (BA)2(MA)Pb2I7 and (BA)2(MA)2Pb3I10, n = 2 and 3, exhibit free carrier behaviour, which is inconsistent with their binding energies of more than 100 meV. Such anomalous exciton and free carrier behaviours are attributed to the effective exciton in-plane transport and dissociation by the edge state. This investigation provides novel insights into exciton and charge carrier dynamics of 2D perovskites as well as the influence of edge states.

A reverse-blocking AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor (RB-MISHEMT) is proposed and fabricated. Compared with the conventional MISHEMT with ohmic drain, the proposed device features a hybrid Schottky-ohmic drain with a low work function Tungsten (W), based on which the state-of-the-art ultralow turn-on voltage ( ${V} _{\mathrm{ on}}$ ) of 0.25 V could be realized without degradation in on-state characteristics. In addition, the fabricated RB-MISHEMT exhibits the excellent reverse blocking voltage of −1332 V (at ${V} _{\mathrm{ GS}}= 0$ V) and forward blocking voltage of 1315 V (at ${V} _{\mathrm{ GS}} = -15$ V) with a specific on-resistance ( ${R} _{\mathrm{ on,sp}}$ ) of 3.5 $\text{m}\Omega $ cm2, leading in the highest power figure-of-merit (FOM) of > 494 MW/cm2. The good thermal stability could also be observed in fabricated RB-MISHEMT. The corresponding operation mechanism of RB-MISHEMT are also revealed by Silvaco ATLAS simulations. These results demonstrate the great potential in power electronics applications.

Blown sand hazards at the Jieqiong section of the Lhasa–Shigatse railway are severe, and their formation mechanism is unclear. Moreover, sand prevention and control work cannot be carried out. Therefore, the dynamic mechanism of blown sand at the Jieqiong section of the Lhasa–Shigatse Railway was investigated by field observation, laboratory analysis, and calculation. Results show that the yearly sand–moving wind at the Jieqiong section commonly originates from the SW direction. The yearly resultant drift direction and the yearly resultant angle of the maximum possible sand transport quantity are NE direction. The angle between railway trend and sand transport direction is 5°–30°. During dry season, sand materials are blown up by the wind, forming wind–sand flow and movement to the NE direction, at which they are blocked by the railway roadbed. Consequently, accumulation occurs and causes serious damage. Strong wind and dryness are synchronous within a season. The directions of sand source and prevailing wind are consistent, thereby aggravating the blown sand dynamic further. The present results provide a reference for controlling sand hazards in the locale.

Three-dimensional (3D) printing has been increasingly employed to produce advanced bone tissue engineering scaffolds with biomimetic structures and matched mechanical strengths, in order to induce improved bone regeneration in defects with a critical size. Given that the successful bone regeneration requires both excellent osteogenesis and vascularization, endowing scaffolds with both strong bone forming ability and favorable angiogenic potential would be highly desirable to induce improved bone regeneration with required vascularization. In this investigation, customized bone tissue engineering scaffolds with balanced osteoconductivity/osteoinductivity were produced via cryogenic 3D printing of β-tricalcium phosphate and osteogenic peptide (OP) containing water/poly(lactic-co-glycolic acid)/dichloromethane emulsion inks. The fabricated scaffolds had a hierarchically porous structure and were mechanically comparable to human cancellous bone. Angiogenic peptide (AP) containing collagen I hydrogel was then coated on scaffold surface to further provide scaffolds with angiogenic capability. A sequential release with a quick AP release and a slow but sustained OP release was obtained for the scaffolds. Both rat endothelial cells (ECs) and rat bone marrow derived mesenchymal stem cells (MSCs) showed high viability on scaffolds. Improved in vitro migration and angiogenesis of ECs were obtained for scaffolds delivered with AP while enhanced osteogenic differentiation was observed in scaffolds containing OP. The in vivo results showed that, toward scaffolds containing both AP and OP, the quick release of AP induced obvious angiogenesis in vivo, while the sustained OP release significantly improved the new bone formation. This study provides a facile method to produce dual-delivery scaffolds to achieve multiple functions., Graphical abstract Schematic illustration of fabricating AP and OP delivered TCP/PLGA composite scaffolds via cryogenic 3D printing and subsequent hydrogel coating. The scaffold can be implanted in bone defects to induce improve bone regeneration with required vascularization.Image 1, Highlights • Dual-delivery scaffolds are structurally and mechanically similar to cancellous bone. • Dual-delivery scaffolds can sequentially release angiogenic and osteogenic peptides. • Dual-delivery scaffolds improve bone regeneration and vascularization in vivo.

Direct X-ray detectors are considered as competitive next-generation X-ray detectors because of their high spatial resolution, high sensitivity, and simple device configuration. However, their potential is largely limited by the imperfections of traditional materials, such as the low crystallization temperature of α-Se and the low atomic numbers of α-Si and α-Se. Here, we report the Sb(2)Se(3) X-ray thin-film detector with a p-n junction structure, which exhibited a sensitivity of 106.3 µC/(Gy(air)·cm(2)) and response time of < 2.5 ms. This decent performance and the various advantages of Sb(2)Se(3), such as the average atomic number of 40.8 and μτ product (μ is the mobility, and τ is the carrier lifetime) of 1.29 × 10(−5) cm(2)/V, indicate its potential for application in X-ray detection. [Image: see text]

In order to improve the dynamic response of synchronous rectified primary-side regulation (PSR) flyback converter with CCM and DCM modes, a novel digital control method is proposed. In a dynamic process, when output voltage is detected to fluctuate greatly, two special working modes called light-to-heavy mode and heavy-to-light mode are introduced. The output capacitor will be quickly charged and discharged by an optimized control scheme to make the output voltage's dynamic fluctuation smaller. On the other hand, during the dynamic process control, for eliminating overshoot and oscillation when the output voltage returns to the reference voltage, the load is detected by the output voltage slope to determine the appropriate operating mode. With the proposed control method, the dynamic performance can be greatly improved. An field programmable gate array (FPGA)-controlled 20-V/5-A synchronous rectified PSR flyback converter is established to verify the proposed control scheme. In the prototype test, compared to the traditional multimode control, the undershoot voltage and overshoot voltage of the proposed control scheme are improved from 5.02 to 1.63 V and 3.15 to 1.73 V, respectively. The undershoot and overshoot recovery times are reduced from 83.43 to 1.79 ms and 40.32 to 1.85 ms, respectively.

The repeated wetting–drying (WD) cycles can cause the deterioration of rock and thus affect the service performance of the related rock engineering, e.g., the crushed-rock embankment and the reservoir. The study comprehensively investigated the deterioration mechanism of sandstone under the WD cycles based on a series of multi-scale experiments, including the microstructure, the meso–micro pore characteristics, and the macroscopic physical and mechanical properties. The results indicate that the content of dissolved minerals and the permeability are two key factors that determine the deterioration effect caused by the WD cycles. During the WD cycles, the pore size range of sandstone becomes wider due to the formation of new small pores and the connection of original pores. Thus, low-density area forms within the samples, which causes the increasing of density dispersion. The structure deterioration weakens the physical and mechanical properties of the samples. The ultrasonic test indicates that the decreasing rate of the P-wave velocity is larger than that of the S-wave velocity, especially in the first 5 cycles. Besides, the exponential equations of uniaxial compressive strength and elastic modulus with the number of WD cycles are established to describe the deterioration of mechanical characteristics.

Autonomous underwater vehicle (AUV) plays an important role in ocean research and exploration. The underwater environment has a great influence on AUV control and human–robot interaction, since underwater environment is highly dynamic with unpredictable fluctuation of water flow, high pressure and light attenuation. The traditional control model contains a large number of parameters, which is not effective and produces errors frequently. The proposal of fuzzy control addressed this issue to a certain extent. It applies fuzzy variables to the controller, which replace the values in an interval. In addition to the controller, underwater human–robot interaction is also difficult. Divers cannot speak or show any facial expressions underwater. The buttons on the AUV also need to overcome the huge water pressure. In this paper, we proposed a method to recognize the gesture instructions and apply it to the fuzzy control of AUV. Our contribution is the gesture recognition framework for the human–robot interaction, including the gesture detection network and the algorithm for the control of AUV. The experiment result shows the efficiency of the proposed method.

In the field of underwater image recognition, a chip with smaller footprint and lower energy consumption is required to be implanted into autonomous intelligent underwater vehicle to make real-time response to the surrounding objects. Therefore, a promising accelerator with high performance and low energy consumption is designed, which optimizes the features possessed by convolutional neural network. The sharing of weights between neurons reduces the memory requirement. With all convolutional neural network data stored within on-chip static random-access memory, the need for memory access is drastically decreased. Besides, several small processing elements are used to form neural functional unit, which considerably reduces the bandwidth requirement through inter-processing element data transmission. By sending control signals to autonomous underwater vehicle, this accelerator enables it to avoid dangerous areas such as rocks and algae in time. The result suggests the proposed accelerator successfully achieves a higher processing speed than that of CPU and GPU with a footprint of 6.09 mm2 only and the energy consumption of 327.3 mW at 1 GHz.

Sulfate and carbonate can cause serious degradation of cement-based materials at low temperature; degradation products generally include ettringite, gypsum and thaumasite. The degradation process is very slow in a natural environment and no useful test method exists to accelerate the degradation process. This study used a voltage of 30 V and an electrical field duration of 20 s to study the acceleration effect of an electrical field on the degradation. Visual observations and compressive strength were used to reflect the degree of degradation. X-ray diffraction, Fourier transform infrared spectroscopy and ion concentration distribution were applied to study the degradation mechanism. The test results indicated that an electrical field can accelerate the degradation within 180 d and that the degradation rate was faster than that associated with full immersion. Moreover, the degree of degradation of a solution with sodium sulfate (Na2SO4) as the cathode and magnesium sulfate (MgSO4) as the anode was higher than that of a solution with magnesium sulfate as both cathode and anode; also the degradation degree of a magnesium sulfate solution under full immersion was higher than that of a sodium sulfate solution under full immersion.

A density functional study of dihydrogen adsorption and storage capacity of reported stable clusters MLi4+ (M = C, Si, Ge) has been performed at different levels. The cationic systems MLi4+ (M = C, Si, Ge) can adsorb up to 12, 12, and 14 hydrogen molecules respectively with respective H2 gravimetric uptake capacity of 37.82, 30.22, and 21.94 wt%. The interactions of MLi4+ (M = C, Si, Ge) with H2 molecules are analyzed by means of the bond critical points (bcp) in the quantum theory of atoms in molecules (QTAIM). The Gibbs free energy corrected adsorption energies indicate that the maximum adsorption of MLi4+ (M = C, Si, Ge) are energetically favorable at low temperature or high pressure. Atom-centered density matrix propagation (ADMP) molecular dynamics simulations are performed at different temperatures. It can be found that MLi4+ (M = C, Si, Ge) can bind 3, 6, and 4 hydrogen molecules with respective gravimetric densities of 13.20, 17.80, and 7.43 wt% at 200 K and 1atm. At room temperature, MLi4+ (M = C, Si, Ge) can adsorb 3, 5, and 3 hydrogen molecules with gravimetric densities of 13.20, 15.29, and 5.68 wt%.

The hydrogen adsorption and storage of Cu3Bx (X = 1–4) compounds have been computationally investigated at B3LYP-D3/6-311G (3df, 3pd) level. The most stable compounds of Cu3Bx (X = 1–4) can adsorb 16, 11, 15, and 9 hydrogen molecules with H2 gravimetric densities of 13.80, 9.46, 11.94, 7.20 wt%, respective. Their average adsorption energies are in the range of 0.26–0.43 eV/H2. The Gibbs free energy corrected adsorption energies indicate that the maximum adsorption of Cu3Bx (X = 1–4) are energetically favorable under ambient conditions. Atom-centered density matrix propagation (ADMP) molecular dynamics simulations are used to analyzed the real time dynamics of H2 and Cu3Bx (X = 1–4). We can find that Cu3Bx (X = 1–4) can bind with 4–5 H2 within 1000 fs at 200 K.

Subsea pipeline is the safest, most reliable, and most economical way to transport oil and gas from an offshore platform to an onshore terminal. However, the pipelines may rupture under the harsh working environment, causing oil and gas leakage. This calls for a proper device and method to detect the state of subsea pipelines in a timely and precise manner. The autonomous underwater vehicle carrying side-scan sonar offers a desirable way for target detection in the complex environment under the sea. As a result, this article combines the field-programmable gate array, featuring high throughput, low energy consumption and a high degree of parallelism, and the convolutional neural network into a sonar image recognition system. First, a training set was constructed by screening and splitting the sonar images collected by sensors, and labeled one by one. Next, the convolutional neural network model was trained by the set on the workstation platform. The trained model was integrated into the field-programmable gate array system and applied to recognize actual datasets. The recognition results were compared with those of the workstation platform. The comparison shows that the computational precision of the designed field-programmable gate array system based on convolutional neural network is equivalent to that of the workstation platform; however, the recognition time of the designed system can be saved by more than 77%, and its energy consumption can also be saved by more than 96.67%. Therefore, our system basically satisfies our demand for energy-efficient, real-time, and accurate recognition of sonar images.

Polyvinylpyrrolidone (PVP) is studied in this paper as an inhibitor of cobalt electrodeposition. The suppression effect of PVP was analyzed through electrochemical methods, including cyclic voltammetry (CV) and galvanostatic measurements (GM) tests. It is indicated that PVP effectively suppresses the electrodeposition of cobalt and chloride ion accelerates this suppression. Further experiments verify that PVP inhibits the deposition of cobalt through the adsorption on the electrode surface. Quantum chemical calculations were employed to calculate the molecular orbitals of PVP and the electrostatic potential (ESP) energy of the involved molecules. The simulation results imply that the amide group acts as the main electrophilic attack region and facilitates nucleophilic reactions to bond with cobalt. High aspect ratio trench filling on silicon wafer was achieved with the addition of PVP, which confirms that PVP is an applicable inhibitor for the practical electrodeposition of cobalt filling. The mechanism of cobalt trench filling was proposed to explain the role of PVP in the electroplating filling. Besides, crystalline and morphological characterizations reveal that PVP is able to inhibit the specific crystal growth of cobalt, especially the growth of 220 crystal plane, affect the crystal morphology of cobalt and improve surface compactness.

A novel additive system comprising bis-(sodium sulfopropyl)-disulfide, polyethylene glycol and hydroquinone (HQ) was developed and investigated to achieve high rate copper electrodeposition at high temperature. HQ, as the key additive compound in this system, refines the Cu grain, makes the coating surface bright and smooth at high current density. The underlying mechanism of the additive-assisted electroplating was investigated through electrochemical, morphological characterizations and molecular dynamics simulation. Nanocubical copper particles were found through chronoamperometry tests, which explains the fine crystalline Cu grains and the bright coating surface. Additionally, the formation of the nanocubical copper particles is caused by the different adsorption energies of HQ on (311), (111) and (220) crystal faces and further leads to a strong suppression on the (220) orient crystal faces. Moreover, the electroplating results of through-holes illustrate the feasibility of this additive system in practical applications.

Photocatalytic CO2 reduction is an appealing approach to convert solar energy into high value-added chemicals. All-inorganic CsPbBr3 quantum dots (QDs) have emerged as a promising photocatalyst for reducing CO2. However, pristine CsPbBr3 has a low catalytic performance, mainly due to severe charge recombination. Herein, a 0D/2D heterojunction of CsPbBr3 QDs/Bi2WO6 nanosheet (CPB/BWO) photocatalysts is fabricated for photocatalytic CO2 reduction. The CPB/BWO photocatalyst achieves excellent photocatalytic performance: the total yield of CH4/CO is 503 μmol g-1, nearly 9.5 times higher than the pristine CsPbBr3. The CPB/BWO heterojunction also exhibits much-improved stability during photocatalytic reactions. On the basis of various characterization techniques, our investigations verified a direct Z-scheme charge migration mechanism between CsPbBr3 QDs and Bi2WO6 nanosheets. The improved photocatalytic performance is originated from the high spatial separation of photoexcited charge carriers in CPB/BWO, which can also preserve strong individual redox abilities of two components. This work reports an efficient direct Z-scheme heterojunction photocatalytic system based on metal halide perovskites. The novel strategy we proposed may bring up new opportunities for the development of metal halide perovskite photocatalysts with greatly enhanced activities.

Surface modification plays a vital role in improving the rate performance and cycling stability of layered Ni-rich LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode materials for Li-ion batteries. In this study, Li2MgTi3O8 (LMTO)-coated NCM622 was successfully synthesized by wet coating combined with sintering process. The results of morphological analysis showed a uniform LMTO layer coated on the surface of NCM622 materials. The dual ions of Ti4+ and Mg2+ on surface structure of NCM622 were identified by X-ray diffraction and X-ray photoelectron spectroscopy. The surface coating layer prevented the direct contact between the active cathode material and the electrolyte which significantly reduced the side reactions, and the doping of Ti4+ and Mg2+ improved the structural stability of the NCM622 materials. The electrochemical performance indicates that NCM622 cathode with a coating layer of 0.5 wt% LMTO exhibited excellent cycle stability and maintained a capacity retention up to 76% after 200 cycles at 25 °C at 1 C-rate, which was higher than the value of 52% for the NCM622.

The advanced rechargeable batteries have been upgraded by the production of free-standing electrodes through electrospinning technology. This study aimed to introduce a novel hybrid composition to design a free-standing carbon nanofiber (CNF) based anode by the addition of iron acetylacetonate Fe(AcAc)3 as active material and TEOS(tetraethoxysilane)/APTES(aminopropyl triethoxysilane) as an additive for Li-ion batteries. Polyacrylonitrile(PAN) was used as the polymer matrix in the spin dope, and the inclusion of Fe(AcAc)3 and TEOS/APTES resulted in compositional change, producing iron oxide and silica nanoparticles throughout the matrix. Different oxidation states and the presence of embedded iron oxide nanoparticles in CNF were identified by XPS and EDX elemental mapping analysis. PAN-TEOS-APTES-Fe(AcAc)3 based anode material was capable of enhancing the reversible specific capacity as much as 732 mAhg−1 at 500 mAg−1 lasting for 300 cycles, along with the rate capability as high as 815 mAhg−1 at 200 mAg−1. Furthermore, EIS analysis and EX-situ FESEM showed decreased impedance after cycling with the stable morphology of PAN-TEOS-APTES-Fe(AcAc)3 CNF-film. Conclusively, non-woven, binder-free, current collector free, free-standing CNF anode film doped with iron-oxide and silica nanoparticles was indeed a novel approach for Li-ion batteries and can be considered for other batteries particularly for Li-S batteries.

The observation of low-energy edge photoluminescence and its beneficial effect on the solar cell efficiency of Ruddlesden–Popper perovskites has unleashed an intensive research effort to reveal its...

Because failures in distribution systems caused by extreme weather events directly result in consumers’ outages, this paper proposes a state-based decision-making model with the objective of mitigating loss of load to improve the distribution system resilience throughout the unfolding events. The system topologies including on/off states of feeder lines are modeled as Markov states, and the probabilities from one Markov state to another Markov state throughout the unfolding events are determined by the component failure caused by the unfolding events. A recursive optimization model based on Markov decision processes (MDP) is developed to make state-based actions, i.e., system reconfiguration, at each decision time. To overcome the curse of dimensionality caused by enormous states and actions, an approximate dynamic programming (ADP) approach based on post-decision states and iteration is used to solve the proposed MDP-based model. IEEE 33-bus system and IEEE 123-bus system are used to validate the proposed model.

An integrated energy system (IES) represents coordinated operations of constrained natural gas (NG), electric power, and thermal systems in three distinctly different time scales. Microturbines (MTs) are increasingly utilized in IES as suppliers of combined cooling, heating and power (CCHP) units, which optimize the delivery and the usage of interdependent NG, electric power, and thermal energy sectors in a distributed IES. In this paper, a dynamic IES model is proposed based on the singular perturbation theory (SPT), which denotes the dynamic interactions of the three energy systems. The dynamic IES model representing a boundary layer system (BLS) is solved and analyzed in three time-scales. The simulation results demonstrate the validity of the proposed dynamic IES model in three time-scales, highlighting the necessity of incorporating the dynamic characteristics of NG, electric power, and thermal energy in dynamic analyses of distributed IES.

The accurate alignment between visual features and semantic concepts is a challenging problem in zero-shot object detection. To address that, this brief proposes a new algorithm using attributes based category similarity. An unsupervised learning method is utilized to evaluate and adjust an attribute table, which helps to establish a better synergy between visual and semantic domains. Based on that, the similarity between categories is exploited to simultaneously detect and recognize novel concept instances with visual attributes. Experimental results on the MS-COCO dataset show that the proposed algorithm can achieve the highest mean average precision (15.34%), compared with the state-of-the-art algorithms.

The strength of light-matter interaction is of central importance in photonics and optoelectronics. For many widely studied two-dimensional semiconductors, such as MoS2, the optical absorption due to exciton resonances increases with thickness. However, here we will show, few-layer black phosphorus exhibits an opposite trend. We determine the optical conductivity of few-layer black phosphorus with thickness down to bilayer by infrared spectroscopy. On the contrary to our expectations, the frequency-integrated exciton absorption is found to be enhanced in thinner samples. Moreover, the continuum absorption near the band edge is almost a constant, independent of the thickness. We will show such scenario is related to the quanta of the universal optical conductivity of graphene (σ0 = e2/4ħ), with a prefactor originating from the band anisotropy., For many two-dimensional semiconductors, such as MoS2, the exciton absorption increases with thickness. Here, the authors show that, in black phosphorus, less material absorbs more light due to exciton resonances.

Tissue engineering is promising in realizing successful treatments of human body tissue loss that current methods cannot treat well or achieve satisfactory clinical outcomes. In scaffold-based bone tissue engineering, a high performance scaffold underpins the success of a bone tissue engineering strategy and a major direction in the field is to produce bone tissue engineering scaffolds with desirable shape, structural, physical, chemical and biological features for enhanced biological performance and for regenerating complex bone tissues. Three-dimensional (3D) printing can produce customized scaffolds that are highly desirable for bone tissue engineering. The enormous interest in 3D printing and 3D printed objects by the science, engineering and medical communities has led to various developments of the 3D printing technology and wide investigations of 3D printed products in many industries, including biomedical engineering, over the past decade. It is now possible to create novel bone tissue engineering scaffolds with customized shape, architecture, favorable macro-micro structure, wettability, mechanical strength and cellular responses. This article provides a concise review of recent advances in the R & D of 3D printing of bone tissue engineering scaffolds. It also presents our philosophy and research in the designing and fabrication of bone tissue engineering scaffolds through 3D printing., Highlights • 3D printing of bioceramic pastes followed by sintering improves bone formation. • Cryogenic 3D printing of drug loaded polymer solution supports cell differentiation. • Surface modification of 3D printed scaffolds improves the cellular responses.

A separator film for high-performance Li-ion batteries was prepared by electrospinning. The film had a hybrid morphology of silica nanofibers (SNFs) and alumina nanoparticles (ANPs), with a smooth surface, polymer-free composition, high porosity (79%), high electrolyte uptake (876%), and excellent thermal stability. Contact angle measurements demonstrated the better immersion capability of the SNF-ANP separator film for commercial liquid electrolytes than a commercial CELGARD 2500 separator film. Moreover, compared to the commercial CELGARD 2500 separator, the ionic conductivity of the SNF-ANP separator film was nearly three times higher, the bulk resistance was lower at elevated temperature (120 °C), the interfacial resistance with lithium metal was lower, and the electrochemical window was wider. Full cells were fabricated to determine the cell performance at room temperature. The specific capacity of the full cell with the SNF-ANP separator film was 165 mAh g−1; the cell was stable for 100 charge/discharge cycles and exhibited a capacity retention of 99.9%. Notably, the electrospun SNF-ANP separator film can be safely used in Li-ion or Li-S rechargeable batteries.

Co-delivery systems with programmed release of combined drugs are of great value for combination cancer therapy. However, design of such co-delivery systems for potent synergistic cancer therapy is still a great challenge. In the present work, dimethylcurcumin (DMC) and docetaxel (DTX) co-loaded branched worm-like nanoparticles (NPs) with programmed release of DMC and DTX were developed for potent synergistic castration-resistant prostate cancer (CRPC) therapy. (2-Hydroxypropyl)-β-cyclodextrin-retinoic acid (HP-β-CD-RA) conjugates with different molar ratios of RA to HP-β-CD were synthesized and used for the preparation of DMC and DTX co-loaded NPs. The as-prepared DMC and DTX co-loaded NPs (Dh 170–190 nm) have branched worm-like morphologies, and DMC/DTX@HP-β-CD-RA3.0 NPs show the highest drug loading content and encapsulation efficiency. DMC/DTX@HP-β-CD-RA3.0 NPs exhibit programmed drug release patterns with DTX released much faster than DMC, which could be ascribed to the difference between DMC and DTX in the interaction with HP-β-CD-RA3.0 as analyzed by molecular simulation, phase solubility method, and fluorescence spectra. DMC/DTX@HP-β-CD-RA3.0 NPs exhibit enhanced cellular uptake as compared to DMC/DTX. Mechanism dissection reveals that the cellular uptake of DMC/DTX@HP-β-CD-RA3.0 NPs is energy-dependent in which macropinocytosis and clathrin- and caveolae-independent endocytosis pathways are involved. Benefited from their enhanced cellular uptake and programmed drug release, DMC/DTX@HP-β-CD-RA3.0 NPs exhibit significantly enhanced antitumor effect as compared to DMC/DTX. Such mechanisms for potent synergistic antitumor effect, by enhancing cellular uptake of DMC and DTX together with programmed drug release, may provide new therapeutic options for CRPC.

Oxygen defect-rich iron oxide (ODFO) nanoparticle catalyst on nanocarbon is in situ synthesized with the assistance of multi-ion modulation in one pot. The nanoparticle catalyst is employed to propel electrochemical kinetics in lithium/sulfur batteries. Electrochemical analysis and theoretical simulation evidently verify the critical role of defect sites on catalyzing conversion reactions of sulfur species and reducing energy barriers. As a consequence, the ODFO-enhanced sulfur cathode exhibits a high specific capacity of 1489 mA h g-1 at 0.1 C, an excellent rate performance of 644 mA h g-1 at 10 C, and a superior cycling stability with an average capacity fading rate of as low as 0.055% per cycle under an ultrahigh rate of 10 C. More importantly, even with a high sulfur loading of 11.02 mg cm-2, the Li/S cell can still deliver an areal capacity of 8.7 mA h cm-2 at 0.5 C (9.23 mA cm-2). Such performance is the highest among reported metal oxide-catalyzed sulfur cathodes. This work opens a new route to boosting conversion reaction kinetics by introduction of active oxygen defect sites in electrodes of various emerging ultrafast batteries.

Chemical control is the major approach to handle the American Hyphantria cunea issue; however, it often causes chemical pollution and resource waste. How to precisely apply pesticide to reduce pollution and waste has been a difficult problem. The premise of accurate spraying of chemicals is to accurately determine the location of the spray target. In this paper, an algorithm based on a convolutional neural network (CNN) is proposed to locate the screen of American Hyphantria cunea. Specifically, comparing the effect of multicolor space-grouping convolution with that of the same color space-grouping convolution, the better effect of different color space-grouping convolution is first proved. Then, RGB and YIQ are employed to identify American Hyphantria cunea screen. Moreover, a noncoincident sliding window method is proposed to divide the image into multiple candidate boxes to reduce the number of convolutions. That is, the probability of American Hyphantria cunea is determined by grouping convolution in each candidate box, and two thresholds (E and Q) are set. When the probability is higher than E, the candidate box is regarded as excellent; when the probability is lower than Q, the candidate box is regarded as unqualified; when the probability is in between, the candidate box is regarded as qualified. The unqualified candidate box is eliminated, and the qualified candidate box cannot exit the above steps until the number of extractions of the candidate box reaches the set value or there is no qualified candidate box. Finally, all the excellent candidate boxes are fused to obtain the final recognition result. Experiments show that the recognition rate of this method is higher than 96%, and the processing time of a single picture is less than 150 ms.

The structures, energetics, and infrared (IR) spectra of the cationic monomethylamine-water clusters, [(CH $_3$ NH $_2$ )(H $_2$ O) $_n$ ] $^+$ ( $n$ =1 $-$ 5), have been studied using quantum chemical calculations at the MP2/6-311+G(2d,p) level. The results reveal that the formation of proton-transferred CH $_2$ NH $_3$ $^+$ ion core structure is preferred via the intramolecular proton transfer from the methyl group to the nitrogen atom and the water molecules act as the acceptor for the O $\cdots$ HN hydrogen bonds with the positively charged NH $_3$ $^+$ moiety of CH $_2$ NH $_3$ $^+$ , whose motif is retained in the larger clusters. The CH $_3$ NH $_2$ $^+$ ion core structure is predicted to be less energetically favorable. Vibrational frequencies of CH stretches, hydrogen-bonded and free NH stretches, and hydrogen-bonded OH stretches in the calculated IR spectra of the CH $_2$ NH $_3$ $^+$ and CH $_3$ NH $_2$ $^+$ type structures are different from each other, which would afford the sensitive probes for fundamental understanding of hydrogen bonding networks generated from the radiation-induced chemical processes in the [(CH $_3$ NH $_2$ )(H $_2$ O) $_n$ ] $^+$ complexes.