Search

After the first report of a graphene-based passive mode-locking ultrafast fiber laser, two-dimensional materials as efficient saturable absorbers offer a new horizon in ultrafast fiber laser. However, the interactions on atomic scale between these two-dimensional materials and fiber and the fiber effect on the carrier dynamics have not been realized. To figure out the exact role of fiber and the carrier dynamics affected by the fiber substrate related to ultrafast photonics, bismuthene, a newly reported 2D quantum material used in a passive mode-locking fiber laser, deposited on a-quartz has been investigated. We surprisingly found that the a-quartz substrate can strongly accelerate the nonradiative electron–hole recombination of bismuthene in theory, and the transient absorption spectra of bismuthene on normal glass and a-quartz further verify the substrate effect on carrier dynamics of bismuthene. The discovery provides new thinking about substrate effect to regulate the performance of ultrafast mode-locking fiber lasers as well as ultrafast photonics.

Intensive global research is focused on advanced conductive materials to meet the electrical requirements of the telecommunication and power industry. The primary aim is to enhance electrical conductivity, resulting of improved current-carrying capacity and reduced energy loss during transmission. Copper and its composites are vital for power transmission and telecommunications due to their electrical, thermal, and mechanical qualities. However, current methods have drawbacks, such as compromised conductivity with alloying. Graphene, an extraordinary carbon allotrope with exceptional properties and high conductivity, offers promising opportunities for the development of superior materials; such as graphene-incorporated copper (GrCu). The incorporation of graphene into copper wire holds significant potential for various industries, including electronics, energy transmission, and telecommunications, where high conductivity and reliability are paramount. This study investigates GrCu characteristics through mixing graphene and copper, vacuum melting, fine copper wire drawing, and GrCu coaxial cable manufacturing. Graphene infusion enhances conductivity and mechanical properties, altering microstructure and inducing twin boundaries in copper grains. Graphene's disruption during wire drawing triggers this effect, elevating wire conductivity to 103.5% by IACS. GrCu coaxial cable demonstrates performance coherence with HFSS simulation up to 6 GHz. Graphene's inclusion offers tailored material properties. Ongoing research promises further optimization and advancement of graphene-copper composites, paving the way for novel technological progress.

Spacecraft pose estimation plays an important role in an increasing number of on-orbit services: rendezvous and docking, formation flights, debris removal, and so on. Current solutions achieve excellent performance at the cost of a huge number of model parameters and are not applicable in space environments where computational resources are limited. In this paper, we present the Squeeze-and-Excitation based Spacecraft Pose Network (SESPNet). Our primary objective is to make a trade-off between minimizing model parameters and preserving performance to be more applicable to edge computing in space environments. Our contributions are primarily manifested in three aspects: first, we adapt the lightweight PeleeNet as the backbone network; second, we incorporate the SE attention mechanism to bolster the network’s feature extraction capabilities; third, we adopt the Smooth L1 loss function for position regression, which significantly enhances the accuracy of position estimation.

Although the fast tool servo (FTS) exhibits unique advantages for surface texturing, its intrinsic form accuracy is capped by the position and motion accuracy of the manufacturing system. In this article, a novel FTS combining the sensing and control capability of 2-DOF tool position and cutting force is developed to enable the high-performance adaptive surface texturing. The proposed design of FTS features a motion-decoupled symmetric configuration and functions via leveraging the system dynamics and online position monitoring of two pairs of actuation-force sensing observers. Analytical models and the differential evolution algorithm are established to describe the essential working performances and guide the optimal structural parameter design, which are validated using finite element simulation. The performance assessments suggest positioning resolution around 20 nm and force-sensing resolution at the millinewton level for both cutting and thrust directions, along with motion strokes of tens of micrometers and resonant frequency of up to 4172 Hz. Moreover, the adaptive texturing of microgrooved surfaces with consistent geometry is demonstrated without prior knowledge of workpiece shapes. The outcomes of this article contribute to developing the next-generation of intelligent FTS for flexible and intelligent manufacturing.

Anxiety is a normal and transitory emotional state that allows the organisms to cope well with the real or perceived threats, while excessive or prolonged anxiety is a key characteristic of anxiety disorders. We have recently revealed that prolonged anxiety induced by chronic stress is associated with the circuit-varying dysfunction of basolateral amygdala projection neurons (BLA PNs). However, it is not yet known whether similar mechanisms also emerge for acute stress-induced, short-lasting increase of anxiety. Here, using a mouse model of acute restraint stress (ARS), we found that ARS mice showed increased anxiety-like behavior at 2 h but not 24 h after stress, and this effect was accompanied by a transient increase of the activity of BLA PNs. Specifically, ex vivo patch-clamp recordings revealed that the increased BLA neuronal activity did not differ among the distinct BLA neuronal populations, regardless of their projection targets being the dorsomedial prefrontal cortex (dmPFC) or elsewhere. We further demonstrated that such effects were mainly mediated by the enhanced presynaptic glutamate release in dmPFC-to-BLA synapses but not lateral amygdala-to-BLA ones. Furthermore, while optogenetically weakening the presynaptic glutamate release in dmPFC-to-BLA synapses ameliorated ARS-induced anxiety-like behavior, strengthening the release increased in unstressed mice. Together, these findings suggest that acute stress causes short-lasting increase in anxiety-like behavior by facilitating synaptic transmission from the prefrontal cortex to the amygdala in a circuit-independent fashion.

The unique reactivity of in situgenerated propargylic para-quinone methides as a new type of five-carbon synthon has been discovered by a novel bismuth(III)-catalyzed tandem annulation reaction. This 1,8-addition/cyclization/rearrangement cyclization cascade reaction is characterized by unusual structural reconstruction of 2-vinylphenol, involving cleavage of the C1′═C2′ bond and formation of four new bonds. This method provides a convenient and mild approach to generate synthetically important functionalized indeno[2,1-c]chromenes. The mechanism of the reaction is proposed from several control experiments.

In the present work, the uniformly sized bismuthene quantum dots (BiQDs) with an average diameter of 26 nm were fabricated viathe solvothermal approach. By transferring the BiQDs onto the plane of micro-machined D-shaped fiber (DSF), a new type of saturable absorber (SA) was successfully prepared. Based on the evanescent field effect of D-shaped fiber, the prepared SA exhibits excellent saturable absorption properties with the maximum modulation depth of 5.1% at around 1.5 μm. To further investigate its potential applications in ultrafast photonics, we demonstrated passive mode-locking operation in the erbium-doped fiber laser (EDFL) with BiQDs/DSF-SA. The conventional soliton pulses with duration of 835 fs at the repetition rate of 9.23 MHz and dissipative soliton pulses with duration of 575 fs at the repetition rate of 7.83 MHz were generated successfully. In addition, stable bound state of solitons with the pulse duration of 1.04 ps and sub-pulse time interval of 15.9 ps were also obtained based on the conventional soliton state by adjusting the pump power and polarization state. Our work reveals the great potential and capacity of BiQDs/DSF-SA in soliton mode-locking operations and promotes the explorative investigation of bismuth-based optoelectronic devices.

Pansharpening has been extensively studied in recent years. However, one drawback of the known image fusion methods is that the fusion performance is degraded by the registration error. We develops a variational framework for joint pansharpening and registration with structure tensor total variation regularization method. The proposed framework can fully capture the target image’s first-order information around a local neighborhood and align image gradient domain. An efficient optimization method based on the scheme of fast iterative shrinkage-thresholding algorithm (FISTA) is proposed to solve the objective fusion model. This framework consists of two key steps: (i) pansharpening with structure tensor total variation regularization; (ii) image registration in image gradient domain. Extensive experiments demonstrate the effectiveness of our method compared with the existing state-of-the-art fusion models.

Two-dimensional (2D) tin halide perovskites have recently emerged as very promising materials for eco-friendly lead-free photovoltaic devices. However, the fine control of the bulky organic cations orderly embedding into the perovskite structure with a narrow quantum-well width distribution and favorable orientation is rather complicated. In this study, we proposed to introduce the F-substituted phenylethlammonium (PEA) cation (i.e., 4-fluorophenethylammonium FPEA) in 2D tin halide perovskite, which may mitigate phase polydispersity and crystal orientation, thus potentially increasing attainable charge-carrier mobility. A strong interlayer electrostatic attraction between electron-deficient F atoms and its adjacent phenyl rings aligns the crystal structure, working together with the validated dipole interaction. Therefore, the fluorination of organic cation leads to orderly self-assembly of solvated intermediates and promotes vertical crystal orientation. Furthermore, the interlayer electrostatic interaction serves as a supramolecular anchor to stabilize the 2D tin halide perovskite structure. Our work uncovers the effect of interlayer molecular interaction on efficiency and stability, which contributes to the development of stable and efficient low-toxicity perovskite solar cells.

Multiband image fusion has become a thriving area of research in a number of different fields, such as space robotics, and remote sensing, etc. Many multiband image fusion methods have been proposed for hyperspectral sharpening with panchromatic images, hyperspectral sharpening with multispectral images and panchromatic images, etc. Despite the different motivations, we observe that many existing methods possibly lead to over-smooth regions. In this work, we consider a new problem formulation of two image fusion problems. A novel fusion model with total generalized variation regularization term is proposed, where the fusion process is performed on hybrid gradient domains. The optimization framework of alternating direction multiplier of method is used to solve the resulting problem. In an extensive evaluation, our method outperforms some state-of-the-art methods.

Amorphous oxides have unique physicochemical properties with extensive opto-electronic applications such as the thin-film transistor, light-emitting diode backplanes, and supercontinuum generation. In this contribution, we synthesize the amorphous ZrO2/SiO2nanoporous aerogel with high structural integrity. With the femtosecond excitation laser at 800–1,064 nm, the broadband second harmonic generation is observed. The nonlinear optical properties of the as-prepared ZrO2/SiO2aerogel are investigated at 1.0 μm and 1.5 μm for the first time. Subsequently, the amorphous ZrO2/SiO2saturable absorber is originally applied in the Yb-doped and Er-doped fiber lasers to realize the mode-locking operations. In the Yb-doped fiber laser, the dissipative soliton resonance mode-locking operation is demonstrated with the largest pulse duration of 22 ns at a repetition rate of 7.8 MHz and a high signal-to-noise ratio of 64 dB. In the Er-doped fiber laser, a conventional soliton mod-locking regime is observed with an ultrashort pulse width of 960 fs, a repetition frequency of 6.55 MHz, and a time-bandwidth production of 0.347. Our work shows the good ability of the ZrO2/SiO2aerogel in generating ultrafast pulses and extends the saturable absorber into the amorphous material realm.

Herein, we report an efficient Brønsted acid-catalyzed formal (3+3)-annulation of (aza)-para-quinone methides generated in situ from propargylic alcohols with naphthol derivatives, which involves a 1,8-conjugate addition/6-endo annulation process. This protocol provides an effective method for preparing important functionalized pyranocoumarins under mild conditions.

Mid-infrared (MIR) photonics has attracted tremendous interest because of its broad applications at atmospheric windows. In this work, we report high-performance MIR photonics based on large-scale and good-quality monolayer molybdenum disulfide (MoS2). The open-aperture Z-scan measurement on the nonlinear saturable absorption features shows that the as-grown monolayer MoS2possesses a modulation depth of 26% and a low saturable intensity of 271 kW/cm2, enabling its application as an excellent saturable absorber for the MIR pulse generation. This is further evident by the measured high effective nonlinear absorption coefficient βeff(−16 cm/MW). In addition, the two-photon absorption coefficient and the nonlinear refractive index of monolayer MoS2are also determined by the closed-aperture Z-scan technology. As an application, we demonstrate a passively Q-switched Tm,Ho:CaLu0.1Gd0.9AlO4(Tm,Ho:CLGA) disordered crystal laser at 2.1 μm by using the monolayer MoS2as the saturable absorber for the first time, producing a minimum pulse width of 765 ns and a pulse repetition rate of 36 kHz. Our results demonstrate that large-scale monolayer MoS2is a promising candidate for the MIR photonic applications.

Through a liquid-phase synthesis route, zeolitic imidazolate framework-67 (ZIF-67) nanomaterials are prepared and deposited onto a quartz glass to form a new type of saturable absorber (SA), of which nonlinear optical (NLO) properties are measured at a wavelength of 2 μm with a homemade nanosecond pulsed laser. The result shows that the ZIF-67 sample exhibits an excellent NLO response. As an application, a stable passively Q-switched (PQS) 2 μm solid-state laser with ZIF-67 as a SA was demonstrated. The pulsed laser with a minimum pulse width of 278 ns at a repetition frequency of 131 kHz was generated via an output coupler (OC) of 5% transmittance, corresponding to a maximum single-pulse energy of 1.5 μJ. It is the first presentation of a 2 μm solid-state PQS laser with ZIF-67 utilized as a modulator, to the best of our knowledge. Taking into account the laser performance in experiments, ZIF-67 is shown to be a novel nanomaterial for the application of a modulator for mid-infrared (MIR) pulse generation.

An efficient and straightforward Lewis-acid-mediated stereoselective (4 + 3)-cyclization of indole-substituted alkylidene malonates and donor–acceptor cyclopropanes has been developed involving the Friedel–Crafts/Michael addition cyclization cascade. This reaction provides a mild and effective method for the construction of synthetically and structurally interesting functionalized cycloheptannelated indoles.

Satellite image classification plays an important role in many fields. It can be divided into two groups: supervised and unsupervised classification. The former requires a large number of labeled data, while, in practice, satellite images usually lack of sufficient ones. How to achieve high accuracy on unsupervised satellite image classification is a key problem. For tackling this problem, based on the idea of partial transfer learning, we propose an novel end-to-end unsupervised classification method called coordinate partial adversarial domain adaptation (CPADA) for satellite image classification. Under the aid of a novel coordinate loss, our framework transfers relevant examples in the shared classes to promote performance, and ignore irrelevant ones in the specific classes to mitigate negative transfer. Experiments show that our CPADA exceeds state-of-the-art results for unsupervised satellite image classification task.

The emerging photovoltaic technology, namely perovskite photovoltaics, follows a style to the blooming flower with superficial prosperity described by the ancient poet Yuxi Liu. Metal-halide perovskite has become one of the most promising photovoltaic materials for thin-film solar-cell applications, mainly due to its exellent visible light capture capability, large diffusion coefficients and long diffusion lengths of charge carriers (both electrons and holes). The reported power conversion efficiency of laboratory produced perovskite solar cells (PSCs) has exceeded 25%. However, this value was only achieved for devices of less than 0.1 cm2dimensions, and decreases significantly with the increase in area (for example, down to 11.6% for a device area of ∼800 cm2, showing the issues with the scalability). In PSCs, the electron transport layer (ETL) has to perform two essential functions, which are related: (i) to collect and transfer charges after the injection of electrons from the perovskite light harvester; and (ii) to block the backflow of holes, thus realizing effective charge separation and suppressing charge carrier recombination. However, there are several critical issues associated with the ETLs which limit the further development of the PSCs. For example, the experimentally obtained open-circuit voltages in PSCs are typically much lower compared to the theoretical voltage limit with their optical bandgaps between 1.59 and 1.63 eV. This is mainly attributed to inefficient charge transport in the PSCs due to inhomogeneous charge accumulation and serious interfacial recombination at the interfaces between the ETL and the perovskite active layer. We scan recent developments of ETLs in PSCs, and discuss design methodologies, mechanisms, processing and characterization of new types of ETLs. High power conversion efficiency with large open-circuit voltages/photo-currents could be achieved through designing materials and microstructures for high-quality ETLs with a high electron mobility, high electrical conductivity and pinhole-free film morphology. It is crucial to balance the charge diffusion processes in the respective charge collective layers of PSCs as the interfaces between the ETLs and perovskites along with their interfacial structures play key roles in achieving new solid-state mesoscopic solar cells optimized open circuit voltages and output photocurrents.

Few-layered InSe nanosheets were fabricated by the simple liquid-phase exfoliation method. The morphology and crystal structure features of InSe nanosheet sample were characterized comprehensively. The photoluminescence (PL) spectrum indicated that the liquid-phase exfoliated InSe nanosheets contained variously layered nanoflakes, where eight layers nanosheets dominate. In addition, the first-principle simulation was carried out to describe the electron density of states (DOS) and the electronic band structures. Moreover, the few-layered InSe nanosheets performed excellent nonlinear absorption properties in a broad spectral band. As an application, the stable passively Q-switched (PQS) lasers with few-layered InSe nanosheets saturable absorbers (SAs) were realized with the operating wavelengths at 1.06, 1.34, and 1.91 μm. The shortest pulse durations were 599, 520, and 210 ns, respectively. Our results confirmed that the few-layered InSe nanosheets could be an excellent candidate for pulsed lasers in wide spectral bands.

We report the passively $Q$Q-switched (PQS) operation in the near infrared (NIR) regime with as-prepared zeolitic imidazolate framework-67 (ZIF-67) as saturable absorbers (SAs) for the first time, to the best of our knowledge. Based on the excellent saturable absorption properties of the as-prepared ZIF-67, passively $Q$Q-switched Nd:GdVO_4 lasers were achieved operating at $^4{{\rm F}_{3/2}} \to {^2}{{\rm I}_{11/2}}$^4F_3/2?^2I_11/2 and $^4{{\rm F}_{3/2\:}} \to {^2}{{\rm I}_{13/2}}$^4F_3/2?^2I_13/2 transitions. The stable $Q$Q-switched laser’s pulses with a pulse width of 120 ns at a repetition rate of 566 kHz and a pulse width of 108 ns at a repetition rate of 415 kHz were obtained, corresponding to the transition $^4{{\rm F}_{3/2}} \to {^2}{{\rm I}_{11/2}}$^4F_3/2?^2I_11/2 at 1 µm and the transition $^4{{\rm F}_{3/2\:}} \to {^2}{{\rm I}_{13/2}}$^4F_3/2?^2I_13/2 at 1.3 µm, respectively. The results indicate that the ZIF-67 saturable absorber with the advantages of large modulation depth and high thermal stability is a promising saturable absorber candidate for the NIR pulse generation.

Object detection on multi-source images from satellite platforms is difficult due to the characteristics of imaging sensors. Multi-model image fusion provides a possibility to improve the performance of object detection. This paper proposes a fusion object detection framework with arbitrary-oriented region convolutional neural network. First, nine kinds of pansharpening methods are utilized to fuse multi-source images. Second, a novel object detection framework based on Faster Region-based Convolutional Neural Network structure is used, which is suitable for large-scale satellite images. Region Proposal Network is adopted to generate axially aligned bounding boxes enclosing object sin different orientations, and then extract features by pooling layers with different sizes. These features are used to classify the proposals, adjust the bounding boxes, and predict the inclined boxes and the objectness/non-objectness score. Smaller anchors for small objects are considered. Finally, inclined non-maximum suppression method is utilized to get the detection results. Experimental results showed that the proposed method performs better than some state-of-the-art object detection techniques, such as YOLO-v2, YOLO-v3, etc. Some numerical tests validate the efficiency and effectiveness of the proposed method.

Few-layered ${{\rm MoSe}_2}$MoSe_2 nanosheets were prepared by the low-cost, simple liquid-phase exfoliation method. The ${{\rm MoSe}_2}$MoSe_2 nanosheets possessed the modulation depth of 16.5% with a saturation intensity of ${0.84}\;{{\rm MW/cm}^2}$0.84MW/cm^2 at 1.34 µm, indicating the performance as the saturable absorber. The passively $Q$Q-switched c-cut ${\rm Nd}:{{\rm GdVO}_4}$Nd:GdVO_4 laser at 1.34 µm was demonstrated with the few-layered ${{\rm MoSe}_2}$MoSe_2 saturable absorber for the first time. The minimum pulse duration of 420 ns at a repetition rate of 238 kHz could be obtained. In order to significantly reduce the pulse duration, dual-loss modulation simultaneously using both ${{\rm V}^{3 + }}:{\rm YAG}$V^3+:YAG and ${{\rm MoSe}_2}$MoSe_2 saturable absorbers was implemented. The pulse duration was compressed to a 82.4 ns pulse at a repetition rate of 409.3 kHz at the pump power of 10.66 W. The experimental results provide a solid fundament for the short pulse generation with ${{\rm MoSe}_2}$MoSe_2 saturable absorber at 1.34 µm.

With strict enforcement of the legal protection for Asian elephants (Elephas maximus) in China, the elephant population has steadily increased from 146 elephants in 1976 to over 300 elephants in 2023. More elephants occur in highly fragmented and human‐dominated landscapes, resulting in serious human–elephant conflicts (HEC). We investigated the temporal and spatial aspects of HEC in Xishuangbanna Prefecture, China, from 2011‒2015 and 2016‒2020. We analyzed the characteristics of crop raiding, property damage, and human injury and death by elephants. Then, we employed a multi‐model ensemble forecasting framework to perform a risk assessment, and compared the changes in HEC hotspots to explore the factors influencing conflict. Our data revealed that 91,311 HEC compensations were recorded from 2011‒2020 with a total compensation amount of 127.01 million yuan (17.40 million USD), 89.75% of which was crop compensation. Areas of risk in 2011‒2015 and 2016‒2020 were 2,505 km2and 3,157 km2, respectively, with an increase in area of 26.01%. The HEC risk areas were mainly distributed in nature reserves and surrounding areas, and >65% of the risk areas were located in land‐use types dominated by artificial planting. Distance to farmland, distance to sparse wood, and slope had the greatest relative importance in the risk model evaluation. The mitigation measures that we recommend include strengthening the monitoring system for Asian elephants in areas with current and potential HEC risks; improving compensation mechanisms, such as determining accurate annual premiums, establishing a shared loss compensation mechanism, and ensuring a fair, transparent, and timely compensation process; and proposing habitat conservation measures, such as restoring suitable habitats for Asian elephants, establishing ecological corridors between nature reserves, and creating a nature reserve system based on the Asian Elephant National Park to enhance the habitat of Asian elephants. We investigated elephant damage characteristics, predicted the human–elephant conflict risk distribution, and analyzed hotspots in Xishuangbanna, China. We present new interpretations relevant to the conservation of Asian elephant populations in China, which will contribute to guiding effective policy development and achieving conservation goals in China and other Asian elephant range countries.

The δ subunit-containing GABAAreceptor [GABAA(δ)R], which is exclusively situated in the extrasynaptic space, has considerable influence on emotion and behavior. Although the expression of this receptor experiences dramatic fluctuation during postnatal development, it remains unknown whether it regulates emotion in a development-dependent manner. Here, by using mice with genetic deletion of GABAA(δ)R (knockout) and their wild-type littermates, we examined the role of GABAA(δ)R in regulating anxiety-like behavior, as measured with open field test (OFT) and elevated plus maze during the transition from puberty to adulthood. We observed that for female mice, the knockout ones at puberty but not adulthood showed increased anxiety-like behavior in the OFT relative to their wild-type littermates. However, such increase was not observed in elevated plus maze. For male mice, no between-genotype differences were observed in both tests at the above two developmental stages. Our results suggest that GABAA(δ)R preferentially affects the anxiety-like behavior in OFT in a development-dependent manner, but only in female mice.

•Novel donor-acceptor-donor small molecular hole transport materials were reported.•Devices using the novel material achieve a power conversion efficiency of 14.21%.•Novel material show advantages in hole mobility and conductivity over spiro-OMeTAD.

For maneuvering target-tracking problem, suboptimal H∞filtering is a typical approach to acquire robust target trajectory with optimized conservativeness. However, for tracking a space target that has intermittent thrust, disturbance strength is time variant in finite horizon and the level of filtering robustness should become adaptive to the variation of system uncertainties. Considering that the traditional suboptimal H2/H∞filter expresses infinite-horizon robustness, kept at constant level, in this paper, we proposed a new adaptive suboptimal H∞filter (ASO-H∞F) to establish the robustness-level adaptability. The proposed ASO-H∞F is built on a standard H∞F, embedded by an adaptive mechanism. The mechanism is derived by minimizing a unified optimality-robustness cost function (ORCF), where the weight ratio we named robustness-level index (RLI) provides a flexible level of filtering robustness. The RLI is designed as a function adaptive to real disturbance strength and tunable with an innovation sensitivity exponent (ISE) of controlling the sensitivity to disturbance. With introduction of the adaptive RLI, robustness level of the ASO-H∞F can vary with real-time disturbance strength, leading to the best balance between filtering precision and accuracy. In the ASO-H∞F, ISE is the only parameter need given for filter implementation, independent with any system uncertainty. In addition, due to the extension of suboptimal scheme, the ASO-H∞F represents a unified form of suboptimal H∞filters. A numerical example of space-maneuvering target tracking has illustrated the superior estimation performance of the ASO-H∞F to other typical H∞filters.

Soft robots refer to robots that are softer and more flexible when compared with conventional rigid-bodied robots. Soft robots are adapted to unstructured environments due to their flexibility, deformability and energy-absorbing properties. Thus, they have tremendous application prospects in on-orbit servicing (OOS). This study discusses the configuration and manipulation of soft robotics. Usually, learning from living beings is used to develop the configurations of most soft robots. In this study, typical soft robots are introduced based on what they mimic. The discussion of manipulation is divided into two parts, namely actuation and control. The study also involves describing and comparing several types of actuations. Studies on the control of soft robots are also reviewed. In this study, potential application of soft robotics for on-orbit servicing is analyzed. A hybrid configuration and manipulation of space soft robots for future research are proposed based on the current development of soft robotics, and some challenges are discussed.

The role of δ subunit-containing GABAAreceptor (GABAA(δ)R) in fear generalization is uncertain. Here, by using mice with or without genetic deletion of GABAA(δ)R and using protocols in which the conditioned tone stimuli were cross presented with different nonconditioned stimuli, we observed that when the two tone stimuli were largely similar, both genotypes froze similarly to either of them. However, when they differed markedly, the knockout mice froze much more than their wild-type littermates to the nonconditioned but not conditioned stimuli. Thus, GABAA(δ)R may prevent inappropriate fear generalization when the incoming stimuli differ clearly from the learned threat.

It is a challenge to investigate the interrelationship between the geometric structure and performance of sensor networks due to the increasingly complex and diverse architecture of them. This paper presents two new formulations for the information space of sensor networks, including Lagrangian and energy–momentum tensor, which are expected to integrate sensor networks target tracking and performance evaluation from a unified perspective. The proposed method presents two geometric objects to represent the dynamic state and manifold structure of the information space of sensor networks. Based on that, the authors conduct the property analysis and target tracking of sensor networks. To the best of our knowledge, it is the first time to investigate and analyze the information energy–momentum tensor of sensor networks and evaluate the performance of sensor networks in the context of target tracking. Simulations and examples confirm the competitive performance of the proposed method.

Protectin conjugates in tissue regeneration 1 (PCTR1) is a novel anti-inflammatory and proresolving lipid mediator biosynthesized from docosahexaenoic acid. Excessive activation of NLR family pyrin domain containing 3 (NLRP3) inflammasome and consequent pyroptosis are involved in diverse inflammatory diseases. However, how PCTR1 affects NLRP3 inflammasome activation and pyroptosis are still unclear. Here, we demonstrated that PCTR1 inhibited NLRP3 inflammasome activation and pyroptosis. These results show that PCTR1 dose-dependently inhibited gasdermin D cleavage in lipopolysaccharide (LPS)-primed murine primary macrophages upon nigericin stimulation. Additionally, PCTR1 treatment after LPS priming inhibited caspase-1 activation and subsequent mature interleukin-1β release independent of the nuclear factor-kappa B pathway. PCTR1 exerted its inhibitory effects by blocking NLRP3-apoptosis-associated speck-like protein containing a CARD (ASC) interaction and ASC oligomerization, thereby restricting NLRP3 inflammasome assembly. However, the inhibitory effect of PCTR1 could be reversed by KH7 and H89, which are the inhibitors of the cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) signaling pathway. Moreover, PCTR1 treatment alleviated lung tissue damage and improved mouse survival in LPS-induced sepsis. Our study unveils the molecular mechanism of negative regulation of NLRP3 inflammasome activation and pyroptosis by a novel lipid mediator and suggests that PCTR1 may serve as a potential treatment option for NLRP3-inflammasome driven diseases.

Here, we investigated the nonlinear optical (NLO) characteristics of carboxyl-functionalized graphene oxide (GO-COOH) in the near-infrared (NIR) region. The results revealed that GO-COOH samples exhibit strong saturable absorption at low pump levels and a gradual transition to reverse saturable absorption (RSA) with increasing pump power. Then the saturable absorber (SA) by depositing the GO-COOH on the side-polished fiber (SPF) was employed in Yband Er-doped fiber lasers. Stable ultrashort pulses operating in the dissipative soliton (DS) and conventional soliton (CS) regimes were obtained with pulse widths of 26.6 ps and 968 fs, respectively. Besides, the dissipative soliton resonance (DSR) phenomenon caused by the RSA of GO-COOH was also observed with increasing pump power. The high-stable DSR mode-locked pulses with the maximum pulse energy of 1.91 nJ and 0.74 nJ were obtained in YDFL and EDFL respectively. These results not only reveal the potentiality of GO-COOH in ultrafast photonics applications but also open a new avenue to explore high-pulse-energy laser sources based on two-dimensional materials.

We synthesized monoclinic bismuth vanadate (m-BiVO4) nanoparticles via the sol-gel method. The modulation depths were 20.1% and 8.8% at 1.34 and 2 μm, respectively. Passively Q-switched bulk lasers with m-BiVO4saturable absorber were demonstrated operating at 1.34 and 2 μm. At 1.34 μm, the shortest pulse duration was 355 ns with a pulse repetition frequency of 242.6 kHz, while in a Tm-doped bulk laser at ∼2 μm, the minimum pulse width was 540 ns with a pulse repetition rate of 53.7 kHz. Results showed that m-BiVO4possessed good broadband optical nonlinearities and can be applied for the optical pulse generation.

Electrical safety is a major threat to public safety worldwide, with fires and explosions causing damage to property and loss of life. Detection and monitoring of the occurrence of destructive current spikes can provide valuable insights into system health and inform preventative maintenance. Current sensors based on the Magnetoelectric (ME) effect have been regarded as optimal solutions because of the low power consumption and high sensitivity of ME devices compared to conventional current sensors (current transformers, Hall-effect current sensors, etc.). However, none of the conventional sensing techniques can provide ex-situ recording or a means for a human-readable signal output. Development of a current sensor that can sense, visualize, and record a current level remains a challenge. Here, we report an electric current visualization sensor that uses a coupled magnetoelectric/electrochromic effect to transform environmental current energy into electrical signals, and subsequently to a color change readily interpreted by a human observer. The current visualization sensor uses a PZT piezoelectric microfiber composite (MFC) / FeSiB alloy (Metglas) laminate combined with a Prussian blue-based electrochromic device (ECD). Such a current sensor demonstrates high efficiency self-powered current sensing and non-volatile signal recording.

We report VO_x/NaVO _3 nanocomposite as a novel saturable absorber for the first time, to the best of our knowledge. The efficient nonlinear absorption coefficient and the modulation depth are determined by the Z-scan technology. As a saturable absorber, a passively Q-switched Nd-doped bulk laser at 1.34 µm is demonstrated, producing the shortest pulse duration of 129 ns at a repetition rate of 274 kHz. In the passively Q-switched Tm:YLF laser with the prepared saturable absorber, the shortest pulse duration was 292 ns with a repetition rate of 155 kHz. Our work confirmed the saturable absorption in VO_x/NaVO _3 for possible optical modulation in the near-infrared region.

"HaiYangShiYou 115" chain cable in use process was found in more broken wires. Through the chemical composition analysis, mechanical property testing, fracture analysis, metallographic examination methods, the cause of the broken wire are analyzed. The results show that: the material of steel cable anchor chain mechanical performance is basic comply with the design requirements, the broken wire fracture is relatively serious wear, all send the samples of the present wear trace shape is consistent, should be the same kind of wear the way by damage, and reduced the steel wire tensile strength, lead to fracture .

The dynamic temperature field of a concrete pier is actively studied in this study with the aiding of the commercial package ANSYS. Thermal boundary conditions are utilized to obtain the temperature distribution of the concrete bridge pier. The surface temperature of the pier is measured by using a thermal infrared imager at different time instant. The ambient temperature and wind velocity are also collected at the same time. The made observations demonstrate that the simulated temperature variation of the concrete pier agrees well with measurement results. The thermal gradient of the concrete in the thickness direction is a little large. It is seen that the numerical models can successfully predict the structural temperature field at different time. The methodology employed in the paper can be applied to other concrete bridges as well.

Starch as the material, MBAA as the cross-linking agent, Tween60 and Span60 as the emulsifier, K2S2O8-Na2SO4 as the initiator, the cyclohexane as the oil phase and the removal rate of methyl violet as an index, crosslinked starch microspheres (CSM) was synthetized by means of reverse suspension emulsion and graft-copolymerization method through orthogonal test and single factor optimization experiment. The results showed the optimal conditions of the preparation of the crosslinked starch microspheres(CSM) were as follow: the concentration of the starch is 5%, the dosage of the MBAA, initiator and emulsifier are 0.125g, 0.5g and 0.6g, the volume ratios between the Span60 and Tween60 is 85:15, and the volume ratio between the cyclohexane and water is 4:1.

Some conditional experiments for the preparation of Poly Silicate Aluminium Ferric Boron (PSAFB) composite flocculant and its coagulation and flocculation for the removal of CODCr were conducted and discussed．Preliminary results show the optimum synthesis condition as follows: Si/Al( mole ratio) =2/1, Si/Fe( mole ratio)=1/1,Si/B( mole ratio)=10/1. Under optimal operating conditions，PSAFB can remove 69.3％ of CODCr from the printing and dyeing wastewater.

AbstractRiver and sediment have unique carbon dynamics and are important sources of the dominant greenhouse gases (GHG), carbon dioxide (CO2) and methane (CH4). To understand the relationship between CO2/CH4emissions and water quality/sediment characteristics, we have investigated critical parameters in the river water. Eight parameters of water quality (dissolved oxygen, oxidation-reduction potential [ORP], chemical oxygen demand, biochemical oxygen demand [BOD5], suspended solid, nitrate [NO3‐], NH4+, and bacteria) and four sediment characteristics (total organic carbon [TOC], total nitrogen [T-N], NO3‐, and ammonium [NH4+]) were measured in two of the larger rivers in Taiwan, and relevant environmental conditions were recorded. The experimental results indicated that CO2emissions from the river were mainly affected by BOD5concentrations and the levels of bacteria. CH4emissions, on the other hand, were greatly affected by the ORP in the river. The correlation between CO2emissions and sediment characteristics was insignificant (R2< 0.3). However, TOC and T-N in the sediment may lead to increases in CH4emissions into the atmosphere. A deeper analysis of the relationship between the different parameters and GHG emissions by ANOVA and the multiple regression method revealed that CO2emission (y) was significantly related to bacteria number (x1) and BOD concentration (x2). The regression equation takes the form y= 0.00032x1+ 3.18089x2+ 25.37304. Also, the regression relationship between CH4emission (y) and ORP (x) in the river can be described as y= ‐0.825216x+ 169.02257. The relationship between CH4emission and sediment characteristics may be described as y= 5.073962x1(TOC)+ 2.871245x2(T-N)‐ 12.3262. Extra sampling data were collected to examine the feasibility of the developed multiple regression equations. The experimental results suggest that the emissions of such GHGs as CO2and CH4from rivers can be predicted using the regression equations developed here. Moreover, the emissions may be reduced by manipulating the proper factors.

In this study, ferroelectric Pb 0.6 Sr 0.4 TiO 3 (PST) thin films have been grown on a commercial stainless steel (SS), and metallic oxide La 0.5 Sr 0.5 MnO 3 (LSMO) buffered SS substrates, using pulsed laser deposition. Ferroelectric and dielectric properties of PST thin films were evaluated, PST films exhibited much higher dielectric constants and fatigue-resistance with LSMO-buffered substrate. The ferroelectric properties of PST/LSMO/SS layers are also pronouncedly improved. The present study also indicates that dielectric constants and leakage current density of PST/LSMO/SS films is superior to those obtained from PST/SS films. Ferroelectric properties of PST/LSMO/SS films are much more fatigue-resistant than those of PST/SS films. The results indicate that the electric properties of PST films were significantly influenced by the condition of films/electrode interfaces.

In this study, the PbZr 0.52 Ti 0.48 O 3 (PZT) thin films were prepared by a sol-gel route and spin coated on TiNi-films pre-coated Si substrates, Tini/Si, is both the bottom electrode and the substrate. XRD patterns of 630 -furnace annealed PZT/TiNi/Si films exhibit complicated mixed phases of titanium oxide and nickel oxide diffraction peaks due to the high-temperatures and an oxidizing atmosphere during PZT crystallization. A low-temperature process using CO 2 laser annealing was employed to treat the PZT/TiNi heterostructures. Additionally, a Pt diffusion barrier was deposited between PZT and TiNi to prevent interactions during PZT pyrolysis at 400 . After laser annealing, PZT films crystallized into the perovskite phase and secondary ion mass spectroscopic measurements imply that the interactions between the PZT and the TiNi films could be reduced pronouncedly by introducing the Pt layer. On the other hand, the dielectric constants increase and tan i is reduced when PZT/Pt/TiNi/Si films are subjected to laser annealing with simultaneous substrate heating.

AbstractElectrical properties of ferroelectric Pb0.6Sr0.4TiO3films with La0.5Sr0.5CoO3/Pt and La0.5Sr0.5MnO3/Pt electrodes prepared by the pulsed laser deposition technique were studied in the present work. The experimental results suggest that the PSrT films on La0.5Sr0.5MnO3/Pt electrodes show several superior properties to those on La0.5Sr0.5MnO3/Pt, namely, the larger magnitude of remanent polarization and the higher dielectric constants. Furthermore, the remanent polarization increased and the coercive field shows much slower increasing rate for La0.5Sr0.5MnO3as bottom electrode after the application of an electric field of 400 kV/cm for 1×1010switching cycles. The La0.5Sr0.5MnO3/Pt electrode has been shown to enhance the ferroelectric and fatigue properties of Pb0.6Sr0.4TiO3thin films.

Pb0.6Sr0.4TiO3 (PSrT) thin films are grown on various substrates such as: (m00)-textured La0.5Sr0.5CoO3 (LSCO)/Si, In2Sn2O7-x (ITO)/glass and amorphous glass using Pulse-laser-deposition (PLD). X-ray diffraction results show that the structure and the lattice parameters of the substrate greatly influence the growth of PSrT films. For example, (001)-oriented PSrT films can be successfully deposited on the substrates with (m00)-textured LSCO films and ITO/glass substrates. (100)-like PSrT films tend to grow on the amorphous glass substrates. Both element diffusion and structure stability were found to play an important role on the ferroelectric properties of these deposited films. Microstructural characteristics as well as the electric and optical properties are compared and discussed.

AbstractPb0.6Sr0.4TiO3(PSrT) thin films were fabricated on perovskite buffer layers, La0.5Sr0.5CoO3(LSCO), La0.5Sr0.5MnO3(LSMO) and modified-SrTiO3on either the Si(100) wafer or the Pt/Ti/SiO2/Si substrates using pulsed-laser-deposition technique in the present work and ferroelectric as well as fatigue properties of the specimens were investigated. Polarization-electric field (P-E) measurements imply that PSrT films deposited upon LSCO and LSMO buffer layers exhibit different ferroelectric characteristics after repeated loading. Ferroelectric properties of PSrT films on various buffer layers are quite different and ferroelectric properties deteriorate quickly if the resistance of the buffer is high. PSrT films on oxide/Pt electrodes show ferroelectric properties with higher remanent polarization, lower coercive field and better fatigue-resistance than those of PSrT on an oxide electrode. It is easier to prepare high quality PSrT/LSMO/Pt than to fabricate PSrT/LSCO/Pt. Fatigue resistance of PSrT/LSMO/Pt is better than that of PSrT/LSCO/Pt, which can be attributed to the interfacial stress condition as well as atomic interdiffusion of the films.

Abstract: Power spectral characteristics of the seismic activities before and after the seven large earthquake — Haicheng, Tangshan, Lancang, Longling, Mabian, Puer and Songpan are studied by spectrum analysis method. The results show that they all have continuous power spectrum and aperiodic behaviour. When the time away from the large earthquake occurrence, the characteristics of the seismic activities are obviously accompanied by stochastic components. About one year before main shock, the moving orbits constructed by spectrum amplitudes showed the contracting tendency. And the properties during that time may display as flicker noise. One’s another time almost mixed whole phase space. But the essence of seismic activities after main shocks is a chaotic state accompanied with much noises.