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Joint communications and sensing (JCAS) is regarded as a major technology building block in 6G networks. The combination of communications and radar sensing systems benefits from saved hardware costs, reduced energy consumption, and less spectrum occupation. Phase-modulated continuous waveform (PMCW) is regarded as an attractive candidate waveform for future automotive JCAS systems due to its perfect anti-interference properties and radar sensing performance. However, PMCW-based JCAS systems usually suffer from extremely low data rates and undesirable communications reliability in dynamic environments, limiting their applicability in traffic scenarios, where the propagation channel may suffer from a high Doppler shift and spread and a large data throughput is expected. To overcome the shortcomings, in this work, a novel PMCW approach with simultaneously transmitted pilot and data sequences, named code-orthogonal PMCW (CO-PMCW), is introduced. The presented CO-PMCW approach benefits from significantly improved data rate and robustness in dynamic environments. Regarding the differences in system architecture between PMCW and CO-PMCW, the authors verified the advantages and investigated the potential side effects of the CO-PMCW system. The properties including the interference between the pilot and data, influence on transmission power, behavior in multipath fading channels, etc. are measured. The result shows that the presented CO-PMCW approach significantly improves the communications performance with slightly influenced radar properties. Based on the simulation result, the application feasibility and scenarios of the CO-PMCW-based JCAS system are analyzed.

Joint communications and sensing (JCAS) is regarded as a key technology of 6G communications since it allows the integration of sensing functions into communications networks with lower hardware costs, less energy consumption, and saved spectrum. As distributed sensing benefits from increased spatial diversity and accuracy, the combination of coordinated multipoint (CoMP) transmission technology and JCAS has become an attractive research direction. CoMP transmission has been applied in 4G and 5G communications networks due to its attractive capability in suppressing inter-cell interference and improving channel capacity, while CoMP sensing and CoMP JCAS have been widely discussed in recent years. However, relevant researches mainly focus on waveform design and optimization issues in the processes of CoMP signal transception and processing, while their system architecture and operation modes are less discussed. To fill the blank in these areas and discuss the benefits provided by CoMP JCAS, in this work, based on the modern CoMP transmission technologies in state-of-the-art mobile network architecture, we analyze the network architecture and required enabler technologies of CoMP JCAS in future mobile networks, focusing on the sensing aspect. In addition, we propose the potential sensing operation and clustering types and discuss their respective advantages and shortcomings. In the simulation, the sensing coverage and accuracy of different CoMP sensing types and conventional standalone sensing are compared. The simulation results show that CoMP sensing outperforms conventional single-radar sensing in accuracy, and the difference between them increases with the distance between the sensors. In addition, it is described that the coordinated passive sensing scheme extends the service area, while the active sensing scheme benefits from higher accuracy with the same bandwidth.

The sixth generation (6G) mobile communication networks are expected to intelligently integrate into various aspects of modern digital society, including smart cities, homes, health-care, transportation, and factories. While offering a multitude of services, it is likely that societies become increasingly reliant on 6G infrastructure. Any disruption to these digital services, whether due to human or technical failures, natural disasters, or terrorism, would significantly impact citizens’ daily lives. Hence, 6G networks need not only to provide high-performance services but also to be resilient in maintaining essential services in the face of potentially unknown challenges. This paper provides a general review of the state of the art on resilient systems, definitions, concepts, and approaches. Moreover, it introduces a comprehensive concept, i.e., resilience-by-design (RBD), in three different levels for designing resilient 6G communication networks, summarizing our initial studies within the German Open6GHub project. First, we outline the general RBD enabling principles and discuss their related sub-categories. Next, adopting an interdisciplinary approach, we propose to embed these principles across all 6G layers/perspectives including electronics, physical channel, network components and functions, networks, services, and cross-layer and cross-infrastructure considerations and discuss their challenges. We further elaborate the RBD principles and their realizations along with several 6G use-cases. The paper is concluded by presenting a comprehensive list of open problems for future research on 6G resilience.

Existing testing methods inadequately capture the internal stress state of concrete, a vital structural safety metric, resulting in a divergence between measured and actual internal stress states, especially in larger structures. There is an urgent need for innovative theoretical and technical approaches that can directly, accurately, and instantly reflect the internal stress state of concrete, meeting the growing demand for such detection. This paper conducts experimental research on the internal stress detection of concrete based on the principle of displacement current. Firstly, the theoretical relationship between the internal stress and oscillation frequency of concrete is established. Secondly, two dielectric plates are embedded in the concrete specimen as a sensing unit, and an LC oscillation circuit is connected externally to express the internal stress state of the concrete in the form of oscillation frequency. The research findings suggest that there is a decrease in the oscillation frequency as the dielectric constant of the concrete increases. Additionally, a significant change in the oscillation frequency is observed because of the dielectric polarization effect that takes place during the pouring and curing of the concrete specimen. The concrete age starts from about 25 days, and its oscillation frequency gradually stabilizes; the internal stress of the concrete is proportional to the oscillation frequency, and they show a good correlation in the experiment.

JCRS applications are currently being hailed as the innovation of the next generation of mobile communications. The combination of communications and sensor technology on one hardware platform offers various advantages, such as significant savings in space and costs. The two technologies are no longer being optimized and developed side by side, as has been the case in the past, but jointly. The physical channel is used by both simultaneously, including the transmitter and receiver structures, which must be optimized for the combined application. This inevitably leads to an influence on the performance of both systems. In this work, this influence is considered and analyzed with respect to the effects of the radio frequency components. For this purpose, our previously published code-division multiple access (CDMA)-based and vehicle-to-vehicle-focused model is extended to a joint communications and radar sensing (JCRS) model and evaluated according to the achieved bit error rate as well as the mean deviation of the detected distance and velocity in Simulink. The influence of the non-ideal hardware components (mixers, power amplifier, low noise amplifier, filter, antenna) and characteristics (S-parameters, non-linearity of the amplifiers and the noise) on the sensing and communications are analyzed and compared in this automotive context. The results reveal that the noise of the low noise amplifier at the receiver side has the most decisive influence. In contrast, the noise generated by the power amplifier at the transmitter has no effect due to the relatively high signal power. The non-linearity of amplifiers at the transmitter also significantly impacts the available sensing range by limiting and compressing signal power. Besides, the phase noise with a frequency offset higher than 10MHz can increase the communications and sensing error rate. In contrast, the influence of S-parameters is negligible, as the performance of communications and sensing is almost unchanged with different S-parameters. In the future, the proposed single-target scene will be further extended to a multi-target one.

Microbial activities play a pivotal role in the migration and transformation of arsenic (As) within groundwater systems, particularly at high concentrations. Focusing on the Kuitun River Basin, this study used high-throughput sequencing to unravel the intricate diversity of microbial communities and their influence on As enrichment. Groundwater with elevated As hosted richer and more diverse microbial populations compared to that with lower As levels. The Sobs and Shannon diversity indices for the high-As group initially declined before rising with increasing As concentrations. Key microbial taxa dominating these ecosystems included Pseudomonas , Acinetobacter , Aquabacterium , Novosphingobium , and Sphingobium , with Pseudomonas showing substantial variation in abundance across different As concentrations. Distance-based redundancy analysis emphasized the importance of dissolved oxygen in shaping the microbial landscape, followed closely by the interplay between iron and As concentrations. Flavobacteriaceae and Burkholderiaceae displayed inverse correlations with As levels, highlighting the multifaceted relationship between microbial communities and groundwater chemistry. This investigation underscores the profound impact of As concentration gradients on microbial biodiversity and elucidates a complex regulatory framework where environmental parameters and microorganisms collaborate in governing As accumulation in groundwater. The results enrich our understanding of the biogeochemical dynamics underlying arsenic behavior in subterranean aquatic habitats.

Vehicular communication systems get more and more attention with the upcoming fifth and sixth generation. Hereby, the focus lies on the development of the co-design or co-existence of communications and sensing. So called joints communications and radar sensing systems are seen as one key technology of 6G. As joint systems will have shared waveforms and hardware platforms, there is a huge benefit in cost and space which is one essential argument for the automotive industry. However, to design such a system for new applications like platooning or intersection assistance a physical layer has to be set up to represent the real physical layer properly. The proposed system design closes the lack of such a simulation tool and allows for full physical layer simulations, including e.g. the hardware non-idealities and the channel model for 77GHz. The whole signal processing chain of the physical layer is built up and will be integrated in the higher layer state-of-the-art simulation frameworks like Veins or Artery in the next step. The communications design is developed in Simulink, whereas the sensing part is discussed. The proposed communications architecture covers several transmission approaches (serial, parallel), a CDMA based spreading, a radio frequency representation, the channel (simulated in a 3D-Ray-Tracing-tool) and the receiver structure (e.g. the synchronisation or the channel estimation). Several design criteria are discussed, like the serial or parallel design architecture, the maximum ratio combining or the phase and frequency compensation method. The whole system architecture is freely available (https://doi.org/10.5281/zenodo.6482565) and in consequence, the different signal blocks and parameters can be enabled or disabled for evaluations according to future design criteria requirements.

Stress loss of prestressed steel strands of existing bridges influences their bearing capacity, so it is of great significance to realize the stress detection. A steel strand that has an inductive property is designed into the resonant circuit, which can realize the stress measurement of the steel strands by testing the resonant frequency. This method is a promising approach for the stress detection of the steel strands. Previous research found that structural stress made the permeability of steel strands change due to the influence of magnetoelastic effect. In the process, the length of steel strands is also changed. Therefore, further research needs to be done to verify the main influence parameter affecting the resonant frequency of the circuit. Furthermore, it is very important to know how the stress affects the resonant frequency to realize the detection of the prestressed force of the steel strands. Therefore, in this paper, the relationship between stress and relative permeability and length is analyzed theoretically, and the theory of stress frequency of steel strands is modified and verified by experiments. The stress-frequency experiments of steel strands and aluminum strands with great difference in relative permeability are carried out. Experiments on stress frequencies of 7-Ф15.20 mm steel strands with different lengths are carried out. The influence of length and permeability parameters on resonance frequency is analyzed. The experimental results show that under the same conditions, the resonant frequencies of steel strands and aluminum strands are almost the same on LC electric circuits, and the resonant frequency decreases linearly with the increase of the natural length of the component and increases linearly with the increase of stress. Consequently, compared with the influence of length change on LC electromagnetic resonance frequency, the relative permeability of the stress change component can be ignored. The stress changes the resonant frequency mainly by changing the length of the strands.

This study aims to enhance the digital drilling process monitoring (DPM) or monitoring while drilling (MWD) technique, which is a widely recognized method in geological exploration for evaluating rock mass quality. First, robust displacement and torque measurement facilities for rotary-core drilling are discussed. The conventional cable encoder for displacement measurement is replaced with a magnetostrictive displacement sensor, which is more reliable in harsh field drilling environments. This enables the measurement of the bit position with an accuracy of 1 mm. In addition, by measuring the electric current of the driving motor, the torque applied to the bit is conveniently and accurately converted. These innovations ensure high-quality data collection for DPM practices. Second, two indices derived from DPM are proposed to quantitatively describe rock mass quality. The specific energy index (SEI) and specific penetration index (SPI) are based on the principles of energy conservation and Mohr-Coulomb failure criterion, respectively. Extensive field tests conducted in a dam grouting area confirm a linear relationship between the thrust force and penetration per rotation, and between the torque and penetration per rotation. The correlation ratios of the related regressions are typically >0.9. These two indices allow for the quantitative interpretation of DPM data into rock mechanics characteristics, such as uniaxial compressive strength, rock quality designation (RQD), and rock mass permeability, eliminating the need for subjective judgment normally involved in the currently used rock mass quality rating approaches.

Abstract Background The intestinal barrier is the first line of defense against intestinal invasion by pathogens and foreign antigens and is closely associated with the gut microbiota. Astragalus polysaccharides (APS) have a long history of use in traditional Chinese medicine owing to its protective properties against intestinal barrier function. The mechanism of APS-induced gut microbiota enhancing intestinal barrier function is urgently needed. Results Dietary polysaccharide deprivation induced intestinal barrier dysfunction, decreased growth performance, altered microbial composition (Faecalibacterium, Dorea, and Coprobacillus), and reduced isobutyrate concentration. The results showed that APS facilitates intestinal barrier function in broiler chickens, including a thicker mucus layer, reduced crypt depth, and the growth of tight junction proteins. We studied the landscape of APS-induced gut microbiota and found that APS selectively promoted the growth of Parabacteroides, a commensal bacterium that plays a predominant role in enhancing intestinal barrier function. An in vitro growth assay further verified that APS selectively increased the abundance of Parabacteroides distasonis and Bacteroides uniformis. Dietary APS supplementation increased the concentrations of isobutyrate and bile acid (mainly chenodeoxycholic acid and deoxycholate acid) and activated signaling pathways related to intestinal barrier function (such as protein processing in the endoplasmic reticulum, tight junctions, and adherens junction signaling pathways). Conclusions APS intervention restored the dietary polysaccharide-induced dysfunction of the intestinal barrier by selectively promoting the abundance of Parabacteroides distasonis, and increasing the concentrations of isobutyrate and bile acids (mainly CDCA and DCA). These findings suggest that APS-induced gut microbiota and metabolic niches are promising strategies for enhancing intestinal barrier function. Graphical Abstract

Using the case studies of China’s shared bicycle and mobile battery-sharing industries, this report examines how late entrants reversed leading firms that gained a competitive advantage in emerging industries. The first entrant gained a competitive advantage in both industries by quickly occupying the first-tier city market. However, the rise of second-tier and lower-tier city markets has led to a phenomenon where the first entrant has been overtaken by a late entrant that has consolidated its position in the second-tier and lower-tier cities. This report traces the behavior of each player in the two industries over time and analyzes each player’s learning in different markets and its response to changes in the market environment. The analysis revealed that under market uncertainty, although the market entered by the late entrant grew to become the main market, the resources and capabilities accumulated by the early entrant in the market were not adaptable to the market entered by the late entrant, resulting in the late entrant overtaking the early entrant.

High-temperature furnaces and coal-fired boilers are widely employed in the petrochemical and metal-smelting sectors. Over time, the deterioration, corrosion, and wear of pipelines can lead to equipment malfunctions and safety incidents. Nevertheless, effective real-time monitoring of equipment conditions remains insufficient, primarily due to the interference caused by flames generated from fuel combustion. To address this issue, in this study, a through-flame infrared imager is developed based on the mid-wave infrared (MWIR) radiation characteristics of the flame. The imager incorporates a narrowband filter that operates within the wavelength range of 3.80 μm to 4.05 μm, which is integrated into conventional thermal imagers to perform flame filtering. This configuration enables the radiation from the background to pass through the flame and reach the detector, thereby allowing the infrared imager to visualize objects obscured by the flame and measure their temperatures directly. Our experimental findings indicate that the imager is capable of through-flame imaging; specifically, when the temperature of the target exceeds 50 °C, the imager can effectively penetrate the outer flame of an alcohol lamp and distinctly capture the target’s outline. Importantly, as the temperature of the target increases, the clarity of the target’s contour in the images improves. The MWIR through-flame imager presents considerable potential for the real-time monitoring and preventive maintenance of high-temperature furnaces and similar equipment, such as detecting the degradation of refractory materials and damage to pipelines.

ABSTRACT Dietary polysaccharides are closely associated with gut microbiota and intestinal function homeostasis. This study aimed to investigate the mechanisms by which the β-glucan, arabinoxylan, and resistant starch selectively modulate gut microbiota and microbiota-derived metabolites to protect the intestinal mucus barrier in broiler chicken. In the present study, cecal microbiota samples from 21-day-old broilers were cultured in vitro with β-glucan, arabinoxylan, or resistant starch as the sole carbon source. We found that β-glucan, arabinoxylan and resistant starch alter community structure and selectively target the enrichment of Bacteroides, Lactobacillus, Coprococcus, Butyricicoccus, Ruminococcus and Blautia, respectively. Notably, supplementing fiber-deficient diets with arabinoxylan and resistant starch, but not with β-glucan, improved the intestinal mucus barrier by cecal microbiota enrichment and increase in the concentration of microbiota-derived short-chain fatty acids (SCFAs). In addition, we illustrated through bacterial cultures in vitro that the supplementation of arabinoxylan and resistant starch resulted in a change in bacterial biotransformation of secondary bile acids. Our findings provide insight into how arabinoxylan and resistant starch may selectively target gut microbiota and mediate the production of SCFAs and bile acid biotransformation to improve intestinal mucus barrier function. IMPORTANCE The intestinal mucus barrier, located at the interface of the intestinal epithelium and the microbiota, is the first line of defense against pathogenic microorganisms and environmental antigens. Dietary polysaccharides, which act as microbiota-accessible fiber, play a key role in the regulation of intestinal microbial communities. However, the mechanism via which dietary fiber affects the intestinal mucus barrier through targeted regulation of the gut microbiota is not clear. This study provides fundamental evidence for the benefits of dietary fiber supplementation in broiler chickens through improvement in the intestinal mucus barrier by targeted regulation of the gut ecosystem. Our findings suggest that the microbiota-accessible fiber-gut microbiota-short-chain fatty acid/bile acid axis plays a key role in regulating intestinal function.

To better understand the formation and migration of high-arsenic groundwater, the influences of geochemical characteristics of sediments, and land utilization must be further studied. To better understand these dynamics, 76 groundwater samples from different scales of the landscape (alluvial–proluvial plain, downstream flood irrigation zone and downstream drip irrigation zone) were collected and tested to analyze the contents of their major and trace components. Forty-two sediment samples from two boreholes were collected and different variables such as particle size distribution, chemical composition, and concentrations of weakly (S1) and strongly (S2) bound As were tested for physiochemical index analysis. Results showed that high-As groundwater (As concentration >10 μg/L) was mainly distributed at depths of 20–36 m; the groundwater in the alluvial–proluvial plain had a generally low As concentration with an average concentration of 9.6 μg/L; and the groundwater in the flood irrigation zone and that in the drip irrigation zone had relatively high As concentrations with average concentrations of 36.0 and 151.45 μg/L, respectively. In the sediments, As content was positively correlated with Fe and Mn content, and its distribution was controlled by hydrodynamic conditions and lithology, with clay having a relatively high As content. The competitive adsorption by PO4 3– promoted the release of As in the sediments. As concentration in groundwater in the drip irrigation zone (known for growing cotton using drip irrigation, which demands high-phosphate fertilizer) was higher than that in the groundwater in flood irrigation zone (known for vegetable agriculture using flood irrigation, which demands high-potash fertilizer), suggesting that land use patterns have a significant influence on the distribution and migration of As. [ABSTRACT FROM AUTHOR]

The prevalence and transmission of vancomycin-resistant Enterococcus (VRE) in enterococci being as probiotics has been neglected in the scientific literature. The application of enterococci in feed, food and health products may cause VRE transmission through the food chain. This study evaluated phenotypic resistance of Enterococcus species to 20 antibiotics along a pork production chain from feed to food. It also assessed the genetic diversity of Enterococcus faecium isolates. A total of 510 samples (feed, n = 70; swine manure, n = 400; swine carcasses, n = 20, and retail pork, n = 20) were collected in Beijing, China. A total of 328 enterococci isolates with 275 E. faecium and 53 Enterococcus faecalis were identified using 16 S rRNA. Antimicrobial susceptibility to all enterococci isolates was conducted using the K–B method for 20 antibiotics from 9 categories. Multilocus sequence typing (MLST) was conducted on the E. faecium isolates to survey the dissemination of enterococci in the pig industry. The results showed that only 26 enterococci isolates were sensitive to the 20 antibiotics, while half of the isolates (164/328) had acquired multi-drug resistance. The resistant rate to furazolidone was 68.60%, followed by 42.99% to tetracycline. One vancomycin-resistant E. faecium isolates were isolated from feed origin and 2 from manure origin, with minimum inhibitory concentrations to vancomycin of 1,024, 64, and 64 μg/mL, respectively. The MLST outcomes showed that the 275 E. faecium isolates belonged to 11 sequence types (ST) including ST40, ST60, ST94, ST160, ST178, ST296, ST361, ST695, ST726, ST812 and ST1014. The ST of the feed-sourced VRE was ST1014, while the 2 manure-sourced VRE was ST69. ST1014 evolved from ST78, which was the dominant clonal complex in most cities of China, leading to the spreading of VRE. These findings revealed the potential safety hazards of commercial probiotic enterococci in China and showed that there is a risk of the VRE horizontally transferring from feed to food.

As the main driving force for the digital transformation of the construction industry, the uncertainty of digital technology in the application process has seriously hindered the high-quality development of the construction industry. In order to promote the wide application of digital technology in the construction industry and clarify the key uncertainties in its application process, this paper identifies the uncertainty index system of digital technology application based on the LDA topic model and literature analysis; the DEMATEL-ISM method is used to construct the multilevel hierarchical structure model of the uncertainty indicators in the application of digital technology to study the mutual influence among the indicators and to find the key uncertainty indicators. The research results show that the uncertainty indicators of the application of digital technology in the construction industry are divided into five levels: policy, industry, personnel, economy and law, and that the perfection of the policy guarantee system is the key uncertainty indicator for the investment return period of digital technology application. The standard contract model for digital technology is a direct uncertainty indicator for the application of digital technology in the construction industry. The results of this study help researchers and practitioners to focus on the key barriers and provide a list of key elements for construction companies to promote the application of next-generation digital technologies to improve digitalization of the construction industry. This study also provides a policy reference to further promote the digital transformation of the construction industry.

Because of the influence of the far field effect of the collision between Euro-Asian and India plates during the Late Cenozoic, the Tian Shan orogenic belt underwent intense reactivation, forming the Southern Junggar fold-and-thrust belt (SJ-FTB) to the north and the Kuqa fold-and-thrust belt to the south. Most previous research focuses on the deformation features and mechanisms during the Late Cenozoic. However, little research has been done on deformation features and mechanisms during the Late Jurassic. In this paper, we conducted geometric and kinematic analyses of seismic profiles and outcrop data to reveal the Late Jurassic deformation characteristics in SJ-FTB. Furthermore, we carried out sandbox modeling experiments to reproduce the regional structural evolution since the Early Jurassic. Angular unconformity between the Cretaceous and Jurassic is well preserved in the Qigu anticline belt. This unconformity also exists in the Huoerguosi–Manasi–Tugulu (HMT) anticline belt, which is the second fold belt of the SJ-FTB, indicating that the HMT anticline belt started to become active during the Late Jurassic. The Qigu anticline belt reactivated intensively during the Late Cenozoic, and the displacement was transferred to the HMT anticline belt along the Paleogene Anjihaihe Formation mudstone detachment. Therefore, the present-day SJ-FTB forms because of the two-stage compressional deformation from both the Late Jurassic and Late Cenozoic (ca. 24 Ma).

Osteoblastic bone formation is important for maintaining the balance of bone turnover. However, the underlying mechanisms are still needed to be elucidated. Histamine H1 type receptor (H1R) is a major subtype of histamine membrane receptors family, which has displayed diverse biological functions in various tissues and cells. In the current study, we have identified a novel physiological function of H1R in regulating osteoblastic differentiation and mineralization of the MC3T3-E1 cells. We found that H1R is expressed in the MC3T3-E1 cells. Interestingly, H1R is up-regulated in the process of differentiation and mineralization of the MC3T3-E1cells induced by osteogenic medium (OM). Blockage of H1R using its specific antagonist Loratadine prevented differentiation and mineralization of the MC3T3-E1 cells by reducing ALP activity, bone matrix deposition, and the expressions of osteogenic marker genes including ALP, OCN, Osx, and type I collagen as well as the transcriptional factor RUNX-2, which is a central regulator of osteoblastogenesis. In contrast, we found that activation of H1R with Histamine exerts opposite actions by increasing the expressions of RUNX-2. Finally, we found that the effects of H1R in osteoblastic differentiation and mineralization are mediated by the AMPK/eNOS signaling. Based on these findings, we concluded that H1R might be an important therapeutic target for the treatment of skeletal disorders.

The detection method based on anchor-free not only reduces the training cost of object detection, but also avoids the imbalance problem caused by an excessive number of anchors. However, these methods only pay attention to the impact of the detection head on the detection performance, thus ignoring the impact of feature fusion on the detection performance. In this article, we take pedestrian detection as an example and propose a one-stage network Cascaded Cross-layer Fusion Network (CCFNet) based on anchor-free. It consists of Cascaded Cross-layer Fusion module (CCF) and novel detection head. Among them, CCF fully considers the distribution of high-level information and low-level information of feature maps under different stages in the network. First, the deep network is used to remove a large amount of noise in the shallow features, and finally, the high-level features are reused to obtain a more complete feature representation. Secondly, for the pedestrian detection task, a novel detection head is designed, which uses the global smooth map (GSMap) to provide global information for the center map to obtain a more accurate center map. Finally, we verified the feasibility of CCFNet on the Caltech and CityPersons datasets.

At night, visual quality is reduced due to insufficient illumination so that it is difficult to conduct high-level visual tasks effectively. Existing image enhancement methods only focus on brightness improvement, however, improving image quality in low-light environments still remains a challenging task. In order to overcome the limitations of existing enhancement algorithms with insufficient enhancement, a progressive two-stage image enhancement network is proposed in this paper. The low-light image enhancement problem is innovatively divided into two stages. The first stage of the network extracts the multi-scale features of the image through an encoder and decoder structure. The second stage of the network refines the results after enhancement to further improve output brightness. Experimental results and data analysis show that our method can achieve state-of-the-art performance on synthetic and real data sets, with both subjective and objective capability superior to other approaches.

The availability of multiple illuminators in the multi-static airborne passive synthetic radar (SAR) system can provide the improved SAR imaging capability. The reflection coefficients of targets in the observed scene are different due to diverse observation angles and carrier frequencies in multi-static scenarios. To tackle this problem, the study firstly introduces the forward signal model of multi-static airborne passive SAR system and then formulates the imaging problem as an joint sparsity optimisation problem of multiple measurement vectors. Under the distributed greedy sparse recovery framework, the study finally proposes the cross-validation-based simultaneous orthogonal matching pursuit (SOMP) imaging algorithm for multi-static airborne passive SAR system. The proposed imaging algorithm can avoid the requirement of sparsity level of the observed scene and achieve the accurate imaging reconstruction of the observed scene. The simulation results have verified the effectiveness and validity of the proposed imaging method.

Multiview through-the-wall radar imaging (TWRI) can improve the imaging quality and target detection by exploiting the measurement data acquired from various views. Based on the established joint sparsity signal model for multiview TWRI, a cross validation (CV) based distributed greedy sparse recovery algorithm which combines the strengths of the CV technique and censored simultaneous orthogonal matching pursuit algorithm (CSOMP) is proposed in this paper. The developed imaging algorithm named by CV-CSOMP which separates the total measurements into reconstruction measurements and CV measurements is able to achieve the accurate imaging reconstruction and estimation of recovery error tolerance by the iterative CSOMP calculation. The proposed CV-CSOMP imaging algorithm not only can reduce the communication costs among radar units, but also can provide the desirable imaging performance without the prior information such as the sparsity or noise level. The experimental results have verified the validity and effectiveness of the proposed imaging algorithm.

Polarimetric through-the-wall radar imaging (TWRI) system has the enhancing performance in the detection, imaging, and classification of concealed targets behind the wall. We propose a group sparse basis pursuit denoising- (BPDN-) based imaging approach for polarimetric TWRI system in this paper. The proposed imaging method combines the spectral projection gradient L1-norm (SPGL1) algorithm with the nonuniform fast Fourier transform (NUFFT) technique to implement the imaging reconstruction of observed scene. The experimental results have demonstrated that compared to the existing compressive sensing- (CS-) based imaging algorithms, the proposed NUFFT-based SPGL1 algorithm can significantly reduce the required computer memory and achieve the improved imaging reconstruction performance with the high computational efficiency.

TiO2 foams have been prepared by a simple mechanical stirring method. Short-chain amphiphilic molecules have been used to stabilize colloidal suspensions of TiO2 nanoparticles. TiO2 foams were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis absorption spectroscopy, and scanning electron microscopy (SEM). The photoassisted oxidation of NO in the gas phase according to ISO 22197-1 has been used to compare the photoactivity of the newly prepared TiO2 foams to that of the original powders. The results showed that the photoactivity is increased up to about 135%. Foam structures seem to be a good means of improving the photoactivity of semiconductor materials and can readily be used for applications such as air purification devices.

The GPGPU (General Purpose Graphics Processing Units) have become a whole new area for research due to the fast development of GPU hardware and programming tools, such as CUDA (Compute Unified Device Architecture). Here we have made a research on CUDA and its applications in the field of scientific computation, as organ electronics. We propose one solution of the parallel computation in global optimization of the physical characteristics in organ electronics with Monte Carlo, and one cloud service architecture for parallel computation of organ electronics was designed. Finally, one case of computing the organ molecule moving orbit was implemented based on the above solution and architecture, and has got a good display by the cloud service.