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In this article, a patterned honeycomb absorber (PHA) with an embedded frequency-selective surface (FSS) was proposed for broadband applications. The impedance of the FSS embedded in a homogeneous honeycomb absorber (HA) was first analyzed, which suggested that directly combining an FSS with a homogeneous HA was unreliable. Subsequently, a PHA was developed to adjust the input impedance. Using the PHA, an FSS embedded in patterned honeycomb absorber structure with a wide absorption band was developed. The consistency between the simulated and measured results verifies the analysis and design principle. The proposed absorber may be very suitable for various microwave applications owing to its low cost, lightweight, high strength, and environmental friendliness.

In ultra-high frequency (UHF) band, conventional microwave absorbers are limited in application by their thickness or weight. In order to solve this problem, a novel double-sided and dual-tuned active frequency selective surface (AFSS) absorber for the UHF band is designed and implemented for the first time. The physical mechanism is analyzed by the equivalent circuit method (ECM) and current distribution. Non-coplanar bias circuits of p-i-n diodes and varactors are proposed and achieved by a double-sided structure. The Fano resonance introduced by double-sided structure is analyzed and suppressed. The proposed structure covers an ultrabroadband of 0.4–2.5 GHz (144.8% in fractional bandwidth) below −10 dB by changing the working states. The thickness is only $\lambda _{L}$ /30 in the lowest operating frequency, and the areal density is only 1.54 kg/m2. It is worth mentioning that the structure has good angular sensitivity and can be used to complex targets for low-RCS applications.

A high-accuracy unsupervised classification model is developed in a multimode self-interference microring resonator (SIMRR). For the SIMRR, there are many whispering gallery modes (WGMs) present. Each of these resonance modes supported by the SIMRR has a different response to different target parameters, so that the SIMRR-based sensor has the super capability to distinguish between multiple components. In the classification model, principal component analysis (PCA) is firstly used to reduce the dimensionality of this multimode sensing information from the SIMRR-based sensor. When the original higher-dimensional data points are projected onto the lower-dimensional data with only the first few principal components, they can be easily categorized into several different types by using density-based spatial clustering of application with noise (DBSCAN) algorithm. As an example, the unsupervised classification method is numerically validated based on a designed three-gas SIMRR-based sensor. The numerical results prove that the classification model can achieve an ultra high classification accuracy for the designed three-gas sensor with more than 60 dB in signal-to-noise ratio.

Background To investigate the safety, efficacy, and follow-up outcomes of microwave ablation (MWA) in patients with breast fibroadenoma. Methods An institutional review board-approved this study of patients treated with MWA for breast fibroadenoma from October 2017 to March 2019. Clinical features of patients and breast fibroadenoma were analyzed. At follow-up all patients received physical examination and ultrasound imaging. Results In total, 171 patients with 271 lesions were enrolled. The mean lesion diameter was 1.35 ± 0.47 cm. The results revealed differential lesion states, including stability, enlargement, reduction, and complete regression, at 1-6, 6-12, and >12 months of follow-up. The size was reduced in 22.14% (31/140), 26.36% (29/110), and 36.36% (16/44) of the lesions at 1-6, 6-12, and >12 months of follow-up, respectively. The proportion of lesions with complete regression was 24.29% (34/140) at 1-6 months, 45.45% (50/110) at 6-12 months, and 40.91% (18/44) at >12 months of follow up. There was no significant relationship between the curative effect and age, lesion location, and blood flow in patients with breast fibroadenoma after MWA (p > .05), but there was statistically significant relationship with lesion diameter (categorized as

Frequency selective rasorber (FSR) is a special absorber with a transmission window. Due to the characteristics of in-band transmission and out-of-band absorption, FSR is considered as a candidate for stealth radome. By breaking through the technical barrier of traditional FSR transmission windows design, we implement a double lossy layers FSR for the first time in public reports. The FSR is configured by cascading two lossy layers above a lossless layer with two air spaces to separate them. It has two independent absorption bands, which are provided by their lossy layers, respectively. Therefore, it has a broader bandwidth and more stable absorption characteristics. We adopted the equivalent circuit model (ECM), surface current distribution, and loss distribution to comprehend the physical mechanism of the FSR. We fabricated and measured the FSR prototypes to validate the proposed design. The simulated results show that the transmission is −0.78 dB at 6.3 GHz, and the −10 dB reflection is 2.5–14.6 GHz. The measured results achieve a significant agreement with the simulated results. Under the universal guideline, new FSR could do better in terms of absorption bandwidth and scattering stability. It has significance to the engineering progress of FSR acting as a stealth radome in antenna system.

A dual-band electromagnetic absorber based on double-layer frequency selective surface (FSS) is proposed for broadband applications. The layer I is designed with an absorption performance at higher frequency and a transmission window at lower frequency. Simultaneously, the layer II is designed with an absorption performance at lower frequency and a strong-reflection window at higher frequency. Due to the low-pass property of the layer I, this layer is on the top of the absorption structure, allowing the incident waves to transmit to the layer II at lower frequency and be absorbed. Meanwhile, the incident wave is absorbed at higher frequency by the layer I since the layer II acts as the strong-reflection substrate in the bottom of the absorption structure. The reflectivity of absorber below −10 dB covers a bandwidth of 1.3–4.1 GHz and 7.2–10 GHz at normal incidence. Furthermore, the absorber can still maintain an absorption bandwidth below −10 dB at 1.4–4.1 GHz under the 30° oblique incidence. The good agreement between simulation and measurement validates the proposed absorber.

Antireflection coatings consisting of nanoparticles have promising applications in a wide range of UV optical fields, such as high-power laser systems and space telescopes. However, an open question for these coatings is how to minimize light scattering caused by the nanoparticles. Here, we utilize hollow silica nanoparticles to realize antireflection coatings, which largely diminish light scattering and, hence, exhibit excellent transmission even at UV wavelengths. The hollow silica nanoparticles were synthesized using a template-free approach and then dip coated onto fused silica substrates to form antireflection coatings. The coatings were found to exhibit nearly 100% transmission at any wavelength ranging from the UV to IR bands by variation of the coating thickness. Moreover, the coatings showed relatively high environmental stability because their hollow structures were insensitive to contaminants. This study provides a novel route to fabricate UV antireflection coatings with improved optical properties and good environmental stability, which will help promote the understanding, design and fabrication of optical coatings.

Geniposide (GE) possesses excellent neuroprotective effects but with poor brain targeting and short half-life. Liposome was considered to have great potential for brain diseases. Therefore, this research aimed to develop a geniposide liposome (GE-LP) as a brain delivery system for cerebral ischemia reperfusion injury (CIRI) therapy and evaluate its characterization, pharmacokinetics, brain targeting, and neuroprotective effects in vivo. Then, a reverse-phase evaporation method was applied to develop the GE-LP and optimize the formulation. Notably, the GE-LP had suitable size, which was 223.8 nm. Subsequently, the pharmacokinetic behavior of GE solution and GE-LP in mice plasma was investigated, and the brain targeting was also researched. The results showed that GE in plasma of GE-LP displayed three folds longer distribution half-life and a higher bioavailability and brain targeting compared to GE solution. In vivo neuroprotective effects was evaluated through the middle cerebral artery occlusion (MCAO) rat model, and GE-LP exhibited a stronger tendency in preventing the injury of CIRI, which can significantly improve neurological deficits. Overall, this study demonstrates GE-LP as a new formulation with ease of preparation, sustained release, and high brain targeting, which has significant development prospects on CIRI; this is expected to improve the efficacy of GE and reduce the frequency of administration.

With the coming acceleration of global population aging, the incidence rate of cardio-cerebrovascular diseases (CVDs) is increasing. It has become the leading cause of human mortality. As a natural drug, borneol (BO) not only has anti-inflammatory, anti-oxidant, anti-apoptotic, anti-coagulant activities and improves energy metabolism but can also promote drugs to enter the target organs or tissues through various physiological barriers, such as the blood-brain barrier (BBB), mucous membrane, skin. Thus, it has a significant therapeutic effect on various CVDs, which has been confirmed in a large number of studies. However, the pharmacological actions and mechanisms of BO on CVDs have not been fully investigated. Hence, this review summarizes the pharmacological actions and possible mechanisms of BO, which provides novel ideas for the treatment of CVDs.

In this paper, we demonstrate a multimode and broadband absorber that is fabricated directly on PET substrate using a commercial direct-to-garment (DTG) inkjet printer. A design procedure of this kind of absorber is presented. Based on the theory of characteristic mode, the underlying modal behaviors of the absorber structure are firstly analyzed to guide the design of multimode absorber. Two modes on the absorber structure are designed to resonate around 1.83 GHz and 4.28 GHz to cover the working frequency range. Simulation and measurement results show that the multimode absorber with a total thickness of 0.0883λL at the lowest operating frequency can achieve broadband microwave absorption with efficiency over 90% in the frequency band of 1.0 ∼ 4.5 GHz (127.3% in fractional bandwidth) through deliberate design. Both the simulated and experimental results demonstrate the validity of the proposed method and indicate that the method can be applied to other microwave and millimeter-wave regions.

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are challenging diseases with the high mortality in a clinical setting. Baicalin (BA) is the main effective constituent isolated from the Chinese medical herb Scutellaria baicalensis Georgi, and studies have proved that it has a protective effect on ALI induced by lipopolysaccharide (LPS) due to the anti-inflammatory efficacy. However, BA has low solubility which may limit its clinical application. Hence, we prepared a novel drug delivery system—Baicalin liposome (BA-LP) in previous research—which can improve some physical properties of BA. Therefore, we aimed to explore the effect of BA-LP on ALI mice induced by LPS. In pharmacokinetics study, the values of t 1 / 2 and AUC0- t in the BA-LP group were significantly higher than that of the BA group in normal mice, indicating that BA-LP could prolong the duration time in vivo of BA. The BA-LP group also showed a higher concentration in lung tissues than the BA group. Pharmacodynamics studies showed that BA-LP had a better effect than the BA group at the same dosage on reducing the W/D ratio, alleviating the lung injury score, and decreasing the proinflammatory factors (TNF-α, IL-1β) and total proteins in bronchoalveolar lavage fluids (BALF). In addition, the therapeutic effects of BA-LP showed a dose-dependent manner. Western blot analysis indicated that the anti-inflammatory action of BA could be attributed to the inhibition of the TLR4-NFκBp65 and JNK-ERK signaling pathways. These results suggest that BA-LP could be a valuable therapeutic candidate in the treatment of ALI.

A wideband transmission frequency selective surface (FSS) rasorber with low insertion loss for stealthy radome in antenna systems is presented. In order to obtain the wideband transmission with low insertion loss, a choked structure and a 2-order bandpass FSS are adopted. The choke is just a parallel LC resonator or deformation. The passband below the absorption band by using the lumped inductor loaded in the element gap. As a validation, the FSS rasorber is fabricated and measured. The measurement result shows that the transmission above −1 dB covers a bandwidth of 4.1-5.8 GHz and the reflection below −10 dB covers a bandwidth of 7.4-13.4 GHz.

We present a wideband frequency selective surface (FSS) absorber for oblique incidence. The absorber structure with anisotropic elements exhibits different impedances in two polarizations to match free space characteristic impedance at oblique incidence, thus resulting in a low microwave reflectivity over a wideband range. The grating lobe is suppressed by the use of skewed grid. Simulation and measurement results all illustrate that the reflectivity covers a broad band of 1.35-4.0 GHz below −10 dB for both TE and TM polarizations at an incident angle of 45°.

A nanoporous organically modified silicate (ORMOSIL) film with adjustable refractive index from 1.21 to 1.10 was prepared at room temperature via a template-free sol–gel method, using tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) as co-precursors and hexamethylisilazane (HMDS) as surface modifier. Heating the ORMOSIL film, the refractive index of the ORMOSIL film can be further decreased to as low as 1.07. This adjustable refractive index thin film can find potential application in optical and microelectronic fields.

A three-layer tri-wavelength broadband antireflective (AR) coating with 100 % transmittance simultaneously at 1064, 532 and 355 nm was designed using TFCalc™ thin film design software. The refractive indices for the bottom, middle and top layers of the designed AR coating are 1.33, 1.21 and 1.10, respectively. To realize the designed AR coating, a template-free sol–gel process was proposed to regulate the refractive index of silica film from 1.09 to 1.44 by simple hybridization. Silica films with refractive index of 1.21–1.44 were prepared by the hybridization of acid-catalyzed silica and base-catalyzed silica, while organically modified silicates films with refractive index of 1.09–1.21 were prepared by the hybridization of tetraethoxysilane, methyltriethoxysilane and hexamethyldisilazane under base-catalyzed condition. These two hybridization methods could conveniently control the porosity, and hence the refractive index of films. Finally, the three-layer tri-wavelength broadband AR coating, which is very important in high-power laser systems, was realized with the transmittance of 99.9, 99.8 and 99.4 % at 1064, 532 and 355 nm, respectively. A three-layer tri-wavelength broadband antireflection coating with nearly 100 % transmittance simultaneously at 1064, 532 and 355 nm is designed by TFCalc™ thin film design software and prepared by a simple sol–gel process. A template-free sol–gel process was proposed to prepare silica films with controlled and ultra-low refractive index.

Depression is a common global mental disorder that seriously harms human physical and mental health. With the development of society, the increase of pressure and the role of various other factors make the incidence of depression increase year by year. However, there is a lack of drugs that have a fast onset, significant effects, and few side effects. Some volatile oils from traditional natural herbal medicines are usually used to relieve depression and calm emotions, such as Lavender essential oil and Acorus tatarinowii essential oil. It was reported that these volatile oils, are easy to enter the brain through the blood-brain barrier and have good antidepressant effects with little toxicity and side effects. In this review, we summarized the classification of depression, and listed the history of using volatile oils to fight depression in some countries. Importantly, we summarized the anti-depressant natural volatile oils and their monomers from herbal medicine, discussed the anti-depressive mechanisms of the volatile oils from natural medicine. The volatile oils of natural medicine and antidepressant drugs were compared and analyzed, and the application of volatile oils was explained from the clinical use and administration routes. This review would be helpful for the development of potential anti-depressant medicine and provide new alternative treatments for depressive disorders.

Cerebral ischemia reperfusion injury (CIRI), one of the major causes of death from stroke in the world, not only causes tremendous damage to human health, but also brings heavy economic burden to society. Current available treatments for CIRI, including mechanical therapies and drug therapies, are often accompanied by significant side-effects. Therefore, it is necessary to discovery new strategies for treating CIRI. Many studies have confirmed that the herbal medicine has the advantages of abundant resources, good curative effect and little side effects, which can be used as potential drug for treatment of CIRI through multiple targets. It's known that oral administration commonly has low bioavailability, and injection administration is inconvenient and unsafe. Many drugs can't delivery to brain through routine pathways due to the blood-brain-barrier (BBB). Interestingly, increasing evidences have suggested the nasal administration is a potential direct route to transport drug into brain avoiding the BBB and has the characteristics of high bioavailability for treating brain diseases. Therefore, intranasal administration can be treated as an alternative way to treat brain diseases. In the present review, effective methods to treat CIRI by using active ingredients derived from herbal medicine through nose to brain drug delivery (NBDD) are updated and discussed, and some related pharmacological mechanisms have also been emphasized. Our present study would be beneficial for the further drug development of natural agents from herbal medicines via NBDD.

Impedance characteristics and frequency dispersion of typical lossy patterned resistive films are extensively investigated. And on this basis we put forward an improved Circuit-Pattern Direct Extraction Method (CPDEM) for patterned lossy resistive film based broadband absorber design. The pattern parameters are directly extracted from the numerically calculated circuit model and further optimized to meet the design requirements. Herein, two broadband designs are demonstrated, whose relative bandwidth is 127% with the thickness of 0.086 λL at lowest operating frequency of the absorption band and 178% with the thickness of 0.102 λL. Our numerical calculation and full-wave electromagnetic simulation are in good agreement with the experimental results, which proves that this design method is feasible and accurate. This CPDEM design method might also give the guideline for the resistive film absorber design.

In the field of fast and large-scale image retrieval, the binary hash code based on convolutional features enjoys powerful advantages. CNN model's leading recognition ability shows that its high-level features distribute intensively and have stable between-class distances. On the basis of the distribution characteristic of convolutional features, this paper presents a new method of improving retrieval performance by means of using the category centers of high-level features to enhance the common semantic content of high-level features of the query image and making the consequent binary hash code gain better retrieval results. Experimental results indicate that (i) the category centers of CNN feature offer comparable discriminability with the initial model when identifying the semantic information of images; (ii) before calculating binary hash code, the integration of the CNN feature of a query image with category centers weighted by predicted probabilities can boost performance in similar image retrieval. State-of-the-art retrieval performance is obtained on the Cifar-10 dataset in this paper among all hash methods.

In recent years, deep convolutional networks have made a milestone progress in the field of image recognition. However, the recognition ability of the deep convolution network declines in the case of unbalanced training data, in terms of categories with fewer training images, the recognition ability of the deep convolution network declines more seriously. Aiming at this kind of problem, this paper presents a new classification method which recognizes a query image by comparing distances between category centers of CNN features of the whole training dataset and the corresponding CNN feature of this query image. The experimental results on Cifar-10 and Cifar-100 show that the claimed method can more accurately identify images whose categories have only a few training samples and that the mean precision of the recognition can be improved effectively.

In recent years, the number of international students in China has been increasing, which has greatly increased the difficulty of the international students’ information’s management. It’s a difficult problem for all the schools of international education and exchanges to manage international students successfully and normatively in order to ensure that they can complete their studies smoothly in China. Thus, Information technology can provide the necessary technical support to solve these problems. Firstly, the development of this system can realize the efficient management of international students’ information. Secondly, according to the functional requirements of different users, this system has developed modules for students, student managers and administrators, realizing the students’ leaving applications, security warning, the letter and other functions. It is convenient for managers to manage all kinds of information of international students effectively. The development of this system can promote international students’ management in various schools, simplify the process of various work and improve the working efficiency.

A polarization-insensitive tunable frequency selective surface absorber for oblique incidence broadband applications is presented. The design method of combining anisotropy pattern and adjustable impedance is put forward. The influence of the parasitic or additional parameters of the PIN diode on the performance of the FSS absorber is analyzed by circuit model. An improved anisotropy capacitive absorbing circuit is designed and then realized by FSS patterns. Variable resistance PIN devices are loaded in FSS elements, and the impedance of FSS absorber structure is dynamically turned by changing the bias voltage of PIN devices. Far-field simulation results show that the absorber achieves prominent omnidirectional radar cross section (RCS) reduction in the absorbing band by overlaying it to metallic plate. Simulation and measurement results all illustrate that the reflectivity envelope covers a broadband of 1.6–5.1 GHz below -10 dB for both TE and TM polarizations at incident angle from 30° to 50°.

Triple-layer broadband abrasion-resistant antireflective (AR) coatings with excellent transmittance at 400–800 nm were designed with the aid of thin film design software (TFCalc™). SiO2, TiO2 and SiO2–TiO2 hybrid thin films with refractive indices of 1.44, 2.20 and 1.71 for the up, middle and bottom layers, were dip-coated from SiO2, TiO2 and SiO2–TiO2 hybrid sols by sol–gel process, respectively. SiO2 and TiO2 sols were prepared using tetraethyl orthosilicate (TEOS) and tetrabutyl orthotitanate (TBOT) as precursors and hydrochloric acid as catalyst. These designed triple-layer broadband AR coatings with an average transmittance as high as 98.4% at visible region were successfully obtained. Hexamethyldisilazane (HMDS) was further used to modify the surface of the AR coatings, which greatly improved the hydrophobicity of the coatings, and thus gave the AR coatings some self-cleaning property. These triple-layer abrasion-resistant broadband AR coatings with excellent transmittance in the visible region have potential value in the field of solar cells.

The poly(isopropylene oxide) glycerolether (PO) modified silica antireflective (AR) coating films were prepared by sol–gel method. The properties of the silica sols and AR films were characterized by particle size analyzer, transmission electron microscope, UV–Vis spectro-photometry, spectroscopic ellipsometer and contact angle measurement. The results show that PO addition has inconspicuous effect on the transmittance of AR coatings; the maximum transmittance reached 99.5%. Thicknesses of films increase and refractive index decrease with increase of PO concentration. The contact angle with water for the silica films with and without PO was 68.5o and 28.5o, respectively, which indicates an increase of hydrophobicity of the modified coating. When the films were placed in 95% relative humidity at room temperature for 30 days, transmittance loss for the unmodified and modified silica films were 2.5 and 0.6% respectively. Moisture-resistance of the film is greatly improved by PO addition.

A flexible design of a wideband double-layer microwave absorber is proposed. In order to break through the limitation of single-layer absorbers at finite resonant frequencies, a special double-layered structure is adopted. The middle layer functional frequency selective surface is the core of the double-layer absorber. It exhibits two functions, which are resonant or lossy in a low frequency and strong reflective in a high frequency. As a result, the coupling between the two layers is weak, and this feature leads to the absorber having two different absorption bands which are provided by two single-layer absorbers (named as functional layers (FLs)), respectively. It means that an engineer could target the design for a particular band according to requirements without degrading the performance on the other band. For the flexible design, two FLs, a dual-band absorption precursor and a continuous absorption modified absorber are proposed successively. During the whole design process, all structures are fabricated and measured. The measurement result shows that the reflection of the modified absorber below −10 dB covers a bandwidth of 2.98–16.62 GHz in normal incidence. The good agreement between simulation and measurement validates the proposed absorber.

Antireflective (AR) coatings at 351 nm with different thickness were designed and prepared by sol–gel process using tetraethylorthosilicate as precursor and ammonia as catalyst. The parameters of these coatings, including film thickness and refractive index, were calculated by optical formula and the coatings were prepared accordingly. Sol dilution method was used to adjust the film thickness. The wavelengths of maximum transmission measured by UV–Vis spectrophotometer, were used to monitor the film thickness. It was found that AR coatings with higher thickness possess better abrasion-resistance. Hydroxyl terminated polydimethylsiloxane (PDMS) was added into pure silica sol to improve both the abrasion-resistance and moisture-resistance of AR coating.

In this paper, a polarization-insensitive wideband tunable metamaterial absorber is designed and fabricated. The equivalent circuit model for the absorber has been proposed to describe its absorption phenomenon. The proposed absorber is constructed by a periodic array of unit, which contains four split semi-circle ring resonators with 90° rotated. The symmetric structure of the unit gives rise to polarization-insensitivity. Furthermore, the field distribution and the circuit model of the absorber are studied to demonstrate its absorption mechanism. Measurement results show that the proposed metamaterial absorber obtains a reflectivity of less than −10 dB covering 2.1–2.5 GHz and 3.1–6.8 GHz with the total thickness of 8.8 mm, and the reflectivity performance covering the spectrum from 3.1 GHz to 6.8 GHz could be adjusted by tuning the bias voltage on the PIN diodes.