Reliable Determination of Contact Angle from the Liquid Fence.

Traditional methods of measuring contact angles often face difficulties in precisely defining the three-phase contact points. A novel method for accurately defining three-phase contact points based on liquid fences is proposed in this article. The tested liquid is placed in a cubic liquid fence composed of a pair of narrow strips of the tested solid and a pair of transparent wide strips. The transparent wide strip serves as the measurement window, and the surface tension of the liquid on it can be almost ignored. In experimental measurements, the horizontal coordinates of the end points of the liquid profile are fixed by the liquid fence, thus determining the horizontal coordinates of the three-phase contact points, which helps to accurately survey the contact angle. Additionally, since the parameters of the liquid fence are known, the size of the contact angle can also be calculated by measuring the height of the liquid level dome inside the liquid fence. Using the electric wetting effect as an example, we experimentally extracted a series of liquid contour maps with circular tops and square columns under varying voltages. The relationship curve between contact angle and voltage variation was obtained using the above methods, and a contact angle variation tendency seemed to agree well with the theoretical value.

Tunable fiber attenuator for electrically wet-driven micromirrors.

Herein we report an electronically controlled tunable fiber-optic attenuator that leverages the microfluidic electro-wetting effect, which enables a fine-tuning of the solid-liquid interface wetting angle to control the micro-reflector, thus regulating the lens fiber coupling efficiency. Theoretical calculations indicated an optical attenuation regulation effect of 0-45.0 dB in the voltage range of 0-30.0 V. Experimental results align closely with theoretical calculations, demonstrating an attenuation range of 0.59-43.0 dB within a voltage variation range of 0-25.0 V, with control accuracy of 0.56 dB. Our study unveils the potential for designing fiber-optic attenuators with varying tuning accuracy by precisely adjusting the solid-liquid interface wetting angle.

Dielectrophoretic liquid lens driven by interdigitated sidewall electrodes.

This paper proposes a dielectrophoretic (DEP) liquid lens that is driven by interdigitated electrodes distributed on the sidewalls and has a structure similar to that of the electrowetting one produced by the company Corning. The interdigital electrodes are formed by winding double flexible wire electrodes wrapped in dielectric layers on the sidewall. Compared with the traditional planar electrode DEP lens, the proposed model ensures the stability of the optical axis of the liquid lens, simplifies the construction process of the interdigital electrode, realizes a continuous change in the focus from negative to positive, and reduces the response time. A truncated conical cavity dielectrophoretic liquid lens with an aperture of 5 mm is fabricated. When the voltage is 0-260 Vrms, it can reach shortest negative and positive focal lengths of -100 mm and 100 mm with a driving time of 190 ms and a relaxation time of 133 ms.

Artificial Neurons Based on Ag/V2C/W Threshold Switching Memristors.

Artificial synapses and neurons are two critical, fundamental bricks for constructing hardware neural networks. Owing to its high-density integration, outstanding nonlinearity, and modulated plasticity, memristors have attracted emerging attention on emulating biological synapses and neurons. However, fabricating a low-power and robust memristor-based artificial neuron without extra electrical components is still a challenge for brain-inspired systems. In this work, we demonstrate a single two-dimensional (2D) MXene(V2C)-based threshold switching (TS) memristor to emulate a leaky integrate-and-fire (LIF) neuron without auxiliary circuits, originating from the Ag diffusion-based filamentary mechanism. Moreover, our V2C-based artificial neurons faithfully achieve multiple neural functions including leaky integration, threshold-driven fire, self-relaxation, and linear strength-modulated spike frequency characteristics. This work demonstrates that three-atom-type MXene (e.g., V2C) memristors may provide an efficient method to construct the hardware neuromorphic computing systems.

Hypolipidemic effect of Alisma orientale (Sam.) Juzep on gut microecology and liver transcriptome in diabetic rats.

Alisma orientale (Sam.) Juzep (A. orientale) is a traditional herb that is often used to treat disease including edema and hyperlipidemia. However, the molecular mechanism by which Alisma orientale (Sam.) Juzep exerts its hypolipidemic effects remains unclear. In this study, a diabetic rat model was established by feeding a high-fat and high-sugar diet combined with a low-dose streptozotocin injection (HFS). Then the rats were treated with an A. orientale water extract (AOW), an A. orientale ethanolic extract (AOE) or metform (MET). The gut microflora and liver transcriptome were analyzed by high-throughput next-generation sequencing. Ultra-performance liquid chromatography-triple quadrupole-mass spectrometry was employed to analyze the major compounds in the AOE. The results showed that the serum total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) levels in rats of the AOE group (2.10 g/kg/day, 14 days) were significantly lower than those in the HFS group (p<0.01). Moreover, AOE treatment altered the gut microecology, particularly modulating the relative abundance of gut microflora involved in lipid metabolism compared with the HFS group. Furthermore, compared with the HFS group, the mRNA expression levels of Fam13a, Mapk7, Mpp7, Chac1, Insig1, Mcpt10, Noct, Greb1l, Fabp12 and Hba-a3 were upregulated after the administration of AOE. In contrast, the mRNA expression levels of Lox, Mybl1, Arrdc3, Cyp4a2, Krt20, Vxn, Ggt1, Nr1d1 and S100a9 were downregulated. Moreover, AOE treatment for two weeks markedly promoted the relative abundance of Lachnospiraceae (p = 0.0013). The triterpenoids contents in AOE were alisol A, alisol A 24-acetate, alisol B, alisol B 23-acetate, alisol C 23-acetate, alisol F, alisol F 24-acetate, and alisol G. Our findings above illustrated that the hypolipidemic effect of the triterpenoids of A. orientale is mediated mainly through alteration of the gut microecology and the regulation of genes involved in cholesterol metabolism, especially Insig1.

Comparative transcriptome and metabolite profiling of four tissues from Alisma orientale (Sam.) Juzep reveals its inflorescence developmental and medicinal characteristics.

Alisma orientale (Sam.) Juzep (A. orientale) is an important medicinal plant in traditional Chinese medicine. In this study, de novo RNA-seq of A. orientale was performed based on the cDNA libraries from four different tissues, roots, leaves, scapes and inflorescences. A total of 41,685 unigenes were assembled, 25,024 unigene functional annotations were obtained by searching against the five public sequence databases, and 3,411 simple sequence repeats in A. orientale were reported for the first time. 15,402 differentially expressed genes were analysed. The morphological characteristics showed that compared to the other tissues, the leaves had more chlorophyll, the scapes had more vascular bundles, and the inflorescences contained more starch granules and protein. In addition, the metabolic profiles of eight kinds of alisols metabolite profiling, which were measured by ultra-Performance liquid chromatography-triple quadrupole-mass spectrometry showed that alisol B 23-acetate and alisol B were the major components of the four tissues at amounts of 0.068~0.350 mg/g and 0.046~0.587 mg/g, respectively. In addition, qRT-PCR validated that farnesyl pyrophosphate synthase and 3-hydroxy-3-methylglutaryl-CoA reductase should be considered the critical candidate genes involved in alisol biosynthesis. These transcriptome and metabolic profiles of A. orientale may help clarify the molecular mechanisms underlying the medicinal characteristics of A. orientale.

[Correlation study between accumulation of triterpenoids and expression of relative genes in Alisma orientale].

To research the correlation between accumulation of triterpenoids and expression of key enzymes genes in triterpenoid biosynthesis of Alisma orientale,the study utilized UPLC-MS/MS method to detect eight triterpenoids content in the tuber of A. orientale from different growth stages,including alisol A,alisol A 24 acetate,alisol B,alisol B 23 acetate,alisol C 23 acetate,alisol F,alisol F 24 acetate and alisol G,and then the Real time quantitative PCR was used to analyze the expression of key enzymes genes HMGR and FPPS in triterpenoid biosynthesis. Correlation analysis showed that there was a significant positive relation between the total growth of these eight triterpenoids and the average relative expression of HMGR and FPPS(HMGR: r = 0. 998,P<0. 01; FPPS: r = 0. 957,P<0. 05),respectively. Therefore,the study preliminarily determined that HMGR and FPPS genes could regulate the biosynthesis of triterpenoids in A. orientale,which laid a foundation for further research on the biosynthesis and regulation mechanism of triterpenoids in A. orientale.

Simultaneous Detection of Static and Dynamic Signals by a Flexible Sensor Based on 3D Graphene.

A flexible acoustic pressure sensor was developed based on the change in electrical resistance of three-dimensional (3D) graphene change under the acoustic waves action. The sensor was constructed by 3D graphene foam (GF) wrapped in flexible polydimethylsiloxane (PDMS). Tuning forks and human physiological tests indicated that the acoustic pressure sensor can sensitively detect the deformation and the acoustic pressure in real time. The results are of significance to the development of graphene-based applications in the field of health monitoring, in vitro diagnostics, advanced therapies, and transient pressure detection.

Strategy for realizing magnetic field enhancement based on diffraction coupling of magnetic plasmon resonances in embedded metamaterials.

We have demonstrated a straightforward strategy to realize magnetic field enhancement through diffraction coupling of magnetic plasmon (MP) resonances by embedding the metamaterials consisting of a planar rectangular array of U-shaped metallic split-ring resonators (SRRs) into the substrate. Our method provides a more homogeneous dielectric background allowing stronger diffraction coupling of MP resonances among SRRs leading to strong suppression of the radiative damping. We observe that compared to the on-substrate metamaterials, the embedded ones lead to a narrow-band hybridized MP mode, which results from the interference between MP resonances in individual SRRs and an in-plane propagating collective surface mode arising from light diffraction. Associated with the excitation of this hybridized MP mode, a twenty-seven times enhancement of magnetic fields within the inner area of the SRRs is achieved as compared with the pure MP resonance. Moreover, we also found that besides the above requirement of homogeneous dielectric background, only a collective surface mode with its magnetic field of the same direction as the induced magnetic moment in the SRRs could mediate the excitation of such a hybridized MP mode.

Facile fabrication of three-dimensional graphene foam/poly(dimethylsiloxane) composites and their potential application as strain sensor.

A three-dimensional (3D) graphene foam (GF)/poly(dimethylsiloxane) (PDMS) composite was fabricated by infiltrating PDMS into 3D GF, which was synthesized by chemical vapor deposition (CVD) with nickel foam as template. The electrical properties of the GF/PDMS composite under bending stress were investigated, indicating the resistance of the GF/PDMS composite was increased with the bending curvature. To improve the bending sensitivity of the GF/PDMS composite, a thin layer of poly(ethylene terephthalate) (PET) was introduced as substrate to form double-layer GF/PDMS-PET composite, whose measurements showed that the resistance of the GF/PDMS-PET composite was still increased when bended to the side of PET, whereas its resistance would be decreased when bended to the side of GF. For both cases, the absolute value of the relative variation of electrical resistance was increased with the bending curvature. More importantly, the relative variation of electrical resistance for double-layer GF/PDMS-PET composite can be up to six times higher than single-layer GF/PDMS composite for the same bending curvature. These observations were further supported by the principle of mechanics of material. The 3D GF/PDMS-PET composite also has higher flexibility and environment stability and can be utilized as a strain sensor with high sensitivity, which can find important applications in real-time monitoring of buildings, such as a bridge, dam, and high-speed railway.

A cascaded approach for correcting ionospheric contamination with large amplitude in HF skywave radars.

Ionospheric phase perturbation with large amplitude causes broadening sea clutter's Bragg peaks to overlap each other; the performance of traditional decontamination methods about filtering Bragg peak is poor, which greatly limits the detection performance of HF skywave radars. In view of the ionospheric phase perturbation with large amplitude, this paper proposes a cascaded approach based on improved S-method to correct the ionospheric phase contamination. This approach consists of two correction steps. At the first step, a time-frequency distribution method based on improved S-method is adopted and an optimal detection method is designed to obtain a coarse ionospheric modulation estimation from the time-frequency distribution. At the second correction step, based on the phase gradient algorithm (PGA) is exploited to eliminate the residual contamination. Finally, use the measured data to verify the effectiveness of the method. Simulation results show the time-frequency resolution of this method is high and is not affected by the interference of the cross term; ionospheric phase perturbation with large amplitude can be corrected in low signal-to-noise (SNR); such a cascade correction method has a good effect.

[Study on fingerprint spectrum of loquat leaf by HPLC].

OBJECTIVE: To establish the fingerprint spectrum of Loquat Leaf of Fujian authentic medicinal herbs by HPCE. METHODS: The HPLC fingerprints of Loquat Leaf were obtained from instrument HP1100. The HPLC separation was performed on a Eclipse XDB-C18 (4.6 mm x 150 mm, 5 microm) analytical column diluted with methanol-l% glacial acetic acid (90:10) at the flow rate of 1.0 ml/min. The temperature of column was room temperature. The UV detection wavelength was 215 nm. RESULTS: Detected 12 batches samples of different species Lopuat Leaf Fingerprint by the method of HPLC. Eight peaks in the chromatogram were common. All the similarity were above 0.9, the fingerprints integer feature were coincident essentially. CONCLUSION: The method is convenient, quick and exact, and its reproducibility is good. It will be a scientific reference for qualitation identification and quality evaluation of Loquat Leaf.

Attenuation of laser-generated shock waves in Plexiglas.

A simple analytic model is derived for describing the attenuation of a shock wave in a Plexiglas plate. At the same time, experimental measurements are presented with a well-designed optical-fiber sensor based on detection-beam deflection. The amplitude of the shock-wave pressure is measured experimentally and calculated numerically for analytic expressions at different distances from the region of the surface breakdown by the radiation of a single-pulse Nd:YAG laser. Good agreement between the experimental and the calculated values of the shock-wave pressure is established.

Shock-wave propagation and cavitation bubble oscillation by Nd:YAG laser ablation of a metal in water.

A highly sensitive fiber-optic sensor based on optical beam deflection is applied for investigating the propagation of a laser-induced plasma shock wave, the oscillation of a cavitation bubble diameter, and the development of a bubble-collapse-induced shock wave when a Nd:YAG laser pulse is focused upon an aluminum surface in water. By the sequence of experimental waveforms detected at different distances, the attenuation properties of the plasma shock wave and of the bubble-collapse-induced shock wave are obtained. Besides, based on characteristic signals, both the maximum and the minimum bubble radii at each oscillation cycle are determined, as are the corresponding oscillating periods.