Search

As big data and the Internet continue to advance, there is much space for new retail models to emerge. Luckin Coffee, one of the top brands in China’s coffee industry, has seen significant growth in both market share and brand recognition thanks in large part to its marketing approach. This study gathers a great deal of official data to understand the reasons behind Luckin Coffee’s rapid popularity in China. It then applies SWOT analysis to evaluate Luckin Coffee’s marketing approach. Luckin Coffee initially succeeded due to its rapid expansion and technological innovation but faced setbacks due to financial mishandling and excessive reliance on discounts. Fortunately, the company was rescued promptly and focused on developing its products. However, competition in the Chinese beverage industry is very fierce. The authors offer several recommendations for tweaks to the current marketing mix in the conclusion to aid Luckin Coffee in enhancing its core competency. It also knows the demand and market for coffee in China in recent years. To expand the product brand and produce more best-selling items, Luckin Coffee ought to use brand co-branding. Similarly, it is necessary for Luckin Coffee to developLuckin Coffee must develop localized products and establish its ecosystem. The suggestions might also serve as a source of inspiration for creating and growing a mid-range Chinese coffee company.

Integration of more thermodynamically favorable valorization of biomass (e.g., glycerol), compared to sluggish oxygen evolution, with H2 production is of great significance for energy‐saving electrosynthesis of value‐added chemicals. However, its widespread deployment has been challenged by costly electrocatalysts and large overpotential reaching an industrial‐relevant current density (≥400 mA cm−2). Herein, carbon shell‐encapsulated manganese‐doped cobalt nitride nanoarrays immobilizing on nickel foam, denoted Mn‐CoN@C/NF, are crafted via hydrothermal method and ammoniation. As a bifunctional electrocatalyst, the Mn‐CoN@C/NF manifests extraordinary activity for glycerol oxidation reaction (GOR) with an ultralow potential of 1.37 V (versus RHE) at 400 mA cm−2, in conjunction with H2 evolution reaction (HER) with a low overpotential of 31 mV at 10 mA cm−2. A record high Faradaic efficiency (97.7%) for formate production of GOR is delivered at 1.35 V (vs RHE). Impressively, a two‐electrode electrolyzer capitalizing on the Mn‐CoN@C/NF as catalysts reaches 800 mA cm−2 at 1.83 V, delivering an electricity‐saving efficiency of 15.0% compared to pure water splitting. DFT calculations substantiate that Mn species within Mn‐CoN not only optimize hydrogen adsorption kinetics for HER, but also elevate Co3+ active sites' density for GOR. This work offers an energy‐saving and efficient electrosynthesis avenue for coproduction of valuable chemicals. [ABSTRACT FROM AUTHOR]

The giant magnetostrictive transducer is a transducer device that realizes magneto-mechanical energy conversion. Each mechanical component is connected by the joint surface to realize the transmission of ultrasonic vibration energy. To ensure the efficient transmission of energy, the influence of the contact characteristics of the joint surface on the output stability of the transducer is studied. According to the contact conditions between the mechanical joint surfaces of the giant magnetostrictive ultrasonic transducer (GMUT), the key factors affecting the mechanical vibration performance of the ultrasonic system are obtained by analyzing the vibration transmission characteristics of the joint surfaces. The influence of different joint surface contact characteristics (JSCT) on the amplitude–frequency curve of the transducer is analyzed by the ANSYS software. Simulations and experiments have been conducted to verify the predicted results. As the preload force increases, the natural frequency of the transducer increases, but the growth rate decreases. The natural frequency of the double-rod GMUT with a small joint surface area is slightly higher in the optimal output mode shape, while its amplitude is significantly larger. The optimal prestress for the GMUT with different-sized joint surfaces is 3–5 MPa. This paper acquires the JSCT under a high-frequency vibration condition, reveals the influence of the joint surface on the mechanical output performance of the GMUT, and can provide a theoretical basis for the design and analysis of the rotary ultrasonic vibration processing system. [ABSTRACT FROM AUTHOR]

With the rising incidence of various diseases in China and the constant development of the pharmaceutical industry, there is a growing demand for floxacin-type antibiotics. Due to the large-scale production and high cost of waste treatment, the parent drug and its metabolites constantly enter the water environment through domestic sewage, production wastewater, and other pathways. In recent years, the pollution of the aquatic environment by floxacin has become increasingly serious, making the technology to degrade floxacin in the aquatic environment a research hotspot in the field of environmental science. Metal–organic frameworks (MOFs), as a new type of porous material, have attracted much attention in recent years. In this paper, four photocatalytic materials, MIL-53(Fe), NH2-MIL-53(Fe), MIL-100(Fe), and g-C3N4, were synthesised and applied to the study of the removal of ofloxacin and enrofloxacin. Among them, the MIL-100(Fe) material exhibited the best photocatalytic effect. The degradation efficiency of ofloxacin reached 95.1% after 3 h under visible light, while enrofloxacin was basically completely degraded. The effects of different materials on the visible photocatalytic degradation of the floxacin were investigated. Furthermore, the photocatalytic mechanism of enrofloxacin and ofloxacin was revealed by the use of three trappers (▪O2−, h+, and ▪OH), demonstrating that the role of ▪O2− promoted the degradation effect of the materials under photocatalysis. [ABSTRACT FROM AUTHOR]

Energy shortage and environmental pollution have become the most serious problems faced by human beings in the 21st century. Looking for advanced clean energy technology to achieve sustainable development of the ecological environment has become a hot spot for researchers. Nitrogen-based substances represented by urea are environmental pollutants but ideal energy substances. The efficiency of urea-based energy conversion technology mainly depends on the choice of catalyst. The development of new catalysts for urea oxidation reaction (UOR) has important application value in the field of waste energy conversion and pollution remediation based on UOR. In this work, four metal–organic framework materials (MOFs) were synthesized using ultrasound (NiCo-UMOFs) and hydrothermal (NiCo-MOFs, Ni-MOFs and Co-MOFs) methods to testify the activity toward UOR. Materials prepared using the hydrothermal method mostly form large and unevenly stacked block structures, while material prepared using ultrasound forms a layer-by-layer two-dimensional and thinner structure. Electrochemical characterization shows NiCo-UMOFs has the best electrocatalytic performance with an onset potential of 0.32 V (vs. Ag/AgCl), a Tafel slope of 51 mV dec−1, and a current density of 13 mA cm−2 at 0.5 V in a 1 M KOH electrolyte with 0.7 M urea. A prolonged urea electrolysis test demonstrates that 45.4% of urea is removed after 24 h. [ABSTRACT FROM AUTHOR]

In this paper, we put forward a class of weighted extended tree-like fractals and further use them as test bed to unveil the impact of weight heterogeneity on random walks. Specifically, a family of weighted extended tree-like fractals are first proposed, which are parameterized by a growth parameter m and weight parameter w. Then, we explore standard weight-dependent walk on the networks by deploying three traps at initial three nodes. To this end, we derive analytically the average trapping time (ATT) to measure the trapping efficiency and the obtained results show that depending on values of w , ATT may grow sub-linearly, linearly and super-linearly with the network size. Besides, it can also quantitatively impact the leading behavior and pre-factor of ATT simultaneously. Finally, more challenging mixed weight-dependent random walk that takes non-nearest-neighbor hopping is addressed. Analytical solutions of ATT derived under this new scenario imply that weight parameter w still can qualitatively, quantitatively steer leading behavior and quantitatively affect pre-factor of ATT. As to the stochastic parameter controlling mixed random walk, it could only impact the pre-factor of ATT and only have negligible effect on the leading behavior of ATT. In summary, this work could further augment our understanding of random walks on networks. [ABSTRACT FROM AUTHOR]

We propose a surface measurement method based on optical frequency comb heterodyne interferometry ranging. A digital micromirror device is used to establish a single-pixel detection system without a mechanical scanning device and realize high-speed sampling. The measurement range of the step height is extended by synthetic wavelength interferometry from half of the carrier wavelength to half of the synthetic wavelength (40 μm in this system). Thus, a sample composed of three gauge blocks and an MEMS device of the teardrop-shaped groove were measured with an accuracy of 5 nm and a measurement time of 27 ms. [ABSTRACT FROM AUTHOR]

A surface acoustic wave (SAW)-driven acoustofluidic chip of high energy efficiency is proposed through model analysis. The chip supports propagation of Lamb waves in the lid above a fluid-filled channel. Eigenmode resonance in the on-chip channel is then achieved by coupling both the SAWs and the Lamb waves into the fluid. Specifically, the phase velocity of the Lamb mode equals the SAW speed along the substrate, and the leaky angles of both match that required by the expected channel mode. Compared to resonant SAW acoustofluidics (RSA), Lamb wave coupled RSA can make the energy tripled or higher. Meanwhile, the obtained resonance frequency deviates very slightly from the designed value, limiting the error to 0.5, while RSA chips exhibit errors as high as 5.7. The proposed design protocol can help to promote the energy efficiencies and contain the in-channel temperature rise and resonance frequency deviations in SAW acoustofluidics. [ABSTRACT FROM AUTHOR]

How to effectively control the trapping process in complex systems is of great importance in the study of trapping problem. Recently, the approach of delayed random walk has been introduced into several deterministic network models to steer trapping process. However, exploring delayed random walk on pseudo-fractal web with the co-evolution of topology and weight has remained out of reach. In this paper, we employ delayed random walk to guide trapping process on a salient deterministic weighted scale-free small-world network with the co-evolution of topology and weight. In greater detail, we first place a deep trap at one of initial nodes of the network. Then, a tunable parameter p is introduced to modulate the transition probability of random walk and dominate the trapping process. Subsequently, trapping efficiency is used as readout of trapping process and average trapping time is employed to measure trapping efficiency. Finally, the closed form solution of average trapping time (ATT) is deduced analytically, which agrees with corresponding numerical solution. The analytical solution of ATT shows that the delayed parameter p only modifies the prefactor of ATT, and keeps the leading scaling unchanged. In other words, ATT grows sublinearly with network size, whatever values p takes. In summary, the work may serves as one piece of clues for modulating trapping process toward desired efficiency on more general deterministic networks. [ABSTRACT FROM AUTHOR]

Sonodynamic therapy (SDT) activated by ultrasound is attractive as a potential alternative to conventional phototriggered therapies owing to the deeper penetration depth and the absence of phototoxicity. Nevertheless, the low quantum yield of nano‐sonosensitizer and the tumor hypoxia remain significant challenges for SDT. Herein, a novel TiO2‐based nano‐sonosensitizer is reported to bilaterally enhance the quantum yield by simultaneous integration of precious metal Pt nanoparticles (NPs) and an oxygen‐deficient layer. Furthermore, the hollow cavity of TiO2 serves as a reservoir to load doxorubicin, an anticancer drug for chemotherapy as well as a molecular sonosensitizer for SDT. The decorated Pt NPs act as nanozymes to catalyze the decomposition of endogenous hydrogen peroxide for the generation of oxygen to alleviate tumor hypoxia, reduce resistance to chemotherapy, and provide sufficient oxygen source for subsequently facilitating SDT‐induced reactive oxygen species production. The high chemo‐sonodynamic synergistic efficacy is systematically demonstrated both in vitro and in vivo. More importantly, it is believed that the novel design and the new finding in the synthesis of Pt–TiO2 heterostructures can be popularized for the preparation and application of the semiconductor‐based nanoplatforms in many fields. [ABSTRACT FROM AUTHOR]

Due to the ubiquitous occurrence of evanescence in many physical, chemical and biological scenarios, mortal random walks that incorporate evanescence explicitly have drawn more and more attention. It has been a hot topic to study mortal random walks on distinct network models. In this paper, we study mortal random walks on T fractal and a family of treelike regular fractals with a trap located at central node (i.e., innermost node). First, with self-similar setting composed of T fractal, initial position of the walker and location of trap, the total trapping probability of the mortal walker reduces to a function of walker's single-step survival parameter q. In more detail, the total trapping probability is expressed by the n th iteration of map (scaling function) of q. Based on the map, the analytical expression of total trapping probability's dominant behavior, the mean time to trapping (MFPT) and temporal factor are obtained, which are related to random walk dimension. Last, we extend the analysis to a family of treelike regular fractals. On them, the total trapping probability is still expressed as the n th iteration of the map scaling q. Accordingly, dominant behavior of total trapping probability, MFPT and temporal factor are determined analytically. Both analytical results obtained on T fractal and more general treelike regular fractals show that the mean time to trapping and desired random walk dimension can be obtained by tuning the survival probability parameter q. In summary, the work advances the understanding of mortal random walks on more general deterministic networks. [ABSTRACT FROM AUTHOR]

In modelling acoustofluidic chips actuated by surface acoustic waves (SAWs) and using polydimethylsilane (PDMS) as a channel material, reduced models are often adopted to describe the acoustic behaviors of PDMS. Here, based on a standing SAW (SSAW) acoustophoresis chip, we compared three different descriptions of a PDMS chamber and looked into in-chamber physical fields and ensuing particle motion processes through finite element (FE) simulations. Specifically, the PDMS domain was considered as an elastic solid material, a non-flow fluid, and a lossy wall, respectively. The major findings include: (a) the shear waves that propagated in a solid PDMS wall did not influence the in-chamber pressure and ARF fields severely, but induced an observable difference in the acoustic streaming (AS) patterns, and distinctly changed the trajectories of polystyrene particles, especially those whose radii were below 1.5 μm; and (b) the equivalent damping coefficients were linearly dependent on the SAW frequency, characterized by a fixed loss per wavelength, indicating the wave leakage at the interface being the main source of the transmission loss of SAWs. Meanwhile, the acoustic radiation force (ARF) can be overestimated when describing PDMS as a lossy wall, especially at the bottom corners of the chamber, which could cause inaccurate predictions of the motion of big particles. Based on the damping mechanism, a rough protocol is provided for scaling of pressure fields between different models. Some suggestions for device designs and operations are also given based on the obtained findings. [ABSTRACT FROM AUTHOR]

Multiple-input multiple-output (MIMO) radar is an enabling technique for high-resolution imaging, which is especially useful for near-field electromagnetic scattering diagnosis of complex targets. Among others, high sidelobes and radar cross section (RCS) calibration uncertainty are the major challenges for such applications, due to array nonuniformity, imperfect channels, and antenna pattern tapering. These shortcomings prevent a MIMO radar from obtaining high-quality images with enough dynamic range and RCS accuracy. In this paper, we develop a complete solution for these problems. A novel adaptive weighting technique is proposed, where the complex weights are optimized for exact amplitude and phase error calibration of a MIMO array and for azimuth sidelobe reduction. A MIMO filtered backprojection algorithm is developed for image formation with improved RCS calibration accuracy, where propagation path-loss, antenna pattern tapering, and phase distortion due to the near-field spherical wave front are compensated. Both indoor and outdoor field test results are presented to show the high-quality images obtained using the proposed techniques, demonstrating the applicability of a MIMO radar for diagnostic RCS imaging of complex targets. [ABSTRACT FROM AUTHOR]

Carbon materials are of great significance in state‐of‐the‐art electrochemical CO2 reduction (ECR) as key components such as electrocatalysts, gas diffusion electrodes, and current collectors. Notably, dimensionalities of carbons and related manipulations play vital roles in boosting ECR performance, e.g., mass/charge transfer dynamics, exposure of active sites, reaction space, product's Faradaic efficiency/selectivity, and durability. Here, recent endeavors in dimensionality engineering toward advanced carbon‐based materials for ECR is first summarized, including pure carbons (e.g., carbon nanotube and graphene) and carbon composites, and highlight the dimensionality‐dependent properties toward ECR performance. Various engineering strategies referring to dimensionality modulation and integration have been summarized, e.g., top‐down, bottom‐up, and soft chemical approaches. Design principles of dimensionality‐varied carbons are elaborated, the impacts of dimensionalities of carbons and related surface chemistry (e.g., functional group, wettability, and electronic structure) on ECR kinetics and product‐targeted mechanisms are also scrutinized. Some insights into how the dimensionality manipulation of carbons elevates performance of carbon‐based materials in mass/charge transfer acceleration, ECR kinetics, and product selectivity are provided. At last, a perspective for challenges and future development of dimensionality‐varied carbon materials is discussed. This review aims at providing guidance for customizable construction of carbon materials with dimensionality dependence toward green and energy‐saving electrosynthesis systems. [ABSTRACT FROM AUTHOR]

As for the academics and policymakers, more attention has been given to the issue on how to reduce environmental pollution through the cooperation of environmental regulation and local officials' promotion incentives. With the use of a city-level panel data of 266 Chinese cities from 2005 to 2016, this study preliminary explores the impacts of environmental regulations, local officials' promotion incentives, and their interaction terms on urban environmental pollution at national and regional levels by using the spatial Durbin model. The results indicate that the impacts of environmental regulations and local officials' promotion incentives on urban environmental pollution have achieved the desired goal with the other's cooperation, and their interaction term's coefficients on urban environmental pollution are significantly negative. Moreover, spatial heterogeneity is established, and the uneven development of urban environmental pollution among different regions deserves more attention. In order to effectively reduce the level of urban environmental pollution in China, the government should focus on such solutions as enhancing the implementation and supervision efficiency of environmental regulation, optimizing the performance appraisal system of local officials, improving the synergistic effects of environmental regulations and local officials' promotion incentives, and establishing a multi-scale spatial cooperation mechanism based on both geographical and economic correlations. [ABSTRACT FROM AUTHOR]

• Interactive effects of natural-human factors on vegetation coverage were quantified. • The area with a probability of degeneration ≥80% covered 16.6% of study area. • Models with vegetation coverage (2000) largely accounted for the vegetation variance. • The major drivers of vegetation coverage changed with time and variables. Vegetation coverage in coastal wetlands has been significantly altered in response to multiple disturbances over recent decades. However, the major driving factor of vegetation coverage in coastal wetlands remains unclear, with natural and human factors playing interactive roles at the national scale. To identify the major controls of vegetation coverage in coastal wetlands, structural equation modeling (SEM) was conducted to quantify the relative contribution of natural and human factors to vegetation coverage in coastal wetlands in China over a 16-year period (2000–2015). The results showed that, in brief, vegetation coverage was slightly degraded (k = −0.0035) over the 2000–2015 period. The area with a probability of vegetation coverage degeneration ≥80% covered 16.6% of the study area. Most annual mean vegetation coverage was lower but improved near the sea, with inverse results obtained near land. In 2000, human1 (population and GDP, r = −0.31) and topography (r = 0.32) were the major controls of vegetation coverage. The vegetation coverage (2000) played the most important and positive role (r = 0.62, r = 0.66) in the vegetation coverage in 2015. Our findings highlight that the major drivers of vegetation coverage in coastal wetlands changed with time and selected variables. [ABSTRACT FROM AUTHOR]

• Q-switching performance of Yb:LaCOB crystal laser is investigated for the first time. • Pulsed radiation in 2-W level is produced in passively Q-switched action with 2D MoTe 2. • Maximum pulse energy of 6.6 μJ is generated. The passive Q-switching performance of an Yb:LaCa 4 O(BO 3) 3 crystal laser was investigated for the first time to our knowledge. Stable repetitively pulsed laser action was demonstrated with a 2D MoTe 2 saturable absorber under high output couplings ranging from 70% up to 95%. A maximum pulsed output power of 2.11 W was produced at a repetition rate of 357 kHz, with a slope efficiency of 32% in terms of incident pump power. The largest pulse energy, minimum pulse duration, and highest peak power achievable were, respectively, 6.6 μJ, 103 ns, and 52.4 W. Our work suggests that this relatively new monoclinic oxyborate crystal may be more advantageous over most of other Yb-ion materials in making high-energy pulsed lasers passively Q-switched with 2D saturable absorbers. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS)-involved photodynamic therapy (PDT) and chemodynamic therapy (CDT) hold great promise for tumor treatment. However, hypoxia, insufficient H 2 O 2 , and overexpressed glutathione (GSH) in the tumor microenvironment (TME) hinder ROS generation significantly. Herein, we reported CaO 2 @Cu-TCPP/CUR with O 2 /H 2 O 2 /Ca 2+ self-supply and GSH depletion for enhanced PDT/CDT and Ca 2+ overload synergistic therapy. CaO 2 nanospheres were first prepared and used as templates for guiding the coordination between the carboxyl of tetra-(4-carboxyphenyl)porphine (TCPP) and Cu 2+ ions as hollow CaO 2 @Cu-TCPP, which facilitated GSH-activated TCPP-based PDT and Cu + -mediated CDT. The hollow structure was then loaded with curcumin (CUR) to form CaO 2 @Cu-TCPP/CUR composites. Cu-TCPP prevented degradation of CaO 2 , while Cu 2+ ions reacted with GSH to deplete GSH, produce Cu + ions, and release TCPP, CaO 2 , and CUR. CaO 2 reacted with H 2 O to generate O 2 , H 2 O 2 , and Ca 2+ to achieve O 2 /H 2 O 2 /Ca 2+ self-supply for TCPP-based PDT, Cu + -mediated CDT, and CUR-enhanced Ca 2+ overload therapy. Thus, this multilevel ROS amplifier enhances synergistic therapy with fewer side effects and drug resistance.

Background: Psoriasis is a common chronic inflammatory skin disorder. Qingxiong ointment (QX) is a natural medicinal combination frequently employed in clinical treatment of psoriasis. However, the active ingredients of QX and its precise mechanisms of improving psoriasis remain unclear. This study elucidated the effects of QX on an Imiquimod (IMQ)-induced mouse model of psoriasis while also exploring the regulation of the active ingredient of QX, shikonin, on the HIF-1 signaling pathway in HaCaT cells., Methods: A mouse model of psoriasis was established through topical application of IMQ, and the local therapeutic effect of QX was evaluated using dorsal skin tissue with mouse psoriatic lesion and Psoriasis Area Severity Index (PASI) scores, hematoxylin-eosin (HE) staining, and immunohistochemical staining. Elisa and qPCR were employed to identify changes in the expression of inflammation-related factors in the mouse dorsal skin. Immunofluorescence was used to assess changes in the expression of T cell subsets before and after treatment with various doses of QX. HPLC was used to analyze the content of shikonin, and network pharmacology was employed to analyze the main targets of shikonin. Immunofluorescence was used to identify the effects of shikonin on the HIF-1 signaling pathway in IL6-induced psoriasis HaCaT cells. Finally, qPCR was used to identify the differential expression of the HIF-1 signaling pathway in skin tissues., Results: QX significantly reduces PASI scores on the backs of IMQ-induced psoriasis mice. HE staining reveals alleviated epidermal thickness in the QX group. Immunohistochemical analysis shows a significant reduction in ICAM, KI67, and IL17 expression levels in the QX group. Immunofluorescence results indicate that QX can notably decrease the proportions of CD4 + T cells, γδ T cells, and CD8 + T cells while increasing the proportion of Treg cells. Network pharmacology analysis demonstrates that the main targets of shikonin are concentrated in the HIF-1 signaling pathway. Molecular docking results show favorable binding affinity between shikonin and key genes of the HIF-1 signaling pathway. Immunofluorescence results reveal that shikonin significantly reduces p-STAT3, SLC2A1, HIF1α, and NOS2 expression levels. qPCR results show significant downregulation of the HIF-1 signaling pathway at cellular and tissue levels., Conclusion: Our study revealed that QX can significantly reduce the dorsal inflammatory response in the IMQ-induced psoriasis mouse model. Furthermore, we discovered that its main component, shikonin, exerts its therapeutic effect by diminishing the HIF-1 signaling pathway in HaCaT cells., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Objectives: To examined the efficacy and safety of Peng's Shengjing recipe in treating asthenospermia with deficiency and failure of kidney yang. The traditional Chinese medicine (TCM) Peng's Shengjing recipe might have benefits in treating male asthenospermia., Methods: This randomized, positive drug-controlled, single-blind pilot study enrolled outpatients from the Third Department of Traditional Chinese Medicine Surgery, Shanghai University of Traditional Chinese Medicine, Shanghai, China, between April 2020 and September 2020. A total of 99 participants were randomized to Shengjing recipe (n=50) and Xuanju capsule (n=49). They were treated for 12 weeks. The primary endpoint was routine semen examinations, including the percentage of sperm motility rated grade A, A+B, and A+B+C, and the clinical effective rate. The secondary endpoints were the levels of gonadotropins., Results: The A grade sperms (18.9% versus [vs.] 13.9%, p =0.030) and A+B grade sperms (42.9% vs. 32.7%, p <0.001) were higher in the Shengjing recipe group than the Xuanju capsule group. The effective rates were 68% and 53.1% in the Shengjing recipe and Xuanju capsule groups ( p =0.128). No safety signals were observed., Conclusion: Peng's Shengjing recipe improves the quality of sperms and is effective in treating clinical asthenospermia of deficiency of kidney yang. The treatment was well tolerated, without obvious hepatorenal toxicity. Chinese Clinical Research Registry No.: ChiCTR2000030845 ., (Copyright: © Saudi Medical Journal.)

We propose a compression-coding-based surface measurement method that combines single-pixel imaging and heterodyne interference using an optical frequency comb. The real and imaginary parts of the heterodyne interference signals are used to obtain the depth information rapidly. By optimizing the ordering of the Hadamard measurement basis, we reconstruct a three-step sample with heights of approximately 10, 20, and 30 µm without an iterative operation in 6 ms, with a precision of 5 nm. Compared with the uncompressed measurement, the sampling times reduced to 20%, and the measurement time reduced by five times without measurement accuracy loss. The proposed method is effective for rapid measurements, particularly for objects with a simple surface topography.

Acousotophoretic particle separations in counterpropagating surface acoustic wave (SAW) fields, e.g., standing SAWs (SSAWs), phase modulated SSAWs, tilted angle SSAWs, and partial standing SAWs, have proven successful. But there still lacks analytical tools for predicting the particle trajectory and optimizing the device designs. Here, we study the acoustophoresis of spherical Rayleigh particles in counterpropagating SAW fields and find that particle motions can be characterized into two distinct modes, the drift mode and the locked mode. Through theoretical studies, we provide analytical expressions of particle trajectories in different fields and different moving patterns. Based on these, we obtain theory-based protocols for designing such SAW acoustofluidic particle separation chips, which are demonstrated through finite-element simulations. The results here provide theoretical guidelines for designing high throughput and high efficiency particle separation devices.

We present a femtosecond laser-based interferometry for step-structure surface measurement with a large field of view. A height axial scanning range of 348 µm is achieved by using the method of repetition frequency scanning with reference to the Rb atomic clock and the optical path length difference design for 21 times of the pulse interval. A combined method, which includes the envelope peak positioning method for rough measurement, synthetic-wavelength interferometry for connection, and carrier wave interferometry for fine measurement, is proposed to reconstruct the surface. A three-step specimen with heights of approximately 20, 50, and 70 µm was successfully measured with a height precision of 7 nm, and the accuracy was verified by a commercial white light interferometer. The diameter of the field of view that was demonstrated was 17.3 mm, which could be much larger owing to the high spatial coherence of the femtosecond laser. The results show that the femtosecond laser system combines the step-structure measurement performance of white light interferometry and the high-precision large-field performance of phase shifting interferometry, indicating its potential for widespread use in ultra-precision manufacturing of micro/nano-devices, such as semiconductor chips, integrated circuits, and micro-electro-mechanical systems.

We present an absolute distance measurement system using a phase-stable dual-comb system with 56.09 MHz repetition rate and 2 kHz repetition rate difference. A relative phase stability of 0.1 rad in 0.5 ms between two combs is achieved using a mutual locking scheme. The dual-comb ranging system combines the time-of-flight (TOF) method, synthetic-wavelength interferometry (SWI), and carrier wave interferometry (CWI). Each method provides a particular ambiguity range and resolution, and they can be applied simultaneously and linked to enhance the precision and measurement rate of the ranging system. The experimental results demonstrate that a precision of 1.2 μm is obtained without time averaging, and the precision can be improved to 3 nm with only 10 ms averaging time using the SWI method described in this study. The precision reaches a sub-nanometer when the averaging time exceeds 0.1 s. A system with high accuracy and short averaging time would enhance fast measurement performance in various industrial applications. The ambiguity range is about 2.67 m in our system, we test the performance of the system with 1.5 mm range at 1.5 m distance.