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Process knowledge reuse technology can improve the computer numerical control (CNC) programming efficiency and shorten the production cycle for similar parts. However, current process knowledge reuse methods focus on retrieving similar machining cases based on the machining features or topological structures of a part, which failed to deeply consider the close relationship between the 3D part geometry and CNC machining process, can result in incomplete matches between the reused knowledge and CNC process. It is more obvious for the similar complex surface parts that the most existing reuse methods are hardly to integrate 3D part geometry with CNC machining process. To overcome the problem, a reuse method for similar ruled surface blades is proposed through dual mapping mechanism in this paper, which is based on the 3D solid mapping model and spatial transformation relationship. First of all, a dual mapping mechanism is constructed to transfer process knowledge from the parameter domain to physical domain for similar ruled surface blades. Secondly, the acquired process knowledge of the ruled surface blade is characterized to the process knowledge template by the multi-vector function, followed by its inheritability is analyzed for the process knowledge reuse. Finally, two similar ruled surface blades are machined in an experiment, the machined surfaces of both blades are smooth without obvious pits in no violent vibration machining, furthermore, the surface roughness value is 4.314 µm and 4.933 µm of the two similar blades, which can meet the requirement of semi-fishing, this result indicates the correctness and validity of the process knowledge reuse method presented in this paper. [ABSTRACT FROM AUTHOR]

The tolerance of pedestrians to red light signals is a crucial factor in urban residents' travel experiences and road traffic safety. To address the current lack of research on methods for measuring pedestrian red light tolerance time at crossings, this paper proposes a stacking model for predicting the red light tolerance time of individual pedestrians. The model employs the XGBoost (XGB), random forest (RF), support vector machine regression (SVR), and multilayer perceptron (MLP) models as primary models, with a multiple linear regression model as the secondary-layer meta-model, as well as Bayesian hyperparameter tuning. Using random survival forest (RSF) and K-means clustering methods, the dataset was divided into three categories: the low, medium, and high tolerance groups. The feature variables influencing the red light tolerance time were grouped accordingly. Stacking models were established for each tolerance and feature group. The experimental results demonstrated that the feature group voted on by multiple machine learning models performed the best in all three tolerance groups. In the low tolerance group, the mean squared error (MSE), mean absolute error (MAE), and mean absolute percentage error (MAPE) were 6.58, 1.91, and 19.78%, respectively. For the medium tolerant group, the MSE, MAE, and MAPE were 4.82, 1.53, and 7.63%, respectively. For the high tolerance group, the MSE, MAE, and MAPE were 33.32, 3.89, and 10.14%, respectively. Individual XGB, RF, SVR, MLP, and ungrouped stacking models were established for comparative analysis of the test set. The results indicated that the proposed grouped stacking model outperformed the other models overall. The method provides a means of obtaining the probability distribution function of the length of the waiting crowd's tolerance time for each red light range and thus determining the duration of the red light at the crossing signal for different personnel compositions. [ABSTRACT FROM AUTHOR]

Expressway networks are continuously developing and emergency rescue demand is increasing proportionately. The location of expressway emergency rescue nodes needs refinement to meet changing requirements. In this study, the expressway was modeled as an expressway network. The differences in the origin destination (OD) distribution matrices for working days and major holidays were used as the bases for determining the need for temporary emergency rescue nodes. Overlapping and non-overlapping community detection algorithms were used to extract the distribution characteristics of OD during both day categories. These distributions were used to determine permanent and temporary emergency rescue sites. In this study, we considered the differences in traffic volume, distance, and impact of four vehicle types on traffic accidents to select the location of emergency rescue nodes, and allocate emergency resources. An emergency rescue node selection model for an expressway network was established based on spatio-temporal characteristics. The results based on a regional example determined that 22 permanent and 25 temporary emergency rescue nodes were appropriate. The average rescue time for traffic accidents during working days and major holidays compared to the P-center location model, was reduced by approximately 27.08% and 6.70%, respectively. The coefficient of variation of emergency rescue time was reduced by approximately 28.22% and 21.41%, respectively. The results indicated that the model satisfied the expressway emergency rescue demand requirements, and improved the rationality of the rescue center node layout. [ABSTRACT FROM AUTHOR]

The rectangle attack has shown to be a very powerful form of cryptanalysis against block ciphers. Given a rectangle distinguisher, one expects to mount key recovery attacks as efficiently as possible. In the literature, there have been four algorithms for rectangle key recovery attacks. However, their performance varies from case to case. Besides, numerous are the applications where the attacks lack optimality. In this paper, we delve into the rectangle key recovery and propose a unified and generic key recovery algorithm, which supports any possible attacking parameters. Not only does it encompass the four existing rectangle key recovery algorithms, but it also reveals five new types of attacks that were previously overlooked. Further, we put forward a counterpart for boomerang key recovery attacks, which supports any possible attacking parameters as well. Along with these new key recovery algorithms, we propose a framework to automatically determine the best parameters for the attack. To demonstrate the efficiency of the new key recovery algorithms, we apply them to Serpent, AES-192, CRAFT, SKINNY, and Deoxys-BC-256 based on existing distinguishers, yielding a series of improved attacks. [ABSTRACT FROM AUTHOR]

Fabricating porous active metals through chemical dealloying poses challenges due to their reactivity and vulnerability to oxidation in aqueous solutions. The objective of this study was to create micron-sized porous Ti alloy by utilizing the Ti–Mo system as a precursor alloy for chemical dealloying. The impact of phase composition and initial microstructure of the precursor alloys (Tix at% Mo100 − x at%, x = 60 ~ 70) on the morphology of the resulting porous Ti alloy was systematically investigated. To improve the mechanical strength and minimize oxidized phases during the dealloying process, a molten salt electrolysis (MSE) method was employed. The strengthening mechanism of MSE on porous Ti alloys encompassed three key aspects. Firstly, it effectively reduced the presence of oxidized phases, thereby eliminating surface defects. Secondly, MSE facilitated grain growth and eliminated voids and cracks at the grain boundaries, leading to enhanced mechanical properties. Thirdly, the involvement of a secondary phase contributed to the overall strengthening mechanism. Following MSE treatment, the oxygen content in the porous Ti alloy decreased from over 13 to 5 at%, and needle-like nanocrystalline β-Ti precipitates formed within the ligament structure. The accumulation and aggregation of compression-induced dislocations at the grain boundaries of the precipitated phase further improved the mechanical properties. In summary, this work presents an innovative approach to fabricating porous Ti alloy with low oxygen content, high strength, and adjustable microstructure. It elucidates the strength enhancement mechanism by MSE, providing insights for future materials development and applications. [ABSTRACT FROM AUTHOR]

The development of preparation methods for XOFs, as a new class of organic frameworks, plays a crucial role in shaping their structures, functions, and potential applications. In this study, we presented the construction of chiral supramolecular 2D halogen-bonded organic frameworks (XOFs) through a post-synthetic modification strategy. A linear halogen-bonded organic polymer (XOP), XOP-DPBA, decorated with aldehyde groups, was initially prepared to validate the feasibility of post-synthetic modification for XOF construction and functionalization. XOP-DPBA exhibited excellent reactivity with amines, forming imine bonds. By utilizing this reactivity, a series of cross-linked 2D XOFs were efficiently prepared through post-synthetic modified cross-linking reactions. Furthermore, we successfully introduced chiral α/β-cyclodextrins (α/β-CD) into the XOF skeletons via host-guest interactions, resulting in the fabrication of chiral supramolecular 2D XOFs. These chiral XOFs displayed the induced circular dichroism (ICD) signals and assembled them into helical fibers. The post-synthetic modification strategy demonstrated its versatility and simplicity for the construction and functionalization of XOFs. [ABSTRACT FROM AUTHOR]

Prunella vulgaris L. (P. vulgaris) has long been considered to have antipyretic, analgesic and anti-inflammatory effects, lowering blood lipids and pressure. Many studies show that in addition to the traditional telomere attrition, DNA damage and epigenetic changes, immunosenescence is also a new possibility to explore the mechanism of ageing. Therefore, this herb may have potential anti-ageing effects. Typically, there are a series of markers that identify senescent cells, such as superoxide dismutase (SOD)2, an inhibitor of CDK4 (p16INK4A), tumor necrosis factor (TNF)-α, immune cells number, proliferation, and nuclear abnormalities. These changes rarely present in young tissues, while greatly increasing in response to ageing. Firstly, the ageing model of the Institute of Cancer Research (ICR) mouse was established by d-galactose subcutaneous injection. Then, SOD2, p16INK4A and TNF-α were detected by quantitative Real-time PCR (qPCR), Western Blot (WB) and Enzyme-Linked Immunosorbent Assay (ELISA). Simultaneously, senescent cells in livers were stained by hematoxylin and eosin (HE). The viability of splenocytes was detected by Cell Counting Kit-8(CCK-8). The difference in specific immune cells (NK cells, B lymphocytes and T lymphocytes) was detected by flow cytometry. Both low (100 mg/kg) and high (300 mg/kg) concentrations of P. vulgaris treated ageing ICR mice show anti-ageing alterations, such as p16INK4A decreased approximately 1/2 and SOD2 tripled in livers, TNF-α decreased from 1 to 0.6 in plasma, and T cells increased from 0.09 to 0.19%. Compared with the ageing group, the spleen cells in the Prunella-treated group had stronger proliferation ability. Thus, P. vulgaris could have an anti-ageing effect. This is the first study to demonstrate the anti-ageing effect of P. vulgaris. It may also be capable of preventing a variety of age-related diseases. [ABSTRACT FROM AUTHOR]

In the present work, an electrocatalytic electrode NiMoO4@NiCo2O4/NF with heterojunction structure was grown by hydrothermal synthesis and electrodeposition process on nickel foam (NF). The construction and morphology of electrode materials were represented through X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The oxygen evolution reaction (OER) property of NiMoO4@NiCo2O4/NF was researched in basic solution. The consequences show that the heterostructural electrode NiMoO4@NiCo2O4/NF has outstanding OER catalytic performance, and only at 100 mA cm−2 it can achieve 330 mV overpotential, electronic structure of the electrode interface is well regulated by the combination of the two constituents. Meanwhile, the electrode materials show the good performance in the stability test. The experiment presents a novel method for the preparation of inexpensive, high catalytic activity and continuous durability of non-noble metal based water electrolysis catalyst, which has great development potential. [ABSTRACT FROM AUTHOR]

The stability and lifetime of electrical contact pose a major challenge to the performance of microelectro-mechanical systems (MEMS), such as MEMS switches. The microscopic failure mechanism of electrical contact still remains largely unclear. Here conductive atomic force microscopy with hot switching mode was adopted to simulate the asperity-level contact condition in a MEMS switch. Strong variation and fluctuation of current and adhesion force were observed during 10,000 repetitive cycles, exhibiting an "intermittent failure" characteristic. This fluctuation of electrical contact properties was attributed to insulative carbonaceous contaminants repetitively formed and removed at the contact spot, corresponding to degradation and reestablishment of electrical contact. When contaminant film was formed, the contact interface became "metal/carbonaceous adsorbates/metal" instead of direct metal/metal contact, leading to degradation of the electrical contact state. Furthermore, a system of iridium/graphene on ruthenium (Ir/GrRu) was proposed to avoid direct metal/metal contact, which stabilized the current fluctuation and decreased interfacial adhesion significantly. The existence of graphene enabled less adsorption of carbonaceous contaminants in ambient air and enhanced mechanical protection against the repetitive hot switching actions. This work opens an avenue for design and fabrication of microscale electrical contact system, especially by utilizing two-dimensional materials. [ABSTRACT FROM AUTHOR]

The trade-off between the potentially detrimental effects of fine particulate matter (PM2.5) and the benefits of physical activity (PA) is unclear. We aimed to explore the independent and interaction effects between long-term PM2.5 exposure and PA on blood pressure (BP) and hypertension. A total of 8704 adults (≥45 years) without hypertension at baseline in a nationwide cohort of the China Health and Retirement Longitudinal Study (CHARLS) were followed from 2011 to 2015. The participants were selected using a four-stage, stratified, and cluster sampling procedure. The annual PM2.5 concentrations at the residential address were estimated from a two-stage machine learning model with a 10 km × 10 km resolution. A standard questionnaire collected information on PA and potential confounders, and metabolic equivalents (MET·h/wk), which combined frequency, intensity, and duration information, were used to assess PA levels. We adopted mixed-effects regression models to explore the independent and interaction effects between long-term PM2.5 exposure and PA on BP and risk of hypertension. Systolic blood pressure (SBP) decreased by −0.84 mmHg (95% CI: −1.34, −0.34) per an IQR (interquartile range, 175.5 MET·h/wk) increase in PA, and diastolic blood pressure (DBP) decreased by −0.42 mmHg (95% CI: −0.76, −0.07). Each IQR (36.1 μg/m3) increment in PM2.5 was associated with 0.48 mmHg (95% CI: −0.24, 1.20) in SBP and −0.02 mmHg (95% CI: −0.44, 0.39) in DBP. PM2.5 showed an elevated effect with risks of hypertension (odds ratio, OR = 1.01; 95% CI: 1.00, 1.03), while PA showed the inverse result (OR = 0.98; 95% CI: 0.97, 0.99). Interaction analyses indicated PA maintained the beneficial effects on BP, but the negative association was attenuated, accompanied by the increase of PM2.5. PA decreased the BP and hypertension risks, while PM2.5 showed the opposite results. PM2.5 attenuated the beneficial effects of PA on BP and modified the association between PA and the risk of hypertension. [ABSTRACT FROM AUTHOR]

As an effective measure of urban forest management, organic mulching impacts soil properties, the environment, and tree growth. Fine roots are vital for resource acquisition and nutrient cycling in forest ecosystems, but the effects of organic mulching on root morphology and biomass are unknown. We conducted a field experiment in a 15-year-old Ligustrum lucidum urban forest with and without mulch addition (0 cm, 5 cm, 10 cm and 20 cm of mulch). Five cm of organic mulch decreased the specific root length (SRL) and specific surface area (SSA) but increased root tissue density and fine root biomass (FRB) with decreasing bulk density. The SRL and SSA of low-order roots (1st- and 2nd-order roots) and FRB of high-order roots (3rd- to 5th-order roots) were more sensitive to mulching as more nutrients were transported between plants and soil. The SRL and SSA decreased in the topsoil (0–20 cm) and increased gradually in the subsoil (20–40 cm) with mulch, while the root tissue density decreased. Consequently, fine roots extend into the deeper soil after mulching with nutrient loss in the subsoil. The FRB increased during the growing season but decreased in the non-growing season after mulching, indicating that mulching stimulated the growth and turnover of fine roots. Bulk density was the key factor that affected the root morphology and biomass, and root order and soil depth were considerable factors for the fine roots. Organic mulching is an effective measure for urban forest management that benefits root and plant growth. [ABSTRACT FROM AUTHOR]

Better knowledge and comprehensive evaluation of soil quality have important implications for developing sustainable forest management practices. The objective of the present study was to establish a soil quality index (SQI) that can be used to assess soil quality under different thinning intensities in a Chinese fir (Cunninghamia lanceolata [Lamb.] Hook) plantation in southeastern China. We sampled the soil in different seasons of the year from four plots subjected to different thinning intensities: low-intensity thinning (LIT, 30%), moderate-intensity thinning (MIT, 50%), high-intensity thinning (HIT, 70%), and control (0%). We analyzed 16 physical, chemical, and biological soil properties. The SQI was calculated based on total data set (TDS) and minimum data set (MDS) using different scoring functions (linear and nonlinear), integrating procedures (additive, weighted additive, and Nemoro), and weight assignment methods (communality and variation of principal component analysis (PCA)). The SQI calculated by the nonlinear weighted additive method with variation explained by the PCA performed better than the other methods. The SQI values were in the range of 0.26–0.64 under different thinning intensities. A significant increase in the SQI values was observed in MIT (53.2%) and HIT (40.8%) compared with that in CK. The SQI values also showed strong seasonal variability, with the highest values in the summer and the lowest values in the winter. Microbial biomass nitrogen (MBN), soil organic carbon (SOC), and pH were found to be the most crucial indicators of soil quality. Our results confirmed that thinning exerts a strong effect on soil quality, and the studied SQI based on MDS was found to be an effective tool for assessing soil quality. [ABSTRACT FROM AUTHOR]

This paper reports on a novel in-plane and electrostatically actuated bi-stable radio frequency (RF) microelectromechanical systems (MEMS) switch. A lateral RF MEMS switch designed by the inertial generated timing sequence (IGTS) method is able to latch sequentially by only a single voltage signal. In the switch design, we applied a mass block to one of the two mutually perpendicular cantilevers to achieve an extremely simple bi-stable process. Compared with previous bi-stable RF MEMS switches, the proposed device does not require driving signals with complicated timing sequences to realize latch. Therefore, the hardware complexity of RF systems is reduced, and the driving method becomes easier than before. Thanks to the bi-stable function, the power consumption only generates between the OFF and ON state, resulting in zero static power consumption. The switch was fabricated by silicon-on-glass (SOG) processes with only two lithographic masks. Measured results have shown that the manufactured RF MEMS switch successfully realized the bi-stable function at an operating voltage of 38 V. At 6 GHz, the measured isolation was − 33.18 dB, while the insertion loss was below − 1.9 dB. The presented switch in this paper is dedicated for low power consumption and low hardware redundancy wireless communication systems. [ABSTRACT FROM AUTHOR]

To avoid impacts and vibrations during the processes of acceleration and deceleration while possessing flexible working ways for cable-suspended parallel robots (CSPRs), point-to-point trajectory planning demands an under-constrained cable-suspended parallel robot (UCPR) with variable angle and height cable mast as described in this paper. The end-effector of the UCPR with three cables can achieve three translational degrees of freedom (DOFs). The inverse kinematic and dynamic modeling of the UCPR considering the angle and height of cable mast are completed. The motion trajectory of the end-effector comprising six segments is given. The connection points of the trajectory segments (except for point P3 in the X direction) are devised to have zero instantaneous velocities, which ensure that the acceleration has continuity and the planned acceleration curve achieves smooth transition. The trajectory is respectively planned using three algebraic methods, including fifth degree polynomial, cycloid trajectory, and double-S velocity curve. The results indicate that the trajectory planned by fifth degree polynomial method is much closer to the given trajectory of the end-effector. Numerical simulation and experiments are accomplished for the given trajectory based on fifth degree polynomial planning. At the points where the velocity suddenly changes, the length and tension variation curves of the planned and unplanned three cables are compared and analyzed. The OptiTrack motion capture system is adopted to track the end-effector of the UCPR during the experiment. The effectiveness and feasibility of fifth degree polynomial planning are validated. [ABSTRACT FROM AUTHOR]

Zygosaccharomyces rouxii referred as Yeast S is an important microorganism widely applied in traditional fermented food to accelerate flavor formation. Z. rouxii 3-2 referred as Yeast S 3-2 constructed previously is a new strain having higher salt tolerance than wild type. In this study, salt stress response of synthesis key flavor metabolites 3-methylthiopropanol, 2-phenylethyl alcohol, and isoamyl acetate in Yeast S and S 3-2 were investigated based on SPME–GC–MS and RT-qPCR. Analysis of GC–MS data showed that high salinity led to increase the contents of 3-methylthiopropanol and 2-phenylethyl alcohol both in Yeast S and Yeast S 3-2, while inhibited the synthesis of isoamyl acetate, and the induced effect on Yeast S 3-2 was more pronounced than Yeast S. Furthermore, the RT-qPCR results revealed that the salinity could enhance the genes expression of ARO10 and PDC1, and stronger effect on Yeast S 3-2 than S. However, the gene expression of AFT1 was reduced in high-salt culture conditions, which was consistent with the results of GC–MS data. The results presented in this study can provide theoretical support of Z. rouxii 3-2 application during food fermentation. [ABSTRACT FROM AUTHOR]

A tapered single-mode coreless single-mode (SCS) structure with high sensitivity for sensing refractive index is described. In order to achieve high specificity of optical biosensors, here enzyme capsulation film was achieved by embedding urease in zeolitic imidazolate framework (ZIF-8/urease) through in situ growth approach on the coreless fibers. Determination of urea is achieved through online monitoring of its binding to the urease in zeolitic imidazolate framework. Refractive index change result in wavelength shifts of the optical fiber biosensor. The resonance wavelength exhibits a good linear relationship with urea concentration in the range of 1 to 10 mM with detection limit of 0.1 mM and sensitivity of 0.8 mM/RIU (refractive index unit) if operated with broadband light ranging from 1525 nm to 1590 nm. Final assessment of optical biosensor in real sample was performed where excellent performance in terms of sensitivity and selectivity was observed. [ABSTRACT FROM AUTHOR]

Maximum power point tracking (MPPT) circuits in photovoltaic (PV) cell-based wireless sensor nodes often make the systems complex and costly. This paper proposes a novel energy management strategy for PV cell-based systems to remove their MPPT circuit without reducing their working efficiency. By modeling the non-MPPT system, energy storage in different situations is calculated. The key factors to improve the working efficiency of the system, such as operating voltage and number of PV cells in series, are also analyzed. A design is proposed to maximize the working efficiency. Another model for systems including MPPT circuits is also proposed for comparison. Simulation analysis shows that during the monitoring period, the total active time of the non-MPPT system can be as long as that of the system with MPPT circuits. Experimental tests confirm the validity of the proposed energy strategy. More importantly, the number of electronic components in the non-MPPT system’s power module is only approximately 1/5 of that of the other system. This strategy provides a possible approach for practical wireless sensor nodes that are small in size and have low cost. [ABSTRACT FROM AUTHOR]

This paper presents an approach for restoring force enhancement to radio frequency (RF) micro-electro-mechanical systems (MEMS) switch with stiction-recovery actuation mechanism. It is based on additional anti-stiction electrodes which are inserted to the coplanar waveguide (CPW) between the signal line and ground planes of a RF MEMS switch. If the movable membrane sticks to the substrate, electrostatic force, as extra restoring force, generated by the bias voltage between the anti-stiction electrodes can promise restoring action. The designed device with the proposed approach is fabricated. The restoring force of the fabricated device had reached 75, 177 and 520 μN by the bias voltages of 0, 10 and 20 V, respectively. [ABSTRACT FROM AUTHOR]

These findings notwithstanding, future studies on soil quality should involve more potential indicators of soil quality, such as soil structure, microbial community composition, and soil macrofauna, and should also involve the exploration of the relationship between soil quality and stand productivity. Improved microclimatic conditions and substrate input in MIT and HIT may increase soil microbial activity and nutrient availability, thus increasing soil quality. [Extracted from the article]

Supplementary Information Graph: (DOCX 41 kb) Publisher's note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. The online version of the original article can be found at https://doi.org/10.1007/s00604-019-4026-0 B Correction to: Microchimica Acta (2020) 187: 72 b https://doi.org/10.1007/s00604-019-4026-0 The original version of this paper was published with an error in the supplementary information file. [Extracted from the article]

Syringe pumps are commonly used in microfluidic systems to provide flows with precise control. But small periodic fluctuations on flow induced by the stepper motor in syringe pumps are a problem that influences the characteristics of the microfluidic system. This paper presents a microfluidic stabilizer which contains an air chamber. A specific amount of air is sealed in the air chamber and will attenuate the flow fluctuations by expanding or shrinking its volume. A theoretical model based on Euler equation is developed to clarify the characteristics of the microfluidic stabilizer. The result of simulations by finite element analysis is in good agreement with the theoretical model. A new method based on fluorescence detection and three-dimensional hydrodynamic focusing is developed to measure the flow fluctuations induced by the pumps and also to characterize the buffering capacity of the stabilizer. It is experimentally demonstrated that the fluctuation amplitude is cut to 46% by one microfluidic stabilizer and reduced to 14% by two series connected stabilizers. [ABSTRACT FROM AUTHOR]