Ultra‑High Sensitivity Anisotropic Piezoelectric Sensors for Structural Health Monitoring and Robotic Perception

Monitoring minuscule mechanical signals,both in magnitude and direction,is imperative in many application scenarios,e.g.,structural health monitoring and robotic sensing systems.However,the piezoelectric sensor struggles to satisfy the requirements for directional recognition due to the limited piezoelectric coefficient matrix,and achieving sensitivity for detecting micrometer-scale deformations is also challenging.Herein,we develop a vector sensor composed of lead zirconate titanate-electronic grade glass fiber composite filaments with oriented arrangement,capable of detecting minute anisotropic deformations.The as-prepared vector sensor can identify the deformation directions even when subjected to an unprecedented nominal strain of 0.06%,thereby enabling its utility in accurately discerning the 5μm-height wrinkles in thin films and in monitoring human pulse waves.The ultra-high sensitivity is attributed to the formation of porous ferroelectret and the efficient load transfer efficiency of continuous lead zirconate titanate phase.Additionally,when integrated with machine learning techniques,the sensor’s capability to recognize multi-signals enables it to differentiate between 10 types of fine textures with 100%accuracy.The structural design in piezoelectric devices enables a more comprehensive perception of mechanical stimuli,offering a novel perspective for enhancing recognition accuracy.

Distinctive electrochemical performance of novel Fe-based Li-rich cathode material prepared by molten salt method for lithium-ion batteries

For constructing next-generation lithium-ion batteries with advanced performances,pursuit of highcapacity Li-rich cathodes has caused considerable attention.So far,the low discharge specific capacity and serious capacity fading are strangling the development of Fe-based Li-rich materials.To activate the extra-capacity of Fe-based Li-rich cathode materials,a facile molten salt method is exploited using an alkaline mixture of LiOH–LiNO3–Li2O2 in this work.The prepared Li1.09(Fe0.2Ni0.3Mn0.5)0.91O2 material yields high discharge specific capacity and good cycling stability.The discharge specific capacity shows an upward tendency at 0.1 C.After 60 cycles,a high reversible specific capacity of ~250 m Ah g-1is delivered.The redox of Fe3+/Fe4+and Mn3+/Mn4+are gradually activated during cycling.Notably,the redox reaction of Fe2+/Fe3+can be observed reversibly below 2 V,which is quite different from the material prepared by a traditional co-precipitation method.The stable morphology of fine nanoparticles(100–300 nm)is considered benefiting for the distinctive electrochemical performances of Li1.09(Fe0.2Ni0.3Mn0.5)0.91O2.This study demonstrates that molten salt method is an inexpensive and effective approach to activate the extra capacity of Fe-based Li-rich cathode material for high-performance lithium-ion batteries.

FINITE EXTENSIONS OF GENERALIZED BESSEL SEQUENCES TO GENERALIZED FRAMES

The objective of this paper is to investigate the question of modifying a givengeneralized Bessel sequence to yield a generalized frame or a tight generalized frame by finiteextension. Some necessary and sufficient conditions for the finite extensions of generalizedBessel sequences to generalized frames or tight generalized frames are provided, and everyresult is illustrated by the corresponding example.

Pedestrian trajectory prediction method based on the Social-LSTM model for vehicle collision

Techniques for predicting the trajectory of vulnerable road users are important to the development of perception systems for autonomous vehicles to avoid accidents.The most effective trajectory prediction methods,such as Social-LSTM,are often used to predict pedestrian trajectories in normal passage scenarios.However,they can produce unsatisfactory prediction results and data redundancy,as well as difficulties in predicting trajectories using pixel-based coordinate systems in collision avoidance systems.There is also a lack of validations using real vehicle-to-pedestrian collisions.To address these issues,some insightful approaches to improve the trajectory prediction scheme of Social-LSTM were proposed,such methods included transforming pedestrian trajectory coordinates and converting image coordinates to world coordinates.The YOLOv5 detection model was introduced to reduce target loss and improve prediction accuracy.The DeepSORT algorithm was employed to reduce the number of target transformations in the tracking model.Image Perspective Transformation(IPT)and Direct Linear Transformation(DLT)theories were combined to transform the coordinates to world coordinates,identifying the collision location where the accident could occur.The performance of the proposed method was validated by training tests using MS COCO(Microsoft Common Objects in Context)and ETH/UCY datasets.The results showed that the target detection accuracy was more than 90%and the prediction loss tends to decrease with increasing training steps,with the final loss value less than 1%.The reliability and effectiveness of the improved method were demonstrated by benchmarking system performance to two video recordings of real pedestrian accidents with different lighting conditions.

Effect of Different Sowing Dates in South Henan 's Rice-growing Areas on the Growth and Yield of Ratoon Rice

In order to determine the optimal sowing date of ratoon rice in South Henan's rice-growing areas,this paper performs a comparative analysis of rice growth process,seedling quality and yield of first season rice and ratoon rice under different sowing date treatments. The results show that under climatic conditions( 2014),by using dry seedling cultivation in a small plastic shed,the growth of seedling sown on February21 was affected,while the sowing treatments from March 1 to April 11 can breed normal seedlings,and in this period,the maturity period of first season rice was delayed with prolonged sowing date,and ratoon rice yield declined with prolonged sowing date( total production of rice sown on 11 March reaching a peak). Thus,it is considered that the optimal sowing date of ratoon rice in South Henan's rice-growing areas is mid-March.

A New Species of Genus Fomitiporia

[Objectives] This study aimed to study the morphological characteristics and molecular phylogeny of a new strain collected from rotten wood of sea buckthorn in Yanbei area of Shanxi Province. [Methods]The specimens were observed with naked eyes. With Melzer,cotton blue and 5% KOH as floating carriers,the slices were prepared,which were observed under a microscope. The ITS sequence of the new strain was compared with those of the 20 kinds of reported fungi to construct molecular phylogenetic tree based on ITS. [Results] The new strain has horseshoe-shaped basidiocarp and pileus shape and has no stipe. Sometimes,it grows procumbently and scrolled backward. The mycelial system is monomitic. The skeletal hyphae showed a negative reaction in the Melzer reagent and cotton blue reagent. The basidiospores are subglobose or spherical and colorless with thick wall. The results of molecular phylogenetic analysis showed that the new strain had a close relationship with Fomitiporia spp. and was clustered into the same branch with them. It formed an independent sub-branch in the phylogenetic tree. [Conclusions] The new strain was identified as a new species of Fomitiporia,named as Fomitiporia yanbeiensis S. Guo & L. Zhou( Gen Bank: KT861405,Fungal name: FN570360).

Coexistence of Charge Order and Antiferromagnetic Order in an Extended Periodic Anderson Model

The competition between the RKKY interaction and the Kondo effect leads to a magnetic phase transition,which occurs ubiquitously in heavy fermion materials.However,there are more and more experimental evidences indicating that the valence fluctuation plays an essential role in the Ce-and Y-based compounds.We study an extended periodic Anderson model(EPAM)which includes the onsite Coulomb repulsion Ucf between the localized electrons and conduction electrons.By employing the density matrix embedding theory,we investigate the EPAM in the symmetric case at half filling.By fixing the onsite Coulomb repulsion U of the localized electrons to an intermediate value,the interplay between the RKKY interaction,the Kondo effect and the Coulomb repulsion Ucf brings rich physics.We find three different phases,the antiferromagnetic phase,the charge order phase and paramagnetic phase.When the hybridization strength V between the localized orbital and the conduction orbital is small,the Kondo effect is weak so that the AF phase and the CO phase are present.The phase transition between the two long-range ordered phase is of first order.We also find a coexistence region between the two phases.As V increases,the Kondo effect becomes stronger,and the paramagnetic phase appears between the other two phases.

Nitrogen release characteristics of polyethylene-coated controlled-release fertilizers and their dependence on membrane pore structure

In this study, controlled-release fertilizers （CRFs） with five different nitrogen release periods were pre- pared by coating large urea particles with polyethylene （PE） membranes under various experimental conditions. The preliminary and differential solubility rates, release periods, and membrane pore sizes of the obtained CRFs were measured using water immersion, scanning electron microscopy, and mercury porosimetry. For all CRF samples, the median pore diameters of the membranes were equal to 4.5-5.3 nm and pores with sizes smaller than 10 nm accounted for 86-96% of the total pore surface area. The obtained pore diameter distributions differed for the five studied types of CRF, having release periods of 1,2, 4, 6, and 8 months. Thus, for the CRFs with a 1-month release period, the maximum pore diameter reached a magnitude of 4000 nm, while this value did not exceed 30 nm for the CRFs with a release period of 8 months. Hence, we have established a relationship between the release period of CRFs and their effective maximum pore sizes.

HPLC-PDA测定黄桷树叶提取液中绿原酸和芦丁的含量

建立测定黄桷树叶提取物中绿原酸和芦丁含量的HPLC-PDA法,采用ODS2色谱柱,梯度洗脱,流动相甲醇–磷酸溶液(pH 3.0),柱温25±2℃,流速1.0 mL/min。通过质谱和紫外光谱技术对提取物中有效成分进行结构确证。经确证提取物中含有绿原酸和芦丁,所建立的测定绿原酸和芦丁含量的HPLC-PDA法,在所考察的浓度范围内线性关系良好,r≥0.9998。定量限均小于0.06μg/mL,检测限均小于0.02μg/mL;相对回收率范围为99.10%-104.7%。以RSD值表示的日内精密度均小于1.89%,日间精密度均小于1.82%。该方法灵敏度高,准确度好,专属性强,操作简便,可用于黄桷树叶提取液中绿原酸和芦丁的含量测定。经测定黄桷树叶提取液中芦丁和绿原酸含量分别为3.46和3.23μg/mL。

A review of condition-based maintenance: Its prognostic and operational aspects

Condition-based maintenance(CBM)detects early signs of failure and dictates when maintenance should be performed based on the actual condition of a system.In this paper,we first review some of the recent research on CBM under various physical structures and signal data.Then,we summarize several kinds of prognostic models that use monitoring information to estimate the reliability of complex systems or products.Monitoring information also facilitates operational decisions in production planning,spare parts management,reliability improvement,and prognostics and health management.Finally,we suggest some research opportunities for the reliability and operations management communities to fill the research gap between these two fields.

In-house or Outsourcing R&D?Manufacturer Technology Strategy in the Presence of Market Follower Encroachment

Facing the threat of market follower encroachment,this paper constructs game theoretical models based on different channel structures and market structures,investigates following manufacturer's encroachment strategy and technology strategies,and discusses the impact of following manufacturer's strategy on quality decisions.The results show that encroachment always improves consumer surplus by slashing prices when leading manufacturer adopts in-house R&D(IRD);otherwise,it results in lower consumer surplus with mild competition if leading manufacturer is at a technological disadvantage.Furthermore,the technology strategies of following manufacturer are related to their R&D capabilities.The superior one is outsourcing R&D(ORD)for the manufacturers when their R&D capability is weak,otherwise,IRD is optimal.In a word,the leading manufacturer always prefers IRD under certain conditions,while the following manufacturer always prefers ORD.In addition,encroachment restrains quality innovative motivation under fixed or quality-sensitive R&D costs,but can improve quality level when consumers have a higher reference dependency for quality;meanwhile,the following manufacturer adopting ORD is always beneficial to quality improvement.

阴道分泌物荧光染色法检测病原体的临床应用评价

目的通过比较湿片法和荧光法在阴道分泌物病原体检测中的结果,对阴道分泌物荧光染色的临床价值进行评价。方法采集140例阴道分泌物标本,分别采用湿片法和荧光法检测标本中的线索细胞、念珠菌和阴道毛滴虫等病原体,并分析其检测结果。结果湿片法检出线索细胞、念珠菌和阴道毛滴虫的阳性率分别为4.29%、13.57%和2.86%,荧光法的阳性率分别为11.43%、15.00%和2.86%;两种方法在检出线索细胞方面的差异有统计学意义(P<0.05),在检测阴道毛滴虫和念珠菌的阳性率方面一致。结论荧光染色检测检测线索细胞的阳性率高于湿片法,可用于临床阴道分泌物病原体的检测。