A Selective‑Response Hypersensitive Bio‑Inspired Strain Sensor Enabled by Hysteresis Effect and Parallel Through‑Slits Structures

Flexible strain sensors are promising in sensing minuscule mechanical signals,and thereby widely used in various advanced fields.However,the effective integration of hypersensitivity and highly selective response into one flexible strain sensor remains a huge challenge.Herein,inspired by the hysteresis strategy of the scorpion slit receptor,a bio-inspired flexible strain sensor(BFSS)with parallel through-slit arrays is designed and fabricated.Specifically,BFSS consists of conductive monolayer graphene and viscoelastic styrene–isoprene–styrene block copolymer.Under the synergistic effect of the bio-inspired slit structures and flexible viscoelastic materials,BFSS can achieve both hypersensitivity and highly selective frequency response.Remarkably,the BFSS exhibits a high gage factor of 657.36,and a precise identification of vibration frequencies at a resolution of 0.2 Hz through undergoing different morphological changes to high-frequency vibration and low-frequency vibration.Moreover,the BFSS possesses a wide frequency detection range(103 Hz)and stable durability(1000 cycles).It can sense and recognize vibration signals with different characteristics,including the frequency,amplitude,and waveform.This work,which turns the hysteresis effect into a"treasure,"can provide new design ideas for sensors for potential applications including human–computer interaction and health monitoring of mechanical equipment.

Impact of back-gate bias on the hysteresis effect in partially depleted SOI MOSFETs

The hysteresis effect in the output characteristics,originating from the floating body effect,has been measured in partially depleted（PD） silicon-on-insulator（SOI） MOSFETs at different back-gate biases.I D hysteresis has been developed to clarify the hysteresis characteristics.The fabricated devices show the positive and negative peaks in the I D hysteresis.The experimental results show that the I D hysteresis is sensitive to the back gate bias in 0.13-渭m PD SOI MOSFETs and does not vary monotonously with the back-gate bias.Based on the steady-state Shockley-Read-Hall（SRH） recombination theory,we have successfully interpreted the impact of the back-gate bias on the hysteresis effect in PD SOI MOSFETs.

Role of polarization evolution in the hysteresis effect of Pb-based antiferroelecrtics

The electric field-induced irreversible domain wall motion results in a ferroelectric(FE) hysteresis. In antiferroelectrics(AFEs), the irreversible phase transition is the main reason for the hysteresis effects, which plays an important role in energy storage performance. Compared to the well-demonstrated FE hysteresis,the structural mechanism of the hysteresis in AFE is not well understood. In this work, the underlying correlation between structure and the hysteresis effect is unveiled in Pb(Zr,Sn,Ti)O_(3) AFE system by using in-situ electrical biasing synchrotron X-ray diffraction. It is found that the AFE with a canting dipole configuration, which shows a continuous polarization rotation under the electric field, tends to have a small hysteresis effect. It presents a negligible phase transition, a small axis ratio, and electric field-induced lattice changing, small domain switching. All these features together lead to a slim hysteresis loop and a high energy storage efficiency. These results offer a deep insight into the structure-hysteresis relationship of AFEs and are helpful for the design of energy storage material.

A rectifying diode with hysteresis effect from an electroactive hybrid of carbazole-functionalized polystyrene with CdTe nanocrystals via electrostatic interaction

One of the strategies to tune current-voltage behaviors in organic diodes is to combine field-induced charge transfer processes with schottky barrier.According to this principle,a rectifying diode with hysteresis effect was fabricated utilizing a hybrid of electroactive polystyrene derivative covalently tethered with electron-donor carbazole moieties and electrostatic linked with electron-acceptor CdTe nanocrystals.Current-voltage characteristics show an electrical switching behavior with some hysteresis is only observed under a negative bias,with three orders of On/Off current ratio.The hybrid material based rectifier exhibits a rectification ratio of six and its maximum rectified output current is about 5 × 10-5 A.The asymmetric switching is interpreted as the result of both field induced charge transfer and schottky barrier,capable of reducing the misreading of cross-bar memory.Meanwhile,chemical doping of CdTe nanocrystals instead of physical blend favor their uniform dispersion in matrix and stable operation of device.

Two-way Shape Memory Effect in a Ti-Ni-Nb Shape Memory Alloy with Wide Hysteresis

A two-way shape memory effect (TWSM E) in the Ti46.3Ni44.7Nb9 alloy has been systematically investigated by means of bending test and transmission electron microscopy (TEM ) observations. Based on the analysis of the microstructure after training. the mechanism of TWSME in the Ti46.3 Ni44.7Nb9 alloy has been discussed.

Study of Non-Ideal Effects for Extended Gate Field Effect Transistor Chlorine Ion Sensing Device

We use the extended gate field effect transistor (EGFET)as the structure of the chlorine ion sensor,and the chlorine ion ionophores (ETH9033 and TDDMAC1)are incorporated into solvent polymeric membrane (PVC/DOS),then the chlorine ion selective membrane is formed on the sensing window,and the fabrication of the EGFET chlorine ion sensing device is completed.The surface potential on the sensing membrane of the EGFET chlorine ion sensing device will be changed in the different chlorine ion concentration solutions,then changes further gate voltage and drain current to detect chlorine ion concentration.We will study non-ideal effects such as temperature,hysteresis and drift effects for the EGFET chlorine ion sensing device in this paper,these researches will help us to improve the sensing characteristics of the EGFET chlorine ion sensing device.

Estimation of the unfrozen water content of saturated sandstones by ultrasonic velocity

The unfrozen water content(UWC)of rocks at low temperature is an important index for evaluating the stability of the rock engineering in cold regions and artificial freezing engineering.This study addresses a new method to estimate the UWC of saturated sandstones at low temperature by using the ultrasonic velocity.Ultrasonic velocity variations can be divided into the normal temperature stage(20 to 0℃),quick phase transition stage(0 to-5℃)and slow phase transition stage(-5 to-25℃).Most increment of ultrasonic velocity is completed in the quick phase transition stage and then turns to be almost a constant in the slow phase transition stage.In addition,the UWC is also measured by using nuclear magnetic resonance(NMR)technology.It is validated that the ultrasonic velocity and UWC have a similar change law against freezing and thawing temperatures.The WE(weighted equation)model is appropriate to estimate the UWC of saturated sandstones,in which the parameters have been accurately determined rather than by data fitting.In addition,a linear relationship between UWC and ultrasonic velocity is built based on pore ice crystallization theory.It is evidenced that this linear function can be adopted to estimate the UWC at any freezing temperature by using P-wave velocity,which is simple,practical,and accurate enough compared with the WE model.

Resistivity and critical temperature of （Lal-xPrx）0.7Ca0.3MnO3

An empirical formula of the critical temperature that is concentration dependent for polycrystalline （La1-xPrx）0.7Ca0.3MnO3 is presented in this paper. With this formula, the temperature dependence of resistance is simulated for various values of x by using the random resistor network model and the Monte Carlo method. The hysteresis effect in p-T curves is reasonably explained. The simulation results are in good agreement with the relevant experimental measurements.

Diurnal dynamics of soil respiration and the influencing factors for three land-cover types in the hinterland of the Taklimakan Desert,China

Knowledge of soil respiration and the influencing factors in desert ecosystems is essential to understanding carbon dynamics and responses of biotic and abiotic processes in soils to climate change. In this study, soil respiration rate（R_s） for three land-cover types（shifting sandy land, sandy land with straw checkerboard barriers, and shelter forest land） in the hinterland of the Taklimakan Desert was measured in May 2015 using an automated soil CO_2 flux system. The effects of soil temperature（T_s） and soil water content（W_s） on R_s were also analyzed. The results showed that R_s values in shifting sandy land, sandy land with straw checkerboard barriers, and shelter forest land were all low and exhibited obvious diurnal fluctuations. The establishment of straw checkerboard barriers in sandy land had no significant effect on R_s, while the establishment of shelterbelts significantly increased R_s. Shifting sandy land and sandy land with straw checkerboard barriers were carbon sinks at night and early morning and were carbon sources in the daytime, while shelter forest land always acted as a carbon source during the whole day. The synergistic effect of T_s and W_s could better explain the diurnal dynamics in R_s than single factor. In shifting sandy land and sandy land with straw checkerboard barriers, W_s was identified as a limiting factor influencing the diurnal dynamics of R_s. Furthermore, a relatively strong hysteresis loop existed between R_s and T_s. In contrast, in shelter forest land, R_s was significantly influenced by T_s, and a relatively weaker hysteresis loop existed between R_s and W_s.

Cluster-size dependent randomization traffic flow model

In order to exhibit the meta-stable states, several slow-to-start rules have been investigated as modification to Nagel-Schreckenberg （NS） model. These models can reproduce some realistic phenomena which are absent in the original NS model. But in these models, the size of cluster is still not considered as a useful parameter. In real traffic, the slow-to-start motion of a standing vehicle often depends on the degree of congestion which can be measured by the clusters＇ size. According to this idea, we propose a cluster-size dependent slow-to-start model based on the speed- dependent slow-to-start rule （VDR） model. It gives expected results through simulations. Comparing with the VDR model, our new model has a better traffic efficiency and shows richer complex characters.

Interface passivation engineering for hybrid perovskite solar cells

The allure of high efficiency and low-temperature solution-processed organic-inorganic hybrid perovskite solar cells(PSCs)are inspiring scientists to seek for its commercialization.Interface passivation engineering has become an effective way to further enhance the efficiency and stability of PSCs by defect passivation,reduces the charge recombination and ion migration initiation and hysteresis control,etc.Herein,we have summarized the effects and recent research progress of interface passivation engineering in PSCs.Interface passivation layers can be realized by using the solution and/or vacuum evaporation processes which are very adaptable to varied materials with different properties and fabrication processes for enhanced photovoltaic performance and stability.

Numerical investigation on flow nonuniformity-induced hysteresis in scramjet isolator

Numerical simulation and theoretical analysis were conducted to study the hysteresis inside scramjet isolator during the reciprocating process of back pressure variation.It is revealed that only a regular reflection is theoretically possible for two leading shocks when the inflow Mach number is greater than 2.0,and no hysteresis can occur in the transition between shock reflection types.Nevertheless,wall suction,gas injection,and background waves cause non-uniformity of the incoming flow and would make hysteresis possible.Besides the classical hysteresis in the transition between shock reflection,new kinds of hysteresis were found in both the deflection angle of separated boundary layer and the location of the shock train.Moreover,the occurrence of hysteresis in the deflection angle of the separated boundary layer is accompanied with the shock reflection hysteresis.In the case with background waves or gas injection,hysteresis in the starting position of leading shock was observed too.As back pressure decreases,the leading shock does not follow the same path as that as the back pressure increases,and it is anchored at the location where the background shock or the injection interacts with the leading shock.It is inferred that,if two strong adverse pressure gradient regions move towards and interact with each other,hysteresis will take place when they start to separate.

The negative differential resistance characteristics of an RC-IGBT and its equivalent circuit model

A simple equivalent circuit model is proposed according to the device structure of reverse conducting insulated gate bipolar transistors （RC-IGBT）. Mathematical derivation and circuit simulations indicate that this model can explain the snap-back effect （including primary snap-back effect, secondary snap-back effect, and reverse snap-back effect） and hysteresis effect perfectly.

From the water sources of the Tibetan Plateau to the ocean:State of nutrients in the Changjiang linked to land use changes and climate variability

Anthropogenic activity is an important driver of changes in the chemistry of nutrients(N,P,and Si)over watersheds at the sub-continental scale(e.g.,106km~2)and can markedly modify their seaward fluxes to the global ocean.In the present study,we reviewed the current status of nutrient chemistry in Changjiang(Yangtze River)based on data collected through 11 expeditions along a river course spanning 4,500 km and 15–20 major tributaries during 1997–2016 as well as monthly monitoring at the river mouth since 1980.The data were analyzed together with published results in the literature to synthesize the recent developments and current state of nutrients in the Changjiang.Previously published results from the Qinghai-Tibetan Plateau head waters were included to realize the systematics of nutrients for the whole drainage basin.Here,we showed that tributaries of the upper reaches of watersheds collectively determine the regime with high concentration and skewed species ratio of nutrients in the Changjiang mainstream,producing profound effects over a water course of 2,000–2,500 km further downstream and until the river mouth.Moreover,using data across the Three Gorges Reservoir(TGR)during 2003–2016,we evaluated the trapping and/or amplifying effects of the Three Gorges Dam(TGD)on nutrient chemistry.Tide-influenced river delta contributed an additional 20%dissolved inorganic phosphorus and 5–10%dissolved inorganic nitrogen and dissolved silicates to the seaward flux,dramatically affecting the stoichiometry of nutrients at the river mouth.Next,based on compiled data on supply and export,legacy nutrients were evaluated.Both nitrogen and phosphorus are in the accumulation phase over the watersheds,and the legacy nutrient fluxes are much higher than the annual riverine seaward fluxes.Finally,we demonstrated that the seaward fluxes of anthropogenic nutrients from the Changjiang exceed those from other top 10 largest rivers on this planet,which can be attributed to land use changes in the China over the last three to four decades.

绕振荡Clark-Y水翼空化迟滞特性研究

本文针对Clark-Y水翼在雷诺数为Re=4.55×10^(5),空化数为σ=1.33,振荡频率为f*=2 Hz时的空化迟滞特性开展试验与数值研究.实验结果发现,绕振荡水翼的水动力特性和空化面积存在显著的迟滞现象.根据升力系数演化特征,将其划分为区域A、区域B和区域C三部分.对于区域A,下行程的升力系数低于上行程,且曲线上下波动较为明显.分析发现逆时针尾缘涡的形成与发展是导致下行程升力系数下降和波动的主要因素,进而促使滞环的形成.在区域B中,下行程的升力系数曲线相对上行程发生一定程度地平移.延迟效应是动力曲线平移的主要原因,进而形成较小的滞环面积.对于区域C,曲线滞环面积是最大的,且上下行程的升力系数演化曲线呈现峰谷相对的趋势.结果发现水翼在下行程阶段,攻角逐渐减小,空化分离和停留时间被提前,进而导致水动力曲线的差异和滞环面积的增大.