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The uniform ZnO submicron spheres composed of nanodots were synthesized by solvothermal method and then added to PZT5A powder for spark plasma sintering. The effects of ZnO addition on phase composition， microstructure and electric properties of the lead zirconate titanate （PZT） ceramics were studied. The results indicate that PZT ceramics with a relative density higher than 97% can be prepared by spark plasma sintering at 900 ℃ for 5 min. The addition of ZnO submicron spheres is beneficial for speeding up the sintering process and promoting the grain growth of PZT ceramics. With the increase of ZnO addition， the content of the trigonal phase increases gradually. The addition of a proper amount of ZnO submicro spheres can improve the piezoelectric and dielectric property of PZT ceramics. When the mass fraction of ZnO is 0.10%， the superior overall performance of the material is optimal， at a frequency of 1 kHz， the piezoelectric constant d33=432 pC/N， the electromechanical coupling coefficient kp=0.56， the mechanical quality factor Qm=69.8， the relative dielectric constant εr=1360， and the dielectric loss tanδ=0.0227.

Increasing research has focused on how ovarian hormones influence individual prosocial motivation and cooperation. However, most results remain ambiguous and contradictory. Here, we collected progesterone (PROG) and oestradiol from 62 healthy women with regular menstrual cycles to explore whether variations in ovarian hormones could flexibly change their cooperative preference according to their opponents' strategies in multiple rounds of a prisoner's dilemma (PD) game. Participants in different menstrual phases (32 in the follicular phase [FP] and 30 in the luteal phase [LP]) were asked to complete 20 rounds of PD games with each of three computer opponents holding different cooperative strategies. The results revealed that in PD games that did not require cooperation for increased outcomes, women in the LP (high PROG) reduced their cooperation rate more significantly than women in the FP (low PROG). In contrast, when the game design required reciprocity, simultaneously elevated levels of PROG and oestradiol predicted greater instances of participants choosing to cooperate. Furthermore, we found that elevated PROG levels accounted for women's elevated prosocial choices, regardless of the need to increase outcomes through cooperation. These results implied higher levels of PROG and oestradiol influence women's cooperative strategies resulting in increased social interactions.

This research investigated egg freshness of Roman pink in 4 storage temperature change groups. The shell eggs were storage for 0, 10, 20, 30 d, and weight loss, gas chamber height, Haugh unit, yolk index, thick-to-thin albumen ratio and albumen pH of all shell egg experiment groups were evaluated. The results showed that weight loss increased significantly (P

In order to study the mechanical damage characteristics and energy evolution law of coal after ultrasonic fracturing, uniaxial compression experiments were carried out on fractured coal with different power by using electronic universal pressure testing machine, acoustic emission system. The mechanical damage parameters of different power ultrasonic fracturing coal were obtained, and the relationship between acoustic emission signal and damage parameters of coal mass with different power fracturing was explored. The fractal characteristics of coal surface cracks were analyzed by box fractal dimension, and the damage degradation mechanism of ultrasonic fracturing coal caused by different ultrasonic power was clarified. The experimental results show that the characteristic strength and elastic modulus of coal gradually decrease with the increase of ultrasonic fracturing power, and the damage parameters of uniaxial compressive strength and elastic modulus of coal are linearly correlated with the fracturing power. During the uniaxial compression process, the acoustic emission ringing count can be divided into three stages, which are quiet period, rising period and fluctuating period. With the increase of ultrasonic power, the incubation period of crack is shorter and the proportion of relative time is smaller. With the increase of crack growth rate, the weakening effect on the strength of coal is gradually enhanced, the sudden increase of acoustic emission signal is obvious., the final failure of coal sample is more broken, and the failure characteristics change from elastic brittleness to ductility-plasticity with the increase of fracturing power. Coal pore fissure extension, and three is a linear positive correlation between the fractal dimension damage parameters of coal surface cracks and the fracturing power. The greater the fractal dimension damage parameter is, the more complex the coal fracture morphology is. Based on the acoustic parameters, the relationship between the damage parameters and the normalized parameters of acoustic emission is analyzed, and it has a good fitting relationship. The above results show that ultrasonic fracturing causes damage to the coal structure, makes the coal seam damage and deformation, and forms a complex coal seam seepage network, thus improving the permeability of coal seam.

This paper proposes a novel multilevel topology “Modular-Isolated-Multilevel-Converter” which achieves almost zero low frequency capacitor voltage fluctuation. It inherits the structure of MMC but replaces the half bridge module by the newly proposed Isolated Half-Bridge (IHB). The fundamental and 2nd order harmonic frequency current originally in the MMC module capacitor have been eliminated through connecting the secondary sides of the IHB at the same level of the three phases together. The elimination is due to that the 1st and 2nd order components in the arm current are 120° phase shifted in three phases. Therefore, the module capacitance is reduced by more than 10 times since it only carries switching frequency ripple. Moreover, the arm inductance can also be significantly reduced since the 2nd order harmonic current disappears. The topology is specifically suitable for variable frequency drive application, because its capacitance and inductance are not affected by the output frequency. The challenges of zero frequency start-up when MMC is adopted for VSD can be addressed here. In the paper, the operation principle of the proposed MIMC is fully analyzed and the mathematical model is built. Moreover, a methodology of capacitor sizing and arm inductor design for general MMC topology is proposed. The detailed design considerations for MIMC are also discussed and presented. The plant modeling and control strategy have been proposed for MIMC. A 55-kW simulation is carried out to verify the theoretical analysis. And a 6-kW downscaled hardware prototype is also developed to demonstrate the benefits of the new topology over the traditional MMC.

This paper proposes a generalized design methodology of a robust controller to mitigate the impact of system uncertainty on controller stability and performance which includes steady-state error, disturbance rejection, high-frequency noise attenuation and speed of dynamic response. The first step is to select the weighting functions that bound the transfer functions for the entire range of uncertainty. The second step is to form mathematical representation for both robust stability and robust performance. The third step is to conduct the robust H-infinity controller synthesis to generate the full-order controller, and then carry out order reduction and recheck of the design objectives. The last step is to select an optimized controller based on the multi-dimensional Pareto Front algorithm. The proposed method has been firstly applied to the current controller design of a grid-connected inverter with variable grid impedance, and secondly to the voltage controller design of an LLC resonant DC/DC converter with variable resonant capacitance. The results indicate that the selected optimal H-infinity controller has an overall more satisfactory performance in terms of stability, steady-state error, disturbance/noise rejection capability and dynamic performance, compared with conventional PI and PR controllers when there is a large variation of system parameters.

Series connection of devices is an effective way to achieve higher blocking voltage. SiC MOSFETs exhibit narrow short-circuit withstand time and generally much lower short-circuit robustness than silicon IGBTs. This puts a critical concern on their utilization, further stressing the importance of reliable protection. A complete short-circuit protection should be implemented to improve the reliability. In this article, a systematic short-circuit analysis methodology is proposed. Following this methodology, all the possible fault scenarios can be derived. Besides the traditional short-circuit scenarios, some unique short-circuit faults, such as a single device short- or open- circuit, have been found in series-connected SiC MOSFETs. These unique faults may not cause overcurrent, which means the traditional overcurrent-based protection is not applicable. This article proposes a method combining drain-source voltage logic signal and gate signal to comprehensively detect both classic short-circuit scenarios and unique fault scenarios. Another different point in series-connected devices is that the soft turn-off should be synchronized for each serial device to prevent excessive voltage unbalancing. The proposed short-circuit protection scheme is evaluated under each short-circuit scenario. The experimental results demonstrate that the proposed protection scheme can successfully protect the serial devices from further destruction within 500 ns for all short-circuit scenarios.

Plant nutrient stoichiometry indicates the balance of plant internal nutrients and its nutrient-use strategies in response to environmental changes. However, the responses of nutrient stoichiometry in different wetland plant organs under agricultural intervention are poorly understood. Here, we compared the nitrogen (N), phosphorus (P), and the ratio of N:P in the plant organs (leaves, stems, roots, and root hair) of a typical helophyte plant (Glyceria spiculosa) in reference, drained, nutrient-rich, and cultivated wetlands (CW) located downstream of the Tumen River in Northeast China. Compared with that in reference wetlands (RW), the results indicate that the average N content in plant leaves, stems, roots, and root hair in nutrient-rich wetlands (NW) was significantly higher by 76, 61, 56, and 39%, respectively (p < 0.05), whereas the N content of roots and root hair in drained wetlands (DW) was significantly higher by 17 and 32%, respectively (p < 0.05). It was found that plant root P increased only in nutrient-rich and DW (p < 0.05). Interestingly, the agricultural interventions significantly affected soil N and P availability, resulting in positive effects on plant leaves, stems, roots, and root hair. Nutrient stoichiometry analysis showed the highest increase in plant leaf N:P ratio in NW, followed by that in drained and CW, but its ratio in root and root hair showed no significant changes under different agricultural interventions, which suggests that G. spiculosa allocates nutrients differently in different organs under agricultural interventions. These results imply that plant nutrient stoichiometry should incorporate various plant organs for an in-depth understanding of plant strategies against environmental changes.

The voltage rating of the commercial Gallium Nitride (GaN) power devices are limited to 600/650 V due to the lateral structure. Stacking the low-voltage rating devices is a straightforward approach to block higher dc link voltage. However, the unbalanced voltage sharing can occur due to the discrepancies in the gate driving loops, the device parameter tolerance and the device-to-ground displacement currents for the series-connected devices in the stack. The voltage imbalance may cause the over-voltage breakdown, in particular for GaN devices, which do not have the avalanche breakdown mechanism. In this article, a novel controllable current source gate driver is proposed, which addresses the voltage imbalance issue of series-connected GaN HEMTs for both hard switching and soft switching scenarios. The proposed current source gate driver controls the device switching timing and the dv/dt with fine accuracy by directly regulating the device gate current. Without the employment of the lossy snubber circuit or the external Miller capacitor, the switching energy and the switching speed are almost not compromised for each individual device. Meanwhile, the current mirror circuits are utilized as the discontinuous pulsed current sources, which produce negligible additional gate driving loss. A series-connected GaN-based multiple pulse tester is built to validate the proposed current source gate driver and the voltage balancing strategies. It is demonstrated that the drain-to-source voltage difference of the series-connected GaN devices is below 10% for different load current and different switching speed (dv/dt) conditions. Moreover, it is found that the series-connected GaN solution can save 33.6% switching energy compared with the benchmark SiC solution under the same operating condition.

A 48 V Belt-Driven Starter Generator (BSG) System is featured with high output current, high starting torque, and highly efficient thermal management. This paper firstly elaborates hardware design considerations of a high power density three-phase BSG inverter to address the challenges of even current distribution among paralleled MOSFETs, small drain-source voltage spike and good thermal dissipation. In order to satisfy the high-current requirement, a careful selection of MOSFET device with high-current rating and low on-resistance has been presented. In order to suppress circulating current among paralleled devices, individual gate resistors have been placed in the gate loop of each MOSFET. In order to provide good thermal dissipation, an Insulated Metal Substrate (IMS) board and single-layer layout technique have been implemented. Multiple low-profile electrolytic capacitors are used to increase the power density of the prototype. Moreover, the use of automotive gate driver IC TLE9180 and microcontroller TC1782 makes the prototype more readily accepted by industry. An improved Interior Permanent Magnet (IPM) motor control strategy and a pump-back system based on a virtual machine concept have been implemented to facilitate the validation of the prototype under rated condition without using a real motor. The control algorithm automatically adjusts the onset of field-weakening by using an additional inverter voltage loop and takes into account the nonlinearity of the stator flux linkage by using curve fitting technique, which makes the motor drive adaptive to machine parameter changes as well as DC bus voltage fluctuation. A three-phase BSG inverter prototype with a peak power of 12 kW has been built and tested. The prototype power density has reached 20.3 kW/L. Both PLECS simulations and hardware experiments show a continuous and stable operation with up to 200 A phase current and up to 600 Hz output frequency.

The voltage rating of commercial Gallium Nitride (GaN) power semiconductors is limited to 600/650 V because of the lateral structure. Stacking low-voltage switches is an effective way to block higher dc-link voltage. However, unbalanced voltage sharing can occur even with well-matched gate drivers and semiconductors due to the device-to-ground displacement currents. As a result, the low-voltage switches may suffer from over-voltage breakdown. This study presents a novel closed-loop current source gate driver to address the unbalanced dynamic voltage sharing issue. Additional compensation current is actively injected into the switch gate to counteract the voltage imbalance brought by the device-to-ground displacement currents. Compared with the conventional voltage source gate driver-based active gate control method, the proposed current source gate driver tunes the switch turn-off timing and dv/dt more accurately because the switch gate current is directly regulated. Meanwhile, since both the pulse width and amplitude of the compensation gate current can be adjusted, the proposed active gate control is more flexible for adapting to different operating conditions. Moreover, without employing snubber circuits or extra Miller capacitors, the switching speed and switching energy of the GaN devices are not compromised. By implementing the proposed gate driver and voltage balancing schemes, well-balanced voltage sharing can be obtained for both soft-switching and hard-switching scenarios. A series-connected GaN-based multiple pulse tester (MPT) is built to prove the effectiveness of the proposed approach under different load and different switching speed (dv/dt) conditions.

This paper presents a high performance 4-layer communication architecture for a smart micro-grid testbed which consists of a 2 kVA Distributed Energy Resource (DER) inverter with PV and battery channels capable of advanced grid supportive and grid forming functions in the Process layer, a Raspberry Pi computer in the Interface layer, a customized Edge Intelligent Device (EID) in the Sub-station layer, and an end-to-end solar energy optimization platform (e-SEOP) in the Supervisory layer. The Raspberry Pi serves as a communication interface which communicates with the DER inverter using Serial Peripheral Interface (SPI) communication and talks to the EID using Modbus TCP/IP protocol. This paper provides a convenient and comprehensive solution to SPI and Modbus TCP/IP communication implementation in a smart micro-grid. The challenges of coordination between communication and system control and between different communication protocols have been addressed, which leads to a boost in the communication efficiency and makes the system highly scalable, flexible and adaptive. The proposed communication architecture as well as the micro-grid test bench have been validated through hardware experiments. The results indicate a reliable and efficient communication among different layers, which facilitates large-scale status monitoring of edge devices and coordinated control of the entire system.

The microwave probing signal of the rubidium atomic frequency standard (RAFS) is used to excite the transitions between the ground-state energy levels of rubidium atoms, and realize resonance detection. At present, the microwave generation schemes commonly used all have the disadvantages of complicated circuit structure, high power consumption and inconvenient integration. This work introduces a design scheme for generating discontinuous microwave inquiry signal using the phase-locked loop (PLL) technology. The scheme takes the 10 MHz signal as a reference frequency, and is capable of obtain the (6 834.687 5 MHz ±fM) signal directly under a reasonable configuration of single chip microcomputer. The scheme has the advantages of simple circuit structure, low power consumption and high digitization. The stability of the whole machine was found to be better than 1.5E-11/√τ(1 s ≤ τ ≤ 100 s). The performance indexes can meet the requirements of small commercial rubidium atomic clock.

Endometriosis (EM) is a chronic neuroinflammatory disorder that is associated with pain and infertility that affects ∼10% of reproductive-age women. The pathophysiology and etiology of EM remain poorly understood, and diagnostic delays are common. Exploration of the underlying molecular mechanism, as well as novel diagnostic biomarkers and therapeutic targets, is urgently needed. Inflammation is known to play a key role in the development of lesions, which are a defining feature of the disorder. In our research, the CIBERSORT and WGCNA algorithms were used to establish a weighted gene co-expression network and to identify macrophage-related hub genes using data downloaded from the GEO database (GSE11691, 7305). The analysis identified 1,157 differentially expressed genes (DEGs) in EM lesions, of which five were identified as being related to M2 macrophages and were validated as differentially expressed by qRT-PCR and immunohistochemistry (IHC). Of these putative novel biomarker genes, bridging integrator 2 (BIN2), chemokine receptor 5 (CCR5), and macrophage mannose receptor 1 (MRC1) were upregulated, while spleen tyrosine kinase (SYK) and metalloproteinase 12 (ADAM12) were downregulated in ectopic endometria vs. normal endometria. Meanwhile, 23 potentially therapeutic small molecules for EM were obtained from the cMAP database, among which topiramate, isoflupredone, adiphenine, dexverapamil, MS-275, and celastrol were the top six molecules with the highest absolute enrichment values. This is our first attempt to use the CIBERSORT and WGCNA algorithms for the identification of novel Mϕ2 macrophage-related biomarkers of EM. Our findings provide novel insights into the impact of immune cells on the etiology of EM; nevertheless, further investigation of these key genes and therapeutic drugs is needed to validate their effects on EM.

Cyclical fluctuations of the ovarian hormones estrogen (E2) and progesterone (PROG) have multiple effects on reproduction and development. However, little is known about the roles of E2 and PROG in women’s social behaviors. Here, based on evolutionary theory suggesting social sensitivity and inhibition ability are conductive to maintaining social relationships, we provide evidence for the association between menstrual phases and social orientation. In Study 1, 78 women provided saliva samples and reported their intensity of behavioral activation/inhibition system (BAS/BIS) and interpersonal sensitivity at either of two phases of the menstrual cycle: late follicular phase (FP), and mid-luteal phase (LP). A significant between-subject association emerged, revealing that women with higher PROG levels reported higher levels of social feedback sensitivity, and women with relatively high PROG levels showed a positive association between their E2 levels and inhibitory response. In Study 2, 30 women reported their interpersonal anxiety and finished the social value orientation (SVO) measures at both late FP and mid-LP. A significant within-person effect emerged: women in the mid-LP, which is characterized by higher PROG levels, reported higher levels of interpersonal anxiety and SVO. In sum, these findings revealed that women’s social orientation could fluctuate naturally with ovarian hormones across the menstrual cycle.

Hormonal changes across the menstrual cycle have been shown to influence reward-related motivation and impulsive behaviors. Here, with the aim of examining the neural mechanisms underlying cognitive control of impulsivity, we compared event-related monetary delay discounting task behavior and concurrent functional magnetic resonance imaging (fMRI) revealed brain activity as well as resting state (rs)-fMRI activity, between women in the mid-luteal phase (LP) and women in the late follicular phase (FP). The behavioral data were analyzed and related to neural activation data. In the delay discounting task, women in the late FP were more responsive to short-term rewards (i.e., showed a greater discount rate) than women in the mid-LP, while also showing greater activity in the dorsal striatum (DS). Discount rate (transformed k) correlated with functional connectivity between the DS and dorsal lateral prefrontal cortex (dlPFC), consistent with previous findings indicating that DS-dlPFC circuitry may regulate impulsivity. Our rs-fMRI data further showed that the right dlPFC was significantly more active in the mid-LP than in late FP, and this effect was sensitive to absolute and relative estradiol levels during the mid-LP. DS-dlPFC functional connectivity magnitude correlated negatively with psychometric impulsivity scores during the late FP, consistent with our behavioral data and further indicating that relative estradiol levels may play an important role in augmenting cognitive control. These findings provide new insight into the treatment of conditions characterized by hyper-impulsivity, such as obsessive compulsive disorder, Parkinson disease, and attention deficit hyperactivity disorder. In conclusion, our results suggest that cyclical gonadal hormones affect cognitive control of impulsive behavior in a periodic manner, possibility via DS-dlPFC circuitry.

The behavioral activation system (BAS) and the behavioral inhibition system (BIS) have been proposed to relate to stable traits that predict inter-individual differences in motivation. Prior reports point dopamine (DA) pathways, mainly including ventral tegmental area (VTA) and substantia nigra (SN), implicate in subserving reward-related functions associated with BAS and inhibitory functions related with BIS. However, as an important factor that affects DA releasing, it remains an open question whether the ovarian hormones may also be related to BIS/BAS. Here, to investigate effects of the estradiol (E2) and progesterone (PROG) on BIS/BAS and related DA pathways, we employed a BIS/BAS scale and the resting-state functional magnetic resonance imaging (fMRI) during the late follicular phase (FP) and the mid-luteal phase (LP). On the behavioral level, when women had high PROG levels, their E2 levels were found positively correlated with BIS scores, but those women whose PROG levels were low, their E2 levels were negative correlation with BIS scores. On the neural level, we demonstrated BAS was related with the VTA pathway, included brain reward regions of nucleus accumbens (NAc) and orbitofrontal cortex (OFC). Meanwhile, the BIS was correlated with the SN-dorsolateral prefrontal cortex (dlPFC) pathway. ROI-based resting-state functional connectivity (RSFC) analyses further revealed that, RSFC between the SN and dlPFC was modulated by ovarian hormones. With higher PROG levels, increased E2 levels among women were accompanied by stronger RSFC of the SN-dlPFC, but when PROG levels were low, E2 levels were negatively correlated with the SN-dlPFC RSFC. These findings revealed a combined enhancement effect of E2 and PROG on BIS, and the SN-dlPFC pathway was mainly involved in this process.

Abstract Solar-driven water splitting using powdered catalysts is considered as the most economical means for hydrogen generation. However, four-electron-driven oxidation half-reaction showing slow kinetics, accompanying with insufficient light absorption and rapid carrier combination in photocatalysts leads to low solar-to-hydrogen energy conversion efficiency. Here, we report amorphous cobalt phosphide (Co-P)-supported black phosphorus nanosheets employed as photocatalysts can simultaneously address these issues. The nanosheets exhibit robust hydrogen evolution from pure water (pH = 6.8) without bias and hole scavengers, achieving an apparent quantum efficiency of 42.55% at 430 nm and energy conversion efficiency of over 5.4% at 353 K. This photocatalytic activity is attributed to extremely efficient utilization of solar energy (~75% of solar energy) by black phosphorus nanosheets and high-carrier separation efficiency by amorphous Co-P. The hybrid material design realizes efficient solar-to-chemical energy conversion in suspension, demonstrating the potential of black phosphorus-based materials as catalysts for solar hydrogen production.

Taking the electron beam welding process as an example,the tooth profile analysis of the split type herringbone gear is carried out after the deformation of the diameter direction. Finally,the problem of the machining of the herringbone gear without the retreating slot is solved. Through the relation of tooth involute,base circle,radius of curvature,pressure angle and helix angle,the change law of tooth profile and spiral line in the condition of gear diameter deformation is studied,and the influence of the change of diameter on pressure angle,spiral angle and the second influence of the change of spiral angle on the tooth shape are analyzed. The formula for calculating deformation is derived,and the composite deformation amount and the composite deformation and tooth helical line deformation amount of the tooth profile due to change of diameter are calculated,the basis for the reverse compensation of the grinding teeth before welding is provided. Finally,the above analysis is verified by an example,and the calculation method is not limited to the electron beam welding process.

The radiofrequency circuit of traditional miniature rubidium atomic frequency standard (RAFS) uses saturated output, which can stabilize the amplitude, but not the waveform, of the radiofrequency signal. This would lead to insufficient microwave power stability. In this study, an improved circuit for stabilizing power amplitude in miniature rubidium atomic frequency standard was described. The circuit took the bias voltage of step recovery diode (SRD) as a reference to achieve automatic gain control (AGC) through controlling the gain of the variable gain amplifier (VGA). This scheme controlled both the amplitude and the waveform of the radiofrequency signal. The results showed that this scheme can effectively improve power stability of the microwave signal in miniature rubidium atomic frequency standard.

Classification of asynchronous elementary cellular automata (AECAs) was explored in the first place by Fates et al. (Complex Systems, 2004) who employed the asymptotic density of cells as a key metric to measure their robustness to stochastic transitions. Unfortunately, the asymptotic density seems unable to distinguish the robustnesses of all AECAs. In this paper, we put forward a method that goes one step further via adopting a metric entropy (Martin, Complex Systems, 2000), with the aim of measuring the asymptotic mean entropy of local pattern distribution in the cell space of any AECA. Numerical experiments demonstrate that such an entropy-based measure can actually facilitate a complete classification of the robustnesses of all AECA models, even when all local patterns are restricted to length 1. To gain more insights into the complexity concerning the forward evolution of all AECAs, we consider another entropy defined in the form of Kolmogorov–Sinai entropy and conduct preliminary experiments on classifying their uncertainties measured in terms of the proposed entropy. The results reveal that AECAs with low uncertainty tend to converge remarkably faster than models with high uncertainty.

High-frequency seismic data onMars are dominated bywind-generated lander vibrations, which are radiated partially to the subsurface. Autocorrelation functions (ACFs) of seismic data on Mars filtered between 1 and 5 Hz show clear phases at ∼1.3, ∼2.6, and ∼3.9 s. Daily temporal changes of their arrival times (dt/t) correlatewellwith the daily changes of ground temperature, with ∼5% daily variation and ∼50 min apparent phase delay. The following two mechanisms could explain the observations: (1) the interference of two predominant spectral peaks at ∼3.3 and ∼4.1 Hz, assumed to be both lander resonance modes, generate the apparent arrivals in the ACFs; (2) the interference of the lander vibration and its reflection from an interface ∼200 m below the lander generate the 3.3 Hz spectral peak and ∼1.3 s arrival in the ACFs. The driving mechanism of the resolved dt/t thatmost likely explains the ∼50min delay is thermoelastic strain at a near-surface layer, affecting the lander-ground coupling and subsurface structures. The two outlined mechanisms suggest, respectively, up to ∼10% changes in ground stiffness at 1-5 Hz and ∼ 15% velocity changes in the top ∼20 m layer. These are upper bound values considering also other possible contributions. The presented methodology and results contribute to analysis of ACFs with limited data and the understanding of subsurface materials on Mars.