Three-Dimensional Sound Source Location Algorithm for Subsea Leakage Using Hydrophone

Leakages from subsea oil and gas equipment cause substantial economic losses and damage to marine ecosystem,so it is essential to locate the source of the leak.However,due to the complexity and variability of the marine environment,the signals collected by hydrophone contain a variety of noises,which makes it challenging to extract useful signals for localization.To solve this problem,a hydrophone denoising algorithm is proposed based on variational modal decomposition(VMD)with grey wolf optimization.First,the average envelope entropy is used as the fitness function of the grey wolf optimizer to find the optimal solution for the parameters K andα.Afterward,the VMD algorithm decomposes the original signal parameters to obtain the intrinsic mode functions(IMFs).Subsequently,the number of interrelationships between each IMF and the original signal was calculated,the threshold value was set,and the noise signal was removed to calculate the time difference using the valid signal obtained by reconstruction.Finally,the arrival time difference is used to locate the origin of the leak.The localization accuracy of the method in finding leaks is investigated experimentally by constructing a simulated leak test rig,and the effectiveness and feasibility of the method are verified.

Global Solutions to Nonconvex Problems by Evolution of Hamilton-Jacobi PDEs

Computing tasks may often be posed as optimization problems.The objective functions for real-world scenarios are often nonconvex and/or nondifferentiable.State-of-the-art methods for solving these problems typically only guarantee convergence to local minima.This work presents Hamilton-Jacobi-based Moreau adaptive descent(HJ-MAD),a zero-order algorithm with guaranteed convergence to global minima,assuming continuity of the objective function.The core idea is to compute gradients of the Moreau envelope of the objective(which is"piece-wise convex")with adaptive smoothing parameters.Gradients of the Moreau envelope(i.e.,proximal operators)are approximated via the Hopf-Lax formula for the viscous Hamilton-Jacobi equation.Our numerical examples illustrate global convergence.

Trial application of the envelope method to the potential ambiguity problem

The optical potential ambiguity is a long-standing problem in the analysis of elastic scattering data.For a specific collid-ing system,ambiguous potential families can lead to different behaviors in the nearside and farside scattering components.By contrast,the envelope method can decompose the experimental data into two components with negative and positive deflection angles,respectively.Hence,a question arises as to whether the comparison between the calculated nearside(or farside)component and the derived positive-deflection-angle(or negative-deflection-angle)component can help analyze the potential ambiguity problem.In this study,we conducted a trial application of the envelope method to the potential ambiguity problem.The envelope method was improved by including uncertainties in the experimental data.The colliding systems of 16O+28Si at 215.2 MeV and 12C+12C at 1016 MeV were considered in the analyses.For each colliding system,the angular distribution experimental data were described nearly equally well by two potential sets,one of which is“surface transpar-ent”and the other is refractive.The calculated angular distributions were decomposed into nearside and farside scattering components.Using the improved envelope method,the experimental data were decomposed into the positive-deflection-angle and negative-deflection-angle components,which were then compared with the calculated nearside and farside components.The capability of the envelope method to analyze the potential ambiguities was also discussed.

A New Dynamic and Vertical Photovoltaic Integrated Building Envelope for High-Rise Glaze-Facade Buildings

Substantially glazed facades are extensively used in contemporary high-rise buildings to achieve attractive architectural aesthetics.Inherent conflicts exist among architectural aesthetics,building energy consumption,and solar energy harvesting for glazed facades.In this study,we addressed these conflicts by introducing a new dynamic and vertical photovoltaic integrated building envelope(dvPVBE)that offers extraordinary flexibility with weather-responsive slat angles and blind positions,superior architectural aesthetics,and notable energy-saving potential.Three hierarchical control strategies were proposed for different scenarios of the dvPVBE:power generation priority(PGP),natural daylight priority(NDP),and energy-saving priority(ESP).Moreover,the PGP and ESP strategies were further analyzed in the simulation of a dvPVBE.An office room integrated with a dvPVBE was modeled using EnergyPlus.The influence of the dvPVBE in improving the building energy efficiency and corresponding optimal slat angles was investigated under the PGP and ESP control strategies.The results indicate that the application of dvPVBEs in Beijing can provide up to 131%of the annual energy demand of office rooms and significantly increase the annual net energy output by at least 226%compared with static photovoltaic(PV)blinds.The concept of this novel dvPVBE offers a viable approach by which the thermal load,daylight penetration,and energy generation can be effectively regulated.

An envelope-based machine learning workflow for locating earthquakes in the southern Sichuan Basin

The development of machine learning technology enables more robust real-time earthquake monitoring through automated implementations. However, the application of machine learning to earthquake location problems faces challenges in regions with limited available training data. To address the issues of sparse event distribution and inaccurate ground truth in historical seismic datasets, we expand the training dataset by using a large number of synthetic envelopes that closely resemble real data and build an earthquake location model named ENVloc. We propose an envelope-based machine learning workflow for simultaneously determining earthquake location and origin time. The method eliminates the need for phase picking and avoids the accumulation of location errors resulting from inaccurate picking results. In practical application, ENVloc is applied to several data intercepted at different starting points. We take the starting point of the time window corresponding to the highest prediction probability value as the origin time and save the predicted result as the earthquake location. We apply ENVloc to observed data acquired in the southern Sichuan Basin, China, between September 2018 and March 2019. The results show that the average difference with the catalog in latitude, longitude, depth, and origin time is 0.02°,0.02°, 2 km, and 1.25 s, respectively. These suggest that our envelope-based method provides an efficient and robust way to locate earthquakes without phase picking, and can be used in earthquake monitoring in near-real time.

Hepatitis B surface antigen-negative but hepatitis B envelope antigen-positive false occult hepatitis B virus infection:A case report

BACKGROUND Occult hepatitis B infection(OBI)is characterized by the detection of hepatitis B virus(HBV)DNA in serum(usually HBV DNA<200 IU/mL)or the liver but negativity for hepatitis B surface antigen(HBsAg).The diagnosis of OBI relies on the sensitivity of assays used in the detection of HBV DNA and HBsAg.HBsAg assays with inadequate sensitivity or inability to detect HBV S variants may lead to misdiagnosis of OBI in people with overt HBV infection.CASE SUMMARY We report a HBsAg-negative but hepatitis B envelope antigen-positive patient who had a significant HBV DNA level.The patient was initially diagnosed as having OBI.However,sequence analysis revealed a unique insertion of amino acid residues at positions 120-124 in the S protein,which affects the formation of a disulfide bond that is associated with the formation of a loop.It is well known that there is an overlap between the S protein and Pol protein.We found that this new insertion site occurred in polymerase/reverse transcriptase domain,indi-cating that this insertion might be involved in HBV pathogenicity.The patient was finally diagnosed with a false OBI.CONCLUSION An insertion of amino acid residues at positions 120-124 of the S protein affects the formation of immunodominant epitopes and results in negative HBsAg levels.

Evaluation of Energy Efficiency and Analysis of Influencing Factors of Company CW’s Manufacturing Workshops

In this work,the Slacks-Based Measure(SBM)model within Data Envelopment Analysis was employed to establish a set of indicators for evaluating the energy efficiency of manufacturing workshops.The energy efficiency of 12 Company CW’s manufacturing workshops from 2016 to 2022 was assessed.The findings indicated that aside from a few workshops operating at the production frontier,the rest exhibit significant fluctuations in energy efficiency and generally low energy efficiency.Subsequently,a combined GRA-Tobit analysis model was introduced to identify factors influencing the energy efficiency of Company CW’s manufacturing workshops.Regression analysis revealed that technological investments,employee quality,workshop production scale,investment in clean energy,and the level of pollution control all significantly impact the energy efficiency of Company CW’s manufacturing workshops.By evaluating the energy efficiency of Company CW’s manufacturing workshops and studying their influencing factors,this research aids company managers in understanding the energy efficiency of the manufacturing process.It optimizes the combination of various production elements,thereby offering effective guidance for improving the energy efficiency issues of the company’s manufacturing workshops,which can contribute to enhancing the corporation’s overall energy efficiency.

基于三阶段数据包络分析模型的苏浙沪皖经济圈医院运行效率研究

目的分析2019年苏浙沪皖经济圈内27个城市医院运行效率,为优化苏浙沪皖卫生资源配置和规划提供参考。方法选取苏浙沪皖27个城市医院指标数据,运用三阶段数据包络分析(data envelopment analysis,DEA)模型法,在控制环境变量和剔除随机效应后效率分析。结果苏浙沪皖经济圈医院综合技术效率、纯技术效率和规模效率均值分别为0.941、0.948和0.992。结论苏浙沪皖经济圈内医院运行效率有所差异,环境变量对医院运行效率影响较大,对外部的资源配置存在敏感性不同的差异,应统筹区域医疗资源,提高医院运行效率。

Pepper mild mottle virus coat protein interacts with pepper chloroplast outer envelope membrane protein OMP24 to inhibit antiviral immunity in plants

Pepper mild mottle virus(PMMoV)is a devastating viral pathogen of pepper(Capsicum annuum)but it is unclear whether and how peppers protect against PMMoV infection.The expression of the chloroplast outer membrane protein 24(OMP24)of C.annuum was upregulated under PMMoV infection and it interacted with PMMoV coat protein(CP).Silencing of OMP24 in either C.annuum or Nicotiana benthamiana facilitated PMMoV infection,whereas overexpression of N.benthamiana OMP24 in transgenic plants inhibited PMMoV infection.Both C.annuum OMP24(CaOMP24)and N.benthamiana OMP24(NbOMP24)localized to the chloroplast and have a moderately hydrophobic transmembrane domain that is necessary for their localization.Overexpression of CaOMP24 induced stromules,perinuclear chloroplast clustering,and accumulation of reactive oxygen species(ROS),the typical defense responses of chloroplasts transferring the retrograde signaling to the nucleus to regulate resistance genes.The expression of PR1 and PR2 was also upregulated significantly in plants overexpressing OMP24.Self-interaction of OMP24 was demonstrated and was required for OMP24-mediated plant defense.Interaction with PMMoV CP interfered with the self-interaction of OMP24 and impaired OMP24-induced stromules,perinuclear chloroplast clustering and ROS accumulation.The results demonstrate the defense function of OMP24 in pepper during viral infection and suggest a possible mechanism by which PMMoV CP modulates the plant defense to facilitate viral infection.

Ground Penetrating Radar (GPR) Identification Method for Agricultural Soil Stratification in a Typical Mollisols Area of Northeast China

In order to achieve a rapid and accurate identification of soil stratification information and accelerate the development of smart agriculture,this paper conducted soil stratification experiments on agricultural soils in the Mollisols area of Northeast China using Ground Penetrating Radar(GPR)and obtained different types of soil with frequencies of 500 MHz,250 MHz,and 100 MHz antennas.The soil profile data were obtained for 500 MHz,250 MHz,and 100 MHz antennas,and the dielectric properties of each type of soil were analyzed.In the image processing procedure,wavelet analysis was first used to decompose the pre-processed radar signal and reconstruct the high-frequency information to obtain the reconstructed signal containing the stratification information.Secondly,the reconstructed signal is taken as an envelope to enhance the stratification information.The Hilbert transform is applied to the envelope signal to find the time-domain variation of the instantaneous frequency and determine the time-domain location of the stratification.Finally,the dielectric constant of each soil horizon is used to obtain the propagation velocity of the electromagnetic wave at the corresponding position to obtain the stratification position of each soil horizon.The research results show that the 500 MHz radar antenna can accurately delineate Ap/Ah,horizon and the absolute accuracy of the stratification is within 5 cm.The effect on the soil stratification below the tillage horizon is not apparent,and the absolute accuracy of the 250 MHz and 100 MHz radar antennas on the stratification is within 9 cm.The overwhelming majority of the overall calculation errors are kept to within 15%.Based on the three central frequency antennas,the soil horizon detection rate reaches 93.3%,which can achieve accurate stratification of soil profiles within 1 m.The experimental and image processing methods used are practical and feasible;however,the GPR will show a missed detection for soil horizons with only slight differences in dielectric properties.Overall,this study can quickly and accurately determine the information of each soil stratification,ultimately providing technical support for acquiring soil configuration information and developing smart agriculture.

Effect of dynamic loading conditions on the dynamic performance of MP1 energy-absorbing rockbolts:Insight from laboratory drop test

Energy-absorbing rockbolts have been widely adopted in burst-prone excavation support, and their serviceability is closely related to the frequency and magnitude of seismic events. In this research, the splittube drop test with varying impact energy was conducted to reproduce the dynamic performance of MP1rockbolts under a wide range of seismic event magnitudes. The test results showed that the impact process could be subdivided into four distinct stages, i.e. mobilization, strain hardening, plastic flow(ductile), and rebound stage, of which strain hardening and plastic flow are the primary energy absorbing stages. As the impact energy per drop increases from 8.1 to 46.7 k J, the strain rate of the shank varies between 1.20 and 2.70 s^(-1), and the average impact load is between 240 and 270kN, which may be considered as constant. The MP1 rockbolt has a cumulative maximum energy absorption(CMEA) of 31.9–40.0 k J/m, with an average of 35.0 k J/m, and the elongation rate is 11.4%–14.7%, with an average of 12.7%, both of which are negatively correlated with the impact energy per drop. Regression analysis shows that energy absorption and shank elongation, as well as momentum input and impact duration,conform to the linear relationship. The complete dynamic capacity envelope of MP1 rockbolts is proposed, which reflects the dynamic bearing capacity, elongation, and distinct stages. This study is helpful to better understand the dynamic characteristics of energy-absorbing rockbolts and assist design engineers in robust reinforcement systems design to mitigate rockburst damage in seismically active underground excavations.

Density-dependent carrier-envelope phase shift in attosecond pulse generation from relativistically oscillating mirrors

The carrier-envelope phase(CEP)φ_(0)is one of the key parameters in the generation of isolated attosecond pulses.In particular,“cosine”pulses(φ_(0)=0)are best suited for generation of single attosecond pulses in atomic media.Such“cosine”pulses have the peak of the most intense cycle aligned with the peak of the pulse envelope,and therefore have the highest contrast between the peak intensity and the neighboring cycles.In this paper,the dynamics of single attosecond pulse generation from a relativistically oscillating plasma mirror is investigated.We use an elementary analytical model as well as particle-in-cell simulations to study few-cycle attosecond pulses.We find that the phase of the field driving the surface oscillations depends on the plasma density and preplasma scale length.This leads us to a counterintuitive conclusion:for the case of normal incidence and a sharp plasma-vacuum boundary,the CEP required for the generation of a single attosecond pulse phase is closer toφ_(0)=π/2(a“sine”pulse),with the exact value depending on the plasma parameters.

A Novel Compact Highly Isolated UWB MIMO Antenna with WLAN Notch

This paper presents a compact Multiple Input Multiple Output(MIMO)antenna with WLAN band notch for Ultra-Wideband(UWB)applications.The antenna is designed on 0.8mmthick low-cost FR-4 substrate having a compact size of 22mm×30 mm.The proposed antenna comprises of two monopole patches on the top layer of substrate while having a shared ground on its bottom layer.The mutual coupling between adjacent patches has been reduced by using a novel stub with shared ground structure.The stub consists of complementary rectangular slots that disturb the surface current direction and thus result in reducing mutual coupling between two ports.A slot is etched in the radiating patch for WLAN band notch.The slot is used to suppress frequencies ranging from 5.1 to 5.9 GHz.The results show that the proposed antenna has a very good impedance bandwidth of|S11|<−10 dB within the frequency band from 3.1–14 GHz.A low mutual coupling of less than−23 dB is achieved within the entire UWB band.Furthermore,the antenna has a peak gain of 5.8 dB,low ECC<0.002 and high Diversity Gain(DG>9.98).

基于DEA方法的江苏省制造业上市企业创新绩效研究

基于道格拉斯生产函数,构建了企业创新绩效评价指标体系,运用DEA-CCR、DEA-BCC、DEA-Malmquist模型测算了2018—2020年169家江苏省制造业上市企业静态效率和动态效率。研究表明,江苏省制造业上市企业研发投入呈现逐年递增趋势,但创新绩效整体没有达到最优状态,主要是由于纯技术效率较低所致,需要提升资源配置效率;且受疫情影响创新绩效整体上经历了一个从增长到衰退的过程,相对来说企业技术进步率大于技术效率变化率。

Transfer of the zp3a gene results in changes in egg adhesiveness and buoyancy in transgenic zebrafish

Reproductive strategies and spawning habits play key roles in the evolution of endemic East Asian cyprinids.However,the molecular mechanisms underlying the regulation of spawning habits are not well understood.We recently identified zona pellucida(Zp) as the top differentially expressed protein between East Asian cyprinids that produce adhesive and semi-buoyant eggs,suggesting that Zp protein may play important roles in the regulation of egg type.In this work,we generated transgenic zebrafish in which oocyte-specific expression of zp genes from rare minnow(Gobiocypris rarus),an East Asian cyprinid laying adhesive eggs,was driven by a zebrafish zp3.2 gene promoter.We found that the transgenic eggs obtained partial adhesiveness and exhibited alteration in hydration and buoyancy.Abnormal metabolism of vitellogenin(VTG) may contribute to enhanced hydration and/or buoyancy.Our work shows that expression of the exogenous zp3a gene from an adhesiveegg producing fish is sufficient to induce changes in both egg adhesiveness and buoyancy in zebrafish,emphasizing the important role of zp genes in the regulation of spawning habits.Our results thus provide new insights into how endemic East Asian cyprinids may have adapted to the Yangtze river-lake system via changes in spawning habits.

Data envelopment analysis for scale elasticity measurement in the stochastic case:with an application to Indian banking

In the nonparametric data envelopment analysis literature,scale elasticity is evaluated in two alternative ways:using either the technical efficiency model or the cost efficiency model.This evaluation becomes problematic in several situations,for example(a)when input proportions change in the long run,(b)when inputs are heterogeneous,and(c)when firms face ex-ante price uncertainty in making their production decisions.To address these situations,a scale elasticity evaluation was performed using a value-based cost efficiency model.However,this alternative value-based scale elasticity evaluation is sensitive to the uncertainty and variability underlying input and output data.Therefore,in this study,we introduce a stochastic cost-efficiency model based on chance-constrained programming to develop a value-based measure of the scale elasticity of firms facing data uncertainty.An illustrative empirical application to the Indian banking industry comprising 71 banks for eight years(1998–2005)was made to compare inferences about their efficiency and scale properties.The key findings are as follows:First,both the deterministic model and our proposed stochastic model yield distinctly different results concerning the efficiency and scale elasticity scores at various tolerance levels of chance constraints.However,both models yield the same results at a tolerance level of 0.5,implying that the deterministic model is a special case of the stochastic model in that it reveals the same efficiency and returns to scale characterizations of banks.Second,the stochastic model generates higher efficiency scores for inefficient banks than its deterministic counterpart.Third,public banks exhibit higher efficiency than private and foreign banks.Finally,public and old private banks mostly exhibit either decreasing or constant returns to scale,whereas foreign and new private banks experience either increasing or decreasing returns to scale.Although the application of our proposed stochastic model is illustrative,it can be potentially applied to all firms in the information and distribution-intensive industry with high fixed costs,which have ample potential for reaping scale and scope benefits.

Cutting Force Fluctuation Suppression and Error Homogenization of Noncircular Gear Hobbing Based on the Tool Shifting Method

The current research on noncircular hobbing mainly focuses on the linkage model and motion realization.However,the intermittent cutting characteristics of hobbing would increase uncertainties in the manufacturing process.In this paper,a hobbing machining model with tool-shifting characteristics was proposed to solve the problems of cutting force fluctuation and inconsistency of tooth profile envelope accuracy at different positions of the pitch curve in noncircular gear hobbing.Based on the unit cutting force coefficient method,the undeformed chip volume generated by interrupted cutting was used to characterize the fluctuation trend of the hobbing force.The fluctuation characteristics of the cutting force generated by different hobbing models were compared and analyzed.Using the equivalent gear tooth and hob slotting numbers,an analysis model of the tooth profile envelope error of the noncircular gear was constructed.Subsequently,the tooth profile envelope errors at different positions of the pitch curve were compared and analyzed based on the constructed model.The transmission structure of the electronic gearbox was constructed based on the proposed hobbing model,and the hobbing experiment was conducted based on the selfdeveloped noncircular gear CNC hobbing system.This paper proposes a hobbing method that can effectively suppress the fluctuation of the peak and whole circumference cutting force and reduce the maximum envelope error of the whole circumference gear teeth.

Failure Envelopes of Single-Plate Rigid Helical Anchors for Floating Offshore Wind Turbine

Helical anchor is a kind of novel foundation for floating offshore wind turbines,which should be subjected to combined tensile loading caused by wind,wave and current.However,the research about the capacity of helical anchor was mainly examined under uniaxial loading and scarcely explored under combined loading.In this study,three-dimensional finite element limit analysis is adopted to assess the bearing capacities of single-plate rigid helical anchors with different ratios of helix to shaft diameter,D_(H)/D_(S) and embedment ratios L/D_(S).Result shows that the vertical,horizontal and moment bearing capacities increase with increasing D_(H)/D_(S) and L/D_(S).The normalized V-H failure envelopes expands with increasing L/D_(S),while the normalized V-M failure envelopes tend to contract with the increase of D_(H)/D_(S).With increasing D_(H)/D_(S) or decreasing L/D_(S),the normalized H-M failure envelopes expand when the horizontal and moment loading act in the same direction and contract when they act in the opposite direction.The effect of D_(H)/D_(S) and L/D_(S) on the shape of H-M failure envelope become insignificant when L/D_(S)≥4.A series of failure mechanisms under different loading conditions were observed and can be used to explain the trend.Besides,a series of approximate expressions were proposed to fit the uniaxial bearing capacities and the failure envelopes.

A robust symbol timing strategy for cellular systems

In cellular systems,establishing the initial symbol timing of potential preambles is the first step of a cell search.The envelope fluctuation of the downlink signal hinders the successful timing of conventional symbol timing methods.To solve this problem,a hybrid timing strategy is proposed with two novel detectors,namely the normalized replica-based detector and normalized differential detector.The strategy first detects all potential preambles via the normalized replica-based detector and then employs the normalized differential detector to verify the target preamble,which comes from the target cell and has the highest power.The strategy is unaffected by envelope fluctuation and has computational complexity comparable to that of conventional methods.Simu-lations and real-data tests show that the hybrid timing strategy is robust and practical for initial symbol timing.

Molecular dynamics simulation of interaction between nanorod and phospholipid molecules bilayer

Natural and artificially prepared nanorods'surfaces have proved to have good bactericidal effect and self-cleaning property.In order to investigate whether nanorods can kill the enveloped virus,like destroying bacterial cell,we study the interaction between nanorods and virus envelope by establishing the models of nanorods with different sizes as well as the planar membrane and vesicle under the Dry Martini force field of molecular dynamics simulation.The results show that owing to the van der Waals attraction between nanorods and the tail hydrocarbon chain groups of phospholipid molecules,the phospholipid molecules on virus envelope are adsorbed to nanorods on a large scale.This process will increase the surface tension of lipid membrane and reduce the order of lipid molecules,resulting in irreparable damage to planar lipid membrane.Nanorods with different diameters have different effects on vesicle envelope,the larger the diameter of nanorod,the weaker the van der Waals effect on the unit cross-sectional area is and the smaller the degree of vesicle deformation.There is synergy between the nanorods in the nanorod array,which can enhance the speed and scale of lipid adsorption.The vesicle adsorbed in the array are difficult to desorb,and even if desorbed,vesicle will be seriously damaged.The deformation rate of the vesicle adsorbed in the nanorod array exceeds 100%,implying that the nanorod array has a strong destructive effect on the vesicle.This preliminarily proves the feasibility of nanorod array on a surface against enveloped virus,and provides a reference for the design of corresponding nanorods surface.