Study on theoretical model for electrical explosion resistivity of Al/Ni reactive multilayer foil

Al/Ni reactive multilayer foil(RMF)possesses excellent comprehensive properties as a promising substitute for traditional Cu bridge.A theoretical resistivity model of Al/Ni RMF was developed to guide the optimization of EFIs.Al/Ni RMF with different bilayer thicknesses and bridge dimensions were prepared by MEMS technology and electrical explosion tests were carried out.According to physical and chemical reactions in bridge,the electrical explosion process was divided into 5 stages:heating of condensed bridge,vaporization and diffusion of Al layers,intermetallic combination reaction,intrinsic explosion,ionization of metal gases,which are obviously shown in measured voltage curve.Effects of interface and grain boundary scattering on the resistivity of film metal were considered.Focusing on variations of substance and state,the resistivity was developed as a function of temperature at each stage.Electrical explosion curves were calculated by this model at different bilayer thicknesses,bridge dimensions and capacitor voltages,which showed an excellent agreement with experimental ones.

Including predator presence in a refined model for assessing resistance of alfalfa cultivar to aphids

The aphid quantity ratio（AQR） is defined as the number of aphids on each cultivar divided by the number of aphids on all cultivars. AQR is based on the correlation between aphid populations and their host plants and is an important tool that has been utilized in evaluating Medicago sativa（alfalfa） cultivar resistance to aphids. However, assessment of alfalfa resistance to aphids can be confused by the presence of aphid predators, causing the assessment of plant resistance to aphids to be based on incorrect aphid population data. To refine the AQR and account for the effect of predators on aphid population assessments, we introduced a parameter ‘α＇, corresponding to the predator quantity ratio, and used αAQR as the ratio to quantify aphid populations. Populations of both aphids（4 species） and their predators（12 species） occurring in 28 M. sativa cultivars were sampled over two years at a research station near Cangzhou, Hebei Province, China. Results showed that the most suitable evaluation period was from May to June, as the aphid population was stable during this period. Compared with the AQR method, the predator population numbers based on the αAQR had a significant inverse relationship with aphid population numbers and the 28 cultivars were clustered into three classes： the resistant class, tolerant class, and susceptible class. In addition, 17 cultivars were reassigned when evaluated using αAQR. All numerical values calculated by αAQR were displayed as a Gaussian distribution, which showed that the 28 cultivars could be clustered into nine groups using a median value（±SE） of 1±0.1. Hence, ongoing alfalfa breeding trials will be assessed using the αAQR to establish a robust system that includes agronomic performance parameters in order to generalize the new method for further studies.

Ecological Land Suitability for Arid Region at River Basin Scale:Framework and Application Based on Minmum Cumulative Resistance(MCR) Model

As an important and typical arid inland region in China,Shiyang River Basin plays an important role in maintaining the sustainable development of eco-environment,whose ecological land suitability restricts the development of the local human activities.Therefore,Shiyang River Basin was selected as the case study,the minimum cumulative resistance(MCR)model and GIS technique were integrated to create land suitability evaluation map.We calculated the MCR value of ecological source and living source,and divided the whole basin into five partitions according to the difference between ecological source and living source,and analyzed the patterns and characteristics of the ecological land suitability evaluation(ELSE)regions,respectively.The results showed that:1)The suitable ecological land includes prohibited development region and restricted development region,which accounts for 15.45%and 23.35%of the total land area of the Shiyang River Basin,respectively.These two regions mainly distributed high altitude region in the southern Qilian Mountain and low altitude region where had high density of rivers.2)The protection of ecological land requires not only conserving existing ecological land but also focusing on ecological buffer belts around ecological sources and improving ecological land service ability.3)Ecological networks should be constructed through artificial planting trees around the boundary of oasis and ecological restoration region.Buffer greenbelts should also be established between optimized development region and ecological restoration region.

Effects of Three Typical Resistivity Models on Pulsed Inductive Plasma Acceleration Modeling

The effects of three different typical resistivity models（Spitzer, Z＆L and M＆G） on the performance of pulsed inductive acceleration plasma are studied. Numerical results show that their influences decrease with the increase of the plasma temperature. The significant discriminations among them appear at the plasma temperature lower than 2.5 eV, and the maximum gap of the pulsed inductive plasma accelerated efficiency is approximately 2.5%.Moreover, the pulsed inductive plasma accelerated efficiency is absolutely related to the dynamic impedance parameters, such as voltage, inductance, capacitance and flow rate. However, the distribution of the efficiency as a function of plasma temperature with three resistivity models has nothing to do with the dynamic impedance parameter.

Role of visfatin in obesity-induced insulin resistance

The growing worldwide burden of insulin resistance(IR) emphasizes the importance of early identification for improved management.Obesity,particularly visceral obesity,has been a key contributing factor in the development of IR.The obesity-associated chronic inflammatory state contributes to the development of obesity-related comorbidities,including IR.Adipocytokines,which are released by adipose tissue,have been investigated as possible indicators of IR.Visfatin was one of the adipocytokines that attracted attention due to its insulinmimetic activity.It is released from a variety of sources,including visceral fat and macrophages,and it influences glucose metabolism and increases inflammation.The relationship between visfatin and IR in obesity is debatable.As a result,the purpose of this review was to better understand the role of visfatin in glucose homeostasis and to review the literature on the association between visfatin levels and IR,cardiovascular diseases,and renal diseases in obesity.

Salivary resistin level and its association with insulin resistance in obese individuals

The escalating global burden of type 2 diabetes mellitus necessitates the implementation of strategies that are both more reliable and faster in order to improve the early identification of insulin resistance(IR)in high-risk groups,including overweight and obese individuals.The use of salivary biomarkers offers a promising alternative to serum collection because it is safer,more comfortable,and less painful to obtain saliva samples.As obesity is the foremost contributory factor in IR development,the adipocytokines such as leptin,adiponectin,resistin,and visfatin secreted from the adipose tissue have been studied as potential reliable biomarkers for IR.Measurement of salivary adipokines as predictors for IR has attracted widespread attention because of the strong correlation between their blood and salivary concentrations.One of the adipokines that is closely related to IR is resistin.However,there are conflicting findings on resistin’s potential role as an etiological link between obesity and IR and the reliability of measuring salivary resistin as a biomarker for IR.Hence this study reviewed the available evidence on the potential use of salivary resistin as a biomarker for IR in order to attempt to gain a better understanding of the role of resistin in the development of IR in obese individuals.

Improving a method for evaluating alfalfa cultivar resistance to thrips

The thrips quantity ratio（TQR） model is an important tool for evaluating crop resistance to thrips based on the correlation between thrips quantities and cultivars. Unfortunately, it is inaccurate, and the results appear significantly inconsistent when analysing the same cultivars in the same field study. To improve this model, we first studied the resistance of 28 alfalfa cultivars to thrips in Cangzhou, Hebei Province, north China. The results showed that the most suitable evaluation period was from May to June, as the thrips population was stable during this period. Second, we found that the natural enemy population was significantly positively correlated with the thrips population density（R=0.7275, P〈0.0001）, which might influence resistance estimation. Hence, we introduced a parameter ‘α＇, corresponding to the natural enemy quantity ratio, to eliminate the effect of the natural enemy using ＂αTQR＂. Using the improved method, 28 cultivars were clustered into three classes： the resistant class, sensitive class, and median class. All numerical values were calculated for αTQR displayed as a Gaussian distribution. This information showed that all data should be divided into nine groups using a median value of 1±0.1 with an equal difference of 0.1. Based on the new standard cultivars, Gongnong 1, Alfaking, Cangzhou and Algonquin were classified as highly resistant cultivars; Zhongmu 3, Gongnong 2, Zhongmu 1 and Zhongmu 2 were classified in the resistant group; Queen was classified in the moderately resistant group; Derby, WL354HQ, KRIMA, Apex, 53 HR, SARDI 5 and Farmers Treasure were classified in the median class; WL319HQ, WL343HQ and Sitel were classified as the low sensitive group; WL440 HQ and SARDI7 as the moderately sensitive group; WL168HQ and Sanditi as the sensitive group; and SARDI 10, WL363HQ, FD4, WL323 and SOCA as the highly sensitive group.

Wrist circumference: A new marker for insulin resistance in African women with polycystic ovary syndrome

BACKGROUND Insulin resistance(IR)is the main complication found in 35%-80%of women with polycystic ovary syndrome(PCOS).However,there is no definite consensus regarding which marker to use for its assessment in PCOS women.Research has shown that hyperinsulinemia is correlated with increased bone mass.Given that most women with PCOS are insulin resistant,which is independent from body fat and characterized by hyperinsulinemia,it could be hypothesized that there would be an increased bone mass in the patient as a result.Subsequently,increased bone mass could be measured using the wrist circumference method.AIM To assess the wrist circumference as an easy-to-detect marker of IR in Congolese women with PCOS.METHODS Seventy-two Congolese women with PCOS and seventy-one controls from the same ethnic group,were enrolled in the study(mean age 24.33±5.36 years).Fasting biochemical parameters,and the Homeostasis Model Assessment of insulin resistance(HOMA-IR)and body composition were evaluated.The nondominant wrist circumference was measured manually,as was the waist circumference(WC),hip circumference,height and weight.Calculated measures included evaluation of body mass index(BMI),Waist-to-Height(WHtR)and Waist-to-hip ratio(WHR).In addition,body composition was assessed by Bioelectrical Impedance Analysis using a body fat analyzer.RESULTS The non-dominant wrist circumference was more closely correlated with HOMAIR(r=0.346;P=0.003)and was the best anthropometrical marker correlated with IR(P=0.011)compared with other anthropometrical markers in women with PCOS:Dominant Wrist Circumference(r=0.315;P=0.007),Waist Circumference(WC)(r=0.259;P=0.028),BMI(r=0.285;P=0.016),WHR(r=0.216;P=0,068)and WHtR(r=0.263;P=0.027).The diagnostic accuracy of the non-dominant wrist circumference for the presence or absence of IR using Receiver-operating characteristic(ROC)curve analysis showed that the area under the ROC curve was 0.72.A cutoff value for the non-dominant wrist circumference of 16.3 cm was found to be the best predictor of IR in Congolese women with PCOS.CONCLUSION Non-dominant wrist circumference is,to date,the best anthropometrical marker of IR in Sub-Saharan African women with PCOS.It could be suggested as an easy-to-detect marker for assessing IR.

The Association of Visceral Adiposity Index with Insulin Resistance in Adults with Prediabetes

Visceral adiposity mediates insulin resistance, but their association among adults with prediabetes is scarce in the literature. This study is aimed to determine the association of visceral adiposity index (VAI) with insulin resistance in adults with prediabetes. This cross-sectional study was done among 117 adults with newly detected prediabetes [m/f;23/94;mean ± SD: Age 36.30 ± 9.99 years, BMI 28.89 ± 4.35 kg/m2] based on American Diabetes Association 2018 criteria and 141 matched healthy controls [m/f: 28/113;mean ± SD: 35.30 ± 6.88 years, BMI 25.03 ± 4.58]. Waist circumference, body mass index, fasting triglyceride, HDL cholesterol, fasting blood glucose and insulin were measured in each group to calculate VAI and homeostatic model assessment of insulin resistance (HOMA-IR). People with prediabetes had significantly higher median value of VAI {3.08 (2.26) vs. 1.86 (2.31);p < 0.001} with higher frequency of high VAI (>1) (98.3% vs. 85.8%;p < 0.001) than the control population. HOMA-IR level was significantly higher in prediabetes with high VAI (cut-off of 2.64) than control with normal VAI [2.78 (2.22, 4.15) vs. 2.20 (1.53, 3.36);p = 0.002]. VAI was positively correlated with HOMA-IR in females with prediabetes (r = 0.299, p = 0.003). VAI had predictive association with prediabetes [OR (95% CI: 9.504 (2.173, 41.576);p = 0.03] and high insulin resistance (HOMA-IR ≥ 2.6) in females with prediabetes [OR (95% CI) = 3.50 (1.476, 8.297);p = 0.004] only. It could satisfactorily discriminate prediabetes in both sexes (male: AUC = 0.767, p = 0.001;female: AUC = 0.641, p < 0.001) and high insulin resistance in females with prediabetes (AUC = 0.641;p = 0.019) only. So, VAI was associated with prediabetes and insulin resistance only in females with prediabetes.

Analysis and modeling of resistive switching mechanisms oriented to resistive random-access memory

With the progress of the semiconductor industry,the resistive random-access memory（RAM） has drawn increasing attention.The discovery of the memristor has brought much attention to this study.Research has focused on the resistive switching characteristics of different materials and the analysis of resistive switching mechanisms.We discuss the resistive switching mechanisms of different materials in this paper and analyze the differences of those mechanisms from the view point of circuitry to establish their respective circuit models.Finally,simulations are presented.We give the prospect of using different materials in resistive RAM on account of their resistive switching mechanisms,which are applied to explain their resistive switchings.

Dual-objective pattern optimization method for land suitability zoning in mountain counties

As the basic administrative unit of China,counties have grown rapidly in recent years in the context of rapid urbanization,especially for counties located in mountainous areas.The drastic changes in land in mountainous areas can easily cause irreversible damage to the sensitive ecological environment.Through the dual-objective suitability zoning of ecological and construction balance,regional sustainable land use patterns can be realized.In this study,Hantai District in Southern Shaanxi province,China,was chosen as the research area aiming at creating a balance between ecological supply and the development of construction in spatial planning.A dual-objective process evaluation system for ecological protection and construction development was proposed with 15 resistance factors selected from three attributes:natural ecology,economic society,and policy.The minimum resistance surface discrimination methods for ecological land and construction development land were proposed based on vertical space superposition and horizontal minimum cumulative resistance models.Finally,the land in Hantai District was divided into four development grades from the optimal angle of dual goals,i.e.,the construction core zone being 134.56 km^(2),the suitable construction zone 115.77 km2,the ecological buffer zone 153.74 km^(2),and the ecological control zone 151.93 km^(2),using the method combining resistance difference and threshold division.In addition,the development direction of each town under jurisdiction was identified.This study compensates for the deficiency of traditional methods that evaluate land only from a single vertical or horizontal process.

Conductivity characteristics of landslide considering porosity,saturation,temperature and ion concentration

High-density resistivity imaging method is widely used in landslide monitoring.The resistivity of rock and soil is closely related to factors,such as porosity,moisture content,saturation and temperature.In this study,the resistivity test was designed to investigate the influence of physical factors and pore solution components on the resistivity of landslide soil.Experimental and analytical results find that both moisture content and volumetric water content varies greatly under the same resistivity.At different temperatures,soil resistivity exhibits great changes.Under the same temperature,the ion concentration and species in pore solutions have great influence on soil resistivity.Based on the test results and grey correlation analysis,this study established a resistivity model by considering porosity,saturation,temperature and ion concentration.The study lays a foundation for the high-density resistivity method to measure the moisture content of landslides.

Applicability of discrete element method with spherical and clumped particles for constitutive study of granular materials

Discrete element method(DEM)has been intensively used to study the constitutive behaviour of granular materials.However,to what extent a real granular material can be reproduced by virtual DEM simulations remains unclear.This study attempts to answer this question by comparing DEM simulations with typical features of experimental granular materials.Three groups of models with spherical and clumped particles are investigated from four perspectives:(i)deviatoric stress and volumetric behaviour;(ii)critical state behaviour;(iii)stress-dilatancy relationship;and(iv)the evolution of principal stress ratio against axial strain.The results demonstrate that DEM with spherical or clumped particles is capable of qualitatively describing macroscopic deviatoric stress responses,volumetric behaviour,and critical state behaviour observed in experiments for granular materials.On the other hand,some qualitative deviations between experiments and the investigated DEM simulations are also observed,in terms of the stress-dilatancy behaviour and principal stress ratio against axial strain,which are proven to be critical for constitutive modelling.The results demonstrate that DEM with spherical or clumped particles may not necessarily fully capture experimental features of granular materials even from a qualitative perspective.It is thus encouraged to thoroughly validate DEM with experiments when developing constitutive models based on DEM observations.

Landscape Ecological Security Assessment of Low-Slope Hilly Region in Lu County,China

Low-slope hilly land( LSHL) refers to regions with relatively lower altitude,smaller topographic changes and gentler slopes. Exploitation and utilization of such areas is acting as an efficient approach to release the intensity in land utilization for mountainous areas in China, and needs further study. By summarizing related domestic concepts regarding LSHL,and taking Lu County of Sichuan province as the sample,this paper defined the scope of LSHL and extracted a total coverage of 331. 71 km2 LSHL.Then based on the landscape ecological security patterns theory,we have established the landscape ecological security pattern of Lu County by the minimum cumulative resistance model,targeting to achieve ecological land protection. Moreover,LSHL of different landscape security levels is further classified through overlay analysis on the current utilization status of the LSHL. The LSHL is classified into four categories, including prioritized development type,moderate development type, limited development type and prohibited development type. Their scopes of areas are 108. 72,97. 03,68. 36 and 57. 60 km2 respectively. In addition,respective land utilization and exploitation plan for LSHL are proposed according to the analysis of characteristics of each type. The result has provided scientific references for the definition,establishment of landscape ecological security pattern as well as the appropriate exploitation and utilization of the LSHL.

无腹杆钢筋混凝土拱型屋架单层厂房振动台模型试验研究

本项研究通过模型结构的振动台模拟地震试验和计算分析，对采用无腹杆钢筋混凝土拱型层架的单层墙柱厂房的抗震性能作出评价，其成果已在实际工程中得到应，并被新修订的《建筑抗震鉴定标准》所采纳。在本项试验研究中特别注意输入地震动的频谱特性与模型结构动力特性的关系，以使试验结果有效。

Thermal Analysis of Vehicular Twin-Tube Hydraulic Gas-Precharged Shock Absorbers

In this study of temperature rising in vehicular twin-tube hydraulic gas-precharged shock absorbers,thermodynamic analyses were conducted via simulations.Equations on heat conduction,heat convection as well as radiation were derived by applying certain laws governing heat transfer;an equivalent thermal resistance network model of a shock absorber undergoing heat transfer was established innovatively;moreover,the shock absorber’s thermodynamic model of control volume system was built by using the first law of thermodynamics;and finally,time required for shock absorber to reach thermal equilibrium and corresponding value of steady temperature were calculated by programming.In this way,a lower thermal equilibrium temperature will be achieved,hence help to improve reliability of shock absorbers in work by offering low ambient temperature,by reducing amplitudes and frequencies of external incentives exerted on them and by increasing flow rate of ambient air passing around them.

Application of 2-D geoelectrical resistivity tomography for subsurface cavity detection in the eastern part of Saudi Arabia

The presence of natural voids and cavities in subsurface karstic limestones causes severe problem for civil engineering and environmental management. The presence of such features hinders the extension of urbanizations particularly in the new metropolitan. The eastern part of Saudi Arabia contains various types of karstic limestone, sinkholes, solution cavities and voids. In this context, geophysical methods particularly electrical resistivity technique is used as a cost-effective solution for investigating subsurface caves, voids, and shallow weathered zones. 2-D electrical resistivity data sets have been acquired along seven profiles in the new urbanization at AI Hassa area. Data processing has been carried out taking into consideration the response of synthetic models, which simulates physical models of the most common karstic features in the area. The results are very useful to determine the extension of shallow weathered zones and to locate different cavities underneath them. The hard limestone bedrock can also be detected and traced along the surveyed profiles.

Modeling deformation resistance for hot rolling based on generalized additive model

A model of deformation resistance during hot strip rolling was established based on generalized additive model.Firstly,a data modeling method based on generalized additive model was given.It included the selection of dependent variable and independent variables of the model,the link function of dependent variable and smoothing functional form of each independent variable,estimating process of the link function and smooth functions,and the last model modification.Then,the practical modeling test was carried out based on a large amount of hot rolling process data.An integrated variable was proposed to reflect the effects of different chemical compositions such as carbon,silicon,manganese,nickel,chromium,niobium,etc.The integrated chemical composition,strain,strain rate and rolling temperature were selected as independent variables and the cubic spline as the smooth function for them.The modeling process of deformation resistance was realized by SAS software,and the influence curves of the independent variables on deformation resistance were obtained by local scoring algorithm.Some interesting phenomena were found,for example,there is a critical value of strain rate,and the deformation resistance increases before this value and then decreases.The results confirm that the new model has higher prediction accuracy than traditional ones and is suitable for carbon steel,microalloyed steel,alloyed steel and other steel grades.

On the Origin of Crustal High Conductivity Zone in theWestern Tibet Plateau

The subduction of the Indian continental lithosphere under the Asian continent caused the uplift of the Tibet Plateau,resulting in the formation of a thickened continental crust twice of the normal value and the crustal shortening of at least 1500 km.Therefore,many models have been proposed to explain the shortening and material transportation mechanism of the Tibetan Plateau.

PARAMETRIC MATCHING SELECTION OF MULTI-MEDIUM COUPLING SHOCK ABSORBER

To achieve the dual demand of resisting violent impact and attenuating vibration in vibration-impact-safety of protection for precision equipment such as MEMS packaging system, a theo- retical mathematical model of multi-medium coupling shock absorber is presented. The coupling of quadratic damping, linear damping, Coulomb damping and nonlinear spring are considered in the model. The approximate theoretical calculating formulae are deduced by introducing transformation-tactics. The contrasts between the analytical results and numerical integration results are developed. The resisting impact characteristics of the model are also analyzed in progress. In the meantime, the optimum model of the parameters matching selection for design of the shock absorber is built. The example design is illustrated to confirm the validity of the modeling method and the theoretical solution.