Properties Of Grains Research Articles

An analysis of the correlations between the hardness index and selected physicochemical properties of wheat grain

The processes of grain grinding and milling are affected by the physical properties of kernels, whereas energy consumption during these processes is influenced mainly by their mechanical properties. Therefore, the main aim of this study was to determine the relationships between selected physicochemical properties of wheat grain classified into different hardness groups. Technological (processing), mechanical and geometric properties of grain were evaluated in 12 wheat cultivars produced in Poland. The cultivars were divided into four grain hardness groups. The results were analyzed using the following statistical modules: descriptive statistics, one-way analysis of variance (ANOVA), correlation analysis, and regression analysis. Kernels of various hardness were found in each of the evaluated wheat cultivars, in particular those classified as medium soft and medium hard. The type and strength of correlations between the analyzed properties of grain were considerably affected by kernel hardness. The greatest differences were observed in comparisons of the following pairs of kernel parameters: length and width, length and relative strain, length and rupture force, and rupture force and relative strain. On average, the strongest correlations were noted between rupture force and rupture energy, and between kernel thickness and mass, whereas the weakest correlation was found between kernel mass and relative strain. The study demonstrated that the mechanical properties of wheat grain were not affected by crude protein content or total ash content. Grain hardness was correlated with kernel length, vitreousness, rupture force, and rupture energy. The hardness index (HI) increased by 110% within the range of average kernel length values (from approx. 5.4 mm to approx. 8.0 mm). The increase in HI values was accompanied by an increase in rupture force (by approx. 90%) and rupture energy (by approx.115%).

TECHNOLOGICAL AND BAKERY PROPERTIES OF GRAIN FORMS OF WHEAT CREATED BY HYBRIDIZATION OF TRITICUM AESTIVUM L. × TRITICUM SPELTA L.

TECHNOLOGICAL AND BAKERY PROPERTIES OF GRAIN FORMS OF WHEAT CREATED BY HYBRIDIZATION OF TRITICUM AESTIVUM L. × TRITICUM SPELTA L.

Enhanced thermal and dielectric properties of CaCu3Ti4O12 by (Fe, La)-co-doping

Enhanced thermal and dielectric properties by (Fe, La)-co-doping to modulate the electrical transport properties of grains and grain boundaries of CaCu3Ti4O12 materials.

Operational control of grain grinding efficiency

The authors of the article consider the properties of grain as an expensive and very complex raw material. With varietal milling of wheat in the cost of flour, the main share falls on the purchase of grain - up to 80 ... 85%. Therefore, when organizing and maintaining varietal grinding, it is required to optimize the modes of the main processes of the technology both in the preparatory and grinding sections of the mill, moreover, based on the choice of objective criteria for the efficiency of processes. The authors found out that the values obtained are significantly behind modern ones, which indicates the progress made in the organization and management of flour technology, in particular, characterizes the success in equipping our technology with highly efficient equipment.

Physical properties of grain and protein-proteinase complex of spring triticale under different nitrogen fertilizer doses

Physical properties of grain and protein-proteinase complex of spring triticale under different nitrogen fertilizer doses

Thermal softening-suppressed inter-granular embrittlement of polycrystalline 3C-SiC under diamond cutting

While the deformation behavior of grain boundaries has a strong impact on the mechanical response of polycrystalline materials, investigating the coupled thermal–mechanical properties of grain boundaries in their real formats is crucial for enhancing the ductile machinability of hard brittle polycrystalline ceramic materials. In the present work, we report the thermal softening-suppressed inter-granular fracture, accompanied with enhanced stacking fault formation, increased healing ability of grain boundaries and promoted ductile material removal, in diamond cutting of polycrystalline 3C-SiC at elevated temperatures by multi-scale simulations. Molecular dynamics simulations and experiments of high temperature nanoindentations are performed to derive the temperature-dependent mechanical properties of bulk polycrystalline 3C-SiC. Furthermore, molecular dynamics simulations of Mode I (tension) and Mode II (shearing) loading of a Σ9<110>{122} symmetric tilt grain boundary at elevated temperatures are performed to extract the temperature-dependent mechanical properties of grain boundaries in polycrystalline 3C-SiC. A novel finite element model of heat treatment-assisted diamond cutting of polycrystalline 3C-SiC with the comprehensive consideration of thermal properties of both grains and grain boundaries at elevated temperatures is established to reveal the transition of material removal mode, grain boundary failure behavior, cutting force characteristics and chip profile with temperature.

Technological properties of winter common wheat varieties depending on the forecrops

Introduction. Wheat is the main grain cropwhich is used for fodder and food purposes in most countries of the world. Flour is the main product of wheat processing, it is subject to a number of quality and safety requirements depending on the use. The purpose of the current work was to identify varietal traits and the effect of the forecrops on the formation of technological properties of grain and flour of winter common wheat varieties, thento select the best of them according to the studied properties.Methods. There were estimated the technological properties of 17 winter common wheat varieties (Triticum aestivum L.) developed by the Agricultural Research Center “Donskoy”, 10 of them were included in the State List of Breeding Achievements, 7 of them are currently being studied. The indicators of the technological, flour-milling, biochemical and physical traits of grain were assessed in accordance with the GOSTs.Results. There has been established that for the entire period the varieties formed a large nature grain weight and corresponded to the first quality class according to the two studied forecrops. As a result of the conducted study there was found out that the choice of a forecrop affected protein percentage in grain and flour. There has been identified varieties ‘Zhavoronok’, ‘Podarok Krymu’, ‘Zolotoy Kolos’, ‘Ayuta’ and ‘Premiera’ had high flour properties according to the technological efficiency of milling (E) after both of the studied forecrops. The varieties ‘Zhavoronok’, ‘Podarok Krymu’ and ‘Premiera’ were characterized by high values of flour-milling estimation (MS).

Low-pressure ozone injection system: relationship between reaction kinetics and physical properties of grains.

The ozonation of grains in a closed system at low pressure is a strategy with the potential for treating packaged products. Research is necessary to characterize the reaction kinetics of ozone in this type of injection system so that it is possible to design chambers and determine the ozone concentrations suitable for commercial-scale applications. The objective of this study was therefore to characterize the low-pressure ozone injection system in relation to the physical properties of the grains and determine possible changes in their quality. Samples (5 kg each) of common beans, cowpea beans, corn, popcorn kernels, paddy rice, and polished rice were exposed to ozone in a 70 L hypobaric chamber. Initially, the internal pressure of the chamber was reduced to 500 hPa. Then, ozone was injected at a concentration of 32.10g m-3 at a volumetric flow rate of 1L min-1 until reaching a pressure of 1000 hPa. To relate the decomposition of ozone to the grains that were being evaluated, different physical properties were determined, and quality analysis was conducted. Ozone gas half-life outside and inside the package depended on the grain type. Ozone decomposition was quickest in polished rice and slowest in common beans. The half-life of the different grains ranged from 17.8 to 52.9 and 16.4 to 52.9min, outside and inside the package, respectively. Considering the physical properties, specific surface (Ss), surface area (SA), and sphericity (φ) exhibited a significant correlation with the decomposition rate constant (k) of ozone. However, the variables volume (V), permeability (K), porosity (ε), and specific mass (ρ) showed no correlation with k. The physical properties of grain influenced the reaction kinetics of ozone gas during the low-pressure injection process. Ozone gas injection at low pressures did not alter the quality attributes of the grains under study. © 2022 Society of Chemical Industry.

ФОРМУВАННЯ ТЕХНОЛОГІЧНИХ ВЛАСТИВОСТЕЙ ЗЕРНА ПШЕНИЦІ ОЗИМОЇ ЗА ВНЕСЕННЯ РІЗНИХ ДОЗ ТА ТЕРМІНІВ ЕЛЕМЕНТІВ АЗОТНОГО ЖИВЛЕННЯ

The influence of nitrogen fertilization on the formation of technological properties of grain of modern varieties of soft winter wheat was established – with increasing intensity of cultivation technology the protein content increased by 10–15%, gluten to 27.9%, the volume yield of bread increased by 25.8%. The optimal doses and terms of nitrogen fertilization of winter soft wheat were specified in order to optimize nitrogen nutrition of plants and grain formation with the improved technological properties: N70N30N70 – combination of early spring N70 with foliar fertilization at the stage of stem elongation N30 and N70 at the beginning of wheat earing and N100N70N70 – combination of early spring N100 with foliar fertilization in the phase of stem elongation N70 and N70 at the beginning of wheat earing. The varieties of winter soft wheat were evaluated for their ability to form high-quality grain that meets the requirements of bakery production. The positive effect of nitrogen fertilization on all the varieties studied was established by trial baking, the best results were obtained in the variety Lira Odeska.

Regionalization of microstructure characteristics and mechanisms of slip transmission in oriented grains deposited by wire arc additive manufacturing

Regionalization of microstructure regulation and mechanical property adjustment during the thermal cycle of the deposition process plays a vital role in the grain morphology and orientation of aluminum alloy components manufactured using wire arc additive manufacturing (WAAM) technology. However, the microscopic mechanism of the mechanical property difference caused by uneven microstructure in different regions remains unclear for the WAAM 2319 alloy. The geometric properties of grains are described quantitatively in different regions for the WAAM 2319 alloy through EBSD data processing and analysis. The effect of grain orientation on grain boundary, including subgrain boundaries and the boundary of coincidence site lattice (CSL boundary), are explored with EBSD data. The grain boundary and dislocations are characterized by transmission electron microscopy (TEM). The distribution of geometrically necessary dislocation (GND) in the WAAM block at different regions is studied through EBSD analysis. The high Schmidt factor or Taylor factor (M) percentage was quantitatively calculated in different regions. Then the relationship between grain morphology and plastic deformation ability is established through these factors. The results indicate that the average grain size is small and located in the top and middle of the WAAM sample with a low critical Taylor factor (Mc). The Taylor factor in most grains easily exceeds Mc (Mc < M), which causes most dislocations to pass through grain boundaries quickly, and plastic deformation easily occurs in these regions. There are various CSL boundaries except Σ3 boundaries existing in the middle of the sample, which can maintain the high mobility of the grain boundaries. Therefore, more slip transmission in the middle of the WAAM sample can provide the driving force for grain boundary migration. Most grains with a high subgrain boundary density (above 2.5) and the geometrically necessary dislocation (GND) density (5 × 1014 m−2) can hinder the movement of dislocations and improve the strength of materials at the sidewall of the sample. The Schmidt factor of columnar crystals is generally low (below 0.25), and the sliding system does not start rapidly in columnar crystals, especially at the bottom of the WAAM sample.

STUDY OF SORPTION PROPERTIES OF QUINOA SEEDS

The paper provides an analysis of the current state of the quinoa seed market in the world and the prospects for its production in Ukraine. The main producers of quinoa are Peru, Bolivia and Ecuador. Due to its rich chemical composition, quinoa seeds are rapidly gaining popularity. Ukrainian enterprises use quinoa grain for the production of various products and semi-finished products. Quinoa seeds are attracting increasing attention worldwide not only for their nutritional and functional properties, but also for their ability to grow in adverse climatic conditions. Increasing demand and rising global prices for quinoa is encouraging producers to adapt the crop to low altitudes and grow it in arid conditions. Breeders and scientists of different countries are actively working on the adaptation of quinoa seeds to growing in different regions, which has an important impact on food security. Quinoa grain imported to Ukraine requires long-term storage without weight loss and quality deterioration. An important influence on the state of grain mass during storage is its hygroscopicity, that is, the ability to sorb and desorb water vapor. Knowledge about the hygroscopic properties of grain is of practical importance for the scientific justification of the choice of rational modes of storage and post-harvest processing. The main characteristic of the hygroscopic properties of grain materials is the equilibrium moisture content, therefore, its determination is an important step in preserving grain quality. The equilibrium moisture content of quinoa grain was determined. The research was carried out by the generally accepted tensimetric method in the range of air temperatures ±(5...25)°С and relative air humidity 40...80%, which simulate the conditions of grain storage and correspond to long-term average data, corresponding to warm and cold seasons in Ukraine. The nature of the change in the equilibrium moisture content of quinoa grain depending on the temperature and relative humidity of the air has been established. As the relative humidity increases and the ambient temperature decreases, the equilibrium moisture content of the quinoa grain increases. Empirical coefficients were determined and an equation was proposed that describes the dependence of the equilibrium moisture content of quinoa grain on the parameters of the surrounding air, which can be used to predict its change. The obtained data are of practical importance for the selection of high-quality storage regimes for quinoa seeds.

Stress annealing effects on magnetic properties of grain oriented electrical steel under compressive stress

There is a strict relation between Gross National Product and electric energy consumption; consequently, the improvement of electrical machines efficiency is highly desired. Regarding power transformers, power loss of magnetic core sheets increases due to compressive stresses appearing during its operation, decreasing power transformer performance. In this article, the effects of tensile stress annealing on power loss of grain oriented electrical steel under compressive stress are evaluated. To do that, the power loss of two uncoated sheets was measured before and after tensile stress annealing for several magnetic inductions (0.7, 1.0, 1.3, 1.5, and 1.7 T) and compressive stress (0, 2, 4, 6, 8, and 10 MPa). This thermomechanical procedure was performed at 500°C, 40 MPa for 10–20 min. Although the tensile stress annealing performance depends on crystallographic texture, a power loss reduction occurs for both samples when compressive stresses were higher than 6 MPa, regardless of magnetic induction. In summary, tensile stress annealing could reduce the deleterious effects of compressive stress on power loss, making commercial grain oriented electrical steel more magnetic uniform and improving power transformer efficiency.

THE QUALITY OF WHEAT GRAINS AND THE PROCESS THAT AFFECTS THEIR STORAGE

In this article, the quality of wheat grains and the factors influencing the process of their storage, ie, the yield of grains is reduced due to cochlear disease, and a sharp deterioration in product quality and objective and correct physical, technological and biochemical properties of grain. The form of production of quality flour as a result of the assessment, its uniqueness, the correct organization and implementation of technological processes of cleaning, preparation and grinding of grain. The purpose of our research is to study the status and modernization of the project of JSC "Ferganadonmahsulotlari", the modernization of advanced production and existing grain cleaning technologies, the physical and chemical properties of local varieties of wheat. One of the main directions in improving the technology of flour production is the creation of an enterprise where grain is efficiently cleaned, moistened and well prepared for grinding, while consuming less electricity.

Promising winter durum wheat varieties and their seed production

The main task of agricultural producers has always been and still remains to obtain high and stable yields, which can be provided by new developed varieties, which are the main reserve for increasing grain production. The current paper has presented the study results of the work in 2018–2021, namely, the development of promising varieties and the main features of seed production. The purpose of the study was to estimate promising winter durum wheat varieties according to the main economic and biological traits and properties, quality indicators of grain and pasta, and seed production features. The studied varieties were able to give consistently high yields (from 5.56 to 12.67 t/ha), combining the main economic and biological traits (drought resistance, frost resistance, resistance to major diseases and lodging) and quality indicators of grain and pasta. The study of the physicochemical properties of grain showed that the winter durum wheat varieties met the requirements of GOST 9353-2016 and belonged to the 1–2 quality classes, which was quite enough to produce good pasta and cereal. The pasta color of the varieties ‘Yakhont’, ‘Yantarina’, ‘Uslada’ was yellow (4.3–4.6 points); it was creamy in the variety ‘Yubilyarka’ (3.5 points); the content of carotenoids varied from 507 µg/% (the variety ‘Yubilyarka’) to 610 µg/% (the variety ‘Uslada’). In order to preserve and maintain the main features and properties characteristic for each variety, their seed production is being currently carried out with a comprehensive estimation of both phenotypic (approbation) traits and genotypic ones using protein markers. The varieties ‘Yakhont’, ‘Yubilyarka’, ‘Yantarina’ and ‘Uslada’ have clearly distinguishable spectra of gliadins 3.2.3T2, 13.2T+6T.3.T1, 5.2.4T1 and 13X.4T.3.2, which makes it possible to control their varietal purity at all stages of seed production.

Combined Effects of Starch Sucrose Content and Planting Density on Grain Protein Content of Winter Wheat (&lt;i&gt;Triticum aestivum&lt;/i&gt; L.)

Wheat (Triticum aestivum L.) is a staple crop worldwide, and yield improvement since the green revolution was attributed to chemical nitrogen (N) fertilizer application. We conducted field experiments in Yuncheng County, Shanxi Province, under planting density (2 million plants ha–1, 2.25 million plants ha–1, 2.5 million plants ha–1) and topdressing nitrogen (12 kg ha–1, 22 kg ha–1, 32 kg ha–1). The results shown that the starch content of grains with a density of 2.5 million plants ha–1 increased by 1.9%-7.5%, which improved the water absorption of flour and the processing quality of flour, but decreased the protein content, and gluten properties of grains. The nitrogen topdressing amount of 22 kg ha–1 wheat tiller increased by 6.3%-33.3%, and the dry matter accumulation increased by 1.0%-9.5%. The number of spikes increased by 3.7%-19.2%, and the yield increased by 3.7%-17.8% with the nitrogen topping amount of 22 kg ha–1 the protein content increased by 2.0%-4.2% with the nitrogen topping amount of 22 kg ha–1, the starch content increased by 1.2%-7.2%, and the gluten index increased by 4.3%-21.5%.

COMPARISON OF TECHNOLOGICAL PROPERTIES OF DIFFERENT WHEAT SPECIES

For the widespread introduction of different species of wheat into processing, it is necessary to understand the features of the physicochemical properties of these wheats, which determine the behavior of the grain during its milling and the obtaining flour during the dough making process. Technological properties of grain of four different wheat species and the laboratory milling flour obtained from them were investigated.&#x0D; It was found that according to grain quality indicators, milling properties and quality flour indicators, 4 species of wheat grain grown in the same agro-climatic conditions showed significant differences. Hard wheat with GPC-B1 gene (breeding line) has a superior baking strength due to the GPC-B1 gene, which significantly increases the protein content in grain (13.51%), gluten content (26.1%), test Zeleny (58 ml) and ash content (1.69%) compare to common hard wheat (Kuyalnyk variety). As a result, flour shown high values of: strength (W=396×10-4 J), high SRC in lactic acid (160%), high dough stability (&gt;30 minutes), low degree of softening of the dough (43 UF). According to the obtained data, waxy wheat (Sofiika variety) consimilar with common baking wheat, excluding low value of Falling Number (FN=70 seconds). When determining on the alveograph, the dough is very tight (L&lt;40 mm) due to high water absorption capacity (WAC=67.3%). The results of SRC test in sodium carbonate confirmed the high value of starch damage with the highest result (108%). Soft wheat (Bilyava variety) differs significantly from common hard wheat. In terms of wheat quality indicators, it can be attributed to medium bread-baking strength. Such flour characterized by less ash content (0.47%), but higher whiteness (70.7 units), less protein content (10.79%), less elasticity (Ie=44.3), but greater extensibility, resulting in a lower P/L ratio (0.83) and less water absorption capacity (WAC=52.7%).&#x0D; According to milling properties was investigated that hard wheat with the GPC-B1 locus and common hard wheat Kuyalnik shown similar results. The total yield of flours from these wheats during milling is above 70%, which indicates the economic feasibility of their processing into flour. During milling waxy wheat has a decrease in the reduction flour yield and an increase in the reduction bran yield. Absolutely different results in milling properties show soft wheat. The total yield of soft flour is less – 67.17% with significant increasing of break flour yield and decreasing reduction flour yield.&#x0D; Different properties of grain and flour determine the different end use of grain of each wheat species. Wheat with the GPC-B1 gene can be used in production of flour which is used in low-temperature technologies for the manufacture of frozen convenience foods and also as improver for increase the rheological properties of the dough or for pasta-making properties. For end use of waxy wheat (Sofiika variety) can be recommended in the production of pasta products. Although waxy flour can be used as regulator in flour blending for correcting the indicators of common baking wheat. Blends of flour from waxy wheat grain and flour from hard wheat grain with GPC-B1 gene are ideal for making frozen products. Soft wheat (Belyava variety) flour preferred for low moisture crackers, cookies and can be added in a small amount to special types of bread to give a lighter color to the crumb.

Atomistic Theory of Thermally Activated Magnetization Processes in Nd&lt;sub&gt;2&lt;/sub&gt;Fe&lt;sub&gt;14&lt;/sub&gt;B Permanent Magnet

For the practical use of magnets, particularly at high temperatures, the temperature dependence of magnetic properties is an important ingredient. To study the temperature dependence, methods of treating the thermal fluctuation causing the so-called activation phenomena must be established. To study finite-temperature properties quantitatively, we need atomistic energy information to calculate the canonical distribution. In the present review, we report our recent studies on the thermal properties of the Nd2Fe14B magnet and the methods of studying them. We first propose an atomistic Hamiltonian and show various thermodynamic properties, e.g., the temperature dependences of the magnetization showing a spin reorientation transition, the magnetic anisotropy energy, the domain wall profiles, the anisotropy of the exchange stiffness constant, and the spectrum of ferromagnetic resonance. The effects of the dipole-dipole interaction (DDI) in large grains are also presented. In addition to these equilibrium properties, we also study coercivity, which is the most important issue for magnets. The temperature dependence of the coercivity of a single grain was studied using the stochastic Landau-Lifshitz-Gilbert equation and also by the analysis of the free energy landscape, which was obtained by Monte Carlo simulation. It was found that the upper limit of coercivity at room temperature is about 3 T, which is significantly lower than the so-called theoretical coercivity given by a simple coherent rotation model. The coercivity of a polycrystalline magnet, i.e., an ensemble of grains, is expected to be reduced further by the effects of the grain boundary phase, which is also studied. Surface nucleation is a key ingredient in the domain wall depinning process. Finally, we study the effect of DDI among grains and also discuss the distribution of properties of grains from the viewpoint of first order reversal curve.

An evaluation of selected engineering properties of polish durum wheat grain

The physical properties of durum wheat grain have to be evaluated due to the growing diversity of durum wheat cultivars in the food processing industry and increasing qualitative requirements. The size, texture and mechanical properties of wheat grain play an important role in grain processing. In the present study, the morphological and mechanical properties of grain and the correlations between these traits were investigated in seven Polish genotypes of durum wheat. The kernels of the studied cultivars were relatively similar in shape, and their dimensions and weight approximated the average for durum wheat, which indicates that this wheat species can be processed in standard production lines. Hardness index (HI) values (81–89) were relatively similar, whereas grain vitreousness differed across the tested genotypes. The highest HI values were noted in kernels with a thickness of 2.90–2.95 mm. Kernel structure was damaged within a deformation range of around 18–21%. Rupture force, rupture energy and HI values increased with a rise in grain vitreousness. Rupture force was lowest in kernels with vitreousness of 70–75%.

Energy Saving in Electromechanical Grain Cleaning Systems

The article is concerned with energy conservation in the process of cleaning grain. The study aimed to find ways of reducing energy consumption when cleaning food grains by using energy-saving operating modes (ESOM) on the production lines of grain storage facilities. For this purpose, experimental tests were performed which involved studying the effects of physical and chemical properties of grain as well as the influence of various operating modes of the production lines on the specific energy consumption (SEC), which was found to be the most informative indicator for determining ESOM. The mathematical description of the target function was carried out by conducting a multifactorial experiment with the application of the orthogonal central composite design (OCCD) of the second order. Calculations produced a number of mathematical models describing the dependence of the response function on the input parameters. The proposed approach made it possible to obtain the minimum SEC for cleaning food grains and to develop practical recommendations for ways to reduce energy consumption, which resulted in the development of scientifically based SEC standards for a grain cleaning machine.

Modification of Cu-deficient CaCu2.8Ti4O12 ceramics via Mg2+ substitution at Cu sites for improved dielectric properties and thermal stability

Mg2+ substitution at the Cu sites of Cu-deficient CaCu2.8-xMgxTi4O12 (x = 0.00, 0.05, and 0.10) ceramics was accomplished using a polymer pyrolysis technique. The nonlinear and dielectric properties of all ceramics under various sintering temperatures were investigated. Very low tanδ ∼ 0.011–0.030 and giant ε′ ∼ 4406–13,521 were obtained in these ceramics. Surprisingly, excellent thermal stability, where ε′ remained within± 15% and is adequate for X8R capacitors, is obtained in CaCu2.75Mg0.05Ti4O12 and CaCu2.7Mg0.1Ti4O12 ceramics sintered at 1100 °C for 8 h. Additionally, the nonlinear J-E properties were improved compared to an unmodified sample. Interestingly, a nonlinear coefficient (α) of ∼ 58.05 in the CaCu2.75Mg0.05Ti4O12 ceramic sintered at 1100 °C for 8 h is acceptable for varistor applications. Improvement of nonlinear and dielectric properties arise from the electrical interface responses altered by Mg2+ substitution. The ceramics were characterized using XRD, TEM and FE-SEM techniques to investigate their crystal structure and microstructure. EDXS results confirmed the coexistence of TiO2 and CaTiO3 phases in all ceramics. It was suggested that the enhancement of grain boundary resistance (Rgb) with simultaneously improved electrical and nonlinear J-E behaviors caused by the alternation of electrical interface responses at GBs. XPS measurements of these ceramics presented Cu3+/Cu2+/Cu+ ratios that indicate the semiconducting properties of grains.