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In order to develop reliable constitutive equations for the simulation, the hot deformation behavior of FV520B steel was investigated through isothermal compression tests in a wide range of temperatures from 900 °C to 1100 °C at an interval of 50 °C and strain rate from 0.01 to 10 s−1 on Gleeble-1500D simulator. The effects of temperature and strain rate on deformation behavior were represented by Zener-Holloman parameter in an exponent-type equation of Arrhenius constitutive. The influence of strain was incorporated in the constitutive analysis by material constants expressed as a polynomial function of strain. The constitutive equation (considering the compensation of strain) could precisely predict the flow stress only at strain rate 0.01 s−1 except at the temperatures of 900 °C and 1000 °C, whereas the flow stress predicted by a modified equation (incorporating both the strain and strain rate) demonstrated a well agreement with the experimental data throughout the entire range of temperatures and strain rates. Correlation coefficient (R) of 0.988 and average absolute relative error (AARE) of 5.7% verified the validity of developed equation from statistical analysis, which further confirmed that the modified constitutive equation could accurately predict the flow stress of FV520B steel.

For the precision shear of bars, the kind of rotating high-speed precision cutting method has been given. The structure design of rotary precision shearing machine and the structure design of feeding structure are completed. The method of numerical simulation is used to optimize the cutting tool, and then the experiment platform is completed. Rotary impact and the stress concentration effect of the surface of the bar are used in the paper. The experiment is carried out for the Φ8 mm diameter stainless steel bar stock by changing the speed of the cutting tool through the converter and controlling rod feeding efficiency. The experimental results show that the method is feasible to meet the requirement of various material of the small diameter rod in the industry.

Mechanical and electrical integration is an important direction for future development of the industry. There are many products in hydraulic filed. By connecting electrical and mechanical, we can obtain more precise displacement, velocity and force of controlled object. The simulation can reduct the model and evaluate the performance of the controlled system. The overall development time and costs saved. The aim of the paper is to build a model of cartridge proportional flow valve with LMS Imagine.lab -AMESim and validate the accuracy of the built model by comparing with products catalogue.

Using the estimates of the exponential sums over Galois rings, we discuss the random properties of the highest level sequences [a.sub.e-1] of primitive sequences generated by a primitive polynomial of degree n over [Z.sub.[2.sup.e]]. First we obtain an estimate of 0, 1 distribution in one period of [a.sub.e-1]. On the other hand, we give an estimate of the absolute value of the autocorrelation function |[C.sub.N] (h)| of [a.sub.e-1], which is less than [2.sup.e-1] ([2.sup.e-1] - 1) [square root of (3 [2.sup.2e] - 1)) [2.sup.n/2] + 2.sup.e-1] for h [not equal to] 0. Both results show that the larger n is, the more random [a.sub.e-1] will be. Index Terms--0, 1 distribution, autocorrelation function, exponential sum over Galois ring, highest level sequence, primitive sequence.

The Industrial Internet of Things (IIoT), as a special form of Internet of Things (IoT), has great potential in realizing intelligent transformation and industrial resource utilization. However, there are security and privacy concerns about industrial data, which is shared on an open channel via sensor devices. To address these issues, many searchable encryption schemes have been presented to provide both data privacy-protection and data searchability. However, due to the use of expensive pairing operations, most previous schemes were inefficient. Recently, a certificateless searchable public-key encryption (CLSPE) scheme was designed by Lu et al. to remove the pairing operation. Unfortunately, we find that Lu et al.'s scheme is vulnerable to user impersonation attacks. To enhance the security, a new pairing-free dual-server CLSPE (DS-CLSPE) scheme for cloud-based IIoT deployment is designed in this paper. In addition, we provide security and efficiency analysis for DS-CLSPE. The analysis results show that DS-CLSPE can resist chosen keyword attacks (CKA) and has better efficiency than other related schemes. [ABSTRACT FROM AUTHOR]

In the forming process of long threads by axial self-infeed rolling process, the protrusion generates on the top of the tooth profile, which affects the strength and precision of the formed threads. In this article, the principle of the axial self-infeed rolling process was described, and the finite element model was established to simulate the forming process of threads. The formation mechanism of protrusion was analyzed through material flow, which was verified by experiments. The pre-rolling angle and material's influence on the protrusion size was also investigated. The results showed that the axial motion of the rollers squeezed one flank of the tooth, leading to higher protrusion on the face side as compared to the other side. During the rolling process, the height of the protrusion increased first and then decreased, reaching the maximum value when the height of the formed tooth was 73% of the whole tooth. In order to reduce the protrusion height, the pre-rolling angle should be 2°. [ABSTRACT FROM AUTHOR]

Background: The incidence of acute coronary syndrome is increasing in China. Objective: To investigate gender differences in Chinese patients' acute coronary syndrome symptoms, attribution of symptoms and reasons for seeking medical service. Methods: This was a cross-sectional, multicentre study. Acute coronary syndrome patients were recruited from five university hospitals located in four cities, between June 2013 and February 2014. Data were collected using the McSweeney acute and prodromal myocardial infarction symptom survey. Results: A total of 806 patients with acute coronary syndrome (323 men, 483 women) participated in the study. Adjusted (diabetes, smoking, age) logistic regression models revealed that women were significantly more likely to have pain or discomfort in the: central high chest; back, between, or under the shoulder blades; neck or throat; or arms relative to men. Women were also more likely to have unusual fatigue, weakness, shortness of breath or difficulty breathing, or dizziness relative to men. Conversely, women were significantly less likely to have generalised chest pain relative to men. Gender difference in the attribution of symptoms was largely driven by women's attribution to having a heart attack more frequently than men. Finally, women were more often told by a friend to seek medical help or they knew their symptoms were different, while men more frequently sought medical help because their symptoms did not go away. Conclusions: There were gender differences in pain, discomfort and other symptoms. Both potential patients and healthcare providers need to be more aware of potential gender differences in acute coronary syndrome symptoms and decisions to seek care to ensure quick access. [ABSTRACT FROM AUTHOR]

In recent years, mechanical clinching has been widely used to join aluminium alloy sheets to build the automotive body. The high protrusion on the joint may limit the use of the mechanical clinching in the visible places. In order to get a lower protrusion, a compressing method was investigated in this work. Clinched joints with different geometrical parameters were used to conduct the experiments. AL5052 was taken as the material of the sheets. The protrusion of the clinched joint was compressed by two flat dies. A rivet placed in the pit of the clinched joint was used to control the metal flow in the compressing process. The top die moved downward to compress the protrusion, and the bottom die was fixed. The study shows that the tension-shearing strength and cross-tensile strength can be increased by the compressing method. The compressing method can increase the tension-shearing strength and cross-tensile strength by increasing the neck thickness. The compressed joint has larger neck thickness and lower protrusion than the clinched joint. Neck fracture mode is the main failure mode of the joints. The energy absorption can also be increased after the compressing process. [ABSTRACT FROM AUTHOR]

Rising atmospheric carbon dioxide (CO2) concentration is likely to influence insect–plant interactions. Aphid, as a typical phloem-feeding herbivorous insect, has shown consistently more positive responses in fitness to elevated CO2 concentrations than those seen in leaf-chewing insects. But, little is known about the mechanism of this performance. In this study, the foliar soluble constituents of cotton and the life history of the cotton aphid Aphis gossypii and its mean relative growth rate (MRGR) and feeding behavior were measured, as well as the relative transcript levels of target genes related appetite, salivary proteins, molting hormone (MH), and juvenile hormone, to investigate the fitness of A. gossypii in response to elevated CO2 (800 ppm vs. 400 ppm). The results indicated that elevated CO2 significantly stimulated the increase in concentrations of soluble proteins in the leaf and sucrose in seedlings. Significant increases in adult longevity, lifespan, fecundity, and MRGR of A. gossypii were found under elevated CO2 in contrast to ambient CO2. Furthermore, the feeding behavior of A. gossypii was significantly affected by elevated CO2, including significant shortening of the time of stylet penetration to phloem position and significant decrease in the mean frequency of xylem phase. It is presumed that the fitness of A. gossypii can be enhanced, resulting from the increases in nutrient sources and potential increase in the duration of phloem ingestion under elevated CO2 in contrast to ambient CO2. In addition, the qPCR results also demonstrated that the genes related to appetite and salivary proteins were significantly upregulated, whereas, the genes related to MH were significantly downregulated under elevated CO2 in contrast to ambient CO2, this is in accordance with the performance of A. gossypii in response to elevated CO2. In conclusion, rise in atmospheric CO2 concentration can enhance the fitness of A. gossypii by increasing their ingestion of higher quantity and higher quality of host plant tissues and by simultaneously upregulating the transcript expression of the genes related to appetite and salivary proteins, and then this may increase the control risk of A. gossypii under conditions of climate change in the future. [ABSTRACT FROM AUTHOR]

In this work, a bacterial surface displaying enzyme based two-compartment biofuel cell for the direct electrical energy conversion from degradation products of lignocellulosic biomass is reported. Considering that the main degradation products of the lignocellulose are glucose and xylose, xylose dehydrogenase (XDH) displayed bacteria (XDH-bacteria) and glucose dehydrogenase (GDH) displayed bacteria (GDH-bacteria) were used as anode catalysts in anode chamber with methylene blue as electron transfer mediator. While the cathode chamber was constructed with laccase/multi-walled-carbon nanotube/glassy-carbon-electrode. XDH-bacteria exhibited 1.75 times higher catalytic efficiency than GDH-bacteria. This assembled enzymatic fuel cell exhibited a high open-circuit potential of 0.80 V, acceptable stability and energy conversion efficiency. Moreover, the maximum power density of the cell could reach 53 μW cm −2 when fueled with degradation products of corn stalk. Thus, this finding holds great potential to directly convert degradation products of biomass into electrical energy. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we established the existence of a primitive normal polynomial over any finite field with any specified coefficient arbitrarily prescribed. Let be a positive integer and q a prime power. We prove that for any and any , there exists a primitive normal polynomial such that , with the only exceptions . The theory can be extended to polynomials of smaller degree too. [Copyright &y& Elsevier]

Abstract: In this paper, we prove that for any given , there exists a constant such that for any prime power , there exists a primitive normal polynomial of degree n over with the last coefficients prescribed, where the last coefficient is a primitive element. Furthermore, the number of prescribed coefficients increases from to when the coefficients are specified as with b any primitive element. This result is a complement to the existence of a primitive normal polynomial with the first coefficients prescribed which was proved in [S.Q. Fan, W.B. Han, K.Q. Feng, Primitive normal polynomials with multiple coefficients prescribed: An asymptotic result, Finite Fields Appl. 13 (2007) 1029–1044]. The outline of this paper is similar to the above reference with the following two different treatments. On one hand, we use instead of x in the problem reduction step and as a consequence use the hybrid kloostermann sums instead of hybrid weil sums over Galois rings. On the other hand, the estimates are slightly more complicated and the results in some special cases are better than those in [S.Q. Fan, W.B. Han, K.Q. Feng, Primitive normal polynomials with multiple coefficients prescribed: An asymptotic result, Finite Fields Appl. 13 (2007) 1029–1044]. [Copyright &y& Elsevier]

Abstract: In this paper, we prove that for any given , there exists a constant such that for any prime power , there exists a primitive normal polynomial of degree n over with the first coefficients prescribed, where the first coefficient is nonzero. This result strengthens the asymptotic result of the existence of primitive polynomials with the first coefficients prescribed [S.Q. Fan, W.B. Han, p-Adic formal series and Cohen''s problem, Glasg. Math. J. 46 (2004) 47–61] in two aspects. One is that we discuss in this paper not only the primitivity but also the normality. Another is that the number of the prescribed coefficients increases from to . The estimates of character sums over Galois rings, the p-adic method introduced by the first two authors, and the computation technique used in [S.Q. Fan, W.B. Han, Primitive polynomial with three coefficients prescribed, Finite Fields Appl. 10 (2004) 506–521; D. Mills, Existence of primitive polynomials with three coefficients prescribed, J. Algebra Number Theory Appl. 4 (2004) 1–22] are the main tools to get the above result. [Copyright &y& Elsevier]

Abstract: Let be a finite field with elements. We prove that for any given , and any elements , , there exists a primitive normal polynomial of degree n, , with the first two coefficients , prescribed as a, b, respectively. This result strengthens the results of the existence of primitive polynomials with two coefficients prescribed [S.D. Cohen, D. Mills, Primitive polynomials with the first and second coefficients prescribed, Finite Fields Appl. 9 (2003) 334–350; W.B. Han, The coefficients of primitive polynomials over finite fields, Math. Comp. 65 (1996) 331–340; W.B. Han, On two exponential sums and their applications, Finite Fields Appl. 3 (1997) 115–130] and the existence of primitive normal bases with prescribed trace [S.D. Cohen, D. Hachenberger, Primitive normal bases with prescribed trace, Appl. Algebra Engrg. Comm. Comput. 9 (1999) 383–403]. In order to use the p-adic method which proposed by the first two authors, we first lift the definition of both primitive and normal from finite fields to Galois rings. Then we discuss the existence of lifted primitive normal polynomials over Galois rings and finally establish the existence of primitive normal polynomials with the first two coefficients prescribed with the help of character sums over Galois rings and Cohen''s various sieve techniques. In order to make this paper more succinct, we deal with the case in another paper since the computation is more miscellaneous and complicated. [Copyright &y& Elsevier]

The authors proved in Fan and Han (Finite Field Appl., in press) that, for any given (a1,a2,a3)∈Fq3, there exists a primitive polynomial f(x)=xn-σ1xn-1+⋯+(-1)nσn over Fq of degree n with the first three coefficients σ1,σ2,σ3 prescribed as a1,a2,a3 when n⩾8. But the methods in Fan and Han (in press) are not effective for the case of n=7. Mills (Existence of primitive polynomials with three coefficients prescribed, J. Algebra Number Theory Appl., in press) resolves the n=7 case for finite fields of characteristic at least 5. In this paper, we deal with the remaining cases and prove that there exists a primitive polynomial of degree 7 over Fq with the first three coefficient prescribed where the characteristic of Fq is 2 or 3. [Copyright &y& Elsevier]

Let F q be a finite field of characteristic two. We prove that for any given element a F q, there exists a primitive polynomial of degree n over F q with the m-th (0< m< n) coefficient S m= a when n=7, n is odd. [ABSTRACT FROM AUTHOR]

In this paper, we discuss the 0,1 distribution in the highest level sequence ae-1 of primitive sequence over Z2e generated by a primitive polynomial of degree n. First we get an estimate of the 0,1 distribution by using the estimates of exponential sums over Galois rings, which is tight for e relatively small to n. We also get an estimate which is suitable for e relatively large to n. Combining the two bounds, we obtain an estimate depending only on n, which shows that the larger n is, the closer to 1/2 the proportion of 1 will be. [ABSTRACT FROM AUTHOR]

In the context of Chinese innovation-driven strategy, the role of suppliers has been attracting much attention. Since not every supplier can contribute to the buyer's innovation, scientifically selecting an innovative supplier is highly valued by decision-makers from the new energy vehicle (NEV) manufacturers. This paper focuses on proposing a novel decision framework in the context of collaborative innovation, which helps NEV manufacturers to select an innovative supplier who can work hand in hand with them to enhance their innovation performance. First, a novel capability-willingness-risk (C-W-R) evaluation indicator system is established, considering supply risk from a multi-proximity perspective which is tightly tied to collaborative innovation performance, only considered from geographical proximity in previous supplier selection research. Then a hybrid fuzzy-symmetrical multicriteria decision-making (MCDM) model is proposed that integrates fuzzy linguistic sets, best–worst method (BWM), prospect theory (PT) and VIKOR. With this approach, a final ranking is obtained for innovative supplier selection by NEV manufacturers in China. Moreover, sensitivity analysis and comparison analysis illustrate the proposed decision framework's effectiveness and reliability and dig deep into the buyer−supplier collaborative innovation. Finally, some managerial suggestions are given for supplier selection from the standpoint of NEV manufacturers. [ABSTRACT FROM AUTHOR]

A notch-induced high-speed splitting method was developed for high-quality cropping of metal bars using a new type of electric-pneumatic counter hammer. Theoretical equations and FE models were established to reveal the crack initiation and fracture mode. Comparative tests were conducted for notched and unnotched bars of four types of steels, i.e., AISI 1020, 1045, 52100, and 304, and the section quality and microfracture mechanism were further investigated. The results show that damage initiates at the bilateral notch tips with peak equivalent plastic strain, and propagates through the plane induced by the notch tip; the stress triaxiality varies as a quasi-sine curve, revealing that the material is subjected to pure shearing at the notch tip, and under compression at the adjacent region. High precision chamfered billets were obtained with roundness errors of 1.1–2.8%, bending deflections of 0.5–1.5mm, and angles of inclination of 0.7°–3.4°. Additionally, the notch effectively reduced the maximum impact force by 21.6–23.9%, splitting displacement by 7.6–18.6%, and impact energy by 27.8–39.1%. The crack initiation zone displayed quasi-parabolic shallow dimples due to shear stress, and the pinning effect was larger in AISI 52100 and 1045 steel; the final rupture zone was characterized by less elongated and quasi-equiaxial deeper dimples due to the combination of shear and normal stress. [ABSTRACT FROM AUTHOR]

Abstract Let F q be a finite field with q elements and n a positive integer. Martínez, Vergara and Oliveira (Des. Codes Cryptogr. 77 (1): 277–286, 2015) explicitly factorized x n − 1 over F q under the condition of r a d (n) | (q − 1). In this paper, we factorize x n − 1 into irreducible factors in F q [ x ] and count the number of its irreducible factors when r a d (n) ∤ (q − 1) , r a d (n) | (q w − 1) , and w is a prime. [ABSTRACT FROM AUTHOR]

Permutation trinomials of the form x r h ( x 2 m − 1 ) over F 2 2 m are investigated in this paper, which is a further study on a recent work of Gupta and Sharma. Based on some bijections over the unit circle of F 2 2 m with order 2 m + 1 , the two conjectures proposed by Gupta and Sharma are confirmed and several new permutation trinomials are presented. [ABSTRACT FROM AUTHOR]

Efficient finite field multiplication is crucial for implementing public key cryptosystem. To achieve this, multipliers using Gaussian normal basis have been widely explored in previous works. In this paper, based on proposed Gaussian normal basis Montgomery (GNBM) representation, a semi-systolic even-type GNBM multiplier is developed. Analysis shows that the proposed architecture saves about 57 percent space complexity and 50 percent time complexity when compared with the only existing semi-systolic even-type GNB multiplier. Moreover, due to properties of regularity and modularity, the proposed multiplier is very suitable for VLSI implementation. [ABSTRACT FROM AUTHOR]

Highlights: [•] A novel open-die warm extrusion process of spline shaft with 42CrMo steel is proposed. [•] 42CrMo steel’s material characteristic during the warm forming process is studied. [•] An optimum die angle of entrance section on extrusion die is established. [•] An optimum warm forming temperature during the warm extrusion process is established. [•] The tooth divided flow method is employed to improve the warm extrusion process. [Copyright &y& Elsevier]

In this paper, we present some necessary and sufficient conditions under which an irreducible polynomial is self-reciprocal (SR) or self-conjugate-reciprocal (SCR). By these characterizations, we obtain some enumeration formulas of SR and SCR irreducible factors of x n − λ , λ ∈ F q ⁎ , over F q , which are just open questions posed by Boripan et al. (2019). We also count the numbers of Euclidean and Hermitian LCD constacyclic codes and show some well-known results on Euclidean and Hermitian self-dual constacyclic codes in a simple and direct way. [ABSTRACT FROM AUTHOR]