During the drilling process of the top rock layer with a roof bolter, monitoring certain resultant signals can provide feedback on different rock lithology and thickness parameters of the roof, which ...can optimize support parameters and evaluate the risk of roof fall. This study analyzed and studied the complexity feedback degree of individual indexes (thrust, torque, and propulsion speed) and specific energy index for revealing different rocks while maintaining a certain rotation rate, in order to provide basic data reference and obtain more optimized feedback indexes for measurement-while-drilling (MWD) technology of roof bolter. More importantly, the study analyzed and discussed the composition and feedback degree of torque energy and thrust energy in the specific energy index based on measured feedback level analysis. The results showed that the feedback of torque energy was relatively better and its weight for indicator contribution should be increased, which can provide a basis for optimizing the specific energy index in the later stage.
A pot experiment using root separation technique was conducted to further understand the effect of root interaction played in intercropping system under different nitrogen levels. The results showed ...that root interaction and increasing N application increased the green leaf area per plant and chlorophyll content of soybean, but their effects gradually decreased with increasing N fertilization level. Root interaction and increasing N application can improve photosynthetic characteristics of soybean, but root interaction only had a significant effect under low N level. The number of bacteria, fungi, actinomycetes and Azotobacteria was also obviously affected by root interaction and N fertilization, and the number of Azotobacteria presented a changing trend of first increased and then decreased with increasing N fertilization level. Root interaction and increasing N application improved soybean yield and its components, but their effects gradually decreased with increasing N fertilization level. The root activity of soybean was obviously affected by root interaction, and was significantly positively correlated with green leaf area per plant, chlorophyll content, photosynthetic rate and economic yield per plant. Our results indicate that the advantage effect of root interaction and increasing N application will be partially inhibited with an increasing N fertilization level.
The efficiency of a cryptographic algorithm in terms of security depends on the resistance against cryptanalytic attacks. Besides the complexity of the encryption algorithm, the key plays an ...essential role in the security against cryptanalytic attacks. The strength and complexity of the encryption algorithm do not suffice and serve the fundamental purpose of security if the key is compromised at any stage. So, apart from the cryptanalytically robust encryption algorithm, a strong key schedule is also essential to thwart possible attacks against a particular algorithm. PRESENT, a lightweight encryption technique with a simple design, is resistant to linear and differential attacks but has a weak key schedule and is susceptible to cryptanalytic attacks. This paper proposes an efficient key scheduling algorithm for PRESENT lightweight encryption technique resistant against cryptanalytic attacks. Statistical tests examine the proposed key schedule's cryptographic strength on the properties of subkeys produced in the key generation mechanism. The tests prove the efficiency of the proposed key schedule in terms of cryptanalytic attacks. Implementation and comparison of the efficacy of the proposed key schedule in terms of security and implementation costs are illustrated with the PRESENT-80 key schedule and the PRESENT-128 key schedule. The key scheduling algorithm is implemented on the ARM Cortex M3-based NXP LPC 1857 and 1768 hardware development platforms. The results indicate the efficiency of the proposed algorithm in terms of security, performance, and power consumption across the two hardware platforms.
Sulfur dioxide is a colorless gas with strong pungent odor, and prolonged inhalation can damage the respiratory system and heart. Precise measurement of sulfur dioxide is very important for the human ...health. While the current sulfur dioxide sensor works at a high temperature and is easily interfered by humidity. Therefore, in this work, we used solution method to coat perovskite nanocrystals Cs 3 Cu 2 I 5 with metal oxides Fe 2 O 3 , and obtained the room-temperature sulfur dioxide gas-sensitive materials Cs 3 Cu 2 I 5 @Fe 2 O 3 nanocrystals. Meanwhile, combined with machine learning, the sensor has the ability of self-calibrating under different humidity environment, realizing the high precision and anti-interference measurement of sulfur dioxide. In addition, in this structure, the coating Fe 2 O 3 not only helps to improve water stability, but also transfer the interaction of sulfur dioxide to the inner Cs 3 Cu 2 I 5 , and lower the gas-sensitive temperature to room temperature. The response/recovery time of the sulfur dioxide sensor based on Cs 3 Cu 2 I 5 @Fe 2 O 3 is 31/816 s, and the sensitivity is 0.19 at 10 ppm. Then, intelligent classification algorithm was used for recognition, and the accurate recognition rate was up to 95.0%. Furthermore, density functional theory was implemented to reveal the gas-sensitive mechanism that sulfur dioxide was adsorbed by Cs 3 Cu 2 I 5 @Fe 2 O 3 nanocrystals, the good response was attributed to the band structure changes significantly, and the hybridization of electron orbitals was appeared between gas and nanocrystals. We believe that the sensor will have potential in sulfur dioxide, and the idea of using machine learning to intelligent eliminate humidity interference can also be extended to other gas sensor.
Yager's q -rung orthopair fuzzy set is a generalization of fuzzy sets, whose prominent feature is that the q th power sum of the membership and the nonmembership degrees is equal to or less than one, ...and we call its core, an ordered pair, q -rung orthopair fuzzy number ( q -ROFN). More recently, the scholars have constructed the q -rung orthopair fuzzy calculus ( q -ROFC), which can effectively deal with continuous q -rung orthopair fuzzy information. Nevertheless, the q -ROFC is only based on the basic operational laws of the q -ROFNs, in fuzzy theory, Archimedean t-norms and t-conorms (ATTs) are a significant class of continuous triangular norms and conorms, which are the generalizations of the intersection and union related to fuzzy sets. Thus, in order to extend the q -ROFC to a wider area, in this article, we systematically discuss the q -rung orthopair fuzzy double integrals ( q -ROFDIs) in the frame of ATTs. First, we construct the q -ROFDI in the frame of Archimedean t-conorms in detail, and then provide its concrete value. In addition, we reveal the relationships with respect to two types of q -rung orthopair fuzzy spaces. Based on which, we can easily obtain another types of q -ROFDI. After that, we investigate their fundamental properties in detail so as to comprehend these kinds of q -ROFDIs in-depth. Finally, we point out the essences of these kinds of q -ROFDIs, on the basis of which we provide a practical application to show their effectiveness and elasticity via comparing with the existing methods.
In the conventional sense, a passive intelligent reflecting surface (IRS) is perceived as an ideal phase shifter to the incident signal. It is assumed that the phase of the incident signal can be ...altered to any desired value without affecting its magnitude. In this paper, we question the veracity of this assumption which forms the basis for the communication model that is widely used in the scientific community. Although there exist rigorous electromagnetic (EM) based models to analyze and design metasurfaces, the same cannot be said about its successor, intelligent reflecting surface. Therefore, we attempt to present an EM-based model that accurately describes intelligent scattering by any arbitrary-shaped IRS. Our objective in this paper is to bridge the gap between the fundamental EM formulation for an IRS and the communication model that accurately captures its functioning. We use Method-of-Moments (MoM), a computational electromagnetic approach to quantify the intelligent scattering by an arbitrary-shaped IRS. The proposed theoretical model is then validated with computational EM simulation in Feko. We then adopt the general MoM-based model for a special case where each IRS element is a center-loaded wire. Closed-form expressions for pathloss and beamwidth are derived considering free space propagation. We show analytically and numerically, that the received power predicted by the conventional model vs. what is observed through computational EM simulations can differ by 6 dB. Furthermore, we demonstrate that the impact of optimizing an IRS using the conventional model, where each element is treated as an ideal passive phase shifter, can result in an additional 6 - 8 dB of power loss. As a final remark, we propose correction to the communication model that is currently used for IRS-aided networks when each IRS element is a center-loaded wire.
Several applications require low torque pulsations as they can lead to mechanical vibrations and acoustic noise in the electric motor. Optimization of the rotor permanent magnet (PM) shape is one of ...the effective methods for reducing torque pulsations. Unfortunately, the low versatility of the magnet fabrication technologies limits the development of new motor geometries. Cold spray additive manufacturing can be used for shaping permanent magnets for the direct fabrication of motor parts without the need for additional assembly steps. This fabrication technique allows an increase in the design flexibility of electric machine geometries targeting improved performance. This paper investigates the performance of permanent magnet rotors fabricated using a cold spray additive manufacturing technique for radial flux surface permanent magnet synchronous machines (SPMSM). The permanent magnet rotors considered are conventional rectangular-shaped with unskewed magnets (Model A), skewed magnets (Model B), and sinusoidal-petal shaped magnets (Model C) along the axial direction. The magnitude of magnetization current pulse required to magnetize these rotors is calculated and an impulse magnetizer setup is designed for in-situ magnetization. The performance of the shaped cold sprayed permanent magnet rotors and their effects on back EMF, electromagnetic torque, and cogging torque are analyzed experimentally and comparisons are made between the different rotor designs.
In this work, we report on achieving enhanced performance NiO<inline-formula> <tex-math notation="LaTeX">_{\textit{x}}</tex-math> </inline-formula>/beta gallium oxide (<inline-formula> <tex-math ...notation="LaTeX">\beta </tex-math> </inline-formula>-Ga<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> </inline-formula>O<inline-formula> <tex-math notation="LaTeX">_{\text{3}}</tex-math> </inline-formula>) heterojunction p-n diodes (HJDs) through synergistic interface engineering (SIE), which can greatly improve the electrical characteristics and interface characteristics of HJDs. It is shown that the NiO<inline-formula> <tex-math notation="LaTeX">_{\textit{x}}</tex-math> </inline-formula> surface undergoes morphological improvement and hole concentration enhancement after the UV/ozone treatment (UVO). Owing to the improved interfacial properties of Ni/NiO<inline-formula> <tex-math notation="LaTeX">_{\textit{x}}</tex-math> </inline-formula>, the forward conduction current of NiO<inline-formula> <tex-math notation="LaTeX">_{\textit{x}}</tex-math> </inline-formula>/<inline-formula> <tex-math notation="LaTeX">\beta </tex-math> </inline-formula>-Ga<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> </inline-formula>O<inline-formula> <tex-math notation="LaTeX">_{\text{3}}</tex-math> </inline-formula> HJD has significantly increased. Furthermore, the HJD performance can be improved by SIE with UVO and postannealing, especially for the reverse breakdown characteristics. Finally, a high-performance HJD without any terminal structure is obtained, which exhibits a low specific on-resistance of 2.47 m<inline-formula> <tex-math notation="LaTeX">\Omega \cdot</tex-math> </inline-formula>cm<inline-formula> <tex-math notation="LaTeX">^{\text{2}}</tex-math> </inline-formula> and a high breakdown voltage of 1355 V, yielding a high Baliga's figure of merit (BFOM) of 0.743 GW/cm<inline-formula> <tex-math notation="LaTeX">^{\text{2}}</tex-math> </inline-formula>, which is a 219.17% enhancement in performance compared to untreated device. This work offers a practical and effective strategy for developing advanced Ga<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> </inline-formula>O<inline-formula> <tex-math notation="LaTeX">_{\text{3}}</tex-math> </inline-formula> devices with exceptional performance metrics, paving the way for future technological breakthroughs.
As promising candidates for high-performance power system applications, gallium nitride high electron mobility transistors (GaN HEMTs) have received a lot of attention from the market. However, ...reliability issues, particularly the dynamic on -resistance ( dR <inline-formula><tex-math notation="LaTeX">_{\text{DS(ON)}}</tex-math></inline-formula>), also known as the current collapse effect, severely limit the promotion and application of GaN HEMTs. This article investigates and compares the dR <inline-formula><tex-math notation="LaTeX">_{\text{DS(ON)}}</tex-math></inline-formula> under various power cycle aging conditions for hybrid drain-embedded gate injection transistors (HD-GITs), which serve as representative devices of GaN HEMTs. For the purpose of this, HD-GITs are prepared using power cycling tests, and a voltage clamping circuit is employed to accurately measure the dR <inline-formula><tex-math notation="LaTeX">_{\text{DS(ON)}}</tex-math></inline-formula> during the switching applications in both the double-pulse test and the multipulse test. Experimental results demonstrate that, under certain conditions, the dR <inline-formula><tex-math notation="LaTeX">_{\text{DS(ON)}}</tex-math></inline-formula> of the device deteriorates as it ages. Furthermore, the primary mechanisms responsible for the deterioration of dR <inline-formula><tex-math notation="LaTeX">_{\text{DS(ON)}}</tex-math></inline-formula> characteristics under different aging states are discussed based on systematic electrical test results and reasonable inference. The finds are of great significance for guiding the design, manufacture, and application of GaN devices.
This article presents the design of a CMOS-based voltage-controlled oscillator (VCO) operating in both <inline-formula> <tex-math notation="LaTeX">V</tex-math> </inline-formula>-and <inline-formula> ...<tex-math notation="LaTeX">W</tex-math> </inline-formula>-bands by fully utilizing the harmonics in Class-F<inline-formula> <tex-math notation="LaTeX">_{23}</tex-math> </inline-formula> tank. An auxiliary common mode (CM) resonance is introduced to Class-F<inline-formula> <tex-math notation="LaTeX">_{23}</tex-math> </inline-formula> structure via a transformer for CM resonance expansion. This transformer serves dual functions, also generating the second harmonic output, thereby enhancing the area efficiency. The proposed CM resonance expansion suppresses the flicker noise upconversion in a widehband without manual harmonic tuning. A Class-F<inline-formula> <tex-math notation="LaTeX">_{23}</tex-math> </inline-formula> VCO without CM expansion is designed and fabricated for comparison. Besides, the challenges in high-frequency harmonic extraction are highlighted and addressed. The proposed VCO is fabricated using 40-nm CMOS technology. The frequency can cover from 69.92 to 73.84 GHz and from 104.88 to 110.75 GHz with tuning ranges of 5.7%. The measured <inline-formula> <tex-math notation="LaTeX">V</tex-math> </inline-formula>-and <inline-formula> <tex-math notation="LaTeX">W</tex-math> </inline-formula>-band phase noises (PNs) are <inline-formula> <tex-math notation="LaTeX">-</tex-math> </inline-formula>102.5 and <inline-formula> <tex-math notation="LaTeX">-</tex-math> </inline-formula>92.35 dBc/Hz at 1-MHz offset with figures of merit of <inline-formula> <tex-math notation="LaTeX">-</tex-math> </inline-formula>182.5 and <inline-formula> <tex-math notation="LaTeX">-</tex-math> </inline-formula>176 dBc/Hz, respectively. The power consumption is 44 mW in an area of 0.36 mm<inline-formula> <tex-math notation="LaTeX">^{2}</tex-math> </inline-formula>.
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