As the semiconductor technology node continues to shrink, achieving smaller critical dimension in lithography becomes increasingly challenging. Negative tone development (NTD) process is widely employed in advanced node due to their large process window. However, the unique characteristics of NTD, such as shrinkage effect, make the NTD resist model calibration more complex. Gradient descent (GD) and heuristic methods have been applied for calibration of NTD resist model. Nevertheless, these methods depend on initial parameter selection and tend to fall into local optima, resulting in poor accuracy of the NTD model and massive computational time. In this paper, we propose cluster sampling and scalable Bayesian optimization (BO) with constraints method for NTD resist model calibration. This approach utilizes cluster sampling strategy to enhance the capability for global initial sampling and employs scalable BO with constraints for global optimization of high-dimensional parameter space. With this approach, the calibration accuracy is significantly enhanced in comparison with results from GD and heuristic methods, and the computational efficiency is substantially improved compared with GD. By gearing up cluster sampling strategy and scalable BO with constraints, this method offers a new and efficient resist model calibration.
In this paper, the main purpose is to study how to reduce PAPR in the OFDM-IM system. According to some methods used in the OFDM system, have a further exploration analysis in OFDM-IM system. Firstly, it is about the OFDM-IM system introduction and the effect of PAPR on the OFDM-IM system. Secondly, SLM and PTS are studied in many aspects in the direction of OFDM, like the choice of phase and subcarrier grouping patterns. When phase factor is {1, -1}, the method used in OFDM is borrowed in PTS to improve the calculation time of results in the OFDM-IM system. In addition, the comparative analysis of PAPR under the combination of SLM-PTS and SLM-PTS methods is also studied. It can be concluded that the new method combines the characteristics of both, and its running time is less than that of traditional PTS and the performance of PAPR is less than that of traditional single SLM.
The new development in sublattice-phase-resolved imaging of an electronic structure now allows for the visualization of the nematic-order state characteristic energy of cuprate superconductors in a wide doping regime. However, it is still unclear how this characteristic energy of the nematic-order state is correlated with the enhancement of superconductivity. Here the doping dependence of the nematic-order state characteristic energy in cuprate superconductors and of its possible connection to the enhancement of superconductivity is investigated within the framework of the kinetic-energy-driven superconductivity. It is shown that the characteristic energy of the nematic-order state is found to be particularly large in the underdoped regime, then it smoothly decreases upon the increase of doping, in full agreement with the corresponding experimental observations. Moreover, the characteristic energy of the nematic-order state as a function of the nematic-order state strength in the underdoped regime presents a similar behavior of the superconducting transition temperature. This suggests a possible connection between the nematic-order state characteristic energy and the enhancement of the superconductivity.
In the calculation of process dimensions in the machining of porous parts, the traditional method is complicated in the establishment of the dimensional chain, it is easy to make mistakes in the judgment of increasing and decreasing loops, and there is difficulty in the calculation process; thus, this paper puts forward a method that combines the process path with the design path to analyze the hole system dimensions in response to these problems. First of all, the combination of the process path and design path is used to establish a system of vector equations and, according to the system of vector equations, to establish a matrix model to calculate the process dimensions based on the system of vector equations to construct the process dimensional chain and the dimensional chain function; then, the principle of differentiation is used to carry out a tolerance analysis of the process dimensions, which avoids the drawing of dimensional chain diagrams and the judgement of the incremental/decremental loops. Finally, the development of a process dimension analysis tool for hole system dimensions is completed based on CATIA CAA. In order to verify the effectiveness of the proposed method, the analysis tool was used to solve the three labeling methods of the hole system dimensions of porous parts and compared with the results calculated using the traditional method, and it was found that some of the tolerance results obtained by the proposed method were enlarged by about 50%, which is more in line with the actual production situation. Finally, in order to verify the accuracy of the tool’s calculation results, three porous parts were machined according to the process dimensions and tolerances calculated by the tool, and the center distance of each hole was measured by a coordinate meter. These measurements were compared and analyzed with the design dimensions specified in the engineering drawings, and it was found that the center distances of the holes were in full compliance with the design requirements.
Two-dimensional (2D) Janus transitional-metal dichalcogenides (TMDCs) have great potential for photocatalytic water splitting due to their novel properties induced by the unique out-of-plane asymmetric structures. Here, we systematically investigate the geometric, electronic, and optical properties of 2D Janus MoSSe with titanium doping and vacancies to explore their synergistic effects on photocatalytic activity. We find that there is effective attraction between the substituted or adsorbed Ti atoms and S/Se vacancies. The Ti adatoms dramatically extend the light absorption range to the infrared region. The S/Se vacancies coexisting with Ti adatoms will modulate the transition of photoexcited electrons, thereby enhancing sunlight absorption. The Ti adatoms either existing alone or coexisting with vacancies introduce smaller lattice distortion compared with substituted Ti atoms, and these Ti adatoms induce smaller effective mass of charge carriers. The configuration of S vacancy coexisting with Ti adatoms on the Se surface exhibits the most significant synergistic effects and the best overall photocatalytic performance. Our work reveals the mechanisms and effects induced by doping and vacancies coexisting in 2D Janus TMDCs and also proposes a new practical strategy to improve the performance of 2D photocatalysts.
Mono-metal phosphorus trichalcogenides (MPX3) have attracted intensive interest due to their intriguing magnetic properties and potential applications. Generally, single-layer two-dimensional (2D) MPX3 are believed to be centrosymmetric. However, we discovered that unexpected spontaneous symmetry breaking may occur in some 2D MPX3, i.e., vertical P-P dimers move out of the plane and become tilted, leading to the structural stability being enhanced, the inversion symmetry being simultaneously broken, and ferroelectricity or ferroelasticity emerging. By systematically investigating the family (176) of 2D MPX3, we found that 34 members undergo such symmetry breaking during geometric optimization, in which ten are identified to be dynamically stable. We show that the mismatch between the triangular sublattice of P-P dimers and the hexagonal sublattice of M atoms and the variable accommodation of P lone-pair electrons in different valence states of M atoms play dominant roles in the inversion symmetry breaking and the emergence of ferroicity. We obtained a ferroic atlas of the whole 2D MPX3 family, which also includes many stable antiferromagnetic and non-ferroic members that have never been reported. Our work not only presents ferroelectricity in the 2D MPX3 family but also reveals how diverse ferroicity emerges with various spontaneous symmetry breakings, which will be helpful for further exploration of 2D ferroic materials.
Molecules with precise sultine structures are particularly sought after since the function of a molecule depends on this interesting structure. Despite the positive pivotal significance of the sultines in synthesis, medicine, and materials science, the sultines' chemistry long remains unexplored due to their inaccessibility; only very limited protocols have been developed. Here, we report an energy-transfer-powered intramolecular radical–radical cross-coupling cyclization for the practical and atom-economical assembly of otherwise challenging-to-access sultines under mild and operationally simple conditions using an inexpensive organic photocatalyst. Importantly, this work presents a practical method of trifluoromethyl radical generation from alkyl trifluoromethanesulfinate, and the obtained sultines were confirmed as promising electrolyte additives for high-voltage lithium batteries employing LiNi0.5Mn1.5O4 cathodes and carbonate electrolytes. Sultines were applied to build highly valuable sultones, mercaptoalkanols, and disulfides. Mechanistic studies and density functional theory calculations supported that the reaction likely proceeds through an energy-transfer-powered radical–radical cross-coupling cyclization process.
A structurally stable carbon allotrope with plentiful topological properties is predicted by means of first-principles calculations. This novel carbon allotrope possesses the simple space group $C2/m$, and contains simultaneously $sp$, $sp^2$ and $sp^3$ hybridized bonds in one structure, which is thus coined as \textit{carboneyane}. The calculations on geometrical, vibrational, and electronic properties reveal that carboneyane, with good ductility and a much lower density 1.43 $g/cm^{3}$, is a topological metal with two types of Weyl points, nodal loops and nodal network. By comparing its x-ray diffraction pattern with experimental results, we find that carboneyane might already exist in detonation soot. On account of the fluffy structure, carboneyane is shown to have potential applications in areas of storage, absorption and electrode materials.
In this paper, we study how mobility affects mobile data accounting, which records the usage volume for each roaming user. We find out that, current 2G/3G/4G systems have well-tested mobility support solutions and generally work well. However, under certain biased, less common yet possible scenarios, accounting gap between the operator's log and the user's observation indeed exists. The gap can be as large as 69.6% in our road tests. We further discover that the root causes are diversified. In addition to the no-signal case reported in the prior work [23], they also include handoffs, as well as insufficient coverage of hybrid 2G/3G/4G systems. Inter-system handoffs (that migrate user devices between radio access technologies of 2G, 3G, and 4G) may incur non-negligible accounting discrepancy.
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