Real-time generation of circular patterns in electron beam lithography

Electron beam lithography(EBL)involves the transfer of a pattern onto the surface of a substrate byfirst scanning a thin layer of organicfilm(called resist)on the surface by a tightly focused and precisely controlled electron beam(exposure)and then selectively removing the exposed or nonexposed regions of the resist in a solvent(developing).It is widely used for fabrication of integrated cir-cuits,mask manufacturing,photoelectric device processing,and otherfields.The key to drawing circular patterns by EBL is the graphics production and control.In an EBL system,an embedded processor calculates and generates the trajectory coordinates for movement of the electron beam,and outputs the corresponding voltage signal through a digital-to-analog converter(DAC)to control a deflector that changes the position of the electron beam.Through this procedure,it is possible to guarantee the accuracy and real-time con-trol of electron beam scanning deflection.Existing EBL systems mostly use the method of polygonal approximation to expose circles.A circle is divided into several polygons,and the smaller the segmentation,the higher is the precision of the splicing circle.However,owing to the need to generate and scan each polygon separately,an increase in the number of segments will lead to a decrease in the overall lithography speed.In this paper,based on Bresenham’s circle algorithm and exploiting the capabilities of afield-programmable gate array and DAC,an improved real-time circle-producing algorithm is designed for EBL.The algorithm can directly generate cir-cular graphics coordinates such as those for a single circle,solid circle,solid ring,or concentric ring,and is able to effectively realizes deflection and scanning of the electron beam for circular graphics lithography.Compared with the polygonal approximation method,the improved algorithm exhibits improved precision and speed.At the same time,the point generation strategy is optimized to solve the blank pixel and pseudo-pixel problems that arise with Bresenham’s circle algorithm.A complete electron beam deflection system is established to carry out lithography experiments,the results of which show that the error between the exposure results and the preset pat-terns is at the nanometer level,indicating that the improved algorithm meets the requirements for real-time control and high precision of EBL.

Clinical research on Tai Chi:a review of health benefits

Tai Chi,a traditional Chinese martial art and health exercise,has gained significant global attention and recognition.The clinical benefits of Tai Chi have been studied extensively in recent decades.We conducted a systematic search of PubMed,Web of Science,EMBASE databases,and the China National Knowledge Infrastructure,identifying and reviewing 241 clinical trials on the benefits of Tai Chi from their inception to June 1,2023.Most of these studies have consistently demonstrated the positive impact of Tai Chi on balance,cognitive function,mood regulation,sleep quality,pain relief,cardiorespiratory function,and overall health.In the future,the key to fostering the ongoing development of this field lies in comprehensive research on standardized study designs and reporting,the scope of Tai Chi applications,and the core factors influencing its efficacy.

Lateral abutment pressure distribution and evolution in wide pillars under the first mining effect

The wide pillars are generally popular due to the high productivity and efficiency in Northwest China.The distribution of lateral abutment pressure in coal pillars is important for mining safety.To reveal the effect of the first mining on the lateral abutment pressure distribution and evolution in wide pillars,an in-situ experiment,theoretical analysis and numerical simulation were performed.First,the field monitoring of lateral abutment pressure was conducted from the perspective of time and space in the Chahasu Coal Mine,Huangling No.2 Coal Mine and Lingdong Coal Mine during the first mining.Based on the field monitoring stress,a theoretical model was proposed to reveal the lateral abutment pressure distribution.The methodology was demonstrated through a case study.Aiming at the distribution mechanism,a numerical experiment was conducted through the finite-discrete element method(FDEM).Last,field observations of borehole fractures were performed to further study the damage distribution.In addition,two types of lateral abutment pressure evolution with mining advance were discussed.Suggestions on the stress monitoring layout were proposed as well.The results could provide foundations for strata control and disaster prevention in wide pillars in underground coal mines.

Joint target assignment and power allocation in the netted C-MIMO radar when tracking multi-targets in the presence of self-defense blanket jamming

The netted radar system(NRS)has been proved to possess unique advantages in anti-jamming and improving target tracking performance.Effective resource management can greatly ensure the combat capability of the NRS.In this paper,based on the netted collocated multiple input multiple output(CMIMO)radar,an effective joint target assignment and power allocation(JTAPA)strategy for tracking multi-targets under self-defense blanket jamming is proposed.An architecture based on the distributed fusion is used in the radar network to estimate target state parameters.By deriving the predicted conditional Cramer-Rao lower bound(PC-CRLB)based on the obtained state estimation information,the objective function is formulated.To maximize the worst case tracking accuracy,the proposed JTAPA strategy implements an online target assignment and power allocation of all active nodes,subject to some resource constraints.Since the formulated JTAPA is non-convex,we propose an efficient two-step solution strategy.In terms of the simulation results,the proposed algorithm can effectively improve tracking performance in the worst case.

Resource-saving scheduling scheme for centralized target tracking in multiple radar system under automatic blanket jamming

This paper investigates the problem of Joint Radar Node Selection and Power Allocation(JRNSPA)in the Multiple Radar System(MRS)in the blanket jamming environment.Each radar node independently tracks moving target and subsequently transmits the raw observation data to the fusion center,which formulates a centralized tracking network structure.In order to establish a practical blanket jamming environment,we suppose that each target carries the self-defense jammer which automatically implements blanket jamming to the radar nodes that exceed the preset interception probability.Subsequently,the Predicted Conditional Cramer-Rao Lower Bound(PC-CRLB)is derived and utilized as the tracking accuracy criterion.Aimed at ensuring both the tracking performance and the Low Probability of Intercept(LPI)performance,the resource-saving scheduling model is formulated to minimize the transmit power consumption while meeting the requirements of tracking accuracy.Finally,the Modified Zoutendijk Method Of Feasible Directions(MZMFD)-based two-stage solution technique is adopted to solve the formulated non-convex optimization model.Simulation results show the effectiveness of the proposed JRNSPA scheme.

A survey of FPGA design for AI era

FPGA is an appealing platform to accelerate DNN.We survey a range of FPGA chip designs for AI.For DSP module,one type of design is to support low-precision operation,such as 9-bit or 4-bit multiplication.The other type of design of DSP is to support floating point multiply-accumulates(MACs),which guarantee high-accuracy of DNN.For ALM(adaptive logic module)module,one type of design is to support low-precision MACs,three modifications of ALM includes extra carry chain,or 4-bit adder,or shadow multipliers which increase the density of on-chip MAC operation.The other enhancement of ALM or CLB(configurable logic block)is to support BNN(binarized neural network)which is ultra-reduced precision version of DNN.For memory modules which can store weights and activations of DNN,three types of memory are proposed which are embedded memory,in-package HBM(high bandwidth memory)and off-chip memory interfaces,such as DDR4/5.Other designs are new architecture and specialized AI engine.Xilinx ACAP in 7 nm is the first industry adaptive compute acceleration platform.Its AI engine can provide up to 8X silicon compute density.Intel AgileX in 10 nm works coherently with Intel own CPU,which increase computation performance,reduced overhead and latency.

催化臭氧氧化降解水中有机污染物的研究进展

水污染是当前工业发展中亟待解决的问题之一,催化臭氧氧化降解有机污染物工艺具有绿色、高效和工艺简单的优点而被广泛应用,而其中的关键在于催化剂的选用。本研究对均相催化臭氧氧化和非均相催化臭氧氧化过程的机理进行了分析和总结,着重讨论了非均相催化臭氧氧化过程常采用的贵金属催化剂、过渡金属催化剂、碱土金属催化剂和非金属催化剂对臭氧氧化降解有机污染物的促进作用,对提高这些催化剂催化活性的方法进行了综述,总结了pH值、臭氧浓度、催化剂剂量和有机污染物浓度对催化臭氧氧化降解有机物过程的影响。指出目前催化臭氧氧化降解有机污染物过程面临的主要问题是活性组分的流失导致催化剂催化活性下降。在今后的研究中,开发和制备新型、高效、绿色、稳定的催化剂以及探究最佳工艺条件仍是研究的重点。可以通过提高催化剂的吸附能力以改善臭氧在水溶液中的传质,促进臭氧分子的分解,还可以通过不同活性组分的协同偶联有效抑制活性组分的流失,提高催化剂催化活性的同时提高催化剂的稳定性,以达到高效降解有机化合物的目的。要点:(1)分析并总结了均相/非均相催化臭氧氧化的机理。(2)总结了贵金属催化剂、过渡金属催化剂、碱土金属催化剂及非金属催化剂在催化臭氧氧化降解有机污染物方面的应用。(3)分析并总结了pH值、臭氧浓度、催化剂剂量和反应底物浓度对催化臭氧氧化过程的影响。(4)指出了未来新型催化剂的潜在的研究方向。

Acupuncture therapy for angina pectoris:a systematic review

OBJECTIVE： To assess the effectiveness and safety of acupuncture therapy for angina pectoris. METHODS： Randomized controlled trials （RCTs） concerned with acupuncture treatment of angina pectoris were identified by searching Academic Source Premier, MEDLINE, Science Citation Index Expanded, and three Chinese databases （China biol- ogy medicine database, China national knowledge infrastructure, and VlP database for Chinese techni- cal periodicals）. The valid data were extracted in ac- cordance with our inclusion and exclusion criteria. The main outcomes of the included studies were synthesized using Revman 5.1. RESULTS： Twenty-one articles on 16 individual studies were included and evaluated as having high or moderate risk of bias according to the stan- dards of the Cochrane Collaboration. Meta-analysis indicated that acupuncture combined with conven- tional drugs （ACCD） was superior to conventional drugs alone in reducing the incidence of acute myocardial infarction （AMI） [0R=0.18, 95%CI （0.04,0.84）, P=0.03]. Moreover, ACCD was superior to con- ventional drugs in the relief of angina symptoms [0R=4.23, 95%C/（2.73, 6..56）, P〈0.00001], and im- provement of electrocardiography （ECG） [0R=2.61, 95%C/（1.83, 3.73）, P〈0.00001]. Acupuncture by it- self was also superior to conventional drugs for angi- na symptoms [0R=3.59, 95%C/（1.76, 7.92）, P=0.0004] and ECG improvement [0R=3.07, 95%C/（1.54, 6.10）, P=0.001]. ACCD was superior to conventional drugs in shortening the time to onset of angina relief [WMD=-1.40, 95% CI （-1.65, -1.15）, P〈 0.00001]. However, the time to onset was signifi- cantly longer for acupuncture treatment than for conventional treatment alone [WMD=2A3, 95%O （1.63, 3.23）, P〈0.000 01]. CONCLUSION： ACCD reduced the occurrence of AMI, and both acupuncture and ACCD relieved an- gina symptoms and improved ECG. However, com- pared with conventional treatment, acupuncture showed a longer delay before its onset of action. This indicates that acupuncture is not suitable for emergency treatment of heart attack. Owing to the poor quality of the current evidence, the findings of this systematic review need to be verified by more RCTs to enhance statistical power.