基于伺服运动系统的三步非线性控制方法

为了提高伺服运动系统的瞬态性能,加快系统的响应速度,获得更优的轨迹跟踪效果,本文提出了伺服运动系统三步非线性控制方法。首先假定伺服运动系统达到稳定状态,求得类稳态控制律;其次考虑参考目标的动态变化,求出前馈控制律;接着利用参考目标与实际输出之间的差值设计误差反馈控制律,最后通过仿真验证了所提方法的有效性。

探讨三轨道五阶梯式层级体系在外科护士管理中的应用效果

目的分析三轨道五阶梯式层级体系在外科护士管理中的应用效果。方法选取2022年2月—2023年2月滨州医学院附属医院60名外科护士为研究对象,按照管理模式不同,分为对照组(常规管理)和观察组(三轨道五阶梯式层级体系管理),各30名。比较两组自我效能感、业务素质、职业决策自我效能。结果观察组自我效能感综合量表总分为(138.50±8.30)分,高于对照组的(130.50±6.30)分,差异有统计学意义(t=4.205,P<0.05)。观察组业务素质评分、职业决策自我效能评分高于对照组,差异有统计学意义(P均<0.05)。结论三轨道五阶梯式层级体系与常规管理模式相比,可提高外科护士的业务素质,提高自我效能。

三段式通识教育体系的实践探索与思考

建设教育强国,造就拔尖创新人才是我国高等教育发展的未来方向。“通识教育”重在培养综合素养能力,顺应高等教育发展趋势,正越来越成为人才培养改革的热点。担负着发展航空航天事业使命的B大学,紧跟国家战略需求调整育人模式。从21世纪初B大学经过科学试点、有序推进,最终形成三段式本科通识教育体系,即大类通识培养阶段、专业基础培养阶段与研究能力培养阶段结合。其中在大类培养阶段,以书院制育人与课堂教育结合强化通识教育,塑造基本科学研究思维;在专业基础培养阶段,培养跨学科知识结构和思维方式;在研究能力培养阶段,将科学前沿和交叉学科融合,培养科研能力;通过三阶段结合,创新人才培养效果显著。该文深入分析B大学通识教育实践过程中取得的成果和仍面临的困境,思考如何在新时代高质量人才培养的背景下更加突出B大学特色,进一步升级现有通识教育体系。

装备制造业智能工厂标准体系构建研究

标准体系构建是实现智能制造及建设智能工厂的重要技术基础。本文依据装备制造业智能工厂狭义概念范围,提出构建智能工厂系统架构、构建标准体系框架、制定标准规范的“三步法”标准体系构建方法,并给出了参考的应用实例,对于指导智能工厂建设具有一定借鉴意义。

Enhancing corrosion resistance of 7150 Al alloy using novel three-step aging process

The effects of a novel three-step aging process （T76＋T6） on the electrochemical corrosion behavior of 7150 extruded aluminum alloy were evaluated and compared with those of the conventional retrogression and re-aging process （T77）. The open circuit potential （OCP）, cyclic polarization and electrochemical impedance spectra （EIS） of the A1 alloys were measured after treatment in three solutions （3.5% NaCl （mass fraction）; 10 mmol/L NaCl ＋ 0.1 mol/L Na2SO4; 4 mol/L NaCl ＋ 0.5 mol/L KNO3 ＋ 0.1 mol/L HNO3）. The parameters including the corrosion potential, pitting potential, pit transition potential and steepness, and potential differences were extensively discussed to evaluate the corrosion behavior of the Al alloys. The electrochemical and scanning electron microscopy （SEM） data show that compared with the 7150-T77 Al alloy, the T76 ＋ T6 aged 7150 A1 alloy exhibits better resistance to pitting corrosion, inter-granular corrosion （IGC） and exfoliation corrosion, which is attributed to further coarsening and inter-spacing of the grain boundary particles （GBPs） as revealed by transmission electron microscopy. Furthermore, the hardness tests indicate that an attractive combination of strength and corrosion resistance was obtained for the 7150 Al alloy with T76 ＋ T6 treatment.

Effect of three-step homogenization on microstructure and properties of 7N01 aluminum alloys

The effect of different homogenization treatments on the microstructure and properties of the 7N01 aluminum alloy was investigated using hardness measurements, electrical conductivity measurements, tensile and slow strain rate tests, electron probe microanalysis, optical microscopy, scanning electron microscopy, and transmission electron microscopy. The results revealed that three-step homogenization improved the uniformity of Zr distribution by eliminating segregation of the main alloying elements. During the second homogenization step at 350 °C for 10 h, coarse and strip-like equilibrium η phases formed which assisted the nucleation of Al3Zr dispersoids and reduced the width of the precipitate-free zone of A13Zr dispersoids. As a result, coarse recrystallization was greatly reduced after homogenization at 200 °C, 2 h ＋ 350 °C, 10 h ＋ 470 °C, 12 h, which contributed to improving the overall properties of the 7N01 aluminum alloys.

Effect of a novel three-step aging on strength, stress corrosion cracking and microstructure of AA7085

The influence of a novel three-step aging on strength, stress corrosion cracking(SCC) and microstructure of AA7085 was investigated by tensile testing and slow strain rate testing combined with transmission electron microscopy(TEM). The results indicate that with the increase of second-step aging time of two-step aging, the mechanical properties increase first and then decrease, while the SCC resistance increases. Compared with two-step aging, three-step aging treatment improves SCC resistance and the strength increases by about 5%. The effects of novel three-step aging on strength and SCC resistance are explained by the role of matrix precipitates and grain boundary precipitates, respectively.

Short-term efficacy of robotic and laparoscopic spleen-preserving splenic hilar lymphadenectomy via Huang’s three-step maneuver for advanced upper gastric cancer: Results from a propensity scorematched study

BACKGROUND Robotic surgery has been considered to be significantly better than laparoscopic surgery for complicated procedures.AIM To explore the short-term effect of robotic and laparoscopic spleen-preserving splenic hilar lymphadenectomy(SPSHL)for advanced gastric cancer(GC)by Huang’s three-step maneuver.METHODS A total of 643 patients who underwent SPSHL were recruited from April 2012 to July 2017,including 35 patients who underwent robotic SPSHL(RSPSHL)and 608 who underwent laparoscopic SPSHL(LSPSHL).One-to-four propensity score matching was used to analyze the differences in clinical data between patients who underwent robotic SPSHL and those who underwent laparoscopic SPSHL.RESULTS In all,175 patients were matched,including 35 patients who underwent RSPSHL and 140 who underwent LSPSHL.After matching,there were no significant differences detected in the baseline characteristics between the two groups.Significant differences in total operative time,estimated blood loss(EBL),splenic hilar blood loss(SHBL),splenic hilar dissection time(SHDT),and splenic trunk dissection time were evident between these groups(P<0.05).Furthermore,no significant differences were observed between the two groups in the overall noncompliance rate of lymph node(LN)dissection(62.9%vs 60%,P=0.757),number of retrieved No.10 LNs(3.1±1.4 vs 3.3±2.5,P=0.650),total number of examined LNs(37.8±13.1 vs 40.6±13.6,P=0.274),and postoperative complications(14.3%vs 17.9%,P=0.616).A stratified analysis that divided the patients receiving RSPSHL into an early group(EG)and a late group(LG)revealed that the LG experienced obvious improvements in SHDT and length of stay compared with the EG(P<0.05).Logistic regression showed that robotic surgery was a significantly protective factor against both SHBL and SHDT(P<0.05).CONCLUSION RSPSHL is safe and feasible,especially after overcoming the early learning curve,as this procedure results in a radical curative effect equivalent to that of LSPSHL.

Auxiliary principle and three-step iterative algorithms for generalized set-valued strongly nonlinear mixed variational-like inequalities

An auxiliary principle technique to study a class of generalized set-valued strongly nonlinear mixed variational-like inequalities is extended. The existence and uniqueness of the solution of the auxiliary problem for the generalized set-valued strongly nonlinear mixed variational-like inequalities are proved, a novel and innovative three-step iterative algorithm to compute approximate solution is constructed, and the existence of the solution of the generalized set-valued strongly nonlinear mixed variational-like inequality is shown using the auxiliary principle iterative sequences generated by the algorithm technique. The convergence of three-step is also proved.

ZnO micro-nano composite hydrophobic film prepared by the three-step method

The hydrophobicity of the lotus leaf is mainly due to its surface micro-nano composite structure. In order to mimic the lotus structure, ZnO micro-nano composite hydrophobic films were prepared via the three-step method. On thin buffer films of SiO2, which were first fabricated on glass substrates by the so,gel dip-coating method, a ZnO seed layer was deposited via RF magnetron sputtering. Then two different ZnO films, micro-nano and micro-only flowerlike structures, were grown by the hydrothermal method. The prepared films have different hydrophobic properties after surface modification. The structures of the obtained ZnO films were characterized using x-ray diffraction and field-emission scanning electron microscopy. A conclusion that a micro-nano composite structure is more beneficial to hydrophobicity than a micro-only structure was obtained through research into the effect of structure on hydrophobic properties.

Three-step acupuncture and cupping therapy:an effective approach to treat cervicogenic headache

As early as 1983,Sjaastad proposed the concept of cervicogenic headache(CH)in the World Headache Conference,that is,the pain from upper cervical joints and muscles can be referred to the head.CH is a group of syndromes mainly caused by dysfunction of the upper cervical spine and its component muscles,ligaments,bony,vertebral arteries and/or soft tissue elements,usually not accompanied by neck pain.Therefore,the treatment strategy of CH focuses on pain relief and repair cervical lesions.Patients with painful disorders of upper cervical zygapophysial joints showed significant headache relief after directly treated at disordered cervical joints[1].

Three-Step Difference Scheme for Solving Nonlinear Time-Evolution Partial Differential Equations

In this paper, a special three-step difference scheme is applied to the solution of nonlinear time-evolution equations, whose coefficients are determined according to accuracy constraints, necessary conditions of square conservation, and historical observation information under the linear supposition. As in the linear case, the schemes also have obvious superiority in overall performance in the nonlinear case compared with traditional finite difference schemes, e.g., the leapfrog(LF) scheme and the complete square conservation difference(CSCD) scheme that do not use historical observations in determining their coefficients, and the retrospective time integration(RTI) scheme that does not consider compatibility and square conservation. Ideal numerical experiments using the one-dimensional nonlinear advection equation with an exact solution show that this three-step scheme minimizes its root mean square error(RMSE) during the first 2500 integration steps when no shock waves occur in the exact solution, while the RTI scheme outperforms the LF scheme and CSCD scheme only in the first 1000 steps and then becomes the worst in terms of RMSE up to the 2500th step. It is concluded that reasonable consideration of accuracy, square conservation, and historical observations is also critical for good performance of a finite difference scheme for solving nonlinear equations.

General Convergence Analysis for Three-step Projection Methods and Applications to Variational Problems

First a general model for a three-step projection method is introduced, and second it has been applied to the approximation solvability of a system of nonlinear variational inequality problems in a Hilbert space setting. Let H be a real Hilbert space and K be a nonempty closed convex subset of H. For arbitrarily chosen initial points x0, y0, z0 ∈ K, compute sequences xn, yn, zn such thatT ： K→ H is a nonlinear mapping onto K. At last three-step models are applied to some variational inequality problems.

JOINT RANDOM OPTIMIZED THREE-STEP SEARCH ALGORITHM BASED-ON GRAY AND CHROMATIC INFORMATION

In this letter, an improved three-step search algorithm is presented, which uses both gray and chromatic information to boost the performance with random optimization and converge the motion vectors to global optima. Experimental results show that this algorithm can efficiently improve the PSNR after motion compensation.

A new three-step procedure for pancreatic head carcinoma with invasion of superior mesenteric artery

Pancreatic head carcinoma is characterized by high malignancy and a low survival rate and its mortality ranks fourth for malignant tumors with a 5-year survival rate of only 5%[1].Treatment of this cancer relies on surgical resection.However,the resection rate is only about 20%,because majority of the patients are classified as unresectable when diagnosed due to distant metastasis or

基于三步法的板球系统滑模控制器研究

为解决非线性板球系统滑模控制中出现的抖振现象以及轨迹跟踪过程中多扰动问题,提出了一种基于三步法的滑模控制方案。首先,建立板球系统状态空间模型,设计滑模控制律克服系统存在的不确定性扰动;其次,将三步法控制规律与滑模控制算法相结合,设计三步法滑模控制器,避免了滑模控制中存在的抖振现象;最后,通过李雅普诺夫函数证明了闭环控制系统的稳定性。对比仿真实验结果进一步验证该方法在轨迹跟踪控制中的有效性。

基于三步法的二级倒立摆系统研究

【目的】为解决二级倒立摆系统非线性和强耦合问题,获得更好的稳定性和控制性,本研究设计一种基于三步法的控制器。【方法】建立二级倒立摆系统的状态空间模型,并划分为三个子系统。按照三步法控制器的设计步骤,对二级倒立摆子系统进行控制器设计,避免倒立摆系统在整体分析时出现耦合问题。【结果】通过李雅普诺夫函数证明了该控制器的稳定性。【结论】仿真结果证明,该控制器在二级倒立摆系统稳定控制中的有效性,具有更小的超调和平稳的响应过程。

检察机关员额制改革的反思

检察机关员额制改革虽已进入“后员额”的稳定时期,但其中存在的问题也值得反思。反思之一在于,“办案”定义的教义学缺失,导致围绕“办案”所划分的部门和人员存在逻辑悖论,既非办案,何来员额;既非员额,为何办案。反思之二在于,检察官助理角色定位模糊,检察官助理办案面临“代为履行”与“代位履行”的两难处遇,“助理办案、检察官批案”俨然成为新的审批层级。反思之三在于,检察官助理上升渠道的天花板现象已经显现,现行《检察官法》给检察官助理带来了多重影响。人员分类可由“三分法”走向“四分法”,员额检察官职权不能由检察官助理“代位履行”,同时可创新检察官助理“三阶式”培养机制,建立动态员额调整机制,实现检察机关员额制改革的长远成效。

地面自动站观测资料三级质量控制业务系统的研制

随着我国气象台站地面自动气象观测系统的逐步布设,地面自动站观测资料质量控制系统的研制亦成为业务急需。2004年开始,研制由台站,到省级、国家级资料部门的地面自动站观测资料三级质量控制业务系统。各级质量控制系统融合了自动控制技术和交互式应用技术,允许在必要时对疑误资料进行详细的人工分析、判断与修正。文章介绍了整个质量控制系统的业务流程设置、质量控制技术以及质量控制信息。

三级串联人工快渗系统处理养殖废水

人工快速渗滤系统(constructed rapid infiltration,CRI)是在传统的污水快速渗透系统上发展起来的一种新的生物处理方法。采用猪粪浸泡污水模拟实际猪场处理系统的厌氧出水,研究三级串联人工快渗系统对其污染物的去除效果。试验结果表明,三级串联系统对废水COD、NH3-N的去除率稳定在81%和94.5%,出水均满足了《畜禽养殖行业污染物排放标准》(GB18596-2001)的要求,同时三级串联系统还可以有效预防系统的堵塞。