A hybrid method integrating Green's function Monte Carlo and projected entangled pair states

This paper introduces a hybrid approach combining Green’s function Monte Carlo(GFMC)method with projected entangled pair state(PEPS)ansatz.This hybrid method regards PEPS as a trial state and a guiding wave function in GFMC.By leveraging PEPS’s proficiency in capturing quantum state entanglement and GFMC’s efficient parallel architecture,the hybrid method is well-suited for the accurate and efficient treatment of frustrated quantum spin systems.As a benchmark,we applied this approach to study the frustrated J_(1)–J_(2) Heisenberg model on a square lattice with periodic boundary conditions(PBCs).Compared with other numerical methods,our approach integrating PEPS and GFMC shows competitive accuracy in the performance of ground-state energy.This paper provides systematic and comprehensive discussion of the approach of our previous work[Phys.Rev.B 109235133(2024)].

Enhancing Private Healthcare Effectiveness in Lagos State, Nigeria: An Overview of the Effect of Quality Improvement Initiatives and Implications for Sustainable Healthcare Delivery

Background: Nigeria, a nation grappling with rapid population growth, economic intricacies, and complex healthcare challenges, particularly in Lagos State, the economic hub and most populous state, faces the challenge of ensuring quality healthcare access. The overview of the effect of quality improvement initiatives in this paper focuses on private healthcare providers in Lagos State, Nigeria. The study assesses the impact of donor-funded quality improvement projects on these private healthcare facilities. It explores the level of participation, perceived support, and tangible effects of the initiatives on healthcare delivery within private healthcare facilities. It also examines how these initiatives influence patient inflow and facility ratings, and bring about additional benefits and improvements, provides insights into the challenges faced by private healthcare providers in implementing quality improvement projects and elicits recommendations for improving the effectiveness of such initiatives. Methods: Qualitative research design was employed for in-depth exploration, utilizing semi-structured interviews. Private healthcare providers in Lagos involved in the SP4FP Quality Improvement Project were purposively sampled for diversity. Face-to-face interviews elicited insights into participation, perceived support, and project effects. Questions covered participation levels, support perception, changes observed, challenges faced, and recommendations. Thematic analysis identified recurring themes from interview transcripts. Adherence to ethical guidelines ensured participant confidentiality and informed consent. Results: Respondents affirmed active involvement in the SP4FP Quality Improvement Project, echoing literature emphasizing private-sector collaboration with the public sector. While acknowledging positive influences on facility ratings, respondents highlighted challenges within the broader Nigerian healthcare landscape affecting patient numbers. Respondents cited tangible improvements, particularly in staff management and patient care processes, validating the positive influence of quality improvement projects. Financial constraints emerged as a significant challenge, aligning with existing literature emphasizing the pragmatic difficulties faced by private healthcare providers. Conclusions: This study illuminates the complex landscape of private healthcare provision in Lagos State, emphasizing the positive impact of donor-funded quality improvement projects. The findings provide nuanced insights, guiding policymakers, healthcare managers, and practitioners toward collaborative, sustainable improvements. As Nigeria progresses, these lessons will be crucial in shaping healthcare policies prioritizing population well-being.

Inverse full state hybrid projective synchronization for chaotic maps with different dimensions

A new synchronization scheme for chaotic（hyperchaotic） maps with different dimensions is presented.Specifically,given a drive system map with dimension n and a response system with dimension m,the proposed approach enables each drive system state to be synchronized with a linear response combination of the response system states.The method,based on the Lyapunov stability theory and the pole placement technique,presents some useful features：（i） it enables synchronization to be achieved for both cases of n 〈 m and n 〉 m;（ii） it is rigorous,being based on theorems;（iii） it can be readily applied to any chaotic（hyperchaotic） maps defined to date.Finally,the capability of the approach is illustrated by synchronization examples between the two-dimensional H′enon map（as the drive system） and the three-dimensional hyperchaotic Wang map（as the response system）,and the three-dimensional H′enon-like map（as the drive system） and the two-dimensional Lorenz discrete-time system（as the response system）.

Generalized projective synchronization via the state observer and its application in secure communication

Based on the improved state observer and the pole placement technique, by adding a constant which extends the scope of use of the original system, a new design method of generalized projective synchronization is proposed. With this method, by changing the projective synchronization scale factor, one can achieve not only complete synchronization, but also anti-synchronization, as well as arbitrary percentage of projective synchronization, so that the system may attain arbitrary synchronization in a relatively short period of time, which makes this study more meaningful. By numerical simulation, and choosing appropriate scale factor, the results of repeated experiments verify that this method is highly effective and satisfactory. Finally, based on this method and the relevant feedback concept, a novel secure communication project is designed. Numerical simulation verifies that this secure communication project is very valid, and moreover, the experimental result has been greatly improved in decryption time.

Arbitrary full-state hybrid projective synchronization for chaotic discrete-time systems via a scalar signal

In this paper we present a new projective synchronization scheme, where two chaotic （hyperchaotic） discrete-time systems synchronize for any arbitrary scaling matrix. Specifically, each drive system state synchronizes with a linear combination of response system states. The proposed observer-based approach presents some useful features： i） it enables exact synchronization to be achieved in finite time （i.e., dead-beat synchronization）; ii） it exploits a scalar synchronizing signal; iii） it can be applied to a wide class of discrete-time chaotic （hyperchaotic） systems; iv） it includes, as a particular case, most of the synchronization types defined so far. An example is reported, which shows in detail that exact synchronization is effectively achieved in finite time, using a scalar synchronizing signal only, for any arbitrary scaling matrix.

Investment Invitation Projects for the Suzhou Taihu Lake State Tourism and Holiday Resort

(1) The Pearl Revolving Tower on theTaihu LakeContents: The tower is located on top ofYuyang Hill in the Pearl Garden, with aheight of 100 metres. It is the buildingsymbolic of the area, consisting of a towerbase, viewing room, tubular structure andpower room. its surrounding

基于支持向量机的蓄水工程土地利用分类与动态变化

为进一步恢复和重建蓄水工程建成前后土地利用变化的历史过程,更好掌握和预报土地利用转移方向,本文利用支持向量机理论开展了土地利用类型解译的适应性研究,通过梳理土地利用动态变化,剖析了蓄水工程建成前后土地利用结构的自适应调节能力和演变方向。结果表明:(1)依靠自学习和自适应等优势能力,支持向量机解译土地利用分类的总体精度高达91.7%、Kappa系数为0.90;除耕地生产者精度相对较低外,水体、林地等其他土地类型具有较高的分类识别能力。(2)利用谷歌地球引擎(GEE)平台梳理土地利用类型演变过程发现,受“三北防护林”工程二阶段(2001—2020年)等项目实施影响,建设用地、林地面积出现较大增幅,其中,林地面积较2000年实施初期增加了近5倍。(3)工程建设运行后林地和建设用地近2/3面积保持了原貌,水体和未利用土地受水利和城建工程影响,原貌类型超过65%以上面积变成了其他类型;“三北防护林”工程加快了林地面积的增加和草地植被覆盖度的提高,低覆盖度草地转移到中、高覆盖度草地的面积净增幅达48.0%、50.2%。

“杯水车薪”抑或“雪中送炭”——低利率环境下货币政策的有效性研究

为应对内需不足的内部环境和严峻复杂的外部环境,我国货币政策仍将保持低利率状态,然而低利率环境下货币政策的实施效果究竟如何是政策制定者的核心关切。现有对于低利率环境下的货币政策有效性研究大多集中于发达国家,缺少对于当前中国情景下的深入探讨,而且局部投影模型尚未应用于货币政策非对称效应的研究。本文首先构建理论框架系统性分析了我国高、低利率时期货币政策的作用机理,然后基于状态依存局部投影模型定量分析了我国高、低利率时期货币政策的时变效应。研究发现:(1)我国扩张性货币政策冲击无论在高、低利率时期均能有效提升产出,从而实现预期的调控效果。(2)我国暂未陷入“流动性陷阱”,低利率时期扩张性货币政策冲击对产出、投资和消费的效应会增强,货币政策确实能起到“雪中送炭”的作用,常规货币政策尚能有效刺激消费和投资意愿,进而拉动总需求。(3)高杠杆会增强低利率时期产出和投资对扩张性货币政策冲击的响应,但会削弱消费的响应,这是因为高杠杆促使企业减少用于缓解日常运转的资金,增加用于长期投资的资金,高杠杆还会增加居民房地产投资,增强流动性约束,从而挤占居民消费。文章结论为优化货币政策有效性,增强货币政策传导效果提出建设性政策建议。

考虑电力网络约束的工业园区虚拟电厂调控边界求解方法

构建以新能源为主体的新型电力系统,亟须挖掘负荷侧灵活调节资源参与电网调控。含电解铝、矿热炉等高耗能负荷的工业园区具备良好的调控潜力,但是考虑园区内部电力网络约束,其精确调控边界求解面临着变量维数高、约束非线性的难题,现有方法不能较好地兼顾计算效率和精度。对此,文中将上述问题抽象为高维非线性状态空间在P-Q耦合平面的投影问题:分别建立考虑工业园区安全运行线性化和非线性约束的调控边界投影求解模型,采用一种新颖的高维状态空间投影算法,通过顶点“搜索-映射”的两步式求解过程,得到工业园区型虚拟电厂调控边界的精确投影。算例结果表明,采用所提方法求解的调控边界可由线性不等式组完全表征,与现有调度系统完全兼容,结合与叠加柔性资源调控能力和传统采样方法的对比,验证了该方法的可行性以及高求解精度和效率。

Rb吸附石墨烯纳米带电子性质和光学性质的研究

本文基于密度泛函理论的第一性原理方法了计算了Rb、O和H吸附石墨烯纳米带的差分电荷密度、能带结构、分波态密度和介电函数,调制了石墨烯纳米带的电子性质和光学性质,给出了不同杂质影响材料光学特性的规律.结果表明本征石墨烯纳米带为n型直接带隙半导体且带隙值为0.639 eV;Rb原子吸附石墨烯纳米带之后变为n型简并直接带隙半导体,带隙值为0.494 eV;Rb和O吸附石墨烯纳米带变为p型简并直接带隙半导体,带隙值增加为0.996 eV;增加H吸附石墨烯纳米带后,半导体类型变为n型直接带隙半导体,且带隙变为0.299 eV,带隙值相对减小,更有利于半导体发光器件制备.吸附Rb、O和H原子后,石墨烯纳米带中电荷密度发生转移,导致C、Rb、O和H之间成键作用显著.吸附Rb之后,在费米能级附近由C-2p、Rb-5s贡献;增加O原子吸附之后,O-2p在费米能级附近贡献非常活跃,C-2p、Rb-5s和O-2p电子态之间强烈的杂化效应,促使费米能级附近的杂质能级分裂成能带;再增加H原子吸附之后,Rb-4p贡献发生蓝移,O-2p在费米能级附近贡献非常强,费米能级分裂出两条能带.Rb、O和H的吸附后,明显调制了石墨烯纳米带的光学性质.

ISDS适用的逻辑理路和实践进路:以国际PPP项目合同争端为视角

中国企业“走出去”对国际PPP项目的投资规模持续扩大,由于东道国政府违约或单方面终止合同引发的争端迅速增多,投资者很难通过国内司法或仲裁获得救济,从而更加青睐将争端诉诸ISDS机制予以解决。鉴于ISDS机制的适用需要以国际投资协定和双方合意为基础,加之国际PPP项目合同争端的混合性质,投资者可能面临国际投资仲裁庭不予管辖的困境。理论和实践证明,除纯商业性质的争端外,国际PPP项目合同争端都能以国际投资协定为依据诉诸ISDS机制解决。为了进一步促进和保护我国对外PPP项目投资,应加快修订或签署国际投资协定、适时适用《ICSID附加便利规则》、预先设计国际PPP项目合同争端解决示范条款,进一步探索我国充分利用ISDS机制解决国际PPP项目合同争端的有效路径。

美欧日建筑机器人项目资助特点研究

以建筑机器人为主要研究对象,基于美国国家科学基金会(NSF)的项目数据库、欧盟框架计划项目数据库以及日本竞争性研究经费与科研费(KAKENHI)数据库中的建筑机器人项目数据,从项目数量、承担机构、资助金额、技术方向、项目类型等角度考察美国、欧洲和日本对建筑机器人的政府资助情况。结果表明,三个国家和地区表现出不同的建筑机器人项目资助特点,美国为高度密集、鼓励前沿探索,欧洲为高投入、重视应用开发,日本为长周期、以基础研究为主。

多体非完全经典态的基于Affinity的关联测度

在量子信息理论中,量子关联是一种极其重要的物理资源。文章首先定义了多体非完全经典态基于Affinity的一种量子关联测度,它可以量化多体非完全经典态的关联程度;接下来证明了该关联测度满足量子关联度的一些必要物理性质,包括非负性、局部酉操作下的不变性、局部量子操作下的单调性、凸性以及连续性。

房屋建筑工程招投标管理提升对策研究

随着我国经济的飞速发展,各行各业都进入高速发展时期,房屋建筑领域也不例外。而招投标作为建筑工程的前期环节,至关重要,尤其是对于国有资金投资项目,招投标制度能维护公平公正的建筑市场竞争环境,合理有效地选择参建单位,保证国有资金的使用效果。基于此,本文站在国有资金建设项目的立场上,深入研究安置楼、保障房等房屋建筑工程招投标现状及存在问题,就招投标管理工作提出新的改进策略,以供参考。

基于多元特征融合的电力工程数据处理与预测模型

针对电力工程情况复杂多变、影响因素多、数据处理与经济技术指标预测存在困难的问题,文中提出了一种基于多元特征融合的电力工程数据处理与预测模型。该模型利用多个一维卷积神经网络(1D-CNN)分别从电力工程各类影响因素中提取特征信息,再将特征全连接后使用回声状态网络(ESN)实现信息融合并输出预测结果。多组对比实验验证结果表明,所提方法在数据处理过程中对工程异常数据的识别正确率为95.3%,对工程静态投资数据预测的误差范围为0.51%~6.74%,通过多元特征融合实现了数据处理与合理预测,能够为工程项目的评审提供准确的数据支持。

高质量发展背景下地方国有企业项目投资风险管控研究

近年来,地方国有企业实施的部分对外投资的项目往往是由于决策失败、风险管理不善等原因,造成风险损失事件频发。因此,必须提高对风险的认识,并采取积极措施减少风险。本文从地方国有企业A公司项目投资的风险管控实际工作入手,分析A公司项目投资的风险管控的有效手段,以期给其他国有企业进行项目投资风险管控提供参考。

护理专案模式对肾移植病人术后并发症及心理状态的影响

目的:探讨护理专案模式对肾移植病人术后并发症及心理状态的影响。方法:选取医院2022年1月—2023年5月收治的肾移植病人70例作为研究对象,依据信封法分成专案组、观察组各35例。两组均行肾移植手术且观察组接受常规护理,专案组基于观察组接受护理专案模式干预。统计对比两组并发症发生率、护理满意度及干预前后睡眠质量[匹兹堡睡眠质量指数量表(PSQI)]、心理状态[汉密尔顿焦虑量表(HAMA)、汉密尔顿抑郁量表(HAMD)]、疼痛程度[疼痛视觉模拟评分(VAS)]、生活质量[生活质量核心量表(QLQ-C30)]评分。结果:专案组并发症总发生率0.00%(0/35)低于观察组17.14%(6/35)(P<0.05);干预后,专案组VAS、PSQI、HAMA、HAMD评分低于观察组,QLQ-C30评分高于观察组(P<0.05);专案组护理总满意率100.00%(35/35)高于观察组80.00%(28/35)(P<0.05)。结论:护理专案模式应用于肾移植病人中,可有效降低病人术后并发症发生率,改善病人心理状态,提升其睡眠质量、护理满意度,缓解其疼痛程度,促进生活质量的提高。

科研批产多项目交叉状态下的管理方式探讨

随着科研与批产项目的日益增多,科研企业多项目交叉进行时,常遇到资源分配、进度管理、供应保障和协作难度等方面的挑战。科研企业C主要致力于高科技产品的研发和生产,包括科研项目的探索和批产项目的实施。随着企业业务的不断扩展,C企业面临越来越多的科研项目和批产项目交叉进行的局面。然而,由于企业整体能力的限制,如资源、人力和技术的制约,导致项目延期、资源冲突和管理效率低下等问题频繁出现。这些问题不仅会影响项目的顺利进行,也会威胁企业的长期发展。通过分析科研企业多项目交叉进行时面临的挑战,提出相应的管理改进策略,以期为相关人员提供一定参考。