Management System Activities of the Operation and Utilization of GHARR-1

The Ghana Research Reactor-1 (GHARR-1) is a 34 kW low enriched uranium (LEU) Miniature Neutron Source Reactor (MNSR), tank-in-pool type and cooled by natural circulation under atmospheric pressure operating conditions. GHARR-1 is owned by Ghana Atomic Energy Commission (GAEC) and operated by National Nuclear Research Institute (NNRI), one of the institutes of GAEC. GHARR-1 is housed by Nuclear Reactors Research Centre (NRRC), one of the Centres of NNRI. Management/Administration, Radiation protection, Reactor operation and maintenance, Reactor utilization and Physical protection are the various systems/units that integrate to manage the activities of operation and utilization of GHARR-1 in addition to the quality assurance and quality control management system of the research reactor facility. The GHARR-1 which is currently in operation follows a robust maintenance culture adopted by the management system and this has made it possible to keep the reactor in operation with minimal interruption. The management system activities adopted at the Centre to ensure safety of the workers, public and the research reactor facility include authorization of the operation of the reactor for any experiments/modifications;providing material and financial resources for maintaining the research reactor facility;following standard procedures while carrying out Neutron Activation Analysis;participation in IAEA proficiency test;irradiation sites/positions characterization;following standard procedures while carrying out reactor operation and maintenance including reactor and pool water purification and other related activities;monitoring radiation levels in the controlled, supervised and uncontrolled areas of the research reactor facility as well as during reactor operation and maintenance;controlling the physical entry of the workers and public into the research reactor facility;and ensuring that the security structures provided to protect the reactor facility are functioning properly. The thorough knowledge on the functions of the various components that make up the electrical/electronic and control systems of the reactor has been observed to be important for continuous successful maintenance of the research reactor to keep the reactor in operation. This work provides some management system activities adopted to monitor the activities of the research reactor operation and utilization to guarantee safety of workers, public and the environment as well as to safeguard a continuous operation of the research reactor. These management system activities adopted among others, are in the form of Monitoring Forms provided for monitoring the activities of the research reactor operation and utilization in order to ensure standard procedures and specifications are followed and quality services are rendered to the public.

Study on the risk factors of lymphatic metastasis and the indications of less invasive operations in early gastric cancer

The principle of surgical treatment for gastric cancer is the radical resectioning although the suitable resecting range for different cases of gastric cancer is still being argued upon[1-9]. However, the diagnostic accuracy of early gastric cancer (EGC) without lymphatic metastasis has obviously improved with an improvement in the diagnostic technique and due to the accumulation of knowledge on the biological profiles of EG C[10-17]. The D2 lymph node excision was used as a regular operation to treat the EGC previously. But the concept for the EGC without lymphatic metastasis has gradually changed and the less invasive resections has been applied in some cases[18-20]. This study aimed at investigating the risk factors of lymphatic metastasis in EGC in order to find out the proofs for the suitable indications for less invasive operations such as endoscopic mucosal resectioning (EMR), laparoscopic and laparotomic resectioning.

Acute upper gastrointestinal bleeding in operated stomach: Outcome of 105 cases

AIM: To compare the causes and clinical outcome of patients with acute upper gastrointestinal bleeding (AUGB) and a history of gastric surgery to those with AUGB but without a history of gastric surgery in the past.METHODS: The causes and clinical outcome were compared between 105 patients with AUGB and a history of gastric surgery, and 608 patients with AUGB but without a history of gastric surgery.RESULTS: Patients who underwent gastric surgery in the past were older (mean age: 68.1±11.7 years vs 62.8±17.8 years, P= 0.001), and the most common cause of bleeding was marginal ulcer in 63 patients (60%). No identifiable source of bleeding could be found in 22 patients (20.9%) compared to 42/608 (6.9%) in patients without a history of gastric surgery (P = 0.003). Endoscopic hemostasis was permanently successful in 26 out of 35 patients (74.3%) with peptic ulcers and active bleeding or non-bleeding visible vessel. Nine patients (8.6%) were operated due to continuing or recurrent bleeding,compared to 23/608 (3.8%) in the group of patients without gastric surgery in the past (P= 0.028). Especially in peptic ulcer bleeding patients, emergency surgery was more common in the group of patients with gastric surgery in the past [9/73 (12.3%) vs 19/360 (5.3%), P = 0.025].Moreover surgically treated patients in the past required more blood transfusion (3.3±4.0 vs 1.5±1.7, P = 0.0001) and longer hospitalization time (8.6±4.0 vs 6.9±4.9 d,P = 0.001) than patients without a history of gastric surgery. Mortality was not different between the two groups [4/105 (3.8%) vs 19/608 (3.1%)].CONCLUSION: Upper gastrointestinal bleeding seems to be more severe in surgically treated patients than in non-operated patients.

Coordinated control between a grid forming inverter and grid following inverters suppling power in a standalone microgrid

Battery energy storage systems,fuel cells,and photovoltaic generators are being adopted in distribution networks to achieve CO;emission reduction.These power sources require inverters to connect to AC networks.However,sub-networks,such as a microgrids containing inverter power sources,may be disconnected from the utility network and operated in a standalone mode during extended blackouts.This study focuses on a standalone microgrid supplied by inverter power sources without a synchronous generator and proposes a new microgrid inverter control.In this inverter control,a single grid forming inverter is operated as a master power source to determine frequency and voltage,and other inverters,called grid following inverters,are operated as subordinate power sources with active and reactive power control.The necessary functions in the energy management system are examined,and the coordinated operation of all inverters in the microgrid is demonstrated via simulation.

Commuting Structure Jacobi Operator for Real Hypersurfaces in Complex Space Forms

Let M be a real hypersurface of a complex space form with almost contact metric structure (φ,ξ,η,g). In this paper, we prove that if the structure Jacobi operator Rξ=(·,ξ) ξ is φ▽ξξ-parallel and Rξ commute with the shape operator, then M is a Hopf hypersurface. Further, if Rξ is φ▽ξξ-parallel and Rξ commute with the Ricci tensor, then M is also a Hopf hypersurface provided that TrRξ is constant.

New transformation of Wigner operator in phase space quantum mechanics for the two-mode entangled case

As a natural and important extension of Fan＇s paper （Fan Hong-Yi 2010 Chin. Phys. B 19 040305） by employing the formula of operators＇ Weyl ordering expansion and the bipartite entangled state representation this paper finds a new two-fold complex integration transformation about the Wigner operator A （#, ~） （in its entangled form） in phase space quantum mechanics, and its inverse transformation. In this way, some operator ordering problems regarding to （a1-a2） and （a1＋a2） can be solved and the contents of phase space quantum mechanics can be enriched, where ai,ai are bosonic creation and annihilation operators, respectively.

Allocation Methodology of Multiple SVCs Considering Operation Scheme Changing

针对多静止同步补偿器（staticvarcompensator，SVC）对系统共同影响的问题，提出计及运行方式变化的多SVC布点方法。利用规范形分析，基于摄动方程2阶解析解信息建立拓展静态电压稳定边界的多SVC布点分析方法。首先根据静态电压稳定分析方法，确定系统危险运行方式（即距离系统电压崩溃最近的运行方式1；然后在该运行方式下，利用规范形方法对系统进行小扰动电压稳定分析，求出所有负荷节点的电压振荡曲线解析解；最后利用2阶解析解所给出的小扰动1阶振荡幅值和2阶振荡幅值信息，以多SVC布点多种方案对系统降低小扰动幅值的贡献为指标，给出多SVC布点结果。所提方法应用于IEEE30节点系统，试验结果表明，该方法相对于不考虑多点共同影响的多SVC布点方式，其静态电压稳定边界的拓展效果更好。

ADJOINT OPERATOR METHOD AND NORMAL FORMS OF HIGHER ORDER FOR NONLINEAR DYNAMICAL SYSTEM

Normal form theory is a very effective method when we study degenerate bifurcations of nonlinear dynamical systems. In this paper by using adjoint operator method, normal forms of order 3 and 4 for nonlinear dynamical system with nilpotent linear part and Z(2)-asymmetry are computed. According to normal forms obtained, universal unfoldings for some degenerate bifurcation cases of codimension 3 and simple global characterizations, are studied.

Recapitulating Quantum Phase Space Representation by Virtue of Normally Ordered Gaussian Form of Wigner Operator

Using the normally ordered Gaussian form of the Wigner operator we recapitulate the quantum phase space representation, we derive a new formula for searching for the classical correspondence of quantum mechanical operators; we also show that if there exists the eigenvector ｜q〉λ,v of linear combination of the coordinate and momentum operator, （λQ ＋ vP）, where λ,v are real numbers, and ｜q〉λv is complete, then the projector ｜q〉λ,vλ,v〈q｜ must be the Radon transform of Wigner operator. This approach seems concise and physical appealing.

Estimation of a Type of Form-Invariant Combined Signals under Autoregressive Operators

We focus on a type of combined signals whose forms remain invariant under the autoregressive operators. To extract the true signal from the autoregressive noise, we develop a strategy to separate parameters and use a two-step least squares approach to estimate the autoregressive parameters directly and then further give the estimate of the signal parameters. This method overcomes the difficulty that the autoregressive noise remains unknown in other methods. It can effectively separate the noise and extract the true signal. The algorithm is linear. The solution of the problem is computationally cheap and practical with high accuracy.

智慧停车投建营一体化策略研究

在当前停车供需矛盾突出的背景下,研究具有企业特色的智慧停车项目发展策略,针对智慧停车投资、建设、运营的全生命周期展开研究。在投资阶段通过基于投资成熟度的区域筛选模型,选择确定拟进入的城市投资智慧停车项目。在设计建设阶段通过多因素影响的停车场建设形式的决策,达到社会效益和经济效益的平衡。在运营阶段通过智慧停车系统的绿色低碳运营技术体系,提高运营效益。

产加销一体化经营对农民专业合作社经济绩效的影响机制研究

基于2015-2020年全国30个省(区、市)的合作社数据,采用双向固定效应模型从生产规模和节约交易成本角度分析产加销一体化经营形式对农民专业合作社经济绩效的影响,并进一步对不同地区的合作社进行异质性分析。结果表明:产加销一体化经营通过提高农民专业合作社市场竞争优势从而促进农民专业合作社经济绩效提升;就区域异质性而言,东部和西部地区产加销一体化对合作社经济绩效提升具有促进作用,而中部地区产加销一体化经营对农民专业合作社经济绩效提升无显著的促进作用。因此,现阶段既要重视强化合作社的产加销一体化经营,也要适度扩大合作社产加销一体化服务的广度和深度;既要追求农民专业合作社经济绩效,也要提高社员收入。

基于改进虚拟同步发电机的构网型并联储能逆变器控制研究

针对构网型变换器预同步过程时电力系统频率电压稳定性低导致变换器并网失败的问题,提出一种基于改进线性自抗扰控制(LADRC)的构网型变换器预同步控制策略。首先,采用无锁相环(PLL)控制策略,通过相位偏差的反馈控制对网侧电压的相位和幅值进行快速同步追踪,可避免因PLL精度较低和响应速度慢而引起的电力系统稳定性降低的问题。在此基础上,在有功频率支路模块的角频率输出端引入LADRC,这可以有效解决预同步控制过程中变换器输出电压频率存在过冲的问题,从而确保构网型变换器预同步控制顺利进行最终实现成功并网。最后,在MATLAB/Simulink仿真平台中搭建基于改进LADRC的构网型变换器预同步控制模型并进行仿真验证,结果表明所提控制策略可以有效抑制系统频率震荡,并能够加速系统预同步进程,确保构网型变换器安全运行最终实现成功并网,仿真结果验证了所提方法的有效性。

新零售业态下中小型网店运营策略

新零售背景下,当下网店运营与服务模式均迎来了新的转变,各种企业的信息更加透明化,通过对无形资源价值动态的把握来创造更多的有形、无形资源的抓取。另外新零售模式也使得以前对于不对称、信息差认知的可能逐步降低。新零售模式下整体的行业信息透明化、对策化幅度逐渐升高,从以前的单纯成交的关系逐步转化成现在以客户关系为中心的管理模式。当下针对零售企业提高创新服务模式,做好创新服务模式的绩效,以服务创新驱动力模型将内部和外部因素进行总体把握问题,从经济价值,功能价值,情感价值三方面充分考虑到顾客的主张,希望通过理论综述结合案例分析对于新零售背景下的服务模式以及营销方式背后的作用机理开展进一步的研究,以期对于理论和实践具有一定的指导价值。

以学生为中心理念的形成性评价在临床实践教学管理中的应用思考

迷你临床演练评估(Mini-clinical Evaluation Exercise,Mini-CEX)与操作技能直接观察评估(Direct Ob⁃servation of Procedural Skill,DOPS)等形成性评价工具在岗位胜任力培养上具有显著优势,在临床实践教学中被大力推广。但由于教学管理理念和方法陈旧、师资能力不足、学生主动性缺乏等原因,效果不理想。以学生为中心是当前广为认可的主流教学理念,强调以学生发展和成效为中心。本文探讨通过改革教学管理,将以学生为中心理念深度融合在形成性评价的临床教学管理中,包括改进师资建设方式、培养学生主动学习意识、优化信息化手段、使用学习档案集实施全程管理等。

公共安全治理视域下政府运行保障的形态演变与发展方向

推进公共安全治理现代化是风险社会下实现可持续发展的重要任务,政府运行保障能力的提升是促进公共安全治理效能实现的必然要求。公共安全治理视域下政府运行保障将保障系统优化视为研究焦点,强调复杂风险形势中机关事务部门在统筹管理、增效服务、保障资源方面与其他主体的交互过程。为了从整体上描摹公共安全治理视域下政府运行保障的全貌,文章构建了制度体系—运行机制—技术手段的分析框架,从过去—现在—未来的历史视角对其形态演变进行分析。这种形态的变化既体现出机关事务管理在历史发展中的自我适应与调节,也标志着公共安全治理模式的升级与转向。在公共安全治理视域下,未来的政府运行保障将在进一步夯实制度基础、明确职能定位、拓宽互动网络、深化驱动机制、推动技术落地以及加强技术赋能中形成更加成熟的制度体系、更加高效的运行机制以及更加有力的技术牵引。

重视先天性白内障术后高眼压和青光眼的防治

先天性白内障是严重影响婴幼儿视功能的疾病。随着白内障手术和人工晶体植入手术技术的发展,先天性白内障患者术后多可获得高质量的视觉康复。然而,如何更好防治手术相关的不良事件和并发症、先天性白内障伴随的其他眼部发育不良疾病的治疗以及形觉剥夺性弱视的治疗,仍然是先天性白内障手术后需要重视的临床问题。文章对先天性白内障摘除及人工晶体植入术后高眼压和继发性青光眼的发生、相关危险因素、治疗和预防的手段进行总结,以期进一步提高对先天性白内障术后高眼压和青光眼防治的认识,减少术后并发症对视功能造成的进一步损害。

满足全运行域振荡约束的跟网-构网组合控制及优化配置

弱电网条件下,跟网型变流器存在宽频振荡风险,而构网型变流器的振荡稳定性相对较好。随着构网型变流器在现场得到逐步应用,有必要研究两类变流器的优化配置问题。首先,提出了两种改善新能源场站弱电网振荡稳定性的跟网-构网变流器组合控制方法;其次,基于阻抗稳定性分析结果,定义了变流器并网系统的振荡安全域,并提出了基于多项式拟合的振荡安全域边界快速求解方法;然后,考虑全运行域振荡稳定约束和经济性约束,提出了跟网-构网变流器容量优化配置方法;最后,通过电磁暂态仿真进行了验证。结果表明,所提多项式拟合方法能够准确、快速地求解振荡安全域边界,所提组合控制和优化配置方法能够确保新能源场站在全运行域下保持振荡稳定。

IMPROVEMENT OF MATRIX REPRESENTATION METHOD IN NORMAL FORM THEORY

In this paper, based on the invariant subspace theory and adjoint operator concept of linear operator, a new matrix representation method is proposed to calculate the normal forms of n order general nonlinear dynamic systems. In the method, there is no need to determine the structure of the class of normal forms in advance. Because the subspace is not related to the dimensions of the system and the order of the normal forms directly, it is determined only by a given vector field. So the normal forms with high orders and dimensions can be calculated by the method without difficulties. In this paper, is used the method for selecting the minimal subspace and solving homological equations in the subspace, the examples show that the method is very effective.

Cigar孤立子上加权散度型椭圆算子的特征值估计

本文研究了cigar孤立子(R 2,g,f)上加权散度型椭圆算子LA,f的如下Dirichlet特征值问题:{LA,f u+V u=λρu,inΩ,u=0,on∂Ω,其中V和ρ分别是Ω上的非负连续函数和正连续函数.我们建立了该问题的一些特征值不等式.