关键词： 建筑工程   工程变更   工程造价   图纸会审   变更审核  

摘要： 工程变更是建筑工程施工建设中的普遍难题,一旦出现将对工程造价、进度、质量等产生影响,严重时将造成项目投资失控等情况,很难维护参建主体的合法权益,因此需要采取措施进行合理控制,减少工程变更问题.基于此,围绕工程变更与造价展开研究,在分析工程变更对建筑工程造价影响的基础上,进一步探讨了工程变更产生的原因,提出加强工程变更控制减少造价影响的措施,促进工程项目按时保质地建成,以供参考.

关键词： Magic angle spinning  

摘要： Solid-state nuclear magnetic resonance (NMR) has emerged as an important technique for material characterization, finding extensive applications across a diverse range of disciplines including physics, materials science, chemistry, and biology. Its utility stems from the ability to probe the local atomic environments and molecular dynamics within solid materials, which provides information on the composition of the material. In recent years, the scope of solid-state NMR has expanded into the realm of quantum information science and technology, where its abundant many-body interactions pulse control methodologies make it have significant research value and application potential. This paper offers a comprehensive overview of the research objects and theoretical underpinnings of solid-state NMR, delving into the critical nuclear spin interaction mechanisms and their corresponding Hamiltonian forms. These interactions, which include dipolar coupling, chemical shift anisotropy, and quadrupolar interactions, are fundamental to the interpretation of NMR spectra and the understanding of material properties at the atomic level. Moreover, the paper introduces typical dynamical control methods employed in the manipulation of solid-state nuclear spins. Techniques such as dynamical decoupling, which mitigates the effects of spin-spin interactions to extend coherence times, and magic-angle spinning, which averages out anisotropic interactions to yield high-resolution spectra. These methods are essential for enhancing the sensitivity and resolution of NMR experiments, enabling the extraction of detailed structural and dynamic information from complex materials. Then we introduce some recent advancements in quantum control based on solid-state NMR, such as nuclear spin polarization enhancement techniques, which include dynamic nuclear polarization (DNP) and cross polarization (CP), significantly boost the sensitivity of NMR measurements. Additionally, the control techniques of Floq

关键词： 建筑工程   造价核算   关键因素   成本控制  

摘要： 在建筑工程项目的建设过程中,对影响工程造价的关键因素控制不合理,就容易造成建筑工程造价超预算现象的发生.建筑工程造价超预算,不仅降低了工程项目的预期效益,同时增加在建项目的资金投入,给投资人造成巨大的损失.为了解决建筑工程造价中超预算的问题,对建筑工程项目造价预算中的关键因素进行分析,提出控制工程成本的策略,以期为建筑工程项目成本控制提供参考.