Estimation of Metabolic Rate Constants in PBPK‐Models from Liver Slice Experiments: What Are the Experimental Needs?

A mechanistic model is presented describing the clearance of a compound in a precision-cut liver slice that is incubated in a culture medium. The problem of estimating metabolic rate constants in PBPK models from liver slice experiments is discussed using identifiability analysis. From the identifiability problem analysis, it appears that in addition to the clearance, the compound's free fraction in the slice and the diffusion rate of the exchange of the compound between culture medium and liver slice should be identified. In addition, knowledge of the culture medium volume, the slice volume, the compound's free fraction, and octanol-water-based partition between medium and slice is presupposed. The formal solution for identification is discussed from the perspective of experimental practice. A formally necessary condition for identification is the sampling of parent compound in liver slice or culture medium. However, due to experimental limitations and errors, sampling the parent compound in the slice together with additional sampling of metabolite pooled from the medium and the slice is required for identification in practice. Moreover, it appears that identification results are unreliable when the value of the intrinsic clearance exceeds the value of the diffusion coefficient, a condition to be verified a posteriori.     

钢管相邻缺陷漏磁场相互影响的分析

实际工况中的管道缺陷是非常复杂的,用物理试验的方法研究各种缺陷漏磁场的变化规律有一定的难度。该文针对油气管道常用的钢管缺陷产生的漏磁场建立了三维有限元模型,采用有限元方法计算了几种相邻缺陷的漏磁场模型,给出了计算结果,并分析了各种相邻缺陷对漏磁场信号的影响。结果表明当相邻缺陷的中心线与磁场方向平行时,对缺陷漏磁信号的影响最小;组合型的缺陷对漏磁信号的影响最大。     

Explaining how unexploded ordnance clearance enhances livelihoods in the Lao PDR

BackgroundFollowing violent conflict, the continued presence of landmines and unexploded ordnance pose a barrier to rebuilding livelihoods. Mine action removes these explosive remnants of conflict to enable communities to safely return contaminated land to productive use. There is limited understanding, however, of how, why, in what context and in what respects mine action contributes to livelihoods. Yet, such information is required for effective resource allocation, checking underlying program assumptions, understanding benefits and potential harms.MethodsThe evaluation was undertaken in the Lao People's Democratic Republic. It used an interpretive case study design and applied the principles of realist evaluation. Program staff and local government authorities were interviewed (N = 37) and program beneficiaries. In total, 38 individual interviews with program beneficiaries were conducted and eighteen focus group interviews (9 with males, 9 with females), each with 6–9 participants.ResultsThe evaluation identified two main mechanisms through which the program ‘worked’: (1) communication pre- and post-clearance and (2) the delivery of the product (cleared land).ConclusionThe realist approach helped to refine the program theory, highlighted the role of self- and task-efficacy and community communication, assisted in identifying contextual factors that influence outcomes and suggested a revision of expected outcomes.     

双螺旋加料器输送机理的研究

本文在正位移输送机理的基础上，提出了双螺旋加料器理论输出量模型，并讨论了对其有影响的几个重要因素。     

MUSIC法的有限域单向快速频率搜索

快速傅里叶变换(FFT)算法在应用中速度快,精度较低,而MUSIC法精度高,实时性差。该文通过分析两者联合谐波频率估计的可能性,提出利用FFT算法对谐波频率进行预估计,用二分法将频域划分为有限个细小的频率区间,根据可能的有效频率选取有效区间,再通过MUSIC方法在有限的搜索区间进行频率细化,并在细化的过程中采用趋向谱幅值增大的单向搜索。通过仿真研究,该方法能有效提高信号的处理速度,加强MUSIC算法的应用。     

水东水电站环境水对混凝土坝的影响

混凝土坝坝体严重渗漏，将降低大坝的安全性和耐久性，其危害性不可忽视．通过对水东水电站坝址环境水质特征、水质演变及侵蚀作用进行综合分析，重点分析渗漏水的成因，以找出不利于大坝长期安全运行的因素，为可能采取的工程补强措施提供依据．     

降低量热器法试验台漏热量的设计研究

本文介绍在研制第二制冷剂量热器法试验台时选用合适的制冷量作为设计参数,可降低量热器漏热量,以提高试验台测试精度。经过试验验证,理论和实际测量相符合。     

特殊重大工程项目的风险社会放大效应及启示——以日本福岛核泄露事故为例

福岛核电站泄露事故愈演愈烈,其技术风险引发的社会放大效应不断衍伸,在日本及世界各地蔓延,以致引发出世界范围内关于核电站未来发展的存废之争。以"风险社会放大框架"为分析工具,通过对福岛核泄漏风险社会放大效应的表现、特点、机制等进行梳理和剖析,并结合中国国情,提出保证风险信息公开、鼓励风险中公众参与、建立政民心理契约等政策建议。     

预算立法中若干问题的意见与建议

预算立法的关键是要明确预算过程中公民、人大以及政府之间的权责关系。在我国宪法的框架下,预算立法的实质是通过人民代表大会制度来规范政府的预算行为。我国现行的《预算法》在三者关系方面还没有理顺,新近征求意见的《预算法(修改稿)》虽有所改进,但在预算立法宗旨,预算的公开性、完整性,预算编制标准,预算审批以及调整等方面尚存在值得商榷的地方。本文就这些问题提出了意见与建议。     

水平竞争条件下的供应链信息泄露策略

本文探讨非对称信息下,制造商针对议价能力不同的大型及小型零售商分别采用了收益共享、批发价合约时,大型零售商的市场信息被制造商泄露给竞争对手,从而对供应链产生的影响。通过对比有无信息泄露下各方成员的博弈过程,分析供应链信息泄露的原理;进而在制造商总是会泄露信息的前提下,构建基于信号传递的信息泄露下供应链成员决策模型,分别讨论分离均衡与混同均衡两种情形下,零售商的订货策略及其相应的收益。在此基础上进一步做出扩展,制造商有主动权以选择是否泄露信息的情况,对比分析零售商的策略选择问题。经过分析发现,出于自身利益的角度,制造商总是会泄露信息,从而导致供应链的整体利润下滑。对此,大型零售商的订货策略选择与市场需求的波动程度有关：波动较小则选择混同均衡;波动较大则选择分离均衡。特别地,当市场需求为低时,大型零售商的最优订货量会向下扭曲,即支付一定的“信息租金”作为应对信息泄露的代价。