FibroMeters:诊断肝纤维化的血液学检测指标组合(英文)

FibroMeters是具有多项特异性的诊断肝纤维化的血液学检测指标组合,其3个主要诊断目标为显著肝纤维化、肝硬化以及肝纤维化的定量,并由专业系统针对不同病因进行调整从而保证获得准确的结果。因此,主要存在 6 种不同的 FibroMeters:即针对肝纤维化的3种主要病因慢性病毒性肝炎、酒精性肝病和非酒精性脂肪性肝病的肝纤维化分期和肝纤维化定量。以肝组织病理学方法诊断肝纤维化程度进行对照,FibroMeters 表现出非常高的诊断准确率,是惟一能100%正确区分丙型肝炎患者不伴有肝纤维化或伴有肝硬化的检测方法。在适用性方面,FibroMeters 对于显著肝纤维化的 90%预测值高于其他血清学检测方法。使用包括 7 类内容在内的详细的肝纤维化分期方法,87%的丙型肝炎患者可以获得准确的肝纤维化分期。在实际工作条件下,FibroMeters 重复性高于肝组织病理结果,也高于超声弹性检测。因诊断性能表现非常稳定,FibroMeters 在不同的中心都是稳健的检测方法。目前可选择的检测有:针对肝硬化诊断的 CirrhoMeter,在一项丙型肝炎肝硬化患者的队列中其诊断准确率为 93%(受试者工作特征曲线下面积:0.92),阳性预测值为 100%;针对肝纤维化定量检测的QuantiMeter,是惟一能通过无创方法直接量化肝纤维化程度的手段,对于随访肝硬化及其临床相关事件可能特别有用。除HCV 感染外,FibroMeters对HBV或HIV同时感染患者诊断准确率高,尤其是对酒精性肝病或非酒精性脂肪肝患者,FibroMeters有较高的诊断准确率(对于显著纤维化,受试者工作特征曲线下面积分别为0.96和0.94)。

English and Chinese language frequency time series analysis

<Abstract>English and Chinese language frequency time series (LFTS) were constructed based on an English and two Chinese novels. Methods of statistical hypothesis testing were adopted to test the nonlinear properties of the LFTS. Results suggest the series exhibited non-normal, auto-correlative, and stationary characteristics. Moreover, we found that LFTS follow the power law distributions, and thereby we investigated the fractal structure, long range correlation, and intermittency, which indicated the self-similarity features of LFTS, and also provided hints that human societies are likely to share some universal properties.

Unified modeling of the monotonic and cyclic behaviors of sand and clay

In this study, we aim to investigate a unified modeling method for the monotonic and cyclic behaviors of sand and clay. A simple double-yield-surface model, with plastic hardening modulus and dilatancy relation being dependent on density state unlike in existing approaches, is developed by considering the location of the critical state line. The model is used to simulate the drained and undrained tests of various sands and clays under monotonic and cyclic loadings. Prediction results are compared with experimental results, which show that the proposed approach is capable of modeling the monotonic and cyclic behaviors of sand and clay.

SSUH model: A small-strain extension of the unified hardening model

A small strain unified hardening(SSUH) model is proposed in the present study to tackle the small strain behavior of clay. The model is an extension of the unified hardening(UH) model for overconsolidated(OC) clays accounting for the small strain stiffness. The new features of the SSUH model over the UH model include:(a) a new elastic hysteretic stress-strain relationship to evaluate the stiffness degradation at small strains and to generate the hysteresis loop under cyclic loading condition;(b) a revised unified hardening parameter to enhance the plastic stiffness at small strains; and(c) a new overconsolidation parameter, which is crucial to make the UH model working with the elastic hysteretic stress-strain relationship effectively. With these enhancements, the SSUH model can describe a high initial stiffness and the highly nonlinear stress-strain relationship at small strains, in addition to the shear dilatancy and strain hardening/softening behaviors of OC clays at large strains. In comparison with the Modified Cam-clay(MCC) model, the proposed model needs two more small strain related parameters, which can be easily obtained from laboratory tests. Finally, some drained triaxial compression tests at large strains, drained triaxial compression/extension tests at small strains, an undrained compression test at small strains and a drained cyclic constant radial stress test are employed to validate the new model.

A Linear Quadratic Controller Design Incorporating a Parametric Sensitivity Constraint

The purpose of this paper is to propose a synthesis method of parametric sensitivity constrained linear quadratic (SCLQ) controller for an uncertain linear time invariant (LTI) system. System sensitivity to parameter variation is handled through an additional quadratic trajectory parametric sensitivity term in the standard LQ criterion to be minimized. The main purpose here is to find a suboptimal linear quadratic control taking explicitly into account the parametric uncertainties. The paper main contribution is threefold: 1) A descriptor system approach is used to show that the underlying singular linear-quadratic optimal control problem leads to a non-standard Riccati equation. 2) A solution to the proposed control problem is then given based on a connection to the so-called Lur'e matrix equations. 3) A synthesis method of multiple parametric SCLQ controllers is proposed to cover the whole parametric uncertainty while degrading as less as possible the intrinsic robustness properties of each local linear quadratic controller. Some examples are presented in order to illustrate the effectiveness of the approach.

Influence of natural deposition plane orientation on oedometric consolidation behavior of three typical clays from southeast coast of China

The parameters obtained from oedometric consolidation tests are commonly used in the development of constitutive modeling and for engineering practice. This paper focuses on the influence of the natural deposition plane orientation on oedometric consolidation behavior of three natural clays from the southeast coast of China. Oedometer tests were conducted on intact specimens prepared by sampling at a series of angles relative to the natural deposition plane. For each specimen, yield stress,compressibility indexes, secondary compression, and permeability coefficients were determined. The influence of the sampling angle on these properties was investigated, revealing that yield stress, compression index, swelling index, creep index, ratio of secondary compression coefficient to compression index(Cae/Cc) and permeability coefficient were all dependent to some extent on the sampling angle. These findings indicate the role of the anisotropy due to the natural deposition on the oedometric consolidation behavior.

MICROMECHANICAL MODELLING OF PHASE TRANSFORMATION BEHAVIOUR OF A TRANSITIONAL SOIL

Experiments show that silts and silty soils exhibit contraction followed by dilation during shearing and the slope of failure line decreases at large strains, termed as phase transformation behaviour. This paper is to develop a new micromechanical stress-strain model that accounts for the phase transformation behaviour by explicitly employing the phase transformation line and its related friction angles. The overall strain includes plastic sliding and plastic compression among grains. The internal-friction angle at the phase transformation state and the void state variable are employed to describe the phase transformation behaviour. The model is examined by simulating undrained and drained triaxial compression tests performed on Pitea silts. The local stress-strain behaviour for contact planes is also investigated.

一个结构性软土参数的确定方法（英文）

目的:软土流变和结构破坏的相互耦合导致结构性软土的参数难以准确得到。本文拟建立一个有效的参数确定方法,期望仅基于常规的室内试验得到可靠的、合理的本构参数。创新点:1.通过采用优化方法来实现结构性软土参数的确定;2.仅基于常规的室内试验得到本构参数;3.采用最近提出的考虑各向异性、流变和结构破坏的超应力本构模型。方法:1.建立数值模拟和试验数据之间的误差计算公式;2.通过流变本构模拟室内常规试验,并计算模拟误差;3.采用下山单纯形法(simplex)优化方法,寻找模拟误差的最小值;此最小值对应的这组模拟参数即为土体的最优参数;4.利用最优参数模拟其他类型的试验,验证参数的合理性和可靠性。结论:本文提出的优化程序可以有效的找到结构性土体的流变和结构破坏参数,并且找到的参数非常的合理。