The Role of Echocardiography in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy(HCM)is a common genetic cardiovascular disease and appears in all ethnic groups.HCM is diagnosed on the basis of left ventricular hypertrophy.Echocardiography is a key technique in the diagnosis of HCM,the prognosis of patients with HCM,the management strategy for HCM,and the follow-up of patients with HCM.This review briefly describes and discusses the practical use of established echocardiography techniques and the current and emerging echocardiographic methods that can help physicians in the correct diagnostic and pathophysiological assessment of patients with HCM.

Comparative study on foundation treatment methods of immersed tunnels in China

Based on engineering practices of four typical traffic immersed tunnels built in China,this paper details the features of the four dominant foundation treatment methods for immersed tunnel construction:pile foundation,sand flow foundation,grouting foundation,and gravel bedding foundation.Subsoil stress time-history of different method are specified first,plus a summary of settlement assessment method for foundation quality control.Further,a comprehensive comparison of settlement and cost of these four foundation treatment methods is conducted to highlights the specific merits,disadvantages and conditions encountered in each foundation treatment method,based on real projects information.The findings of this article could henceforth be applied to foundation treatment work in immersed tube tunnel construction.

The influence of hand hole on the ultimate strength and crack pattern of shield tunnel segment joints by scaled model test

With the shield tunnel going deeper and deeper, the circumferential axial force becomes the governing factor rather than the bending moment. The hand hole acts as a weak point and initial damage in the segment joint especially when the circumferential axial force is extremely high. Despite the wide application of steel fiber or synthetic fiber in t|ie tunneling, limited researches focus on the structural responses of segment joint with macro structural synthetic fiber (MSSF). In this paper, a 1:2 reduced-scale experiment was conducted to study the structural perfonnance of the segment joint with different types of hand holes under ultra-high axial force. Special attention is paid to failure mode and structural performance (bearing capacity, deformation, cracking, and toughness). Moreover, segment joints with MSSF are also tested to evaluate the effects of MSSF on the failure mode and structural performance of the segment joints. The experiment results show that the hand hole becomes the weakest point of the segment joint under ultra-high axial force. A\/-type crack pattern is always observed before the final failure of the segment joints. Different types and sizes of the hand hole have different degree of influences on the structural behavior of segment joints. The segment joint with MSSF shows higher ultimate bearing capacity and toughness compared to segment joint with common concrete. Besides, the MSSF improves the initial cracking load and anti-spallling resistance of the segment joint.

河套盆地临河坳陷古近系临河组深层—超深层碎屑岩储层物性差异成因

河套盆地临河坳陷临河组在6 000 m以深仍发育优质储层且高产工业油流,但相似埋深碎屑岩储层物性存在明显的差异性。为明确储层物性差异成因,降低深层—超深层油气勘探的风险,以临河坳陷临河组为研究对象,综合岩心、铸体薄片、扫描电镜和黏土矿物等资料,以岩石学、物性及成岩特征研究为基础,开展储层特征及物性差异成因研究。结果表明:临河组储层岩石以富含石英为主要特征,石英含量平均值为72%,填隙物含量介于1%~28%之间。储层孔隙度介于1%~29.2%之间,储集空间主要为原生粒间孔。储层压实作用和胶结作用强度总体较弱,局部较强。储层主要发育富胶结物砂岩、富泥杂基砂岩和低填隙物砂岩3类岩石相类型。富胶结物砂岩粒度较细,胶结作用强,物性致密;富泥杂基砂岩塑性碎屑含量较高且分选差,压实作用强,物性较差;低填隙物砂岩富含刚性颗粒且分选好,压实和胶结作用弱,原生孔隙发育,物性好。临河坳陷临河组储层物性受沉积和成岩作用共同控制,沉积水动力强弱决定了砂岩的粒度大小、分选好坏和泥质含量高低,进一步控制储层压实强度和物性成岩演化。砂体厚度控制了储层中胶结物含量及分布,进而影响储层物性。