搅拌摩擦加工制备AZ31/CoCrFeNi复合材料的组织、力学性能和磨损性能

采用搅拌摩擦加工工艺制备CoCrFeNi高熵合金颗粒增强AZ31镁基复合材料。采用OM、SEM、EDS和EBSD对复合材料的微观结构进行表征。通过拉伸、显微硬度和干滑动磨损实验研究复合材料的力学性能和磨损性能。结果表明,高熵合金颗粒分布均匀,与镁基体具有良好的冶金结合。复合材料的屈服强度、抗拉强度和硬度分别比母材高80 MPa、46 MPa和HV 54.9。细晶强化是主要的强化机制,对屈服强度的贡献率为43.9%。复合材料的平均摩擦因数由母材的0.331降低到0.240,磨损机制由母材的黏着磨损转变为磨粒磨损。

冷喷摩擦复合增材制造6061铝合金的显微组织、力学性能和腐蚀行为

采用冷喷摩擦复合增材制造(CFAM)技术制备6061铝合金块体材料。采用OM、SEM和EBSD对冷喷涂(CS)和CFAM试样的显微组织进行表征,通过显微硬度、拉伸和腐蚀实验研究两者的力学性能和腐蚀行为。结果表明,与CS试样相比,CFAM试样的显微组织更加致密和均匀,晶粒细小等轴,平均晶粒尺寸为3.1μm,显微硬度、极限抗拉强度和伸长率分别提高了22%、171%和683%。CFAM试样的腐蚀电流密度比CS试样低95.1%~97.8%,腐蚀机理由CS试样的点腐蚀转变为晶间腐蚀。

Pulmonary hypertension concurrent with pericardial effusion and superior vena cava syndrome: who is the initiator?

The diagnosis of pulmonary hypertension(PH) should be made by combining clinical manifestations and echocardiographic probability.[1] Following the confirmation of PH, the classification should begin with the more common groups [group 2(PH due to left heart disease) and group 3(PH due to lung diseases and/or hypoxia)], then group 4(chronic thromboembolic PH and other pulmonary artery obstructions) and finally group 1(pulmonary arterial hypertension) and group 5(PH with unclear and/or multifactorial mechanisms).[1] In this case, we demonstrate a rare scenario of obstruction-caused group 4 PH.

Normalization of plasma growth hormone alleviated malignant ventricular tachycardia in acromegaly

Acromegaly is an insidious endocrine disease character- ized by chronic elevation of growth hormone （GH） and insulin-like growth factor-1 （IGF-1）.Ell Persistent excess se- cretion of GH and IGF-1 damages both cardiac structure and function, leading to acromegalic cardiomyopathy, which is one of the most common causes of increased mortality in acromegaly and can result in an average of 10-year reduction in life expectancy.I2＇31 In patients with acromegaly, approximately 3% have been reported having a unique cardiomyopathy characterized by biventricular hypertrophy, myocardial necrosis, lymphocytic infiltration, interstitialfibrosis.

Search algorithm on strongly regular graphs based on scattering quantum walks

Janmark, Meyer, and Wong showed that continuous-time quantum walk search on known families of strongly regular graphs（SRGs） with parameters（N, k, λ, μ） achieves full quantum speedup. The problem is reconsidered in terms of scattering quantum walk, a type of discrete-time quantum walks. Here, the search space is confined to a low-dimensional subspace corresponding to the collapsed graph of SRGs. To quantify the algorithm＇s performance, we leverage the fundamental pairing theorem, a general theory developed by Cottrell for quantum search of structural anomalies in star graphs.The search algorithm on the SRGs with k scales as N satisfies the theorem, and results can be immediately obtained, while search on the SRGs with k scales as√N does not satisfy the theorem, and matrix perturbation theory is used to provide an analysis. Both these cases can be solved in O（√N） time steps with a success probability close to 1. The analytical conclusions are verified by simulation results on two SRGs. These examples show that the formalism on star graphs can be applied more generally.

Pseudo-Wellens syndrome secondary to postexercise syncope

Dear editor,Wellens syndrome is characterized by electrocardiography(ECG)patterns of the biphasic or inverted T wave in the precordial leads with normal R wave progression and absence of Q waves,[1,2]which indicates occlusive lesions of the proximal left anterior descending(LAD)coronary artery and warrants.[1]These ECG changes usually occur during a pain-free interval and turn to a fatal consequence if without urgent intervention therapy.[1,3]However,in some cases,coronary stenosis was absent and ECG patterns manifested as Wellens syndrome,which was defined as pseudo-Wellens syndrome.

Prolonged and recurrent hypoglycemia induced by trimethoprim-sulfamethoxazole in a Hodgkin lymphoma patient with Pneumocystis carinii pneumonia

To the Editor:A 64-year-old Chinese man(65 kg)with fever and lymphadenopathy was admitted to the hematology department of the Peking University First Hospital.Before admission,he had had intermittent fever for the past 3 months with a body temperature high of 38.5°C.He had no accompanying discomfort and his temperature sometimes dropped to normal without drugs.One month before admission,he found several palpable enlarged cervical lymph nodes.Upon admission,a lymph node biopsy was conducted and the pathological diagnosis showed a nodular sclerosis,a subtype of classical Hodgkin lymphoma.

Universal and General Quantum Simultaneous Secret Distribution with Dense Coding by Using One-Dimensional High-Level Cluster States

A universal and general quantum simultaneous secret distribution(QSSD)protocol is put forward based on the properties of the one-dimensional high-level cluster states,in which one sender dispatches different high-level classical secret messages to many users at the same time.Due to the idea of quantum dense coding,the sender can send different two-dit classical messages(two d-level classical numbers)to different receivers simultaneously by using a one-dimensional d-level cluster state,which means that the information capacity is up to the maximal.To estimate the security of quantum channels,a new eavesdropping check strategy is put forward.Meanwhile,a new attack model,the general individual attack is proposed and analyzed.It is shown that the new eavesdropping check strategy can effectively prevent the traditional attacks including the general individual attack.In addition,multiparty quantum secret report(MQSR,the same as quantum simultaneous secret submission(QSSS))in which different users submit their different messages to one user simultaneously can be gotten if the QSSD protocol is changed a little.

Numerical studies of dynamic behavior of liquid film on single-layer wire mesh with different wettabilities

Droplet impacting on the stainless steel wire mesh is very common in chemical devices,like a rotating packed bed.Surface wettability of wire mesh significantly affects the liquid flow pattern and liquid dispersion performance.However,the effect of surface wettability on the impaction phenomena at microscale such as liquid film is still unknown.In this work,the dynamic behavior of liquid film on the surface of wire mesh was analyzed by computational fluid dynamics simulation.The dynamic behavior of liquid film on the surface of wire mesh can be divided into the following three steps:(1)spreading step;(2)shrinkage process;(3)stabilizing or disappearing step.Effects of surface wettability,as well as operating conditions,on wetting area and liquid film thickness were studied.Compared to the hydrophilic wire mesh,the final wetting area of hydrophobic wire mesh is zero in most cases.The average liquid film thickness on the surface of hydrophilic wire mesh is 30.02–77.29μm,and that of hydrophobic wire mesh is 41.76–237.37μm.This work provided a basic understanding of liquid film flow at microscale on the surface with various surface wettabilities,which can be guiding the packing optimization and design.

Improving Blood Monocyte Energy Metabolism Enhances Its Ability to Phagocytose Amyloid-βand Prevents Alzheimer’s Disease-Type Pathology and Cognitive Deficits

Deficiencies in the clearance of peripheral amyloidβ(Aβ)play a crucial role in the progression of Alzheimer’s disease(AD).Previous studies have shown that the ability of blood monocytes to phagocytose Aβis decreased in AD.However,the exact mechanism of Aβclearance dysfunction in AD monocytes remains unclear.In the present study,we found that blood monocytes in AD mice exhibited decreases in energy metabolism,which was accompanied by cellular senescence,a senescence-associated secretory phenotype,and dysfunctional phagocytosis of Aβ.Improving energy metabolism rejuvenated monocytes and enhanced their ability to phagocytose Aβin vivo and in vitro.Moreover,enhancing blood monocyte Aβphagocytosis by improving energy metabolism alleviated brain Aβdeposition and neuroinflammation and eventually improved cognitive function in AD mice.This study reveals a new mechanism of impaired Aβphagocytosis in monocytes and provides evidence that restoring their energy metabolism may be a novel therapeutic strategy for AD.