Role of micro-Ca/In alloying in tailoring the microstructural characteristics and discharge performance of dilute Mg-Bi-Sn-based alloys as anodes for Mg-air batteries

The influence of micro-Ca/In alloying on the microstructural charac teristics,electrochemical behaviors and discharge properties of extruded dilute Mg-0.5Bi-0.5Sn-based(wt.%)alloys as anodes for Mg-air batteries are evaluated.The grain size and texture intensity of the Mg-Bi-Sn-based alloys are significantly decreased after the Ca/In alloying,particularly for the In-containing alloy.Note that,in addition to nanoscale Mg_(3)Bi_(2)phase,a new microscale Mg_(2)Bi_(2)Ca phase forms in the Ca-containing alloy.The electrochemical test results demonstrate that Ca/In micro-alloying can enhance the electrochemical activity.Using In to alloy the Mg-Bi-Sn-based alloy is effective in restricting the cathodic hydrogen evolution(CHE)kinetics,leading to a low self-corrosion rate,while severe CHE occurred after Ca alloying.The micro-alloying of Ca/In to Mg-Bi-Sn-based alloy strongly deteriorates the compactness of discharge products film and mitigates the"chunk effect"(CE),hence the cell voltage,anodic efficiency as well as discharge capacity are greatly improved.The In-containing alloy exhibits outstanding discharge performance under the combined effect of the modified microstructure and discharge products,thus making it a potential anode material for primary Mg-air battery.

两步升温热轧工艺对AZ31镁合金薄板各向异性及成形性能影响

采用两步梯度升温轧制工艺对AZ31镁合金板材进行轧制,探究轧制过程对镁合金板材显微组织织演化、各向异性及成形性能的影响。第I步轧制在300℃开展,其每道次压下量为15%;第II步轧制在550℃进行,其每道次压下量为40%。经过共4道次轧制后,最终获得厚度为1 mm的镁合金薄板。结果显示,第I步低温轧制过程不更换轧制方向时,试样中生成大量剪切带;而更换轧制方向时,组织内部主要为孪晶和再结晶晶粒。随着II步轧制温度的升高,由于动态再结晶急剧激发,剪切带数量及尺寸逐渐减小,晶粒明显细化。根据IGMA分析得出,非基面滑移,特别是棱柱面滑移活动增强。轧制退火后的AZ31镁合金薄板的力学性能得到提高,各向异性减小,冲压成形性能得到明显改善。

Factors influencing discharge readiness among patients with mild-to-moderate ischemic stroke:a cross-sectional study

Objective:To describe discharge readiness and determine whether self-efficacy,social support,and the quality of discharge teaching can predict discharge readiness among patients with mild-to-moderate ischemic stroke.Methods:A total of 120 patients with mild-to-moderate ischemic stroke were recruited using simple random sampling.Five instruments,namely,the Demographic Data Questionnaire,the Chinese version of the Readiness for Hospital Discharge Scale(RHDS_C),the SelfEfficacy for Managing Chronic Disease 6-Item Scale(SES6),the Perceived Social Support Scale(PSSS),and the Quality of Discharge Teaching Scale(QDTS),were used for data collection.Descriptive statistics and standard multiple linear regression were used for data analysis.Results:The mean score of discharge readiness among patients with mild-to-moderate ischemic stroke was at a moderate level(M=7.6,SD=0.92),and 75.8%of the participants felt ready for discharge.Standard multiple linear regression revealed that selfefficacy(β=0.62,P<0.001)and the quality of discharge teaching(β=0.28,P<0.001)were the influencing factors.However,social support could not predict discharge readiness significantly.All the factors combined explained 64.9%of the variance in discharge readiness.Conclusions:Intervention programs aimed at improving self-efficacy and the quality of discharge teaching may be helpful in promoting discharge readiness in patients with mild-to-moderate ischemic stroke,especially in coping ability.

挤压态低合金化Mg-0.5Bi-0.5Y-0.2Zn合金的腐蚀行为及力学性能

研发一种新型低合金化Mg-Bi-Y-Zn合金系,该合金系在673 K的挤压温度下成功成型。通过扫描电子显微镜(SEM)、电子背散射衍射(EBSD)、电化学试验和拉伸试验研究挤压态合金的腐蚀行为和拉伸性能。挤压后,合金表现出几乎完全的动态再结晶组织和典型的挤压织构,在晶粒内可以观察到一些亚微米级析出相。在SBF溶液中,合金的腐蚀模式由最初的点蚀为主转变为中间过程的丝状腐蚀为主;最后经长时间浸泡后,腐蚀模式转变为丝状腐蚀和局部晶粒脱落。挤压态Mg-0.5Bi-0.5Y-0.2Zn合金的屈服强度为237 MPa,极限抗拉强度为304 MPa,伸长率为31%,平均腐蚀速率为0.14 mm/a。由此可见,该合金表现出良好的拉伸性能和耐腐蚀性能匹配度,这主要归因于其均匀的晶粒结构和亚微米级析出相。因此本文所研发的Mg-0.5Bi-0.5Y-0.2Zn合金具有在生物医药领域的广阔应用前景。

Tailoring the microstructural characteristics and enhancing creep properties of as-cast Mg-5Bi-5Sn alloy through Mn addition

The creep properties, microstructural characteristics and creep mechanisms of as-cast Mg-5Bi-5Sn(BT55) alloy without and with Mn(BTM550) addition were investigated via creep at 423, 448, and 473 K as well as stresses of 30, 50 and 75 MPa. The results indicate that adding Mn can result in the formation of primary and the dynamic precipitated α-Mn phases. In addition, the morphology of the precipitated Mg_(3)Bi_(2) phase and the orientation relationship between Mg_(2)Sn precipitates and α-Mg can be effectively modified. Tailoring the microstructural characteristics is responsible for the improved creep performance of BTM550 alloy. The dominant creep mechanisms in BT55 and BTM550 alloys are dislocation cross-slip and climb, respectively. Furthermore, twinning and pyramidal slip play an assisting part in both alloys during creep process.

Diagnosis of tuberculous uveitis by the macrogenome of intraocular fluid:A case report and review of the literature

BACKGROUND Tuberculous uveitis caused by tuberculosis infection factors is common,but tuberculous uveitis caused by Mycobacterium tuberculosis found in the intraocular fluid is rare.This report describes the use of intraocular fluid in the diagnosis of tuberculous uveitis in a patient and reviews the relevant literature.CASE SUMMARY A 24-year-old woman who was 31-wk pregnant visited Hebei Chest Hospital due to intermittent chest pain,fever,and decreased vision for 3 mo.The hydrothorax test suggested“tuberculous pleurisy”,and yellow effusion was extracted from the chest tube twice resulting in a total volume of approximately 800 mL.The patient chose to continue the pregnancy without treatment,and was hospitalized again due to high fever.Following 2 mo of anti-tuberculosis treatment,a healthy boy was delivered by cesarean section.Tuberculous uveitis was diagnosed using tuberculosis Xpert,and intraocular infection was detected by second-generation gene sequencing.Following systemic treatment,the patient gradually improved,and the corrected visual acuity of the left eye gradually increased from 0.08 to 1.0.CONCLUSION The etiology of uveitis is complex,and it is necessary to assess the patient’s general condition and apply molecular biology methods to determine the pathogenesis and guide precise treatment,to improve clinicians’awareness and standardize treatment of the disease.

Mechanical properties of Mg-Gd-Zr alloy by Nd addition combined with hot extrusion

The effect of Nd addition on the microstructure and mechanical properties of as-extruded Mg-9Gd-0.5Zr(wt.%) alloy was investigated. The Mg-9Gd-0.5Zr and Mg-9Gd-2Nd-0.5Zr alloys were extruded at 673 K. The elongated non-dynamic recrystallized(un-DRXed) grains disappear after adding Nd, and uniformly distributed dynamic recrystallized grains with a grain size of 1.68 μm were obtained in the alloy. In addition, numerous nano-Mg5(Gd,Nd)particles were found to precipitate dynamically in the Mg-9Gd-2Nd-0.5Zr alloy, which gave rise to the dynamic recrystallization process via providing nucleation energy through hindering the release of deformation energy and promoting an increase in the strength through the Orowan strengthening mechanism. Moreover, the dynamically recrystallized(DRXed) grains have a weak texture, which plays a significant role in improving the ductility. Therefore,the Nd addition favors the improvement of strength and elongation for the as-extruded Mg-9Gd-0.5Zr alloy,simultaneously.

Inhibition of Obtusifolin on retinal pigment epithelial cell growth under hypoxia

AIM: To explore the effect of Obtusifolin on retinal pigment epithelial cell growth under hypoxia.METHODS: In vitro chemical hypoxia model of ARPE-19 cells was established using cobalt chloride(CoCl2). Cell viability was tested by cell counting kit-8(CCK-8) assay. Western blot and real-time quantitative polymerase chain reaction were applied to detect proteins and mRNAs respectively. Flow cytometry was used to examine the cell cycle. Secretion of vascular endothelial growth factor(VEGF) was tested by using enzyme linked immunosorbent assay(ELISA).RESULTS: Under the chemical hypoxia model established by CoCl2, hypoxia inducible factor-1α(HIF-1α) mRNA and protein levels was up-regulated. Cell viability was increased and the proportion of S phase was higher. Obtusifolin could reduce cell viability under hypoxic conditions and arrest cells in G1 phase. Obtusifolin reduced the expression of Cyclin D1 and proliferating cell nuclear antigen(PCNA) in the hypoxic environment and increased the expression of p53 and p21. The levels of VEGF, VEGFR2 and eNOS proteins and mRNA were significantly increased under hypoxia while Obtusifolin inhibited the increasing.CONCLUSION: Obtusifolin can inhibit cell growth under hypoxic conditions and down-regulate HIF-1/VEGF/eNOS secretions in ARPE-19 cells.

Effect of isotope on state-to-state dynamics for reactive collision reactions O(3P)+H2^+→OH^++H and O(3P)+H2^+→OH+H^+ in ground state 1^2A" and first excited 1^2A' potential energy surfaces

We carry out quantum scattering dynamics and quasi-classical trajectory（QCT） calculations for the O+H2+ reactive collision in the ground（12 A"）.nd first excited（12 A’） potential energy surface.We calculate the reaction probabilities of O+H2+（v=0,j=0）→OH++H and O+H2+（v=0,j=0）→OH+H+reaction for total angular momentum J=0.The results calculated by QCT are consistent with those from quantum mechanical wave packet.Using the QCT method,we generate in the center-of-mass frame the product state-resolved integral cross-sections（ICSs）;two commonly used generalized polarization-dependent differential cross-sections（PDDCS s）,（2π/σ）(dσ00/dωt),（2π/σ）(dσ20/dωt));and three angular distributions of the product rotational vectors,p（θr）,P（φr）,and p（θr,φr）.We discuss the influence on the scalar and vector properties of the potential energy surface,the collision energy,and the isotope mass.Since there are deep potential wells in these two potential energy surfaces,their kinetic characteristics are similar to each other and the isotopic effect is not obvious.However,the well depths and configurations of the two potential energy surfaces are different,so the effects of isotopic substitution on the integral cross-section and the rotational polarization of product are different.

Multimodal imaging study of lipemia retinalis with diabetic retinopathy:A case report

BACKGROUND Lipemia retinalis(LR)is a rare disease related to hypertriglyceridemia.However,the symptoms of hypertriglyceridemia are insidious and difficult to detect without blood tests.The fundus is the only site where blood vessels can be observed directly.Understanding the specific performance of LR in multimodal imaging fundus examinations can help diagnose more patients with abnormal hyperlipidemia.CASE SUMMARY A 29-year-old woman with type 2 diabetes presented to our clinic complaining of a six-day loss of visual acuity in the left eye.The fundus color images showed typical LR:Arteries and veins were the same pink-white color.Infrared images showed hyperinfrared reflections of the arteries and veins.Optical coherence tomography(OCT)showed numerous high point-like reflections in the retinal section,corresponding to different calibers of blood vessel sections.Medium reflections were seen in the big vessels of the choroid.Fundus fluorescein angiography(FFA)and optical coherence tomography angiography(OCTA)showed no significant changes.Laboratory examination found a total cholesterol level of 13.98 mmol/L,triglyceride 20.55 mmol/L,which confirmed the diagnosis of LR.After treatment to lower blood lipids and control blood glucose,the fundus imaging showed that the blood lipids in the patient had returned to normal.CONCLUSION LR shows specific changes in fundus color photography,infrared photography,and OCT.FFA and OCTA were not sensitive to LR changes.

Effects ofslip mode on microstructure evolution and compressive flow behavior of extruded dilute Mg−0.5Bi−0.5Sn−0.5Mn alloy

The influence of the slip mode on the microstructure evolution and compressive flow behavior at different strains in an extruded dilute Mg−0.5Bi−0.5Sn−0.5Mn alloy was analyzed through electron backscatter diffraction,X-ray diffraction,transmission electron microscopy,and hot compression tests.The results showed that at a low strain of 0.05,the basal<a>,pyramidal<a>and<c+a>slip modes were simultaneously activated.Nevertheless,at the middle stage of deformation(strain of 0.1,0.2 and 0.5),the<a>slip mode was difficult to be activated and<c+a>slip mode became dominant.The deformation process between strains of 0.2 and 0.5 was primarily characterized by the softening effect resulting from the simultaneous occurrence of continuous dynamic recrystallization and discontinuous dynamic recrystallization.Ultimately,at strain of 0.8,a dynamic equilibrium was established,with the flow stress remaining constant due to the interplay between the dynamic softening brought about by discontinuous dynamic recrystallization and the work-hardening effect induced by the activation of the basal<a>slip mode.

Tailoring the microstructure and improving the discharge properties of dilute Mg-Sn-Mn-Ca alloy as anode for Mg-air battery through homogenization prior to extrusion

Mg-0.5Sn-0.5Mn-0.5Ca(wt.%) alloys with different microstructures are designed through casting and extrusion with and without homogenization treatment prior to extrusion(HPE).The influence of HPE treatment on the microstructural characteristics and resultant discharge properties of Mg-Sn-Mn-Ca alloy in extruded condition as anode for Mg-air battery was investigated.HPE treatment exerts a prominent effect on the grain structure and orientation,distribution of the second phase particles as well as the dislocation density of the extruded alloy.The HPE alloy exhibits a distinctly high cell voltage together with specific energy compared with that of Non-HPE one.Intermittent discharge tests confirm that the HPE alloy possesses a more excellent discharge activity and more stable discharge process than the NonHPE one.All results demonstrate that the HPE alloy is an attractive anode material for Mg-air battery with long-term storage and under intermittent discharge.

Unveiling the twinning and dynamic recrystallization behavior and the resultant texture evolution in the extruded Mg-Bi binary alloys during hot compression

The twinning behavior, dynamic recrystallization(DRX) mechanism and the resultant texture evolution of the extruded Mg-xBi(x=0.5 wt.%, 2.0 wt.%) alloys were systematically investigated during hot compression at the strain rate of 10 s^(-1) and temperature of 200℃. The results indicate that the types and intensities of the texture are greatly dependent on the twining behavior and DRX mechanism. At the initial stage, the evolution of texture is mainly domination by the formation and variation of {1012} extension twins, which is benefcial to the compression direction(CD)-tilted basal texture. With an increase in the strain, the texture evolution is more greatly regulated by the DRX mechanism. Besides, the pyramidal<c + a> slip and basal slip are activated during the compression process, resulting in the Schmid factors(SF) of pyramidal slip remain at ~0.4 and the average SFs for basal slip increase from 0.2 to0.34 as the strain increase. These fndings provide a new insight into controlling the texture of wrought Mg-Bi-based alloys during hot deformation processing.