Effects of a combination therapy with a compound Chinese medicine and an enteral nutrition powder in the treatment of mice with chronic obstructive pulmonary diseases

目的 评估健脾益气复方中药颗粒剂联合肠内营养粉剂安素治疗慢性阻塞性肺疾病（COPD）的有效性与安全性。方法 选取雄性小鼠96只,其中24只作为正常对照组,其余72只采用烟熏小鼠法建立COPD模型,随机分3组：COPD模型组、安素治疗组（0.558 g/m L安素,0.1 m L/10 g小鼠）及中药联合安素治疗组（0.558 g/m L安素,0.1 m L/10 g小鼠＋2.5 g/m L中药,0.06 m L/10 g小鼠）。所有小鼠在实验全程进行体重监测,并分别在治疗前、治疗后2周及5周进行血清学检测及肺组织切片检查。结果 与正常对照组小鼠相比,COPD模型组小鼠体重增加明显减缓,血清总蛋白和白蛋白含量均明显降低（P〈0.05）,血清谷草转氨酶和谷丙转氨酶含量均明显升高（P〈0.05）。与COPD模型组小鼠相比,中药联合安素治疗组小鼠的体重明显回升,治疗后5周,血清总蛋白和白蛋白含量均显著增加（P〈0.05）,血清谷草转氨酶和谷丙转氨酶含量均明显下降（P〈0.05）。病理切片结果也证实了中药联合安素治疗对COPD肺部病理改变具有明显改善作用。结论 健脾益气复方中药联合肠内营养粉剂安素可明显改善COPD营养不良状况,并有效改善其肺组织受损情况。Objective To evaluate the validity and safety of a combination therapy with a compound Chinese medicine and an enteral nutrition powder ensure on chronic obstructive pulmonary diseases （COPD）. Methods Among 96 male mice, 24 mice were randomly selected as a normal control group, the other 72 mice were induced as COPD mice after 60-day smoking. These COPD mice were then randomly divided into 3 groups： COPD positive group, Ensure treatment group （0.558 g/mL Ensure, 0.1 mL/10 g mice）, combina- tion therapy group （0.558 g/mL Ensure, 0.1 mL/10 g mice＋2.5 g/mL traditional Chinese medicin, 0.06 mL/10 g mice）. The weights of all mice were monitored during the whole experimental period. The serologic tests were carried out before and at different time points （2 weeks or 5 weeks） after the treatments began. Meanwhile, histological examinations of their lungs were performed. Results Compared with the normal control group mice, COPD mice showed a lower amount of serum albumin （P 〈 0.05） and a higher level of serum aminotransferase activity （P 〈 0.05） with a much slower rate in weight gaining. After 5-week treatments with the combination albumin were increased gradually （P 〈 0.05） therapy, compared with the COPD positive group, the amounts of serum and the serum aminotransferase activities were returned to normal （P 〈 0.05）. Results from histological examinations confirmed the efficacy of the combination therapy on COPD mice. Conclusion The combination therapy with a compound Chinese medicine and an enteral nutrition Ensure is effective in improvement of poor nutrition status in COPD mice induced by smoking, and effectively improve the lung tissue damage.福建省福州市卫生系统科技计划项目（2014-S-W29）;福建省福州市科技计划项目（2015-S-141-4）;福建省福州经济技术开发区科技计划项目（2015mw08）

Investigation on strengthening, toughening and dynamic deformation mechanisms for CoCrNi-based medium entropy alloys with multi-heterogeneous structures

实现金属材料高强高韧性是现代文明永恒的追求目标，也是中国制造2025计划的行动纲领和关键目标，金属材料的强度、塑性对相关产品应用甚至国防工业都有着至关重要的影响。按照金属材料学科传统均质理论，强度上升的同时会不可避免的带来塑性的降低，强度和塑性的此消彼长 (trade-off)&nbsp;现象是制约金属材料工程应用的巨大障碍。中熵合金 (Medium entropy&nbsp;alloys, MEAs)&nbsp;是近些年来兴起的具有三主元金属元素的新型合金，引起了国内外学者广泛的研究。未进行异构化处理的中熵合金呈均匀晶粒结构，按照传统均质理论仍然不可避免的存在强度与塑性的本征矛盾。异质结构 (Heterogeneous structure, HS) 指的是内部具有性能迥异以及塑性变形行为具有显著差异的跨尺度微结构，变形时内部几何必需位错 (Geometrically necessary dislocations, GNDs) 和应变梯度开始产生，从而产生异质变形诱导硬化 (Heterogeneous&nbsp;deformation induced hardening, HDI hardening)，提供应变硬化能力，提升材料综合力学性能，改善强度与塑性的此消彼长，解决高强度材料的塑性瓶颈问题。常见的异构类型为晶粒尺寸异构，双相异构，层片异构，梯度异构等。在中熵合金中构建异构组织能带来很好的性能提升，然而随着应用需求的苛刻化以及科研的深入，单一形式的异构强韧化已经无法满足应用需求，因此将多种异构类型结合进行研究成了目前异构金属材料强韧化领域的一个新的热点。本文基于双相CoCrNi中熵合金进行剧烈的塑性变形和合适的热处理工艺构建出了多重异构组织结构并实现了强韧化，同时分析了力学行为和变形机理，得出结论如下： 基于双相CoCrNi中熵合金 (成分为Co34.5Cr32Ni27.5Al3Ti3&nbsp;,in at%) 进行合适的固溶、冷轧、退火、时效处理，构建出了具有晶粒尺寸异构和纳米沉淀相的复合异构CoCrNi中熵合金，发现其拉伸性能优于均匀晶粒组织结构和单一晶粒尺寸异构组织的CoCrNi中熵合金，在复合异构组织中观察到瞬态上升的应变硬化行为，且时效试样的瞬态硬化行为比未时效试样更为明显。复合异构组织结构在低温下的屈服强度和均匀延伸率均高于室温，低温拉伸变形后，复合异构CoCrNi合金的HDI加工硬化率和GND位错密度增殖幅度均高于室温变形情况。复合异质结构中的L12纳米沉淀相在室温变形下可以通过阻碍位错运动，使得位错在析出相周围堆积堵塞从而带来硬化，析出相在拉扯过程中会变形。低温拉伸下相比室温拉伸应力应变更大，层错和L12纳米析出相的交互作用强烈导致L12纳米析出相破裂碎化，这些破裂碎化后的析出相相当于使得整体L12颗粒物的间距减小，因此与室温拉伸条件下相比，低温也能够提供更大应变硬化。 基于双相CoCrNi中熵合金 (成分为Co34.5Cr32Ni27.5Al3Ti3&nbsp;,in at%) 进行合适的固溶、冷轧、退火、表面机械研磨、时效处理，构建出了具有晶粒尺寸梯度和纳米沉淀相分布梯度的CoCrNi中熵合金，发现与单一晶粒尺寸的梯度结构和含有L12纳米沉淀的均匀粗晶结构相比，双梯度结构的屈服强度和均匀伸长率的协同提升，性能有所改善。与室温相比，双梯度CoCrNi在低温下均具有更高的硬化能力、更强的HDI硬化和更高的GND密度增殖幅度，从而获得更好的低温拉伸性能。室温和低温下，双梯度结构的硬化机制均以高密度的SFs和L-C锁为主。这些SFs和L-C锁一方面可以提供强硬化&nbsp;(动态Hall-Petch效应)，另一方面可以与相干L12纳米析出相相互作用，产生强沉淀硬化。双梯度结构在低温下拥有更好的拉伸性能应归因于特殊的层错诱导塑性，即层错网格的形成及其与纳米沉淀的相互作用。 基于双相CoCrNi中熵合金 (成分为Co34.46Cr32.12Ni27.42Al4Ti2&nbsp;at.%) 进行合适的固溶、冷轧、预时效、退火、时效处理，获得了更随机分布、尺寸更均匀的纳米沉淀相复合异构组织，经过预时效处理的析出相呈均匀分布的试样在没有明显降低强度的情况下，均匀伸长率有大幅度的增加，均匀分布的纳米沉淀相的切割促进位错的平面滑移，有利于GNDs的堆积，产生高幅值的HDI应力，拉伸变形过程中形成了多种类型缺陷，包括层错、L-C锁和9R结构，通过阻碍位错运动和塞积产生了显著的应变硬化水平，由于L12纳米沉淀物的分布更加随机弥散，缺陷与相干L12纳米沉淀物之间的相互作用频率更高，从而获得更好的延展性。 基于双相CoCrNi中熵合金 (成分为Co34.5Cr32Ni</

中高熵合金的动态力学行为研究进展

中高熵合金是近二十年提出的一种多主元金属合金，打破了传统合金以1-2种金属元素为主元的设计理念.中高熵合金由于多主元的成份设计提高了材料的构型熵和混合熵，展现出许多奇特的组织结构和性能.相比铝合金、钛合金以及钢铁等传统金属，中高熵合金表现出优异的准静态力学性能和动态力学性能等.在高应变速率下，材料的塑性变形受到更多因素的影响，如应变率、温度等.本文首先介绍中高熵合金动态力学性能(包括动态剪切、夏比冲击，动态层裂强度，侵彻自锐性等)的相关研究，并总结了中高熵合金动态变形的微结构变形机理；随后综合概括了中高熵合金中绝热剪切带行为和温度效应的研究现状；最后对中高熵合金在冲击动力学领域的应用和研究趋势提出展望

Tensile behaviors and hetero-deformation-induced hardening mechanisms in medium entropy alloys with dual gradients of grain size and coherent nanoprecipitate

Heterogeneous structures with dual gradients of grain size and coherent L12 nanoprecipitation have been designed and fabricated in a Co34.46Cr32.12Ni27.42Al3Ti3 medium entropy alloy. These heterogeneous structures with dual gradients show improved tensile properties over both the single grain-size gradient structure and the coarse grained structures with homogeneously distributed L12 nanoprecipitates. Hetero-deformation-induced hardening rate was observed to be higher and the strain hardening capacities at each depth were also found to be higher in the structures with dual gradients, as compared to the single grain-size gradient structure. Deformation twins and stacking faults were observed at both the topmost and center layers, while deformation bands at two directions were only found at the topmost layer after tensile deformation in the single grain-size gradient structure. Strong interactions between defects and coherent L12 nanoprecipitates can be observed at all depths after tensile deformation in the structures with dual gradients, resulting in strong precipitation hardening. While, stronger precipitation hardening was achieved at the topmost layer due to the higher volume fraction and smaller spacing of coherent L12 nanoprecipitates, which could delay the early necking trend at the topmost layer for better tensile ductility in the structures with dual gradients

异构金属材料的冲击动力学行为研究进展

高强度金属材料往往塑性/韧性较差,而异构金属的微结构设计能够使得金属在获得高强度的同时具有良好的塑性/韧性。因此,异构金属在准静态、动态载荷下的力学行为成为材料力学/冲击动力学的研究热点。综述了梯度结构、双相结构、多尺度晶粒结构等异构金属的动态力学性能及微结构机理方面的研究进展。相比于均匀材料,异构金属表现出更优越的动态剪切韧性和冲击韧性。由于异构材料微观结构的非均匀性,绝热剪切带的萌生与扩展往往不同于均匀材料。异构金属中的界面或软区能够有效抑制绝热剪切带的萌生及扩展,延缓材料失效。异构材料中,非均匀变形产生的额外加工硬化使得异构金属表现出优异的动态力学性能

Enhanced tensile properties by heterogeneous grain structures and coherent precipitates in a CoCrNi-based medium entropy alloy

A dual heterogeneous structure with both heterogeneous grain structure and coherent L1(2) nanoprecipitates was obtained in a CoCrNi-based medium entropy alloy (MEA) with chemical composition of Co34.5Cr32-Ni27.5Al3Ti3 (in at%). The volume fraction of L1(2) phase is observed to become higher and the corresponding interspacing becomes smaller after aging, resulting in a more severe heterogeneity. The unaged samples are found to have better tensile properties as compared to those for the CoCrNi MEA with homogeneous and het-erogeneous grain structures. The aged samples display an even better synergy of strength and ductility than the corresponding unaged samples. The hetero-deformation-induced hardening plays a more important role in the aged samples than in the unaged samples, especially at the elasto-plastic transition stage, producing higher density of geometrically necessary dislocations for better tensile properties. Multiple deformation twins, stacking faults and Lomer-Cottrell locks are the dominant deformation mechanisms for the unaged samples, while in-teractions between these defects and L1(2) nanoprecipitates play important roles in the aged sample, the shearing hardening mechanism is observed for L1(2) nano-particles

Tailoring multi-type nanoprecipitates in high-entropy alloys towards superior tensile properties at cryogenic temperatures

In this work, the quasi-static tensile properties in the face-centered cubic-based Al0.5Cr0.9FeNi2.5V0.2 HEAs containing two types of heterogeneous nanoprecipitates, i.e., dual-lamellar and spherical nanoprecipitates, at ambient (293 K) and liquid nitrogen (77 K) temperatures are thoroughly investigated. The microstructure formed by aging at 873 K comprises L12 and body-centered cubic dual-lamellar (DL) nanoprecipitates. In contrast, aging at 773 K results in solely spherical L12 nanoparticles. Both nanoprecipitates enhance mechanical strength as temperatures drop to 77 K; however, the DL nanoprecipitates additionally boost the work hardening rate, whereas the spherical nanoparticles notably improve ductility. To investigate the underlying deformation mechanisms, we perform interrupted mechanical tests and microstructure characterizations at various strains. The DL nanoprecipitates are observed to go through a multistage work hardening rate response by gradually introducing new boundaries to block dislocation motion, activating the stacking fault (SF) networks, and forming Lomer-Cottrell locks. A combination of interface hardening, dislocation hardening, SF-induced hardening, and precipitation hardening in DL samples leads to stronger hetero-deformation-induced hardening at cryogenic temperatures. In comparison, while samples with only spherical nanoparticles exhibit a monotonous decrease in the work-hardening rate, the spherical nanoparticles can be sheared by dislocations, effectively alleviating strain concentration and thereby enhancing ductility at cryogenic temperatures. Overall, this work provides practical design principles of nanoprecipitates for fine-tuning the balance of strength and ductility in FCC-based HEAs at cryogenic temperatures

Tailoring size and fraction of coherent L12 nanoprecipitates to achieve strong hardening in medium entropy alloys with heterogeneous grain structures

Heterogeneous grain structures with coherent L12 nanoprecipitates were constructed in a medium entropy alloy with chemical composition of Co34.5Cr32Ni27.5Al3Ti3 (at. %). The volume fraction and size of L12 nanoprecipitates are observed to become higher and larger, and the interspacing is found to become smaller with increasing aging time, resulting in a severer heterogeneity. The domain of tensile properties was expanded by varying the size and volume fraction of coherent L12 nanoprecipitates after aging treatment. The samples after longer-time aging treatment show stronger strain hardening as compared to those after shorter-time aging treatment. The hetero-deformation-induced (HDI) hardening plays a more vital role in the longer-time aged samples than the shorter-time aged samples, especially at the elasto-plastic transition stage. The dominant precipitation hardening mechanism is observed to transit from dislocation-cutting to Orowan dislocation-looping with increasing precipitation size, as predicted by a theoretical model and validated by experimental results. Multiple deformation defects, such as deformation twins, stacking faults and Lomer-Cottrell locks, are the dominant deformation mechanisms for all samples, while interactions between these defects and L12 nanoprecipitates were observed to be more intensive in the longer-time aged samples than in the shorter-time aged samples, resulting in stronger precipitation and HDI hardening

Superior tensile properties at cryogenic temperature induced by dual-graded structures in medium entropy alloys

The dual-graded structure with both gradients of grain size and coherent L12 precipitation was applied to a (CoCrNi)96Al3Ti3 medium-entropy alloy for achieving superior tensile properties. Simultaneous improvement on yield strength and uniform elongation is observed in the dual-graded structure at cryogenic temperature, compared to those at room temperature. Stronger hetero-deformation-induced hardening and higher density of geometrically necessary dislocations are observed at cryogenic temperature in both single-grain-size-graded and dual-graded structures. The hardening mechanisms at room temperature are characterized by low density of deformation twins and stacking faults (SFs) on one slip system, while are dominated by high density SFs at two slip systems and formation of Lomer-Cottrell (L-C) locks at cryogenic temperature for the single-graded structure. The hardening mechanisms at both room and cryogenic temperatures are revealed by high density of SFs and L-C locks in the dual-grade structure. These SFs and L-C locks can provide strong hardening themselves as dynamic Hall-Petch effect on one hand, and can interact with coherent L12 precipitates for intense precipitation hardening on the other hand. The better tensile properties for the dual-graded structure at cryogenic temperature should be attributed to a special SF-induced plasticity, i.e., the formation of SF networks and their interactions with nanoprecipitates