基于深度学习和图像处理的马体尺测量设计

以伊犁马为研究对象,通过马场图像采集、实地测量,完成了马体尺测量中关键技术的研究。基于YOLACT实例分割技术,在MS-COCO数据集完成马体与背景的快速、高性能分割;采用边缘检测Canny算子对分割后的图像进行轮廓提取;在获取的马体轮廓上,对比动物特征点的Harris角点检测算法,提出动态网格的测点标定方法,完成马体尺特征点的数据标定,同时部分解决了马体站姿与摄像头不平行带来的体长修正问题;比较Regress及Polynomial的多元线性回归方式,量化、完成马体尺数据中胸围、管围的数据拟合及三维预测,并以像素为640*480两匹伊犁马体图像为例,获得了体尺测量结果。结果表明,基于深度学习和图像测量技术,可有效进行伊犁马体尺的自动测量并将其误差控制在较小范围之间,就大体型动物的体尺测量技术而言,该研究具备范例参考意义。

先锋霉素Ⅰ在马体内代谢动力学特征的研究

本文选用高效液相色谱(HPLC),测定先锋霉素I在4匹成年健康重挽马体内动力学过程。色谱柱采用反相ODS柱[25×4.6mm(ID))柱温35℃,流动相由甲醇:双重蒸馏水:36％醋酸:1.77％磷酸盐缓冲液(40:60:0.1:6)组成。流速为0.8 ml/min。紫外检测器波长为245nm。用高效液相色谱仪测定了不同时间血药浓度数据,符合开放式二室模型,用夏普PC—1500袖珍计算机处理数据。主要动力学参数如下:消除半衰期(t1/2β)为0.50±015(小时),分布半衰期(t1/2α)为0.05±0.01(小时),曲线下面积(AUC)为49.122±29.01(微克/毫升·小时),总表现分布容积(V_d)为0.3050±0.1488(升/公斤),总清除率(CIB)为0.3877±0.1418(毫升/公斤·小时),有效浓度维持时间[TCP(ther)]为2.78±0.49(小时)。按单剂量给药有关参数计算出多剂量给药参数如下:给药间隔时间(τ)为4小时,积累系数(R)为1.00,最高[(C∞)_(man))、平均(C)与最低((C∞)_(min)]稳态浓度分别为223.99(微克/毫升)、12.28(微克/毫升)与0.06(微克/毫升)。首次剂量(D_0~*)为15(毫克/公斤)。

罗卡利马体新种:Rochlimaea heaselae

Rochlimaea、henselae(Rh)系近年发现的罗卡利马体属新种,是引起杆菌性血管瘤(BA)、紫癜性肝病和败血症的病原体。本文就Rh的生物学、遗传学特性、致病性及实验诊断等研究进展作一简介。

Microstructures of TC21 alloys after hydrogenation and dehydrogenation

Microstructural evolution and phase transformation of hydrogenated and dehydrogenated TC21 alloys were investigated by optical microscopy （OM）, X-ray diffraction （XRD） and transmission electron microscopy （TEM）. XRD peaks ofαandβphases after hydrogenation shifted to low angle because of lattice expansion with the solution of hydrogen atoms. Microstructure of TC21 alloy after hydrogenation changed apparently. Compared to the as-received one, the contrasts of equiaxedαphase and transformedβphase under optical microscope were reversed. In addition, XRD and TEM analyses revealed that hydrides and α′ martensite precipitated fromαandβphases. Bulk of twins and some Ti3Al particles were observed in hydrogenated TC21 alloy, which means that hydrogen led to the redistribution of alloying elements inαandβphase. After dehydrogenation, the microstructure of TC21 alloy was similar to that of the as-received one, which consisted ofαandβphases.

High Altitude Adaptation and Phylogenetic Analysis of Tibetan Horse Based on the Mitochondrial Genome

To investigate genetic mechanisms of high altitude adaptations of animals living in the Tibetan Plateau, three mitochondrial genomes （mt-genome） of Tibetan horses living in Naqu （4,500 m） of Tibetan, Zhongdian （3,300 m） and Deqin （3,100 m） of Yunnan province were sequenced. The structures and lengths of these three mt-genomes are similar to the Cheju horse, which is related to Tibetan horses, but little shorter than the Swedish horse. The pair-wise identity of these three horses on nucleotide level is more than 99.3%. When the gene encoding the mitochondrial protein of Tibetan horses was analyzed, we found that NADH6 has higher non-synonymous mutation rate in all of three Tibetan horses. This implies that NADH6 may play a role in Tibetan horses＇ high altitude adaptation. NADH6 is one of the subunits of the complex I in the respiratory chain. Furthermore, 7 D-loop sequences of Tibetan horse from different areas were sequenced, and the phylogeny tree was constructed to study the origin and evolutionary history of Tibetan horses. The result showed that the genetic diverse was high among Tibetan horses. All of Tibetan horses from Naqu were clustered into one clade, and Tibetan horses from Zhongdian and Deqin were clustered into others clades. The first molecular evidence of Tibetan horses indicated in this study is that Tibetan horse population might have multiple origins.

Ni_(56)Mn_(25-x)Cr_xGa_(19)(x=0,2,4,6) high temperature shape memory alloys

The microstructure,martensitic transformation behavior,mechanical and shape memory properties of Ni56Mn25-xCrxGa19（x=0,2,4,6） alloys were investigated.Single phase of martensite with tetragonal structure is present for x=0,and dual-phase containing martensite and γ phase is observed for x≥2.The martensitic transformation peak temperatures decrease monotonically from 401 ℃ for x=0 to 197 ℃ for x=6.The introduction of γ phase by Cr addition is proved to be effective in improving the workability and ductility.The tensile stress and strain are 497 MPa and 8 % for x=4,and 454 MPa and 5.5 % for x=6,respectively.The shape memory strain values are 2.7 % under a residual strain of 4.5 % for x=4,and 1.9 % under a residual strain of 3.5 % for x=6,respectively.

Influence of Ni_4Ti_3 precipitates on phase transformation of NiTi shape memory alloy

Ni Ti shape memory alloy samples were aged for 2 h at 573, 723 and 873 K, respectively. Two R-phase variants are observed in the Ni Ti samples aged at 573 and 723 K, where the orientation relationship between the two R-phase variants and the B2 matrix is determined. In the Ni Ti samples aged at 573 and 723 K, fine and homogeneous Ni4Ti3 precipitates are coherent with the B2 austenite matrix. The Ni4Ti3 particles precipitate in the grain interior and at the grain boundaries, where the heterogeneous Ni4Ti3 precipitates are coherent, semi-coherent and incoherent with the B2 matrix in the Ni Ti sample aged at 873 K. As for the Ni Ti sample aged at 873 K, one-stage phase transformation from B19＇ martensite to B2 austenite occurs on heating, but two-stage phase transformation of B2-R-B19＇ arises on cooling. The Ni Ti sample aged at 723 K shows two-stage phase transformation of B2-R-B19＇ on cooling as well, but exhibits two-stage phase transformation of B19＇-R-B2 on heating. The Ni Ti sample aged at 573 K exhibits three-stage transformation on cooling due to local stress inhomogeneity and local composition inhomogeneity around the Ni4Ti3 precipitates.

Constitutive modeling of hot deformation behavior of X20Cr13 martensitic stainless steel with strain effect

Hot deformation behavior ofX20Cr13 martensitic stainless steel was investigated by conducting hot compression tests on Gleeble-1500D thermo-mechanical simulator at the temperature ranging from 1173 to 1423 K and the strain rate ranging from 0.001 to 10 s^-1. The material constants of a and n, activation energy Q and A were calculated as a function of strain by a fifth-order polynomial fit. Constitutive models incorporating deformation temperature, strain rate and strain were developed to model the hot deformation behavior of X20Cr13 martensitic stainless steel based on the Arrhenius equation. The predictable efficiency of the developed constitutive models of X20Cr13 martensitic stainless steel was analyzed by correlation coefficient and average absolute relative error which are 0.996 and 3.22%, respectively.

Antiphase boundary-like structure in α′′ martensite of TC21 titanium alloy

The morphology and formation mechanism of the substructure of martensite in TC21 alloy was investigated by XRD and TEM. The results showed that the martensitic transformation from β to α＂ occurs upon quenching after solution treatment between 960-1000 ℃. The antiphase boundary （APB）-like structure was observed clearly in the α＂ martensite plates. The APB-like contrasts exist along the （001） and （020） planes of α＂ martensite. This APB-like structure of α＂ martensite was identified as a kind of stacking fault with an APB-like morphology induced by martensitic transformation and not by order/disorder transition. During martensitic transformation, martensitic domains nucleate and grow, eventually encounter each other, resulting in the formation of the APBdike contrast.

Phase transformation and damping behavior of lightweight porous TiNiCu alloys fabricated by powder metallurgy process

Porous TiNiCu ternary shape memory alloys （SMAs） were successfully fabricated by powder metallurgy method. The microstructure, martensitic transformation behavior, damping performance and mechanical properties of the fabricated alloys were intensively studied. It is found that the apparent density of alloys decreases with increasing the Cu content, the porous Ti50Ni40Cu10 alloy exhibits wide endothermic and exothermic peaks arisen from the hysteresis of martensitic transformations, while the porous Ti50Ni30Cu20 alloy shows much stronger and narrower endothermic and exothermic peaks owing to the B2-B19 transformation taking place easily. Moreover, the porous Ti50Ni40Cu10 alloy shows a lower shape recovery rate than the porous Ti50Ni50 alloy, while the porous Ti50Ni30Cu20 alloy behaves reversely. In addition, the damping capacity （or internal friction, IF） of the porous TiNiCu alloys increases with increasing the Cu content. The porous Ti50Ni30Cu20 alloy has very high equivalent internal friction, with the maximum equivalent internal friction value five times higher than that of the porous Ti50Ni50 alloy.

Influence of cooling rate on phase transformation and microstructure of Ti-50.9%Ni shape memory alloy

Heat treatment of Ti-50.9%Ni （mole fraction） alloy was studied by differential scanning calorimetry, X-ray diffraction, scanning electron microscopey and energy dispersive X-ray analysis to investigate the influence of cooling rate on transformation behavior and microstructures of NiTi shape memory alloy. The experimental results show that three-stage phase transformation can be induced at a very low cooling rate such as cooling in furnace. The cooling rate also has a great influence on the phase transformation temperatures. Both martensitic start transformation temperature （Ms） and martensitic finish transformation temperature （Mf） decrease with the decrease of the cooling rate, and decreasing the cooling rate contributes to enhancing the M→A austenite transformation temperature. The phase transformation hysteresis （Af-Mf） increases with the decrease of the cooling rate. Heat treatment is unable to eliminate the textures formed in hot working of NiTi sample, but can weaken the intensity of them. The cooling rate has little influence on the grain size.

Construction and Analysis of Asexual Mutant Population of Tetraploid Potato Longshu 7 Induced by EMS

[Objective] This study was conducted to detect the variation induction ability of ethyl methanesulfonate （EMS）, to construct a mutant population. [Method] 0.6%, 1.2% and 2.4% EMS solutions were used for inducing 2 400 stem segments of test-tube plantlets of tetraploid potato Longshu 7, and an asexual mutant population including leaf, plant type, stem, stolon, glandular hair traits was constructed. [Result] Twenty two mutation types, i.e. etiolated plantlet, albino plantlet, leaf-color gradient, etiolated vein, wrapped bud, lobed leaf, crinkled leaf, deformed compound leaf, cluster, branch, top enlargement, top bifurcation, succulent, stolon distortion, stolon shift, early tuberization, hair stolon, stem enlargement, vine stem, foliage stem, glandular hair and whorled leaf types were observed in total. There were 52 mutant single plants in total, with a mutation rate of 21.67‰. [Conclusion] The glandular hair, clustered short-stem, branched stem and early tuberization types of mutants have higher application value, and are anticipated to be used in potato functional genome research, gene improvement and germplasm innovation.

Microstructure and transformation behavior of Ni_(54)Mn_(25)Ga_(15)Al_6 high-temperature shape memory alloy

The microstructure, martensitic transformation behavior, mechanical properties and shape memory effect of Ni54Mn25Ga15Al6 high-temperature shape memory alloy were investigated. By comparing with the Ni54Mn25Ga21 alloy, the effect of Al addition on the properties of Ni-Mn-Ga alloys was analyzed. The results show that the Ni54Mn25Ga15Al6 alloy has a single-phase tetragonal non-modulated martensite structure with lamellar twins. The martensitic transformation start temperature of this alloy is up to 190 ℃, displaying the promising application as a high-temperature shape memory alloy. Al addition in Ni-Mn-Ga alloy can decrease the martensitic transformation temperatures due to the effect of size factor and improve the strength and plasticity. However, the shape memory effect is reduced remarkably with the Al addition.

Magnetocaloric effect in Ni-Mn-In-Co microwires prepared by Taylor-Ulitovsky method

Ni-Mn-In-Co microwires with diameter of 30-100 μm are prepared by glass-coated metal filaments（Taylor–Ulitovsky） method. The effects of magnetic field on martensite transformation temperature in the as-prepared and annealed microwires are investigated using a physical property measurement system（PPMS）. Magnetocaloric effect（MCE） attributed to field-induced austenite transformation in the as-prepared and annealed microwires is analyzed indirectly from the isothermal magnetization（M-B） curves. The as-prepared microwire has a 7-layer modulated martensite structure（7M） at room temperature. The changes of austenite starting temperature induced by an external magnetic field（ΔAs/ΔB） in the as-prepared and annealed microwires are-1.6 and-4 K/T, respectively. Inverse martensite to austenite transformation exists in annealed microwires when an external magnetic field is applied at temperatures near As. The entropy change（ΔS） obtained in the annealed microwires is 3.0 J/（kg·K）, which is much larger than that in the as-prepared microwires 0.5 J/（kg·K）. The large entropy change and low price make Ni-Mn-In-Co microwires a potential working material in magnetic refrigeration.

Construction of Efficient Multiple Planting Patterns of Potato for Tridimensional Climate in Subtropical Region of China

[Objective] The aim was to make full use of light-heat resources to expand the potato planting area on the base of ensuring the production of main grain crops and the limited arable land. [Methods] Through catch crops, multiple cropping and intercropping, new multiple planting patterns of potato with efficiency are constructed, for the purpose of increasing yield and benefit of potato. [Result] In irrigated plain and hill area, three new planting patterns such as autumn potato/rope-rice,winter potato-rice-autumn potato, and autumn（winter） potato-rice were constructed.In dry land of plain and hill area, three new planting patterns such as spring（winter）potato/maize/sweet potato, spring（winter） potato/maize-autumn potato, and wheat ＋ winter potato/maize/sweet potato were constructed. In plateau mountainous area, spring potato/maize was constructed. [Conclusion] With use of new planting patterns, the cropping index of new patterns was 200%-300%, while the accumulated temperature utilization was 68.9%-93.4%, light energy utilization was 0.98%-1.59% and straw utilization was 50%-100%. To compared with traditional planting patterns, the yield increased by 2.6%-93%, and benefit increased by 15.8%-284.3%. Furthermore,multiple planting patterns of potato have become main planting patterns in increasing yield and income in Sichuan.

Influence of recovery heating rate on shape memory effect in up-quenched Cu-Al-Mn alloy

The effect of recovery heating rate on shape memory effect of the up-quenched Cu-8.88Al-10.27Mn（mass fraction, %） alloy was investigated by optical microscopy, electron transmission microscopy（TEM） and electrical resistivity measurement. It is found that the shape recovery rate decreases as the heating rate decreases. It can reach 75% when the heating rate is 20 ℃/min, while it is only 8% when the heating rate is 1 ℃/min. In situ microstructure observation indicates that the dependence of shape memory effect on recovery heating rate is caused by the stabilization of twinned martensite induced by deformation. The analysis of electrical resistivity shows that the stabilization of twinned martensite may be ascribed to formation of compound defects of vacancies and dislocations at the boundaries of twinned martensite during the slow heating. The compound defects prevent the reverse transformation of twinned martensite.

Modeling of Ni_4Ti_3 precipitation during stress-free and stress-assisted aging of bi-crystalline NiTi shape memory alloys

The phase field method was applied to study the microstructure evolution of Ni4Ti3 precipitates during stress-free and stress-assisted aging of bi-crystalline NiTi shape memory alloys （SAMs） with two different initial Ni-contents of 51.5% and 52.5% （mole fraction）, respectively. The simulation results show that, during stress-free aging of the NiTi alloy with a low supersaturation of Ni （i.e., Ti-51.5%Ni）, the Ni4Ti3 precipitates exhibit a heterogeneous distribution with a high number density of particles at the grain boundary, leaving most of the grain interiors free of precipitates; while for the NiTi alloy with a high supersaturation of Ni （i.e., Ti-52.5%Ni）, the Ni4Ti3 precipitates show a homogeneous distribution across the entire simulation system. The stress-assisted aging can give rise to homogeneous distribution of the precipitates, regardless of the initial Ni-content; however, the distribution of variant type within the two grains is heterogeneous.

Evaluation model of individual thermal comfort based on mean skin temperature

The local skin temperatures of 22 subjects at air temperatures of 21,24,26,29 ℃ are measured,and the mean skin temperatures are calculated by ten skin temperature measuring points.The thermal comfort levels and the thermal sensations of these subjects are also investigated by a questionnaire.The Mahalanobis distance discrimination method is applied to establish the evaluation model for the thermal comfort based on the mean skin temperature.The experimental results indicate that the difference of the mean skin temperatures between the comfort level and the discomfort level is significant.Using the evaluation model,the mean skin temperature at the thermal comfort level is 32.6 to 33.7 ℃,and the thermal comfort levels of 72% of the subjects are correctly evaluated.The accuracy of the evaluation model can be improved when the effects of sex of the subject on the mean skin temperature and the thermal comfort are considered.It can be concluded that the mean skin temperature can be used as an effective physiological indicator to evaluate human thermal comfort in a steady thermal environment.

Effect of Sn substitution and heat treatment on microstructure and microhardness of Co_(38)Ni_(34)Al_(28-x)Sn_x magnetic shape memory alloys

Sn was used to replace Al in Co38Ni34Al28 alloy. The microstructure and microhardness of Co38Ni34Al28-xSnx （x=0, 1, 2, 3） magnetic shape memory alloys were investigated at different heat treatment temperatures （1373 K, 1473 K, and 1573 K） for 2 h. The results show that more Sn substitution reduces the content of γ-phase and a partial phase of martensite can be obtained in Co38Ni34Al28-xSnx （x=1, 2, 3） alloys after treatment at 1573 K for 2 h. The maximum martensite phase appears when 2% Al is substituted by Sn. The reverse martensitic transformation temperature of Co38Ni34Al28-xSnx alloys increases at x=1 and 2, then decreases as x=3. As the content of Sn and the temperature increase, the microhardness will increase.