Seasonally reproducing animals show many behavioral and physiological changes during the mating period, including increased signaling for intrasexual competition and mate attraction. We collected 102 anogenital gland ...
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Seasonally reproducing animals show many behavioral and physiological changes during the mating period, including increased signaling for intrasexual competition and mate attraction. We collected 102 anogenital gland secretions(AGS) from marking trees in Foping Nature Reserve, and used gas chromatography mass spectrometry to analyze these chemical composition. Of these marks, all but one were from males, confirmed with DNA analysis. We found that several chemical constituents, especially volatile compounds, were present only during the mating season and that the relative abundance of many compounds changed as a function of breeding season, whereas nonvolatile compounds were lower in the mating season. This seasonal variation in chemical composition of AGS most likely plays an important role in governing giant panda reproduction, including mate location, attraction, and male-male competition. The chemical properties of many of these putative chemosignals—such as volatility and longevity—are suggestive of these roles, and undoubtedly contribute to successful reproduction for this species with a characteristically sophisticated chemical communication system. We also found a number of important differences between the chemical constituents of AGS from wild pandas and those found in previous studies with captive pandas, suggesting that inappropriate chemosignal composition may contribute to poor reproductive success in captive breeding programs.
目的系统评价关于早发型痴呆症患者照顾者角色过渡体验的质性研究。方法计算机检索Cochrane Library、PubMed、Web of Science、Embase、中国知网、万方数据库、维普网、中国生物医学文献数据库中关于早发型痴呆症患者照顾者角色过渡体...
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目的系统评价关于早发型痴呆症患者照顾者角色过渡体验的质性研究。方法计算机检索Cochrane Library、PubMed、Web of Science、Embase、中国知网、万方数据库、维普网、中国生物医学文献数据库中关于早发型痴呆症患者照顾者角色过渡体验的质性研究,检索时限为建库至2024年5月。采用澳大利亚乔安娜布里格斯研究所循证卫生保健中心质性研究质量评价标准对文献进行质量评价,应用汇集性整合方法对结果进行Meta整合。结果共纳入14篇文献,提炼出46个结果,归纳形成9个类别,综合得出3个整合结果,分别为个人及家庭受到多重困扰、过渡期间角色支持需求强烈、积极应对并获得角色成长。结论早发型痴呆症患者照顾者在角色过渡期间存在多重困扰和多样化的照护需求,在此过程中积极应对可收获角色成长。
A SnBiSb low-temperature lead-free solder and a preparation method therefor, related to the technical field of low-temperature soft solders. The compositionthe lead-free solder in percentage by mass is: 32.8-56.5％ of...
标准号:
WO2018028080(A1)
A SnBiSb low-temperature lead-free solder and a preparation method therefor, related to the technical field of low-temperature soft solders. The compositionthe lead-free solder in percentage by mass is: 32.8-56.5％ of Bi, 0.7-2.2％ of Sb, the remainder Sn, and the percentages by mass of Bi and Sb satisfy the relationship of b = 0.006a2 – 0.672a + 19.61 + c, where a is the percentage by mass of Bi, b is the percentage by mass of Sb, and c is in the range of -1.85 ≤ c ≤ 1.85. The solder alloy is an eutectic or near-eutectic composition, has a low melting point, provides great mechanical properties and reliability, and is applicable in the field of low-temperature soft solders.
The use of externally-bonded Carbon Fibre Reinforced Polymer (CFRP) sheet is a promising and effective method for increasing the shear and flexural strength of existing timber members. This study examines the bond beh...
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ISBN:
(纸本)9781315641645;9781138029279
The use of externally-bonded Carbon Fibre Reinforced Polymer (CFRP) sheet is a promising and effective method for increasing the shear and flexural strength of existing timber members. This study examines the bond behaviour of CFRP sheet adhesively bonded to a Douglas Fir timber substrate using a single-shear pull-off test. Eleven specimens were tested to analyse the failure mechanism, FRP strain and FRP-timber interfacial bond stress distributions. The influence of parameters including bond length and width are also discussed. The concept of effective bond length was demonstrated to be applicable for CFRP-to-timber bonded systems, which was found to be approximately 60 mm and 40 mm for the 0.167 mm and 0.111 mm thick CFRP sheets used in this study.
Throughout the development of electronic packaging technology, Sn-58Bi lead-free solder has been widely applied because of its low-temperature welding. However, during the production process, the formation of solder b...
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ISBN:
(纸本)9781509013968
Throughout the development of electronic packaging technology, Sn-58Bi lead-free solder has been widely applied because of its low-temperature welding. However, during the production process, the formation of solder bead is a terrible problem that is commonly encountered with Sn-58Bi solder joint. This problem not only damages the macroscopic appearance of the solder joint, but may encompass other solder joints as well. Due to factors such as vibration and temperature variation, the formation of solder bead could potentially lead to circuit fault. The purpose of this study is to investigate how the oxidation of Sn-58Bi solder powder, under different temperature and humidity, impacts the formation of solder bead and microstructure of the solder joint. The scanning electron microscope and auger electron spectroscopy were used to analyze the oxidation process of Sn-58Bi solder powder. The results indicated that, the formation of solder bead was enhanced with the increased temperature and humidity which also led to the deteriorated microstructure and poor wettability. In addition, the oxidation behavior of Sn-58Bi solder powder revolved around the adsorption and decomposition of 0 molecules and the subsequent interaction between the 0 atoms with the Bi atoms.
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