The development of Bi Fe O_3-based ceramics

The multiferroic properties of Bi Fe O3-based ceramics were improved through optimizing their sintering method and doping with certain rare earth elements in pure Bi Fe O3. Some methods, especially liquid-phase sintering method has largely decreased the densities of oxygen vacancies and Fe2in Bi Fe O3-based ceramics, and thus their resistivity became high enough to measure the saturated polarization and the large piezoelectric d33 coefficient under the high electric field of [150 k V/cm. Besides,multiferroic properties were improved through the rare earth elements’ doping in pure Bi Fe O3. Magnetization commonly increases with the proportional increase of Nd,La, Sm and Dy contents up to ＊30 %, while ferroelectric phase can transform to paraelectric phase at a certain proportion. An improved magnetoelectric coupling was often observed at ferroelectric phase with a relatively large proportion. Besides, an enhanced piezoelectric coefficient is expected in Bi Fe O3-based ceramics with morphotropic phase boundaries as they are already observed in thin epitaxial Bi Fe O3 films.     

李洲坳东周墓出土玉器的红外光谱和X射线粉晶衍射特征

通过对李洲坳东周墓出土玉器进行傅里叶变换红外光谱（FTIR）、X射线粉晶衍射（XRD）分析,结果表明：红外光谱显示所测4件样品均为透闪石质软玉;X射线衍射分析显示样品G47∶3和G36∶1由较纯的透闪石组成,G21∶1和G21∶2主要矿物为透闪石,但是出现高岭石矿物的峰,表示其受沁后,出现黏土化。     

基于ARCGIS的塌陷塘水质特征研究及评价——以淮南矿业集团谢桥矿为例

为了解矿区塌陷水体的水质污染特征及规律,结合物理、化学和生物指标,运用营养状态综合指数法及基于ARCGIS的空间差值分析法对淮南矿业集团谢桥矿塌陷塘水质进行了分析与评价。矿区塌陷塘水质pH值呈弱碱性,透明度较低,BOD5、CODMn指标含量较高;用营养状态综合指数法对塌陷塘水质富营养化进行了评价,其污染级别为轻度富营养;运用ARCGIS的空间分析模块,利用总磷、总氮、BOD5、CODMn4个因子的空间插值栅格图建立多因子综合污染模型进行综合评价,得出水体综合水质标准处于地表水Ⅲ类到Ⅳ类之间,水质有待改善。本研究结果为塌陷塘水体水质监管及管理提供科学依据。     

Effect of Al on microstructure and mechanical properties of as-extruded Mg–1Mn alloy sheet

The effect of Al addition on microstructure and mechanical properties of hot extruded Mg–1 Mn alloy sheet was investigated. The results revealed that the dynamic recrystallization was promoted by increasing Al content. The ultimate tensile strength and yield strength of the alloy increased with the increase of Al content. The Mg–9 Al–1 Mn alloy exhibited the highest strength, with tensile strength of 308 MPa, 307 MPa, 319 MPa, yield strength of 199 MPa, 207 MPa, 220 MPa and the elongation of 20.9%, 20.1%, 19.2% in 0°, 45°, 90°, respectively.The high strength was mainly attributed to the formation of fine dynamically recrystallized grains and large amounts of the second phase. The strengthening mechanism of the alloys was explained.     

Biological characterization of the obligate symbiosis between Acropyga sauteri Forel (Hymenoptera: Formicidae) and Eumyrmococcus smithii Silvestri (Hemiptera: Pseudococcidae: Rhizoecinae) on Okinawa Island,southern Japan

The ant Acropyga sauteri Forel has an obligate, mutualistic symbiosis with a mealybug, Eumyrmococcus smithii Silvestri, on Okinawa Island, southern Japan. The mealybugs live inside ant nests nearly all their lives, and the ants depend on them for food. Alate foundress queens carry mealybugs during their nuptial flights, using them to establish new colonies at new sites. However, important aspects of the symbiosis have not yet been elucidated. The present study characterizes the basic biology of the symbiosis and describes for the first time the morphologies of all growth stages of E. smithii. Our study suggests that E. smithii has only one nymphal stage, followed by a female pupal stage or male prepupal stage. Intensive sampling of ant nests across seasons showed that A. sauteri prefers nest sites 5–20 cm underground. Acropyga sauteri produced reproductive stages mainly in mid‐March or early April, and numbers of both ant workers and mealybugs increased from spring to summer. Experimental determination of colony identity with a method using nestmate recognition by ants suggested that each ant colony rarely has a perimeter greater than 30 cm, that the ants are monogynous, and that different ant colonies are densely aggregated along the root system of a plant, adjacent to each other but not interflowing. Both symbiotic partners were vulnerable to attacks by several common subaerial ant species following physical disturbance to their nests.     

The atyid shrimp (Crustacea: Decapoda: Atyidae) rostrum: phylogeny versus adaptation,taxonomy versus trophic ecology

Cave shrimps of the subgenus Troglocaris (Atyidae), exhibit high variability in rostral length and dentition. In shrimp populations that co-occur with the amphibian predator Proteus anguinus, longer rostra armed with more numerous teeth are recorded. These shrimps are also larger than those living in a presumably Proteus-free environment. Discrepancies between molecularly established phylogenetic relationships and distributions of rostral length, as well as body size, directed our search towards possible environmental influences. These discrepancies suggest that rostral shape is not a reliable taxonomic character in some generic and many specific diagnoses in Atyidae. We discuss some taxonomic consequences of sexual and ontogenetic rostral differences with regard to the molecular phylogenetic tree. In preliminary laboratory observations, no frontal attack by Proteus was successful on shrimps with long rostra. Proteus also needed more time to swallow shrimps with long rostra.     

The host-plant range of twig-girdling beetles (Coleoptera: Cerambycidae: Lamiinae: Onciderini) of the Atlantic rainforest in southeastern Brazil

In this study, the host-plant range of Onciderini beetles was investigated during 4 years in an Atlantic rainforest of southeastern Brazil. Twelve species of Onciderini beetles girdled thirty-six plant species in the study site. In total, 1046 plants were girdled by Onciderini beetles as follows: 44.6% were Vochysiaceae, 15% were Mymosaceae, 12% were Melastomataceae, 9% were Lauraceae, 4% were Anacardiaceae and 15% were distributed among Meliaceae, Euphorbiaceae, Bombacaceae, Fabaceae, Thymelaeaceae, Cecropiaceae, Myrtaceae, Lecythidaceae, and Myrsinaceae. Onciderini beetles did not select hosts randomly. Most of the associations (70%) with host plants were caused by polyphagous beetles and different plant families showed different ratios of polyphagous, oligophagous and monophagous Onciderini in the study site.     

Studies on induction hardening of powder-metallurgy-processed Fe-Cr/Mo alloys

Induction hardening of dense Fe-Cr/Mo alloys processed via the powder-metallurgy route was studied. The Fe-3Cr-0.5Mo, Fe-1.5Cr-0.2Mo, and Fe-0.85Mo pre-alloyed powders were mixed with 0.4wt%, 0.6wt%, and 0.8wt% C and compacted at 500, 600, and 700 MPa, respectively. The compacts were sintered at 1473 K for 1 h and then cooled at 6 K/min. Ferrite with pearlite was mostly observed in the sintered alloys with 0.4wt% C, whereas a carbide network was also present in the alloys with 0.8wt% C. Graphite at prior particle boundaries led to deterioration of the mechanical properties of alloys with 0.8wt% C, whereas no significant induction hardening was achieved in alloys with 0.4wt% C. Among the investigated samples, alloys with 0.6wt% C exhibited the highest strength and ductility and were found to be suitable for induction hardening. The hardening was carried out at a frequency of 2.0 kHz for 2-3 s. A case depth of 2.5 mm was achieved while maintaining the bulk (interior) hardness of approximately HV 230. A martensitic structure was observed on the outer periphery of the samples. The hardness varied from HV 600 to HV 375 from the sample surface to the interior of the case hardened region. The best combination of properties and hardening depth was achieved in case of the Fe-1.5Cr-0.2Mo alloy with 0.6wt% C.     

Guide for Authors

<正>The journal of"Progress in Natural Science:Materials International(PROG NAT SCI-MATER)"sponsored and organized by both Chinese Materials Research Society(C-MRS)and Inter national Union of Materials Research Societies(IUMRS)started to publish     

Whence the eigenstate–eigenvalue link?

David Wallace has recently argued that the eigenstate–eigenvalue (E–E) link has no place in serious discussions of quantum mechanics on the grounds that, as he claims, the E–E link is an invention of philosophers rather than the community of practicing physicists. This raises an historical question regarding the origin of the link. This paper aims to answer this question by tracing the historical development of the link through six key textbooks of quantum mechanics. In light of the historical evidence from these textbooks, it is argued that Wallace provides insufficient grounds for dismissing the E–E link from discussions of quantum mechanics.