[en] A highly sensitive detector for determining the ¹⁴C in low activity has been developed. Its background is 2.35 cpm, and its detection efficiencies to the dry samples of corn and soil are 6.93% and 3.2%, respectively

[en] 5-[2-chroo-4-(trifluoromethyl ) phenoxy]-N-(methyl sulphonyl )-2-niorobenzamide [femesafen] was labeled by six steps. Radio-chemical yield was 19.15%. TLC analysis of the final product showed that the radiochemical purity is not less than 99%. (authors)

[en] Civil engineering works such as buildings and infrastructure are the carriers of human civilization. They are, however, also the origins of various types of disasters, which are referred to in this paper as civil engineering disasters. This paper presents the concept of civil engineering disasters, their characteristics, classification, causes, and mitigation technologies. Civil engineering disasters are caused primarily by civil engineering defects, which are usually attributed to improper selection of construction site, hazard assessment, design and construction, occupancy, and maintenance. From this viewpoint, many so-called natural disasters such as earthquakes, strong winds, floods, landslides, and debris flows are substantially due to civil engineering defects rather than the actual natural hazards. Civil engineering disasters occur frequently and globally and are the most closely related to human beings among all disasters. This paper emphasizes that such disasters can be mitigated mainly through civil engineering measures, and outlines the related objectives and scientific and technological challenges.

[en] Flumorph is a newly invented systemic fungicide. Radio-chemical yield of the target product was 35.9% through three steps of ¹⁴C-labeling synthesis, and its radio-chemical purity was 97.8% by TLC analysis. (authors)

[en] ¹⁴C-Omethoate [O,O-dimethyl-S-(N-methyl carbamoyl-methyl)phosphorothioate] was synthesized by four steps. The radio-chemical yield was 27.81%. TLC analysis of the final product showed the radiochemical purity is higher than 95%. (authors)

[en] The seismic behavior of a school gymnasium, whose steel grid roof was heavily damaged during the Mw6.6 Lushan earthquake in 2013, is simulated through nonlinear dynamic analysis. The simulated damage is compared with field observations to validate the numerical model, based on which a parametric study was performed to provide insight into the failure process and damage patterns of steel grids. The results suggest that the grid damage is strongly related to roof-substructure interactions. These include not only the substructure’s amplification of the vibration, but the uncoordinated displacement of the substructure’s columns which support the grid also play an equally important role. In particular, the latter effect may significantly alter the internal force distribution in the steel grid and lead to unexpected buckling of members that are proportioned as tension-only members. While such interactions are generally not accounted for in the design practice for grid structures in China, similar seismic damage may be expected for other existing grid roofs in future earthquakes. As is also demonstrated in this study, seismic isolation of the roof is a promising solution to protect grid roof structures by mitigating the detrimental effects of roof-substructure interactions.

[en] The vortex glass theory has been successfully employed to describe the vortex phase state of high T_C superconductors (HTSCs). Its validity can be examined by scaling the current-voltage isotherms with appropriate exponents and a universal scaling function. However, this second order phase transition model is not applicable for the layered superconductor Cu_0.03TaS₂ due to its weak pinning, which could be proved by the peak effect in the M-H loop. Finally, we give the different pinning mechanisms with H||ab and H||c. Vortex strings and pancake vortices are formed under parallel and perpendicular magnetic fields, respectively. The vortex strings are pinned by normal layers in layered superconductors, while the pancake vortices are connected by Josephson coupling.

[en] The fishbone model is a simplified numerical model for moment-resisting frames that is capable of modelling the effects of column-beam strength and stiffness ratios. The applicability of the fishbone model in simulating the seismic responses of reinforced concrete moment-resisting frames of different sets of column-beam strength and stiffness ratios are evaluated through nonlinear static, dynamic and incremental dynamic analysis on six prototype buildings of 4-, 8- and 12-stories. The results show that the fishbone model is practically accurate enough for reinforced concrete frames, although the assumption of equal joint rotation does not hold in all cases. In addition to the ground motion characteristics and the number of stories in the structures, the accuracy of the model also varies with the column-beam stiffness and strength ratios. The model performs better for strong column-weak beam frames, in which the lateral drift patterns are better controlled by the continuous stiffness provided by the strong columns. When the inelastic deformation is large, the accuracy of the model may be subjected to large record-to-record variability. This is especially the case for frames of weak columns.

[en] We present a high-pressure study of van der Waals ferromagnetic metal Fe₃GeTe₂ through electrical transport and Raman scattering measurements in diamond anvil cells at pressures up to 22.4GPa. Upon compression, the ferromagnetic transition temperature T _c manifested by a kink in resistance curve decreases monotonically and becomes undiscernable around P _c = 10GPa, indicative of suppression of the itinerant ferromagnetism. Meanwhile, by fitting the low temperature resistance to the Fermi liquid behavior of R = R ₀ + AT ², we found that R ₀ shows a cusp-like anomaly and the coefficient A diverges around P _c. These transport anomalies imply a tricritical point as commonly observed in itinerant ferromagnets under pressure. Unexpectedly, the Raman-active E _2g and A _1g modes soften remarkably after an initial weak hardening and the peak widths of both modes broaden evidently on approaching P _c, followed by complete disappearance of both modes above this critical pressure. A possible underlying mechanism for such anomalous lattice softening near P _c is discussed. (paper)

[en] A comprehensive study of the difference between CaFe_1-xNi_xAsF and CaFe_1-xCo_xAsF systems has been carried out by measuring the efficient charge carrier concentration, the valence states and the superconducting phase diagram. It is found that at the same doping level, Ni doping introduces nearly twice the number of charge carriers as Co doping. However, x-ray absorption near-edge spectroscopy measurements reveal that the valence state of Fe in both systems is close to 2, indicating that there is no valence mismatch. We suggest that the charge carriers in CaFe_1-xM_xAsF (M=transition metal elements) are not induced by valence mismatch but come from the difference in the number of outer-shell electrons. We also suggest that with Ni and Co doping, the systems change from a multi-band material in the underdoped regions to a single-band state in the overdoped regions.