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ABSTRACT In this study, the experiment of one PVC confined concrete column with reinforced concrete beam joint (PRJ) and nine PVC-CFRP confined concrete columns with reinforced concrete beam joints (PCRJ) [...]

The photoperiod sensitivity of rice (Oryza sativaL.) cultivars plays an important role in rice growth and yield formation. To ascertain the different effects of sowing dates on spikelet formation for different photoperiod‐sensitive genotypes, 10 sowing dates were selected to assess differences in spikelet differentiation and degeneration for photoperiod‐sensitive cultivars yongyou 538 (YY538) and xiushui134 (XS134) and photoperiod‐insensitive cultivar chujing27 (CJ27). The yield of the cultivars differed significantly among different sowing dates and was primarily influenced by the spikelet number per panicle. With different sowing dates, shorter daylengths, and increasing temperatures significantly shortened the duration from sowing to heading for YY538 and XS134, while that of CJ27 was less changed and influenced by the average temperature. Rice growth duration was the primary factor limiting dry matter accumulation (DMA), which was correlated with the number of differentiated spikelets (NDS) and the proportion of degenerated spikelets (PGS) in photoperiod‐sensitive varieties. High temperature weather with a relatively large temperature gap and strong solar radiation promoted spikelet differentiation in all three cultivars. Extremely high and low temperatures aggravated spikelet degeneration, but YY538 and XS134 were not exposed to low temperatures because their duration of growth was shortened to a greater extent than that of CJ27 with late sowing dates. Under different sowing dates, the NDS and PGS were evaluated by partial least squares regression (PLSR) with DMA, rice growth duration, temperature, and solar radiation. These results provide a reference for sowing date adjustment with climate changes in different regions. Core IdeasRice yield with different sowing dates was determined by spikelet number.Rice growth duration was the primary factor affecting dry matter accumulation.High temperature and more dry weight increased spikelet differentiation.Sowing photoperiod‐sensitive cultivars at a late date avoided chilling injury.Spikelet formation can be predicted by partial least squares regression with sowing dates. Rice yield with different sowing dates was determined by spikelet number. Rice growth duration was the primary factor affecting dry matter accumulation. High temperature and more dry weight increased spikelet differentiation. Sowing photoperiod‐sensitive cultivars at a late date avoided chilling injury. Spikelet formation can be predicted by partial least squares regression with sowing dates.

Volatile organic amine vapors exist in various areas, which can cause a series of harmful effects on environment and human life. Thus, the detection of organic amine vapors with sensitivity and selectivity is greatly needed. This study reports a simple, low-cost, selective and sensitive fluorescence detection of trace organic amine vapors based on CH3NH3PbBr3(MAPbBr3) nanoplates (NPs) and nanowires (NWs). Upon exposure to organic amines vapors, the fluorescence of MAPbBr3was strikingly and quickly attenuated (<4 s), and the color of MAPbBr3changed from yellow to white for some of the organic amines (depending on the R group of R-NHx). This change was rooted in the change of the crystal structure of MAPbBr3after contacted with different amines. We believe that this result is not only a great advancement in the trace detection of organic amine vapors but is also equally important for fundamental research of organometal halide perovskites.

The Erguna Fault runs along the east bank of the Erguna River in NE China and is a large-scale ductile shear zone comprising granitic mylonites. This paper reports on the geometry, kinematic indicators, and 40Ar/39Ar biotite ages of the granitic mylonites,to constrain the structural characteristics, forming age, and tectonic attribute of the Erguna ductile shear zone. The zone strikes NE and records a top-to-the-NW sense of shear. A mylonitic foliation and stretching lineation are well developed in the mylonites, which are classified as S-L tectonites. Logarithmic flinn parameters (1.18–2.35) indicate elongate strain which approximatesto plane strain. Kinematic vorticity numbers are 0.42–0.92 and 0.48–0.94, based on the polar Mohr diagram and the oblique foliation in quartz ribbons, respectively, suggesting that the ductile shear zone formed under general shear, or a combinationof simple and pure shear. According to finite strain and kinematic vorticity analyses, the Erguna Fault is a lengthening-thinning ductile shear zone that formed by extension. The deformation behavior of minerals in the mylonites indicates that the fault was the site of three stages of deformation: an initial stage of middle- to deep-level, high-temperature shear, a post-stress recovery phase of high-temperature static recrystallization, and a final phase of low-temperature uplift and cooling. The 40Ar/39Ar plateau ages of biotite from the granitic mylonites are 106.16 ± 0.79 and 111.55 ± 0.67 Ma, which constrain the timing of low-temperature uplift and cooling but are younger than the ages of metamorphic core complexes (MCCs) in the Transbaikalia-northeast Mongolia region. Using measured geological sections, microtectonics, estimates of finite strain and kinematic vorticity, and regional correlations and geochronology, we conclude that the Erguna Fault is an Early Cretaceous, NNE-trending, large-scale, sub-horizontal, and extensional ductile shear zone. It shares a similar tectonic background with the MCCs, volcanic fault basins, and large and super-large volcanic-hydrothermal deposits in Transbaikalia-northeast Mongolia and the western Great Khingan Mountains, all of which are the result of overthickened crust that gravitationally collapsed and extended in the Early Cretaceous after plate collision along the present-day Sino-Russia-Mongolia border tract.

Compared with nitroaromatic explosives detection, nitrate esters are far from wide attention possibly because of their shortage of aromatic ring and difficulty in being detected. Three fluorescent chemical probes for trace nitrate ester detection: an intramolecular dimer (P3) of 8-pyrenyl-substituted fluorenes bridged by a 1,6-hexanyl unit as well as its counterparts 2PR-F (P1) and 2PR-Cz (P2) has been synthesized and characterized. Their chemical structures and photophysical and electrochemical properties show that the dimer P3film has a higher molar extinction coefficient, larger steric hindrance, higher area-to-volume ratio, and matching energy level with nitrate ester explosives, which contributes to higher sensitivity and moderate selectivity for sensing of nitrate ester explosives such as nitroglycerin (NG). The fluorescence of the P3film is rapidly about 90% quenched upon exposure to a saturated vapor of NG for 50 s and almost 100% quenched for 300 s at room temperature due to photoinduced electron transfer between the probe and analyte. In addition, a very sensitive, rapid, simple, and low-cost surface-sensing method by disposable filter-paper-based test strips is demonstrated. The contact-mode approach exhibits a detection limit as low as 0.5 fg/cm2for NG. These results reveal that the multiple-pyrenyl-unit-substituted fluorene dimer P3is suitable for preparing a highly sensitive and efficient thin-film device for detecting nitrate esters.

Age and nature of the Budate Group in the Hailar Basin are of great significance in studying the evolution of the Hailar Basin and the Xing’an-Mongolian Orogenic Belt (XMOB). Zircon U-Pb ages of eight volcanic rocks from the Budate Group and two basement granites in the Hailar Basin were reported in this study. The dating results indicated that the formation of these volcanic rocks was consistent with the emplacement of Late Paleozoic basement granite in age (356–290 Ma), i.e., Early Carboniferous to Early Permian rather than Early Mesozoic. Combined with regional geology, it was concluded that the Budate Group is the component of the basement of the Hailar Basin, and these volcanic rocks were formed at an active continental margin, which is related to the closure of the Hegen Mountains suture zone. The captured Neoproterozoic zircons (814–873 Ma) were probably derived from the Neoproterozoic basement materials in the Ergun Block, implying the close genetic relationships between the Ergun Block (including the Hailar Basin) and the Siberian Block.

Nanomaterials and -structures have attracted much attention owing to their applications to ultrasensitive nanodevices. In this work, ordered assembly arrays of ZnO nanorods have been hydrothermally fabricated and used as optical substrates of fluorescence sensors for toxic vapors. The unique fastigiate nanorod assembly combines merits of single fibers and clusters, possessing identical orientation, large surface-to-volume ratio, evanescent transmission, and evanescent coupling. As coated on the assembly arrays, different sensing materials all generated amplified spontaneous emission (ASE) action such that the fluorescence intensity of the narrowed spectrum was 52.4-fold enhanced. Results of sensing experiments indicate that sensors based on the assembly arrays displayed 100% elevated normalized quenching rate and several times longer full-load time compared with reference sensors. This work provides a facile method to fabricate secondary structures of 1D rigid material and presents a new way to design highly sensitive optic sensors. Furthermore, evanescent excitation caused ASE action of fluorescent organics, and the correlative sensitivity gain is of interest in both theoretical research and the applications field.

The Hailar Basin is a Mesozoic-Cenozoic basin, which is superimposed on the Paleozoic collision orogenic belt of Inner Mongolia–Greater Hinggan Mountain. The basin, trending north-east, consists of five first-order structural units (three depressions and two uplifts), they are, from west to east, the Zhalenuoer Depression, the Cuogang Uplift, the Beier Lake Depression, the Bayanshan Uplift and the Huhe Lake Depression, respectively. The Wuerxun Sag and the Beier Sag are two second-order structural units in the south Beier Lake Depression. Research indicates that in the Early Cretaceous Epoch, the Wuerxun-Beier sag underwent two long-term compressions: NW-SE trending during the Damoguaihe Period to the early Yimin Period, and near EW trending during the end of the Yimin Period, respectively. The compressions led to the inversion of some depression-controlling normal faults in the extensional faulted depression, and formed new fault-propagation fold, fault-bend fold, imbricate structure, duplex structure, pop-up structure, and triangular zone etc. Because of the differences in geometric and kinematic features and the variance in the ratio of the uplift rate of compressional structures to the deposition rate of isostructural growing strata in space, syn-compression strata show different depositional features in different structural positions. These structural features are very similar to those of the orogenic belt. The discovery of two phases of compressional structures in the Wuerxun–Beier Sag proved that the crust of Northeast China was not always in the state of extension and thinning in the Early Cretaceous, but showed the features of superimposition and thickening during the two compression periods, and thus formed the structural framework of the alternative distribution of the compression-depression basins and the intra continental (intra plate) orogenic belt in space.

A visible-light-induced chemoselective reactions of quinoxalin-2(1H)-ones with alkylboronic acids in the presence of air (O2) and N2atmosphere was developed under transition-metal free conditions, providing 3-alkylquinoxalin-2(1H)-ones and 3,4-dihydroquinoxalin-2(1H)-ones, respectively. The overall strategy accommodates a broad scope of substituted quinoxalin-2(1H)-ones and alkylboronic acids with good to excellent product yields.