356 research outputs found
An Introduction and Dialogue from a Chinese-American Evolutionary Social Psychologist
No full textEdited by Wang Xiaotian and Su Yanji
A potential terrestrial Albian-Cenomanian boundary in the Yanji Basin, Northeast China
No full textThe terrestrial Albian-Cenomanian (A-C) transition was an important time interval for the co-evolution of animals and flowering plants, as well as for the diversification of dinosaurs and mammals on continents. Due to a worldwide lack of terrestrial sedimentation at that time, and the difficulty of direct correlation between marine and non-marine stratigraphy, only a few studies have discussed the terrestrial A-C boundary; therefore, it remains poorly understood compared with other stratigraphic boundaries. Northeast China is an ideal place to study the terrestrial A-C boundary because the area contains the most complete and continuous terrestrial Cretaceous succession in the world. Here, we report a SIMS U-Pb zircon age of 105.14 +/- 0.37 Ma for the uppermost part of the Dalazi Formation in the Yanji Basin. Additional ostracod-based biostratigraphic data indicate an Albian to Cenomanian age for the conformably overlying Longjing Formation. Alignment of the new comprehensive geochronological and biostratigraphic data with previously published chronological data suggests that a potential terrestrial A-C boundary occurs within the Longjing Formation of the Yanji Basin. This study provides an updated, precise chronostratigraphic framework for the evolution of the major terrestrial faunas and flora in the Yanji Basin, and represents a new contribution to the terrestrial Cretaceous timescale recorded in northeast China
A 7.4-Bit ENOB 600 MS/s FPGA-Based Online Calibrated Slope ADC without External Components
No full textA slope analog-to-digital converter (ADC) amenable to be fully implemented on a digital field programmable gate array (FPGA) without requiring any external active or passive components is proposed in this paper. The amplitude information, encoded in the transition times of a standard LVDS differential input—driven by the analog input and by the reference slope generated by an FPGA output buffer—is retrieved by an FPGA time-to-digital converter. Along with the ADC, a new online calibration algorithm is developed to mitigate the influence of process, voltage, and temperature variations on its performance. Measurements on an ADC prototype reveal an analog input range from 0.3 V to 1.5 V, a least significant bit (LSB) of 2.6 mV, and an effective number of bits (ENOB) of 7.4-bit at 600 MS/s. The differential nonlinearity (DNL) is in the range between −0.78 and 0.70 LSB, and the integral nonlinearity (INL) is in the range from −0.72 to 0.78 LSB
The deformation and permeability of Yanji mudstone under cyclic loading and unloading
No full textDuring the constructions of motorways and high-speed railway lines in the Yanji Basin, large amounts of excess mudstones due to the enormous tunnel excavations and slope cuts would be deposited as landfills. Assessing the deformation and permeability of Yanji mudstone became important for the design, construction and operation of the landfills. This paper presents an experimental study on the deformation and permeability of Yanji mudstone by carrying out a series of oedometer tests with loading/unloading cycles. The results show that the sample with a lower initial water content exhibited greater swelling deformation after inundation, a lower yield stress, greater deformation and a higher hydraulic conductivity during the loading/unloading cycles. As the number of loading/unloading cycles increased, the yield stress and accumulated plastic deformation increased, while the compression index, rebound index and hydraulic conductivity decreased. The samples became stiffer and their hydromechanical behaviour tended to be stable after three cycles. The compression curves could be divided into pre-yield and post-yield zones. The post-yield zones of compression curves and the rebound curves could be normalized into a unique line, and the pre-yield zones of the compression curves could be described as lines. Basic equations were developed to predict mudstone deformation under cyclic loading and unloading. Additionally, an empirical relationship between the hydraulic conductivity and void ratio was also proposed. The ability of the proposed methods was verified by the overall good agreement between the experimental results and predicted values
The timing of final closure along the Changchun-Yanji suture zone: Constraints from detrital zircon U-Pb dating of the Triassic Dajianggang Formation, NE China
No full text© 2015 Elsevier B.V. The Dajianggang Formation is located in the Changchun-Yanji suture zone of central Jilin Province and unconformably overlies the Changchun-Yanji Accretionary Complex (CYAC), which is a mélange resulting from subduction of the Jiamusi-Khanka Block (JKB) beneath the North China Craton (NCC). LA-MC-ICP-MS U-Pb dating of detrital zircon from four samples of the formation yields ages of 2516 to 216. Ma. Zircons with U-Pb ages at 2516-2501. Ma and 1897-1832. Ma indicate a provenance from Precambrian basement rocks of the NCC. The 525-482. Ma ages indicate a provenance from metamorphic rocks of Late Pan-African age in the JKB that have a tectonic affinity to the Central Asian Orogenic Belt (CAOB). Zircon grains with ages of 383-314. Ma and 275-250. Ma were likely derived from the underlying CYAC. The youngest population has a peak age of ca. 225. Ma, which together with Late Triassic fossils, suggests that deposition of the Dajianggang Formation was Late Triassic or younger. This result supports the view that the final collision of the JKB and NCC along the Changchun-Yanji suture took place before the Late Triassic. Furthermore, this closure time is at least 10-20. Ma later than closure along the Solonker-Xar Moron-Changchun suture in the Late Permian. We thus establish that the Changchun-Yanji suture is not related to the collision between the Siberia Craton (SC) and the NCC but was instead related to the Paleo-Pacific plate subduction. Consequently, the Changchun-Yanji suture is not the eastward extension of the Solonker-Xar Moron-Changchun suture as previously considered, but the southern margin of the Jilin-Heilongjiang high-pressure metamorphic belt (Ji-Hei HP belt), and resulted from westward subduction of the Paleo-Pacific Ocean. Thus, the Late Triassic marked the switch in subduction from the Paleo-Asian Ocean to the Paleo-Pacific Ocean in NE China
The Korean language in the linguistic landscape on Jinxue Street, Yanji, China
No full textFor several decades now, linguistic landscape research has served as a sociolinguistic method to examine the vitality of minority language s and the impact of language policy on them. Since no previous case studies have been focused on the linguistic landscape of Yanbian Korean Autonomous Prefecture , which is a bilingual area in China featuring Chinese and Korean languages, the present case study focuses on one of the featured streets in Yanji, the capital of the Yanbian prefecture with the purposes of examin ing the impact of language policy on Korean language, as well as the status of Korean language and its functions in the linguistic landscape . As an empirical study, the present research was informed by Backhaus (2007 ), Scollon and Scollon (2003), Sebba (2013) 2013), Kallen (2009) and other socio linguists as guidelines to the research. And after collect ing 318 photos from the research site, Jinxue Street in Yanji , a coding scheme, including both q uantitative and qualitative analysis, was used to explore the linguistic landscape in this street. The results of the case study indicate that the local language policy is only partially effective and is not fully enforced on Jinxue Street. T he vitality of the Korean language can be clearly seen in the study 's findings , but the dominant Chinese is threatening the Korean language and the local language policy is often ignored . As for the functions of the language, the Korean language still can exhibit some basic information functions in the LL of Jinxue Street, but its symbolic function seems to play a more significant role
Current status and influencing factors of test anxiety of senior one students in Yanji, China: a cross-sectional study
No full textObjectiveExamining the current situation of test anxiety among first year senior high school students in Yanji City and investigating the factors that contribute to exam anxiety.MethodsUsing cluster sampling, a survey was conducted on 1,550 first-year high school students from three high schools in Yanji City in April–May 2023. The survey utilized general information questionnaires, the Minnesota Multiphasic Personality Inventory (MMPI), and the Self-Rating Anxiety Scale (SAS). Logistic regression analysis was used to determine the influencing factors of test anxiety.ResultsA total of 1,550 first-year high school students were included in the analysis, with a test anxiety occurrence rate of 79.8%. Test anxiety exhibited statistical differences among different genders, ethnicities, family economic levels, frequency of communication with parents, and relationships with parents (with results of 53.44, 10.42, 17.31, 20.42, 31.95, all p < 0.05). Scores of hypochondriasis (Hs), depression (D), psychasthenia (Pt), paranoia (Pa), psychopathic deviate (Pd), schizophrenia (Sc), and hypomania (Ma) in the 10 clinical personality scales were significantly positively correlated. Logistic regression analysis revealed that gender, ethnicity, frequency of communication with parents, and scores of hypochondriasis (Hs), depression (D), psychasthenia (Pt), paranoia (Pa), and hypomania (Ma) in the 10 clinical personality scales were the main influencing factors for test anxiety in first-year high school students (all p < 0.05).ConclusionThe test anxiety level of high school students in Yanji City is relatively high, with variations in test anxiety levels among students of different genders, ethnicities, parental communication styles, and deviant personality traits. It is recommended that schools and teachers should give more consideration to test anxiety among high school students, particularly targeting those with potential risk factors. Parents should also be more attentive to their children’s development and advancement, and improve their family education principles
Wetting–Drying–Freezing–Thawing Cycle Effect on the Swelling Pressure of Yanji Mudstone Using Various Determination Methods
No full textSwelling rocks and soils can generate significant swell or swelling pressure upon contact with water due to their special mineralogical composition, and thus a reliable determination of their swelling property is essential when evaluating the long-term safety and stability of adjacent geotechnical infrastructure. In this work, the swelling pressures of Yanji mudstone before and after seasonal wetting–drying (WD), freezing–thawing (FT) and wetting–drying–freezing–thawing (WDFT) processes were experimentally determined by zero-swell, load-swell, and swell-consolidation methods. It was found that the seasonal processes significantly reduced the swelling pressures determined by different methods because of the contraction of aggregates and the appearance of large pores and fissures/cracks. Due to the more intensive microstructure change, the WDFT process had a more detrimental influence on the swelling pressure of Yanji mudstone than separate WD or FT cycles. Moreover, a comparison among three determination methods showed that a larger swelling pressure was measured by the swell-consolidation method owing to the greater resistance of the even microstructure after hydration under a low vertical stress and the possible friction with cell wall during consolidation compared with the load-swell and zero-swell methods. With the increase of WDFT cycles, this difference method decreased because the large pores and fissures/cracks could increase the compressibility of swollen specimens in the swell-consolidation tests and accelerate the water infiltration in the zero-swell and load-swell tests.</p
Engineering geological properties of weathered swelling mudstones and their effects on the landslides occurrence in the Yanji section of the Jilin-Hunchun high-speed railway
No full textTo identify the mechanisms that caused landslides during the construction of the Jilin-Hunchun high-speed railway line in Yanji, China, the engineering properties of weathered swelling mudstones extracted from a representative landslide site were investigated. The experimental results indicate that both yellow-brown and magenta mudstones exhibit significant swelling and shrinkage behaviour due to significant amounts of swelling clay minerals. The yellow-brown mudstone has an obvious schistose structure with stacked flaky plates interconnected with a face-to-face pattern, while the magenta mudstone has an aggregated structure cemented by iron oxides. Both mudstones are prone to disintegration when soaked in water. The shear strengths of swollen samples decrease dramatically compared with those of unsaturated samples, and the lower the initial water content is, the smaller the shear strength of a sample after swelling. By repeatedly increasing the repeated drying-wetting-freezing-thawing cycles, the shear strength decreases. According to the experimental findings, the effects of the engineering properties of mudstones on the landslides occurrence in the Yanji section are discussed. Heavy rainfall and the weathering of mudstones induced by fluctuating climatic conditions are regarded as the principal factors that triggered the landslides. Given the high landslide incidence on south-facing slopes, the influence of slope orientation on the stability of mudstone slopes is studied and discussed.</p
Effects of remoulding and wetting-drying-freezing-thawing cycles on the pore structures of Yanji mudstones
No full textThe pore structure governs the physical and mechanical behaviours of geomaterials, thereby affecting the stability of the infrastructures built on these materials. This study investigated the effects of remoulding and wetting-drying-freezing-thawing (W–D–F–T) cycles on the pore structures of two Yanji mudstones using scanning electronic microscopy (SEM), mercury intrusion porosimetry (MIP) and nitrogen adsorption (NA) techniques. The results show that the pores of both the yellow-brown and magenta mudstones become rounder and more disordered after remoulding. Remoulding leads to an increase in the inter-aggregate pore volume and a decrease in the intra-aggregate pore volume because of the exposure of intra-aggregate pores after crushing and the compaction of aggregates during the compression process. The W-D-F-T cycles make the pores of the remoulded yellow-brown mudstone more disordered and flatter and induce an increase in the inter-aggregate pore volume due to the formation of cracks and large pores. Meanwhile, the intra-aggregate pore volume decreases owing to the contraction of aggregates during the drying process. According to the increased inter-aggregate pore volume and decreased intra-aggregate pore volume, an increase in the hydraulic conductivity and a decrease in the shear strength can be expected after remoulding and W-D-F-T cycles, which decrease the stability of mudstone slopes
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