[Objective] The paper aimed at researching on the ecological remediation materials and related technologies in degraded land.[Method] Pointing at the specific reasons for degradation of soil moisture and fertility conditions,the ecological remediation materials and related technologies for soil moisture had been studied using layered silicates as substrate materials and using straw turnover as the method.The application research had been carried out in degraded cultivated land,compacted land,saline-alkali soil and laboratory of nine provinces and regions on 26 species and 48 varieties.[Result] The materials and related technologies are environment-friendly in formula,processing,application with no hidden trouble as secondary pollution,which can be used for the restoration of positive balance of soil moisture conditions(water,fertilizer,gas,and heat),establishment of the core of a stable circle and improving food production steadily.The materials are more suitable for plant growth than chemical fertilizers,applying of which helps plants obtain better adversity resistance.[Conclusion] The ecological remediation materials for soil moisture can reduce the application of chemical fertilizers effectively and improve the production and quality of crops remarkably.
The effect of air pressure on the release of an alveolar stop consonant closure is simulated with a 2-D finite-element model of the front part of the midsagittal tongue in the vocal tract. Active movement of the tongue is estimated from x-ray microbeam recordings, and intraoral air pressure is also applied to the surface of the tongue as an external force. Air flow in the vocal tract is then coupled to the tongue movement by representing the upper tongue surface as part of the flow boundary. At release, the upward movement of the tongue tip due to the decrease in air pressure introduces an oscillation at the release trajectory of the supraglottal constriction. This oscillation is realized in a quasiarticulatory speech synthesizer HLsyn and causes the appearance of a plateau in the time course of the output airflow. This hesitation in tongue tip movement results in an increase in the duration of the frication noise by about 10 ms, consistent with acoustic data on the stop burst. The simulation shows how the mechanical properties of the tongue and the intraoral air pressure buildup can influence the duration of the frication noise. [Supported by Grant NIDCD DC00075 from NIH.]
In this paper, a new electromagnetic acoustic resonance (EMAR) transducer is proposed for precise thickness measurement in specimen. The new EMAR is composed of a mirror symmetric coil (MSC) and a pair of Nd-Fe-B permanent magnets with the different polarity for enhancing the generation and detection of resonant signals. Firstly, a finite element model was established to simulate the distributions of Lorentz force produced by new EMAR and the resonant process of shear waves. Furthermore, the relationship between the frequency response characteristic of the new EMAR and the common EMAR were explored. Finally, to verify the performance of the EMAR, several experiments were performed. Compared with the common EMAR transducer, the resonant amplitude of the new EMAR transducer was increased by 121.74% and the signal-to-noise ratio was increased by 28.35%, and the resonance frequency interval of the new EMAR was twice that of the common mode in the frequency domain simulation experiment, this advantage effectively reduced the error rate of measurement. The results show that the new EMAR transducer with mirror coil structure has higher accuracy in thickness detection of specimens.
This paper illustrates how to ream holes of Cu Ni alloy tube plate, discusses the choice of material of reamer for machining holes of Cu Ni alloy tube plate, structure of tools and design of geometric angle, and gives technical parameters for machining holes of Cu Ni alloy tube plate and explains the effect of using hard alloy reamer.
During the service process, the thickness of the sheet metal is unevenly changed due to uneven pressure or abrasion. The inner and outer surfaces are in two nonparallel planes, which causes the reflection path of the ultrasonic wave inside the specimen to shift and brings a challenge to electromagnetic ultrasonic thickness measurement. In this work, we used the detection scheme of electromagnetic acoustic resonance (EMAR) combined with the multiplication of n- times compression (MNC) data processing to detect the thickness of the sloped specimens through a fixed-point rotating racetrack coil. A power spectral density (PSD) analysis is performed on the spectrum signals obtained under different rotation angles $\alpha $ to achieve the judgment of the inclination direction of the specimen. The simulation results show that the measured thickness increases with the increase of the inclined angle $\theta $ of the specimen. Within a certain range, the change in the width of the racetrack coil will not have a significant influence on the thickness measurement results of the sloped specimen. The PSD of the resonance signal increases first and then decreases with the increase of the rotation angle $\alpha $ , and the PSD reaches its peak when $\alpha $ is 90°. Experimental results show that when the coil rotation angle $\alpha $ is between 50° and 70°, the scheme can accurately measure the thickness of the sloped specimen, and the direction perpendicular to the rotation angle of the maximum PSD is the inclination direction of the sloped specimen.
The study was based on the actual defect product,and to analyze the actual molding processing conditions which impacted on the accuracy of Moldflow analysis,enhance the input and output of the processing conditions in Moldflow,thereby controlling the actual molding' s disturbance error.Firstly,UDE experimental design was used to find the best combination of processing parameters then optimized the distribution of volume shrinkage through fitting the Ram curve and packing curve's optimization.The results showed that the difference analysis was to help to guide the actual production,which improved the defect product with sink marks for the enterprises and had successfully production.
Abstract The lower Cambrian Niutitang Formation, a widespread black shale deposition, is of geological interest because of its polymetallic beds, Cambrian explosion, depositional ages, dramatic environmental changes and so on. Previous study focused mainly on inorganic geochemistry and few studies have investigated the organic fractions of upper Neoproterozoic‐lower Cambrian strata in South China. Here we report a study of biomarkers plus organic carbon isotopes for black shales from Ganziping, Hunan Province (China). All the saturated hydrocarbon fractions have a unimodal distribution of n ‐alkanes, a high content of short‐chain alkanes and maximize at C 19 or C 20 (C 23 for sample Gzh00–1). The C 27 /C 29 sterane ratio ranges from 0.77 to 1.20 and 4‐methylsteranes are in low abundance. These parameters indicate that algae and bacteria are the important primary producers. Furthermore, biomarker maturity proxies show the samples to be higher maturity. The low Pr/Ph values (<0.7) suggest that the samples were deposited under anoxic conditions and, likely, under stratified water columns. In addition, 25‐norhopanes and gammacerane are present as diagnostic indicators of normal marine salinity and dysoxic to anoxic conditions. During the Early Tommotian, known to coincide with a transgression event, small shelly fossils increased in abundance and diversity. Moreover, positive δ 13 C org excursions close to 1.4‰ occur at the base of the Tommotian stage. In summary, the Early Cambrian black shales were deposited under dramatic paleoenvironmental changes, including oceanic anoxia, higher primary productivity and sea‐level rise.
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