351 research outputs found

    Gas sensors for oxides synthesis by hydrothermal and microwave hydrothermal methods

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    so far, gas sensors are playing an increasingly important role in environmental detection, agricultural production, medical treatment and other fields. Semiconductor oxide gas sensors are often used to detect toxic gases because of their low cost, simple manufacture, fast response, good selectivity and high sensitivity. There are many methods to prepare semiconductor oxides, such as hydrothermal synthesis, microwave hydrothermal synthesis and sol-gel synthesis. The advantages of hydrothermal synthesis and microwave hydrothermal synthesis are high economic efficiency and simple operation. The synthesized oxides have many different morphologies, such as zero dimensional, one-dimensional, two-dimensional, three-dimensional and so on. These diff erent morphologies are conducive to gas diff usion and enhance gas sensing performance. Especially the hierarchical structure can greatly improve the gas sensing performance due to its large specifi c surface area, large porosity and high carrier concentration. This paper describes the SMO gas sensor prepared by hydrothermal method and microwave hydrothermal method

    Safety and preventive effects of rivaroxaban and low-molecular-weight heparin on deep vein thrombosis of lower extremity after total hip arthroplasty

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    Deep vein thrombosis (DVT) is a common complication of skeletal surgery, which can cause disability and death in severe cases. Here, we have compared the preventive effects of rivaroxaban and low molecular weight heparin on DVT of lower extremity after total hip arthroplasty and the safety. A total of 310 patients who received total hip arthroplasty from May 2014 to June 2016 were divided into a rivaroxaban group (n=153) and a low molecular weight heparin group (n=157). The rivaroxaban group was orally administered with rivaroxaban (10 mg, qd) 12 h after surgery for 30 consecutive days, and the other group was subcutaneously injected with low molecular weight heparin calcium injection (0.6 mL, ad) for 7 consecutive days. The incidence rate of lower extremity DVT, drainage blood volume, hemoglobin decline, as well as preoperative and postoperative 7-d prothrombin time (PT), activated partial thromboplastin time (APTT), platelet (PLT) count and D-dimer level of the two groups were compared. The two groups had similar incidence rates of lower extremity DVT, drainage blood volumes and extents of hemoglobin decline (P >0.05). There were no significant differences in the preoperative and postoperative 7-d PT, APTT, PLT counts and D-dimer levels between the two groups (P >0.05). Rivaroxaban and low molecular weight heparin show comparable preventive effects on lower extremity DVT after total hip arthroplasty. Results suggest that rivaroxaban is superior than the low molecular weight heparin in terms of convenient use (oral administration), good compliance and absence of dose adjustment

    Study of Valve Motion in Reciprocating Refrigerator Compressors based on the 3-D Fluid–structure Interaction Model

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    Ă‚ Abstract: In this paper, a 3-D fluid-structure interaction model was established to investigate the working process of the small reciprocating refrigeration compressors. According to the numerical calculation, the working process of the small reciprocating refrigeration compressor, the motion of valve and the impact velocity and the contact stress of discharge valve and suction valve were given. Experiments on a small reciprocating refrigeration compressor for testing the p-v graph were carried out .Experimental results agree well with the numeric model. The result provides a guidance to research and design the small reciprocating refrigeration compressors

    PromptTTS: Controllable Text-to-Speech with Text Descriptions

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    Using a text description as prompt to guide the generation of text or images (e.g., GPT-3 or DALLE-2) has drawn wide attention recently. Beyond text and image generation, in this work, we explore the possibility of utilizing text descriptions to guide speech synthesis. Thus, we develop a text-to-speech (TTS) system (dubbed as PromptTTS) that takes a prompt with both style and content descriptions as input to synthesize the corresponding speech. Specifically, PromptTTS consists of a style encoder and a content encoder to extract the corresponding representations from the prompt, and a speech decoder to synthesize speech according to the extracted style and content representations. Compared with previous works in controllable TTS that require users to have acoustic knowledge to understand style factors such as prosody and pitch, PromptTTS is more user-friendly since text descriptions are a more natural way to express speech style (e.g., ''A lady whispers to her friend slowly''). Given that there is no TTS dataset with prompts, to benchmark the task of PromptTTS, we construct and release a dataset containing prompts with style and content information and the corresponding speech. Experiments show that PromptTTS can generate speech with precise style control and high speech quality. Audio samples and our dataset are publicly available.Comment: Submitted to ICASSP 202

    Phylogeny of the genus Morus (Urticales: Moraceae) inferred from ITS and trnL-F sequences

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    Both nuclear ribosomal ITS and chloroplast trnL-F sequences were acquired from 13 mulberry genotypes belonging to nine species and three varieties, and one paper mulberry. The later belongs to genus B. papyrifera, designed as outgroup, and were analyzed. Within the genus Morus, the sequence diversity of ITS was much higher than that of trnL-F. The results of phylogenetic analyses based on these data (separately or combined) show that the genus Morus is monophyletic group. Strict consensus tree obtained through the Neighbor-joining method can be divided into five major clades in the genus Morus, according to combined sequence data. M. bombycis, M. alba var. venose formed clades A and B, respectively. Clade C comprises of 5 species; M. rotundiloba, M. atropurpurea, M. mongolica, M. australi, and M. mongolica var. diabolica. Clade D comprises of 3 species; M. wittiorum, M. laevigata, and M. alba. Clade E comprises of 2 species; M. multicaulis, and M.alba var. macrophylla. The results from cluster analysis were basically in agreement with the existing morphologic classification.African Journal of Biotechnology Vol. 4 (6), pp. 563-569, 200

    On-Farm-Produced Organic Amendments on Maintaining and Enhancing Soil Fertility and Nitrogen Availability in Organic or Low Input Agriculture

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    Maintaining and enhancing soil fertility are key issues for sustainability in an agricultural system with organic or low input methods. On-farm–produced green manure as a source of soil organic matter (SOM) plays a critical role in long-term productivity. But producing green manure requires land and water; thus, increasing biodiversity, such as by intercropping with green manure crops, could be an approach to enhance the efficiency of renewable resources especially in developing countries. This article discusses soil fertility and its maintenance and enhancement with leguminous intercropping from four points of view: soil fertility and organic matter function, leguminous green manure, intercropping principles, and soil conservation. Important contributions of leguminous intercropping include SOM enhancement and fertility building, biological nitrogen (N) and other plant nutrition availability. Under a well-designed and managed system, competition between the target and intercropping crops can be reduced. The plant uptake efficiency of biologically fixed N is estimated to be double that of industrial N fertilizers. After N-rich plant residues are incorporated into soil, the carbon (C):nitrogen ratio of added straw decreases. Another high mitigation potential of legume intercropping lies in soil conservation by preventing soil and water erosion. Many opportunities exist to introduce legumes in short-term rotation, intercropping, living mulch, and cover crops in an organically managed farm system. Worldwide, long-term soil fertility enhancement remains a challenge due to the current world population and agricultural practices. Cropping system including legumes is a step in the right direction to meeting the needs of food security and sustainability
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