RESUMO
The ultra-short baseline positioning system (USBL) has the advantages of flexible application and easy installation, and it plays an extremely important role in the underwater positioning and communication. The error of the USBL in underwater positioning is mainly caused by a ranging error due to ray tracing, a phase difference error of the USBL, and acoustic noise in the underwater communication. Most of these errors are related to the changes in the sound speed during its propagation through the ocean. Therefore, when using the USBL for underwater detection, it is necessary to correct the sound speed profile in the detection area and optimize the ray tracing. Taking into account the actual conditions, this paper aims at correcting the model of underwater sound speed propagation and improving the tracking method of sound lines when the marine environment in the shallow sea area changes. This paper proposes a combined ray tracing method that can adaptively determine whether to use the constant sound speed ray tracing method or the equal gradient ray tracing method. The theoretical analysis and simulation results show that the proposed method can effectively reduce the error of slant distance in USBL compared with the traditional acoustic tracking method and the constant sound speed ray tracing method. The proposed sound ray correction algorithm solves the contradiction between the number of iterations and the reduction of positioning error and has engineering application value.
RESUMO
Gracilariopsis lemaneiformis is a type of red alga that contains seaweed polysaccharide agar. In this study, a novel non-agar seaweed polysaccharide fraction named GCP (short of crude polysaccharide obtained from Gracilariopsis lemaneiformis) was isolated from Gracilariopsis lemaneiformis. Structural analysis showed that GCP shows triple helical chain conformation when dissolved in water and has many branches and long side chains. Also, 1â3 linkage is the major linkage and the sugar structures are galactopyranose configurations linked by ß-type glycosidic linkages. Two macromolecular substance fractions (GCP-1 and GCP-2) were purified by DEAE Sepharose Fast Flow column chromatography. Moreover, a splenocyte damage assay and splenocyte proliferation assay were used to analyse the bioactivities of GCP, GCP-1 and GCP-2. It was demonstrated that polysaccharides could protect splenocyte damaged by H2O2; GCP-2 shows a greatest protection rate, that is, 92.8%, which significantly enhanced the splenocyte proliferation, and GCP showed the highest proliferation rate, 9.30%. The results suggested that this type of novel non-agar polysaccharide displayed remarkable antioxidant and immunomodulatory activities and early alkali treatment could decrease the activities. It may represent a potential material for health food and clinical medicines.
Assuntos
Polissacarídeos/química , Rodófitas/química , Alga Marinha/química , Animais , Proliferação de Células/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Ensaio de Imunoadsorção Enzimática , Linfócitos/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Camundongos , Microscopia Eletrônica de Varredura , Estrutura Molecular , Peso Molecular , Ácido Periódico/química , Polissacarídeos/isolamento & purificação , Valores de Referência , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Japanese flounder (Paralichthys olivaceus) is an important releasing fish in the Yellow and Bohai Seas of China. The identification of wild and releasing population is the premise to evaluate the enhancement effects. In order to study the application of stable isotope in the identification of released P. olivaceus population, captured juveniles in the offshore releasing area of Qinhuangdao were distinguished into wild and released population using previous method (combination of morphology and molecular). Then, the contents of carbon and nitrogen stable isotope in muscle and otoliths (including the whole and the core region) were measured. The cultured population was set as control. The results showed that δ13C values (wild population: -17.19±0.73; released population: -17.10±0.61; cultured population: -20.75±0.07) and δ15N values (wild population: 11.81±0.38; released population: 11.62±0.48; cultured population: 8.64±0.60) of muscle and δ13C value (wild popu-lation: -4.47±0.35; released population: -4.63±0.29; cultured population: -6.59±0.58) of the whole otolith could be used to identify the cultured population, but could not be used to distinguish the wild from the released population. The δ13C value (wild population: -4.66±0.30; released population: -5.41±0.21; cultured population: -5.37±0.19) of the core region of otolith could be used to identify the wild popu-lation. The δ18O values of the whole and the core region of otolith from these three groups were overlapped and could not be used to distinguish different populations. Our results indicated that the δ13C value of the core area of otolith could be used to identify wild and released population, with application prospect in the identification of broodstocks participating in spawning migration. This study provided basic data and technical methods for evaluating early resources replenishment and the effects of Japanese flounder enhancement.
Assuntos
Linguado , Animais , Carbono , Isótopos de Carbono/análise , Isótopos de Nitrogênio/análise , Oceanos e Mares , Membrana dos OtólitosRESUMO
ABSTRACT Gracilariopsis lemaneiformis is a type of red alga that contains seaweed polysaccharide agar. In this study, a novel non-agar seaweed polysaccharide fraction named GCP (short of crude polysaccharide obtained from Gracilariopsis lemaneiformis) was isolated from Gracilariopsis lemaneiformis. Structural analysis showed that GCP shows triple helical chain conformation when dissolved in water and has many branches and long side chains. Also, 1→3 linkage is the major linkage and the sugar structures are galactopyranose configurations linked by β-type glycosidic linkages. Two macromolecular substance fractions (GCP-1 and GCP-2) were purified by DEAE Sepharose Fast Flow column chromatography. Moreover, a splenocyte damage assay and splenocyte proliferation assay were used to analyse the bioactivities of GCP, GCP-1 and GCP-2. It was demonstrated that polysaccharides could protect splenocyte damaged by H2O2; GCP-2 shows a greatest protection rate, that is, 92.8%, which significantly enhanced the splenocyte proliferation, and GCP showed the highest proliferation rate, 9.30%. The results suggested that this type of novel non-agar polysaccharide displayed remarkable antioxidant and immunomodulatory activities and early alkali treatment could decrease the activities. It may represent a potential material for health food and clinical medicines.