An agonistic display by a white shark was observed and photographed during a cage dive at Guadalupe Island in November 2015. Exhibiting exaggerated pectoral fin depression, agonistic behaviors have been previously obs...An agonistic display by a white shark was observed and photographed during a cage dive at Guadalupe Island in November 2015. Exhibiting exaggerated pectoral fin depression, agonistic behaviors have been previously observed and described in several shark species. This account may be the first record of a white shark in close proximity to a caged diver, exhibiting strong pectoral fin depression significantly dipped, in the mid-agonistic display. Such displays should be considered as aggressive and potentially life-threatening by those using the ocean for recreational or professional purposes.展开更多
<div style="text-align:justify;"> Due to the poor anti-clogging performance of the common drip irrigation emitters, this paper designed a new bionic flow channel in the emitter based on the shape of sh...<div style="text-align:justify;"> Due to the poor anti-clogging performance of the common drip irrigation emitters, this paper designed a new bionic flow channel in the emitter based on the shape of shark dorsal fin. After preliminary structural design, the computational fluid dynamics (CFD) simulation showed that the bionic emitter exhibited superior anti-clogging performance and reasonable hydraulic performance. The passage rate of particles of the bionic emitter in simulation reached 96.3% which was 37.6% higher than 70% of traditional emitter, and the discharge exponent reached 0.4995 which was close to traditional emitter. Physical experiments were consistent with the CFD results, which confirmed the correctness of simulation. After a short cycle anti-clogging performance experiment, the bionic emitter still maintained 96.09% of the initial flow rate. </div>展开更多
The effects of extraction time,alkaline concentration,and the addition of cartilage on the extraction of mucopolysaccharides from shark fin cartilage digested with NaOH were investigated.The main components of mucopol...The effects of extraction time,alkaline concentration,and the addition of cartilage on the extraction of mucopolysaccharides from shark fin cartilage digested with NaOH were investigated.The main components of mucopolysaccharides during the degrading process were analyzed by cellulose polyacetate strip electrophoresis and agarose gel electrophoresis.The results showed that the extraction of mucopolysaccharides was increased with the increase of extraction time,alkaline concentration and the addition of cartilage.According to the different electrophoretic migrations,the preparative mucopolysaccharides composed of different polysaccharides with electronegativity can be divided into two parts,the chondroitin sulfate with higher migration and the other with lower migration.The lower part is unstable and easily degraded with alkaline solution.展开更多
文摘An agonistic display by a white shark was observed and photographed during a cage dive at Guadalupe Island in November 2015. Exhibiting exaggerated pectoral fin depression, agonistic behaviors have been previously observed and described in several shark species. This account may be the first record of a white shark in close proximity to a caged diver, exhibiting strong pectoral fin depression significantly dipped, in the mid-agonistic display. Such displays should be considered as aggressive and potentially life-threatening by those using the ocean for recreational or professional purposes.
文摘<div style="text-align:justify;"> Due to the poor anti-clogging performance of the common drip irrigation emitters, this paper designed a new bionic flow channel in the emitter based on the shape of shark dorsal fin. After preliminary structural design, the computational fluid dynamics (CFD) simulation showed that the bionic emitter exhibited superior anti-clogging performance and reasonable hydraulic performance. The passage rate of particles of the bionic emitter in simulation reached 96.3% which was 37.6% higher than 70% of traditional emitter, and the discharge exponent reached 0.4995 which was close to traditional emitter. Physical experiments were consistent with the CFD results, which confirmed the correctness of simulation. After a short cycle anti-clogging performance experiment, the bionic emitter still maintained 96.09% of the initial flow rate. </div>
文摘The effects of extraction time,alkaline concentration,and the addition of cartilage on the extraction of mucopolysaccharides from shark fin cartilage digested with NaOH were investigated.The main components of mucopolysaccharides during the degrading process were analyzed by cellulose polyacetate strip electrophoresis and agarose gel electrophoresis.The results showed that the extraction of mucopolysaccharides was increased with the increase of extraction time,alkaline concentration and the addition of cartilage.According to the different electrophoretic migrations,the preparative mucopolysaccharides composed of different polysaccharides with electronegativity can be divided into two parts,the chondroitin sulfate with higher migration and the other with lower migration.The lower part is unstable and easily degraded with alkaline solution.
