Starting from the multi-soliton solutions obtained by the Hirota bilinear method,the soli ton molecule structures for the combined mKdV-type bilinear equation(Dt+∑n=1NαnDx2n+1)f*·f=0 are investigated using the ...Starting from the multi-soliton solutions obtained by the Hirota bilinear method,the soli ton molecule structures for the combined mKdV-type bilinear equation(Dt+∑n=1NαnDx2n+1)f*·f=0 are investigated using the velocity resonance mechanism.The two-soliton molecules of the mKdV-35 equation and the three-soliton molecules of the mKdV-357 equation are specifically demonstrated in this paper.With particular selections of the involved arbitrary parameters,especially the wave numbers,it is confirmed that,besides the usual multi-bright soliton molecules,the multi-dark soliton molecules and the mixed multibright-dark soliton molecules can also be obtained.In addition,we discuss the existence of the multi-soliton molecules for the combined mKdV-type bilinear equation with more higher order nonlinear terms and dispersions.The results demonstrate that when N≥4,the combined mKdVtype bilinear equation no longer admits soliton molecules comprising more than four solitons.展开更多
Tungsten heavy alloys(WHAs) produced by powder technology are widely used for the mechanical manufacturing, electronic and defense components, etc.Tribological properties of these alloys need to be improved to meet th...Tungsten heavy alloys(WHAs) produced by powder technology are widely used for the mechanical manufacturing, electronic and defense components, etc.Tribological properties of these alloys need to be improved to meet the severe service conditions demanded. Carburization is a promising way to resolve this problem. In this work, microstructure and tribological properties of the carburized 95W–3.5Ni–1.0Fe–0.5Co heavy alloy were investigated in comparison with those of the untreated alloy. Results show that the carburized layer consists of a porous, outer WC layer and a modified W grain layer surrounded by Fe_6W_6C and Co_6W_6C at 970℃, regardless of the carburizing time. The depth of the carburized layer linearly increases in a relatively short time and slightly increases during the subsequent period. Surface roughness increases with carburizing time. Carburization can stabilize friction coefficient and effectively improve the wear resistance of the tungsten heavy alloy due to its significantly increased hardness and non-deformability, but the porous structure in the WC layer has a negative influence on its wear resistance. The carburized layer is damaged in the porous WC layer in the form of the spalling of WC particles where there are some microcracks and micropores, accompanied with peeling due to the solid tribofilm being pushed away.展开更多
目的了解骨转换标志物(bone turnover markers,BTMs)在高龄(≥80岁)男性骨密度(bone mineral density,BMD)变化中的预测价值。方法对737例高龄男性进行连续2次(间隔12个月)血BTMs[包括Ⅰ型胶原羧基端肽(C-telopeptide of type 1 collage...目的了解骨转换标志物(bone turnover markers,BTMs)在高龄(≥80岁)男性骨密度(bone mineral density,BMD)变化中的预测价值。方法对737例高龄男性进行连续2次(间隔12个月)血BTMs[包括Ⅰ型胶原羧基端肽(C-telopeptide of type 1 collagen,CTX)β特殊序列、总Ⅰ型胶原氨基端前肽(procollagen1 N-terminal peptide,P1NP)和骨钙素(osteocalcin,OC)]和BMD[包括股骨颈骨密度(femoral neck bone mineral density,FNBMD)、总髋部骨密度(total hip bone mineral density,THBMD)和腰椎1-4骨密度(lumbar bone mineral density,LBMD)]测定,分析12个月前后高龄男性BTMs和BMD的变化趋势及其相关性。结果12个月后,高龄男性血清CTX和LBMD上升,血清OC下降(均P<0.01);基线血清CTX与△FNBMD(r=-0.109,P<0.05)、△THBMD(r=-0.135,P<0.01)呈负相关;△CTX(r=-0.119,P<0.05)和△OC(r=-0.137,P<0.01)与△LBMD呈负相关。结论 BTMs对高龄男性BMD变化有一定的预测价值,其中血清CTX水平越高,其股骨颈和总髋部BMD下降越快,而△CTX、△OC越高,腰椎BMD下降越快。展开更多
【目的】明确草地贪夜蛾[Spodoptera frugiperda(J. E. Smith)]对杀虫剂氯虫苯甲酰胺的应答反应,为深入了解和探究草地贪夜蛾在氯虫苯甲酰胺作用下的解毒代谢提供一定的理论基础。【方法】利用超高效液相联用四级杆串联飞行时间质谱仪(U...【目的】明确草地贪夜蛾[Spodoptera frugiperda(J. E. Smith)]对杀虫剂氯虫苯甲酰胺的应答反应,为深入了解和探究草地贪夜蛾在氯虫苯甲酰胺作用下的解毒代谢提供一定的理论基础。【方法】利用超高效液相联用四级杆串联飞行时间质谱仪(UPLC-Q-TOF-MS)对0和0.10 mg/L氯虫苯甲酰胺处理下的草地贪夜蛾3龄幼虫的差异代谢物进行检测,利用Progenesis QI软件在线METLIN数据库对差异代谢物进行注释、筛选、分类和差异代谢通路分析。采用酶标仪测定草地贪夜蛾总糖和可溶性糖含量,对代谢组结果进行验证。【结果】从0和0.10 mg/L氯虫苯甲酰胺胁迫下的正离子质谱采集模式共鉴定出1594种差异代谢物(853种上调,741种下调);负离子质谱采集模式下共鉴定出2202种差异代谢物(1102种上调,1100种下调)。差异代谢物鉴定分类显示,羧酸及其衍生物大分类下代谢物分布与含量最多,其次为甘油磷脂类大分类。在差异代谢物中定位到左旋多巴、磷脂酸、琥珀酸、丝氨酸、麦芽糖和脱氧尿苷等,其中左旋多巴、麦芽糖和脱氧尿苷显著上调(P<0.05,下同),差异倍数分别为515.56、7.31和9.13倍。氯虫苯甲酰胺处理下草地贪夜蛾氨基酸、糖原、糖酵解、能量、嘌呤、嘧啶和脂类等代谢途径发生变化。草地贪夜蛾处理组总糖和可溶性糖含量分别是对照组含量的2.05和1.71倍,与代谢组分析结果一致。差异代谢通路富集分析结果显示,在正、负离子质谱采集模式下分别在矿物质吸收通路和癌症中的胆碱代谢通路显著富集。【结论】氯虫苯甲酰胺胁迫下引起草地贪夜蛾代谢产物发生明显变化,草地贪夜蛾体内氨基酸代谢、能量代谢、嘌呤嘧啶代谢和脂肪酸代谢途径被大幅度调动,这些过程共同作用减少氯虫苯甲酰胺对草地贪夜蛾的毒性。展开更多
基金the National Natural Science Foundation of China(Grant Nos.11975204 and 12075208)the Project of Zhoushan City Science and Technology Bureau(Grant No.2021C21015)the Training Program for Leading Talents in Universities of Zhejiang Province。
文摘Starting from the multi-soliton solutions obtained by the Hirota bilinear method,the soli ton molecule structures for the combined mKdV-type bilinear equation(Dt+∑n=1NαnDx2n+1)f*·f=0 are investigated using the velocity resonance mechanism.The two-soliton molecules of the mKdV-35 equation and the three-soliton molecules of the mKdV-357 equation are specifically demonstrated in this paper.With particular selections of the involved arbitrary parameters,especially the wave numbers,it is confirmed that,besides the usual multi-bright soliton molecules,the multi-dark soliton molecules and the mixed multibright-dark soliton molecules can also be obtained.In addition,we discuss the existence of the multi-soliton molecules for the combined mKdV-type bilinear equation with more higher order nonlinear terms and dispersions.The results demonstrate that when N≥4,the combined mKdVtype bilinear equation no longer admits soliton molecules comprising more than four solitons.
基金financially supported by the Advanced Research Fund of Department of Defense, China (No. 9140A18070114JW16001)Guangdong Natural Science Foundation (No. 2015A030310170)
文摘Tungsten heavy alloys(WHAs) produced by powder technology are widely used for the mechanical manufacturing, electronic and defense components, etc.Tribological properties of these alloys need to be improved to meet the severe service conditions demanded. Carburization is a promising way to resolve this problem. In this work, microstructure and tribological properties of the carburized 95W–3.5Ni–1.0Fe–0.5Co heavy alloy were investigated in comparison with those of the untreated alloy. Results show that the carburized layer consists of a porous, outer WC layer and a modified W grain layer surrounded by Fe_6W_6C and Co_6W_6C at 970℃, regardless of the carburizing time. The depth of the carburized layer linearly increases in a relatively short time and slightly increases during the subsequent period. Surface roughness increases with carburizing time. Carburization can stabilize friction coefficient and effectively improve the wear resistance of the tungsten heavy alloy due to its significantly increased hardness and non-deformability, but the porous structure in the WC layer has a negative influence on its wear resistance. The carburized layer is damaged in the porous WC layer in the form of the spalling of WC particles where there are some microcracks and micropores, accompanied with peeling due to the solid tribofilm being pushed away.
文摘目的了解骨转换标志物(bone turnover markers,BTMs)在高龄(≥80岁)男性骨密度(bone mineral density,BMD)变化中的预测价值。方法对737例高龄男性进行连续2次(间隔12个月)血BTMs[包括Ⅰ型胶原羧基端肽(C-telopeptide of type 1 collagen,CTX)β特殊序列、总Ⅰ型胶原氨基端前肽(procollagen1 N-terminal peptide,P1NP)和骨钙素(osteocalcin,OC)]和BMD[包括股骨颈骨密度(femoral neck bone mineral density,FNBMD)、总髋部骨密度(total hip bone mineral density,THBMD)和腰椎1-4骨密度(lumbar bone mineral density,LBMD)]测定,分析12个月前后高龄男性BTMs和BMD的变化趋势及其相关性。结果12个月后,高龄男性血清CTX和LBMD上升,血清OC下降(均P<0.01);基线血清CTX与△FNBMD(r=-0.109,P<0.05)、△THBMD(r=-0.135,P<0.01)呈负相关;△CTX(r=-0.119,P<0.05)和△OC(r=-0.137,P<0.01)与△LBMD呈负相关。结论 BTMs对高龄男性BMD变化有一定的预测价值,其中血清CTX水平越高,其股骨颈和总髋部BMD下降越快,而△CTX、△OC越高,腰椎BMD下降越快。
