TRH合成研究

ＴＲＨ是由下丘脑合成和分泌的活性肽之一,主要生理作用是促进垂体前叶合成和释放促甲状腺素（ＴＳＨ）,并能促进催乳素（ＰＲＬ）的分泌,它又是一种中枢神经谏Ｕ激剂,可以细８精神抑郁症。八一卜年代后发现ＴＡＮ具有抗休克作用Ｉ‘］。ＴＲＨ的结构为焦谷氨酚组氨酸用氨酸胺卜ｐＧＩＬＩ·ＨＩＳ·ＰｒＯＮＨ。）。其合成方法有液相法和团相法,其偶连顺序可以从Ｃ端,也能从Ｎ端开始,肽键的联接可采用ＤＣＣ法、叠氮物法和活化酯法１１’］。在已报道过的合成方法中,活化酯法较为理想,此方法利用书氧碳基保护Ｌ…ＩＵ．的Ｎ端,通…     

Poly(2,5-dimethoxyaniline) film coating for corrosion protection of iron

A poly(2,5-dimethoxyaniline) (PDMA) film was coated on the iron surface by the electropolymerization of 2,5-dimethoxyaniline in neutral buffer solution (pH?6.86). The PDMA film strongly adhered to the surface because of the polar methoxy groups of the PDMA molecules. The fact that no electrochemical response of the PDMA film-coated iron electrode to dissolved Fe²⁺ exhibited that the PDMA film was less permeable to dissolved species, acting as a diffusion barrier against agents causing corrosion such as H₂O and O₂. The PDMA film coating greatly lowered the anodic current peak ascribed to the anodic dissolution of iron and the corrosion current in strongly acidic medium, 0.5?M H₂SO₄ aqueous solution (1?M?????mol?dm^??) as well as neutral medium (pH?6.86). The high anti-corrosion ability was due to a hybrid effect of the PDMA film not only as the diffusion barrier, but also as an in situ oxidant in spite of the slight redox activity of PDMA. In addition, the PDMA film is much more durable and adhesive than polyaniline film against over-oxidation.     

不同的烧结工艺对Sm-Co2∶17型高温磁体性能的影响

采用中频感应熔炼法制备了Sm( Co0.79 Fe0.09 Cuo.085 Zr0.032) 7.95合金,采用传统烧结工艺,在1200 ～1240℃烧结1h,1165 ～1190℃固溶处理3h,快速风冷淬火后在840 ℃保温12h,以0.4 ·min-1的冷速冷却至420℃,保温10h,最后随炉冷却.磁体经过加工后,采用不同的磁性测试手段对磁体进行测试.结果表明,磁体的剩磁随烧结温度的升高而增大,矫顽力最好的工艺为1230℃烧结1h,然后在1180℃固溶3h.将此工艺制备的磁体采用中国计量科学院NIM-500C超高温永磁测量仪测试,磁体在773 K时的最大磁能积为10.94 MGOe,高于已经报道的同Z值的2∶17型永磁体.磁体的磁滞回线通过振动样品磁强计( VSM)测得,室温下Br=10.5 kGs,Hcj=30.21 kOe,(BH)max=25.60MGOe; 773 K时磁体Br=7.45 kGs,Hcj=6.02 kOe,(BH) max=9.85 MGOe.剩磁温度系数α=-0.0624％·℃-1,矫顽力温度系数β=-0.169％·℃-1.     

微流控纸芯片的加工及其分析应用的实验设计*

设计了一个使用喷墨打印法加工微流控纸芯片的实验,在经烷基烯酮二聚体(AKD)的正己烷溶液浸泡过的滤纸上,以三乙醇胺溶液为打印墨水,用喷墨打印机打印出设计好的芯片图案。滤纸加热后,打印区域呈现亲水性,非打印区域为疏水性,从而制备出纸芯片,用该纸芯片通过数字比色法实现了亚硝酸根离子的定量测定。该实验不使用昂贵仪器设备,易普及。通过实验,促使学生了解微流控芯片这一前沿科学技术,锻炼学生细致、灵巧的动手能力,激发学生科技创新活力。     

光引发甲基丙烯酸聚合改性羟基磷灰石表面的研究

羟基磷灰石(HPA)具有良好的生物相容性和生物活性,被认为是最有前途的陶瓷人工齿和人工骨置换材料。然而,纯HAP的力学性能比较差,断裂韧性(KIC)不超过1.0MPa.m1/2(自然骨为2-12MPa.m1/2)[1],作为人工种植体其使用可靠性较差。这大大限制了它在承载部位骨替换中的应用。为了改善     

低温水热法制备硅胶负载型二氧化钛催化剂

TiO2作为一种优良的光催化材料,能够降解有机物,起到抗菌防污的作用,其在工业上的潜在应用已吸引众多研究者的普遍关注和深入研究[1-3]。为了进一步提高它的光催化活性,研究者试图运用各种方法和技术对纯TiO2进行改进。负载[3]是其中常用方法之一。对于无负载的二氧化钛,由于本     

Investigating bottom-quark Yukawa interaction at Higgs factory

Measuring the fermion Yukawa coupling constants is important for understanding the origin of the fermion masses and their relationship with spontaneously electroweak symmetry breaking.In contrast,some new physics(NP)models change the Lorentz structure of the Yukawa interactions between standard model(SM)fermions and the SM-like Higgs boson,even in their decoupling limit.Thus,the precise measurement of the fermion Yukawa interactions is a powerful tool of NP searching in the decoupling limit.In this work,we show the possibility of investigating the Lorentz structure of the bottom-quark Yukawa interaction with the 125 GeV SM-like Higgs boson for future e^+e^- colliders.