磁致伸缩效应在生物传感器中的应用

我们致力于无线磁传感技术的研究,该技术基于磁致伸缩原理设计。在外加交变磁场中,磁性膜片受磁场激发产生磁矩,将磁能转换为机械能,并产生沿长度方向伸缩振动,即磁致伸缩。当交变磁场频率与磁性膜片机械振动频率相等时,磁片产生共振,具有最大振幅,此时振动频率为磁性膜片共振频率。当磁性膜片传感器表面负载质量发生变化时,其共振频率也会随之改变。由于磁性膜片本身是磁性的,其伸缩振动产生磁通,产生的磁通可由检测线圈检测,信号经放大后由外部仪器测定。磁弹性传感器中信号的激发与传送是通过磁场进行的,传感器与检测仪器之间没有任何物理连接,属于无线无源传感器。磁弹性传感器的无线无源特征使其在活体、在体分析、密闭容器中的无损检测等领域具有广泛的应用前景。如pH传感器、免疫传感器。     

发展中的磁电材料

磁电材料在磁记录等方面具有巨大的潜在应用价值。在过去的几十年内,人们对单相材料和复合材料的磁电效应进行了广泛的研究。只有磁矩有序和电偶极子有序共存的材料才会在磁场作用下极化或在电场作用下磁化。单相材料有一个很大的缺点,即其磁电感应即使在低温下也相当微弱,这就限制了其在实际器件里的应用。复合材料的磁电感应是通过材料中独立的压磁相和压电相或磁致伸缩相和压电相实现的。磁电层合材料巨大的磁电感应电压系数源于压电晶体的巨压电电压系数和磁致伸缩部分的巨弹性屈服度。本文主要阐述磁电颗粒复合材料和层合材料的研究现状并总结了一些重要结果。     

磷酸二氢铝的试制

一、前言磷酸二氢铝是取向硅钢薄板表面涂层中的重要组分。此表面涂层的作用是:(1)具有优良的绝缘性能,使硅钢片叠层应用时减少涡流损耗;(2)涂层很薄,占用空间少,可增大填充系数,减少电器设备的体积;(3)可有效改善取向硅钢片的磁致伸缩特性(磁致伸缩是造成变压器噪音的主要原因),减少磁致伸缩引起的振动,以降低变压器噪音并减少电能的消耗,从而提高电能的利用效率;(4)表面涂层在钢板上附着牢固,在硅钢片进行卷曲、剪切、冲压时不脱落。据国外报导:取向硅钢薄板的表面涂层通常是高温退火中形成的玻璃质薄膜和在其上涂     

组织结构对Co-Ni-P薄膜形貌和磁性的影响

化学镀 Co- Ni- P薄膜镀态下为非晶态结构 ,表面较为平整 ;经 30 0℃× 1 h热处理 ,发生了晶化转变 ,表面由“圆锥峰“所构成 ;随加热温度的提高 ,镀层析出了 Co2 P相 ,并发生了由密排六方结构的α- Co向面心立方结构的β- Co的同素异构转变。非晶态 Co- Ni- P薄膜的矫顽力较低 ,矩形比较高 ;薄膜向晶态转变时 ,矫顽力和矩形比皆呈上升趋势 ;50 0℃× 1 h热处理 ,薄膜由α- Co和 Co2 P相构成时 ,且在晶界上偏聚较多磷的影响下 ,矫顽力和矩形比的值达到最高 ;温度继续升高 ,晶粒长大 ,第二相粗化时 ,薄膜的矫顽力和矩形比都减小。化学镀 Co- Ni- P薄膜具有优秀的高密度垂直记录特性。     

夹心结构FeNi/Cu／FeNi多层膜巨磁阻抗效应的研究

采用MEMS技术在玻璃基片上制备了夹心结构FeNi/Cu/FeNi多层膜,在100KHz-40MHz范围内研究了FeNi/Cu/FeNi多层膜中的巨磁阻抗效应特性。当磁场Hext施加在薄膜的长方向时,巨磁阻抗效应随磁场的增加而增加,在某一磁场下达到最大值,然后随磁场的增加而下降到负的巨磁阻抗效应。在频率为5MHz时,巨磁阻抗效应在磁场Hext=800A/m时达到最大值25．2％;在磁场Hext=9600A／m时,巨磁阻抗效应为-7．3％。巨磁阻抗效应的最大值及负的巨磁阻抗效应与多层膜中磁各向异性轴的取向及发散有关。另外,当磁场施加在薄膜的短方向时,薄膜表现出负的巨磁阻抗效应,在频率5MHz、磁场Hext=9600A/m时,巨磁阻抗效应可达-19．3％。     

采用MAMMOS技术的高密度光记录

MAMMOS(Magnetic Amplifying Magneto－ Optical System:磁畴扩大磁光系统 )是实现高密度磁光盘的有效方法。不仅能得到不依赖于磁畴长度的较大的读出信号振幅,而且还能实现超出光学系统衍射极限的分辨率。过去,为实现磁畴的复印与扩大,要对记录膜面施加垂直方向的外部磁场。而现在得知,同时施加垂直磁场和水平方向的磁场,可大幅度地提高微小磁畴的读出特性。确认采用施加水平磁场的方法,在λ =635 nm, NA=0.55的条件下, 0.15μ m的连续磁畴也能获得 BER=2× 10－ 4的读出效果。     

宁波材料所在柔性磁传感薄膜材料与器件研究方面取得系列进展

正柔性智能可穿戴设备的快速发展,提出了磁电功能器件柔性化的要求。由于磁性材料的逆磁致伸缩特性,弯曲或拉伸状态所产生的应力/应变会改变磁性薄膜的磁各向异性,从而影响磁性器件的性能。如何避免应力磁各向异性对柔性磁性器件性能产生不利的影响,是柔性磁性薄膜与器件发展中所面临的重要挑战之一。近年来,中科院宁波材料所磁性材料与器件重点实验室磁电子材料与器件研究团队,系     

柔性磁传感薄膜材料与器件研究成果

<正>柔性智能可穿戴设备的快速发展,提出了磁电功能器件柔性化的要求。由于磁性材料的逆磁致伸缩特性,弯曲或拉伸状态所产生的应力/应变会改变磁性薄膜的磁各向异性,从而影响磁性器件的性能。如何避免应力磁各向异性对柔性磁性器件性能产生不利的影响,是柔性磁性薄膜与器件发展中所面临的重要挑战之一。近年来,中国科学院宁波材料技术与工程研究所磁性材料与器件重点实验室磁电子     

电场控制交换偏置的原理和研究进展

自旋阀结构是许多自旋电子器件(比如读出磁头、传感器)的基础。传统的自旋阀结构利用了铁磁/反铁磁交换偏置原理并由外磁场对其进行操控。利用电场控制交换偏置的原理制成的电场控制型自旋阀是一种新型结构,具有巨大的潜在应用前景。通过应变调制铁磁材料的应力各向异性场是电场控制交换偏置的重要途径。这种应变调制可通过铁磁材料与巨磁致伸缩材料、压电、多铁性材料的复合来实现。本文将重点介绍铁磁/巨磁致伸缩、压电、多铁性复合结构的应变特性,以及应变对交换偏置的调制原理和研究进展情况。     

磁场条件下化学镀镍薄膜制备及磁性能研究

利用化学镀方法,在没有外磁场和施加弱磁场条件下制备了磁性镍薄膜。薄膜均具有银色金属光泽,表面平整致密。X-射线衍射仪分析表明,弱磁场下制得的薄膜中镍晶粒的取向排列性较强。扫描电子显微镜观察可知,未加磁场制备的镍膜是由粒径200nm的镍纳米颗粒在基底上沉积组成的。在磁场条件下制备的镍膜是由数十微米长的镍纳米线在基底上有序排列组成。磁测量结果表明,磁场条件下制备的镍膜的磁性能有显著改变,原因是由膜层特殊的磁畴结构造成的。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。