用PAT研究银丝生成机理

采用电子湮没技术(PAT)测定常规溴化银乳剂的正电子湮没寿命谱,用量子力学方法计算了自由体积空穴的变化,从而探讨银丝的生长机理.结果表明,用D-19作显影液,溴化银晶体先溶解后被还原,物理显影占据非常重要的地位,生成的银沿着电子密度较高的方向生长.     

用PAT研究银丝生成机理

采用电子湮没技术 (PAT)测定常规溴化银乳剂的正电子湮没寿命谱 ,用量子力学方法计算了自由体积空穴的变化 ,从而探讨银丝的生长机理。结果表明 ,用 D- 19作显影液 ,溴化银晶体先溶解后被还原 ,物理显影占据非常重要的地位 ,生成的银沿着电子密度较高的方向生长。     

显影液中银的成核过程

本文用受阻显影技术和电镜研究方法研究了显影剂量对显影液中银成核速度和核分散度的影响。随着显影液中显影剂量的减小,卤化银颗粒上银的成核速度明显减慢,单个颗粒上显影中心的数目明显增加。实验结果表明显影液中银的成核过程和曝光后的潜影形成过程在机理上是有差别的。文章讨论了显影过程中的一些基本问题:可显性、临界尺寸和显影选择性等等。     

D-76配方的调

黑白负片显影液的种类很多,一般采用米吐尔单剂、米吐尔和几奴尼联用或菲尼酮和几奴尼联用的显影液.目前使用最广的仍是米吐尔和几奴尼联用的显影液,而最常用的则是D-76显影液.这个配方发表于1927年,距今已有70余年了,在此期间,感光材料已有显著的改进和提高,但D-76显影液仍能适应各种感光片的冲洗,能充分发挥胶片的感光度,反差适中,最大限度地发挥其对暗部影像的表现能力,获得较好的颗粒度,显影宽容度极广,受显影液温度的影响较小,使用普通的显影方法都优于其它任何显影液,所以一直为人们所喜用.     

卤化银微晶体灰雾显影的研究

本文研究了卤化银乳剂经硫、金化学敏化后在Ｄ－１９ｂ和ＣＤ－４为显影剂的显影液中的灰雾显影。实验结果表明，经硫、金敏化的乳剂在Ｄ－１９ｂ显影液中灰雾显影所产生的密度均比在ＣＤ－４显影液中灰雾显影所产生的密度大。在Ｄ－１９ｂ显影液中一些硫敏化乳剂比金敏化乳剂灰雾显影密度大，但这些硫敏化乳剂在ＣＤ－４显影液中的灰雾显影密度却比同一金敏化乳剂的灰雾显影密度小，这些实验结果与硫、金敏化的两种乳剂分别在Ｄ－１     

提高显影选择性增力口影像密度

通过在显影液中综合应用有机和无机添加剂,影响显影剂的活性和含潜影卤化银微晶的性质,可使医用X射线胶片和黑白胶卷已曝光和未曝光卤化银之间的催化还原速度差别增大若干倍.研究这一效应的本质表明,影像密度的提高是由于在传统显影液中不显影的小尺寸潜影中心的卤化银微晶也加入到照相显影过程之中的结果,它导致感光涂层的曝光区银量增加.根据研究结果,在医疗机构进行了应用试验,用于医用X射线胶片的加工,由于影像密度的增加,可显著降低X射线的照射剂量.     

乐凯SHD胶卷对不同显影液的适应性

目前，国内大部分爱好黑白摄影的影友使用的黑白胶卷以乐凯SHD为主，又以使用中速感光度的SHD100者居多。这是因为乐凯SHD胶卷自投放市场后，以其细腻的颗粒，很高的清晰度，反差可随显影搅动的强弱进行控制等优点，赢得了大家的一致好评。乐凯SHD黑白胶卷实为物美价廉之国货精品。根据乐凯SHD胶卷使用说明书介绍的加工方法，应采用D-76显影液显影。但是黑白负片的显影配方尚有许多种，而且有一些被证明是优秀显影配方。在胶片后期加工中，显影的好坏有着举足轻重的作用。那么，乐凯SHD胶卷对不同显影液的适应性如何?能否用其它配方显影出与D-76相媲美，甚至更好的效果来?笔者带着上述问题，选用PQ-FGF、D-23和D-76d这3种显影配方对已曝光的乐凯SHD100黑白胶卷(执行标准号：Q/LK103·1029-97，乳剂号Emu1.No271，有效期Dev.Before2001.9)进行了显影实验。     

氧化铝模板中Ag纳米线阵列的选择性生长

利用Ag离子与Br离子之间的化学沉积作用在孔隙中充满明胶的阳极氧化铝（AAO）模板中制备了AgBr/AAO纳米介孔复合材料.材料选择性曝光后,利用原位显影液对其进行化学显影,在AAO模板中选择性得到Ag纳米线阵列.实验结果表明：Ag纳米线是连续的、致密的,且具有多晶结构,充满了曝光部分的模板孔隙.本文还对影响Ag纳米线选择性生长的因素进行了简单讨论.     

应用含硫氰酸铵的稀释显影液提高全息图的衍射效率

本文研究了用含有硫氰酸铵的稀释显影液处理的全息图的特性。利用电子显微镜和分光光度计测量的结果表明,与稀释显影全息图片相比,用含有硫氰酸的稀释显影液处理的全息片中的银颗粒的尺寸变小,其透过率增大。较小的银颗粒引起的光散射也将减小。基于测量结果并利用有效介质理论和耦合波理论可以解释利用含有硫酸铵的稀释显影液能够增加全息图的衍射效率。     

四氮唑化合物在卤化银照相材料中的作用

含有四氮唑化合物的卤化银照相材料采用对苯二酚－菲尼酮显影液显影，可以获得很高反差系数的影像。四氮唑化合物的这种高反差效果，除了与它和上述显影液的反应速率有关外，还与它在卤化银颗粒表面上的吸附程度分不开，但与曝光过程无关。     

Formation of silver nanoparticles created in situ in an amphiphilic block copolymer film

In this work, silver nanoparticles were synthesized with an amphiphilic diblock copolymer, polystyrene‐block‐poly(1‐vinyl‐2‐pyrrolidone) (PS‐b‐PVP), as a template film. First, microphase‐separated amphiphilic PS‐b‐PVP (70 : 30 wt %) was synthesized through atom transfer radical polymerization. The self‐assembled block copolymer film was used to template the growth of silver nanoparticles by the introduction of a silver trifluoromethanesulfonate precursor and an ultraviolet irradiation process. The in situ formation of silver nanoparticles with an average size of 4–6 nm within the block copolymer template film was confirmed with transmission electron microscopy, ultraviolet–visible spectroscopy, and wide‐angle X‐ray scattering. Fourier transform infrared spectroscopy also demonstrated the selective incorporation and in situ formation of silver nanoparticles within the hydrophilic poly(1‐vinyl‐2‐pyrrolidone) domains, which were mostly due to the stronger interaction strength of the silver with the carbonyl oxygens of poly(1‐vinyl‐2‐pyrrolidone) in the block copolymer. This work provides a simple route for the in situ synthesis of silver nanoparticles within a polymer film. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Use of silver nanoparticles as an electron transfer facilitator in electrochemical ligand-binding of haemoglobin

Silver nanoparticles have an activity for high intensity electron transfer. They can facilitate the electron transfer from the redox centre of a protein, as a high volume molecule, to the electrode surface. In this study, silver nanoparticles were deposited on the surface of a graphite carbon electrode in the 1 V potential region. Deposition of silver nanoparticles, with a diameter between 70 and 150 nm, was observed on the graphite electrode by transmission electron microscopy (TEM). The results demonstrated that the fine redox waves of haemoglobin could be achieved after modification of the graphite electrode by silver nanoparticles. The cathodic and anodic peaks of haemoglobin were at −135 and +375 mV vs. Ag/AgCl, respectively. The effect of guanosine 3′,5′-triphosphate (GTP), guanosine diphosphate (GDP) and guanosine monophosphate (GMP) on the structure of haemoglobin was investigated. It was observed that GTP shifts the cathodic and anodic peaks positively, indicating the transfer of the haem group to the surface of protein as a reflex of easier oxidation and reduction, while GDP and GMP do not show this behaviour. GTP binds with haemoglobin, while GDP and GMP do not.     

阳极氧化铝模板有序度影响因素的研究

在酸性电解液中,用阳极氧化法制备了多孔阳极氧化铝模板。用金相显微镜观察了铝箔退火前后的表面形貌,并结合扫描电镜对多孔氧化铝薄膜进行了形貌观察和表征。研究了影响多孔氧化铝模板孔有序性(分布均匀,大小一致)的关键性因素。实验结果表明,多孔阳极氧化铝膜结构特性依赖于铝箔预处理、氧化电压、电解液类型和温度等的选择。     

pn型Cu2O/CdS纳米线的制备及性能

采用电沉积法,在AAO模板中成功制备出pn型Cu₂O/CdS纳米线阵列。利用扫描电子显微镜（SEM）、透射电子显微镜（TEM）和X射线衍射分析（XRD）对样品的形貌和结构进行表征,利用光照开路电位测试和光吸收光谱测试对Cu₂O/CdS纳米线的性能进行了研究。纳米线的直径约100 nm,与AAO模板孔径相同,XRD结果表明Cu₂O/CdS纳米线由立方晶系的Cu₂O和立方晶系与六方晶系混合晶系的CdS组成。Cu₂O/CdS纳米线的光响应性能增强。在Xe灯照射下Cu₂O/CdS纳米线表现出良好的光催化性能,光照7 h后,Cu₂O/CdS纳米线对罗丹明B的降解效率达到66.02%。     

Y型孔洞阳极氧化铝模板的制备研究

阳极氧化铝(AAO)模板由于制备简单,成本较低,其孔径大小具有可控性等优点,是制备形状均匀、有序纳米电子材料的理想无机模板。直流恒压下,在0.3 M草酸溶液中对铝实施两步阳极氧化,并在第二次阳极氧化中途降低电压为初始电压的1/2获得Y形孔洞的氧化铝模板。利用扫描电子显微镜(SEM)对模板进行表征,结果表明:氧化铝模板高度有序,主干孔径约90 nm,分支孔径为(42±5)nm。     

Surface initiated ATRP of acrylic acid on dopamine‐functionalized AAO membranes

A facile method for surface‐initiated atom transfer radical polymerization (ATRP) on the anodic aluminum oxide (AAO) membranes has been developed. The AAO membrane was firstly functionalized by poly(dopamine), the bromoalkyl initiator was then immobilized on the poly(dopamine) functionalized AAO membrane surface in a two‐step solid‐phase reaction, followed by ATRP of acrylic acid in a aqueous solution. The poly(acrylic acid) (PAAc)‐grafted AAO membranes were characterized by X‐ray photoelectron spectroscopy, fourier transform infrared spectroscopy and scanning electron microscopy. The XPS and FTIR results indicated that PAAc was successfully grafted on the AAO membrane surface. The degree of grafting increases linearly with the increase of monomer concentration, and it reaches a plateau when the reaction time up to 4 h. The results indicate that the thickness of the grafted polymer inside the isocylindrical pores of AAO membranes could be well controlled by changing the reaction time and monomer concentration. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation of highly ordered ZnO nanowire arrays by paired-cell deposition

Highly ordered ZnO nanowire arrays were fabricated by paired cell method into nanoporous anodic alumina oxide (AAO) template. ZnO nanowires were uniformly assembled into the ordered channels of the AAO template. TEM and selected-area electron diffraction patterns indicated that the ZnO nanowires grow as a single crystal. The factors influencing the final filled density of ZnO nanowires, including the solution concentration and the diffusing temperature are discussed briefly. In addition, the possible mechanism is also proposed to account for the growth of the ZnO nanowires in the AAO template. This result has established that this paired cell method makes it possible to grow single-crystalline ZnO nanowires in the AAO template under appropriate conditions.     

多孔氧化铝模板法制备取向碳纳米管阵列的研究进展

利用化学气相沉积技术在多孔氧化铝模板上可以制备取向碳纳米管阵列。通过调节阳极氧化参数可以改变模板的孔结构,进而可控制碳纳米管在孔道中生长的形貌。用这种方法制备的碳纳米管的直径、长度和密度可以选择性控制,这将有利于研究碳纳米管的性质和它在电化学及其他领域的应用。介绍了多孔氧化铝模板的形成原理以及碳纳米管在多孔氧化铝模板上的生长机理,讨论了阳极氧化条件、催化剂和气相沉积温度对碳纳米管特性的影响,并指出了这种技术中一些需深入研究的问题。