Thesis submitted in fulfilment of the requirements for the degree Magister Technologiae: Chemical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology 2013 / There are significant quantities of free cyanide (F-CN) and heavy metal contaminated effluent being discharged from electroplating operations globally. However, there is an overwhelming tendency in the industry to use physical and/or chemical treatment methods for cyanides (CNs) and heavy metals in effluent. Although these methods may be effective for certain CNs and heavy metals, they produce toxic by-products and also involve high operational and capital investment costs when compared to bioremediation methods. In this study, the design of a two-stage membrane bioreactor (MBR) system was conceptualised for the bioremediation of CNs and heavy metals in the effluent which was collected from an electroplating facility located in the Western Cape, South Africa. The design included a primary inactive bioremediation stage, to reduce the impact of contaminate concentration fluctuations, and a secondary active bioremediation stage, to remove the residual contaminants, in the effluent under alkaline pH conditions which typify most industrial effluent containing these contaminants. An analysis of the electroplating effluent revealed that the effluent contained an average of 149.11 (± 9.31) mg/L, 5.25 (± 0.64) mg/L, 8.12 (± 4.78) mg/L, 9.05 (± 5.26) mg/L and 45.19 (± 25.89) mg/L of total cyanide (T-CN), F-CN, weak acid dissociable cyanides (WAD-CNs), nickel (Ni), zinc (Zn) and copper (Cu), respectively. An Aspergillus sp., which displayed the characteristic black conidiophores of the Aspergillus section Nigri, was isolated from the electroplating facilities’ effluent discharge using a selective pectin agar (PA) and subcultured on 2% (v/v) antibiotic (10,000 units/L penicillin and 10 mg streptomycin/mL) potato dextrose agar (PDA). The isolate was tolerant to F-CN up to 430 mg F-CN/L on F-CN PDA plates which were incubated at 37 ˚C for 5 days. However, a significant decline in microbial growth was observed after 200 mg F-CN/L, thus indicating that the isolate was suitable for the bioremediation of the electroplating effluent. The identification of the isolate as Aspergillus awamori (A. awamori) was definitively determined using a multi-gene phylogenetic analysis, utilising ITS (internal transcribed spacer), -tubulin and calmodulin gene regions. Although an anomaly in the morphology of the conidia of the isolate was observed during the morphological analysis, indicating a possible morphological mutation in the isolate. A comparative study between “sweet orange” (Citrus sinensis (C. sinensis)) pomace, “apple” (Malus domestica (M. domestica)) pomace, “sweetcorn” (Zea mays (Z. mays)) cob and “potato” (Solanum tuberosum (S. tuberosum)) peel, i.e. waste materials considered to be agricultural residues, was conducted in order to assess their potential and as a sole carbon source supplement for A. awamori biomass development for the bioremediation of CNs and heavy metals. The suitability of these agricultural residues for these activities were as follows: C. sinensis pomace ˃ M. domestica pomace ˃ Z. mays cob ˃ S. tuberosum peel. For purpose of the sensitivity analysis, a temperature range of 20 to 50 ˚C and an alkaline pH range of 7 to 12 showed that: (1) optimal conditions for the uptake of Ni, Zn and Cu occurred at pH 12 and a temperature of 37.91 and 39.78 ˚C using active and inactive A. awamori biomass and unhydrolysed and hydrolysed C. sinensis pomace, respectively; (2) F-CN conversion increased linearly with an increase in pH and temperature using unhydrolysed and hydrolysed C. sinensis pomace; and (3) optimal conditions for the F-CN conversion and the respective by-products and sugar metabolism using active A. awamori biomass occurred at 37.02 ˚C and pH 8.75 and at conditions inversely proportional to F-CN conversion, respectively. The heavy metal affinity was Ni > Zn > Cu for all the biomaterials used and with the heavy metal uptake capacity being inactive A. awamori biomass > active A. awamori biomass > hydrolysed C. sinensis pomace > unhydrolysed C. sinensis pomace, respectively. Hydrolysed C. sinensis pomace had a 3.86 fold higher conversion of F-CN compared to the unhydrolysed C. sinensis pomace. The use of C. sinensis pomace extract as a nutrient media, derived from the acid hydrolysis of C. sinensis pomace, showed potential as a rich carbon-based supplement and also that low concentrations, < 0.1% (v/v), were required for the bioremediation of CNs and heavy metals. The two-stage MBR system was operated at 40 ˚C since this temperature was conducive to the bioremediation of CN and heavy metals. The primary bioremediation stage contained hydrolysed C. sinensis pomace while the secondary bioremediation stage contained active A. awamori biomass, supplemented by the C. sinensis pomace extract. After the primary and secondary bioremediation stages, 76.37%, 95.37%, 93.26% and 94.76% (primary bioremediation stage) and 99.55%, 99.91%, 99.92% and 99.92% (secondary bioremediation stage) average bioremediation efficiencies for T-CN, Ni, Zn and Cu were achieved. Furthermore, the secondary bioremediation stage metabolised the CN conversion by-products with an efficiency of 99.81% and 99.75% for formate (CHOO-) and ammonium (NH4+), respectively. After the first, second and third acid regeneration cycles of the hydrolysed C. sinensis pomace, 99.13%, 99.12% and 99.04% (first regeneration cycle), 98.94%, 98.92% and 98.41% (second regeneration cycle) and 98.46%, 98.44% and 97.91% (third regeneration cycle) recovery efficiencies for Ni, Zn and Cu were achieved. However, the design only managed to treat the effluent for safe discharge and the use of a post-treatment stage, such as reverse osmosis, is recommended to remove the remainder of the trace contaminants and colour from the effluent to ensure that the effluent met the potable water standards for reuse. There was a relatively insignificant standard deviation (≤ 3.22%) detected in all the parameters measured in the continuous operation and this indicates the reproducibility of the bioremediation efficiency in this continuous system.

The Telecommunications industry in Southern Africa is faced with the problem of theft of the signal carrying copper wire, both from the ground and from telephone poles. In many cases, if the offenders are caught, the prosecuting party has no way of proving that the wire is the property of any one Telecommunication company, as any inked markings on the insulating sheaths have been burned off along with the insulation and protective coatings themselves. Through this work we * describe the problem, * specify the necessary and preferred technical properties of a viable solution, * report the preliminary investigations into the devising of an unambiguous "fingerprinting" of the 0.5 mm wires, including some of those solutions that, upon investigation, appear non-viable, * describe the development and implementation of an electrochemical marker with detection mechanism which has shown in proof-of-principle to work, * outline the road-map of necessary future work.

X-ray Computed Tomography (CT) is a process that produces three-dimensional x-ray images, allowing for better diagnosis and analysis of complex internal medical conditions. New advances in the optical techniques used in this process promise to produce better results while reducing patient risk. One of these developments calls for precise optical gratings that can be expensive and difficult to manufacture. This paper presents a simple process developed specifically for the production of these gratings using cost effective techniques. The process uses well understood semiconductor fabrication steps including oxidation, deep reactive ion etching and electroplating. While not entirely successful, the process presented within provides a proof of concept for development of the gratings and discusses improvements that could be made to allow for success. / Master of Science

In hybrid pixel detector fabrication, high-density interconnection between focal plane array and the read-out integrated circuit is important. Bump bonding is the preferable assembly method, it is small in size, low cost, high performance and flexible I/O. Flip-chip bonding is a vertical connection technique of focal plane array and top substrate with solder bumps. In this paper, Flip-chip bonding by electroplated indium bumps is described. There are advantages of using indium as the solder material. It is relatively inexpensive, it has good thermal and electrical conductivity, it is ductile, and it is cryogenically stable. Indium bumps with a diameter of 30 µm are successfully prepared by an electroplating method, however removing indium conductive layer after electrodeposition is challenging. The corresponding electroplating indium bump process is also discussed. Electrical measurement was applied to detect the connection integrity of the flip-chip assemblies.

No description available.

The low density and high relative strength of Mg alloys means they can offer engineering benefits over steels or Al alloys. However, the susceptibility of Mg alloys to corrosion has limited their exploitation and restricted their use to more benign environments. An Mg-Al intermetallic surface layer is a good candidate for a robust corrosion protection method. This work demonstrates their development by using a novel ionic liquid electroplating process to deposit Al on to Mg substrates that when heat treated diffuses to form discrete intermetallic layers. Examination of three Mg-Al-Zn alloys showed that the amount Mg-Al intermetallic phases in their microstructures was linked to the quantity of Al they contained. Subsequent self-corrosion measurements using electrochemical impedance spectroscopy demonstrated that their performance was connected to the amount of intermetallic present, and in particular the strength of the micro-galvanic couples generated between the anodic and cathodic phases. Measurements of the self-corrosion behaviour of manufactured samples of the Mg-Al intermetallics confirmed that they could provide significant improvements, but it was acknowledged that their noble nature compared to an Mg substrate would encourage galvanic corrosion if a surface layer was damaged. As such the galvanic activity of the Mg-Al-Zn alloys and Mg-Al intermetallics was compared against a pure Mg standard using zero resistance ammetry and the resistance box technique. Galvanic models of alloy self-corrosion and a damaged intermetallic surface layer were also used to assess the potential problem. These measurements demonstrated that the intermetallics could act as strong cathodes, but further discussion on the nature of the behaviour suggested means by which galvanic corrosion might self-limit or self-repair. The galvanic corrosion experiments also revealed how the combination of current flow and a solution saturated with Mg2+ ions could lead to the formation of a highly protective Mg(OH)2 film with promising characteristics.

Foram estudados os efeitos da presença de surfatantes aniônicos (dodecilsulfato de sódio - SDS e dodecilbenzenosssulfonato de sódio - SDBS) e catiônico (cloreto de dodecilamônio - DAC) em diferentes interfases metal/cloreto de sódio, em valores de pH iguais a 5,8 e 3,0 . Platina, cobre e níquel foram utilizados como substratos. Técnicas eletroquímicas (polarizações potenciostáticas catódicas e anódicas; voltametria cíclica; cronoamperometria; impedância eletroquímica, com eletrodo parado e com eletrodo de disco rotativo - EDR) foram empregadas, bem como técnicas não eletroquímicas (espectroscopia Raman \"in situ\" SERS; microscopia eletrônica de varredura (MEV) / espectroscopia de dispersão de energia - EDS) a fim de caracterizar a ação destes surfatantes em processos anódicos e catódicos que ocorrem nas interfases citadas. DAC apresentou ação inibidora acentuada para as reações de oxidação e redução da água, na interfase Pt/NaCl 0,1 mol.L1 , não sendo eletroativo na faixa de potenciais compreendida entre estes dois processos. Utilizando-se eletrodo parado, o surfatante mostrou ação inibidora mais acentuada para os processos anódicos do que para os catódicos. Com convecção forçada empregando EDR, o surfatante apresentou graus de inibição da ordem de 90 % para ambos os processos, sugerindo que o transporte de massa favorece a adsorção do DAC sobre a platina. Tal comportamento pôde também ser comprovado quando se utilizou cobre e níquel como substratos, -1 em meio de pH igual a 5,8. Para a interfase Cu / NaCl 0,1 mol.L-1 pH = 3, com EDR, os três surfatantes tiveram seus efeitos estudados na região catódica, a fim de se verificar a sua atuação na reação de desprendimento de hidrogênio. Os surfatantes aniônicos não apresentaram efeito inibidor sobre a referida reação, aumentando a sua velocidade para potenciais mais negativos + do que -1,0 V / ECS. DAC, ao contrário, inibiu a reação H+ / H2 , com valores de grau de cobertura 2 da ordem de 50 %. A adsorção dos surfatantes sobre cobre foi caracterizada por espectroscopia Raman (SERS), cujos estudos mostraram que os três surfatantes são adsorvidos através da cadeia carbônica (hidrofóbica), no potencial de corrosão (Ecorr ) e a valores de potencial mais positivos e Ecorr . Os resultados espectroscópicos sugerem a presença da parte polar do SDS na interfase, enquanto que, no no caso do DAC, não foi possível caracterizar, por esta técnica, a adsorção do grupamento amônio Foram realizados também estudos sobre o efeito destes surfatantes em processo de eletrodeposição de níquel sobre cobre. SDS apresentou aumento de rendimento de 28% para 43% a um potencial de -1,10 V / ECS, em relação ao processo efetuado em ausência de surfatante. Os depósitos obtidos em presença de SDS e SDBS apresentaram-se mais brilhantes e visualmente mais homogêneos do que aquele obtido em ausência de surfatante, confirmando a ação abrilhantadora destes aditivos utilizados em banhos comerciais de deposição. A presença de DAC inibiu a reação Ni2+ /Ni, obtendo-se depósito de níquel apenas nas bordas do eletrodo de cobre. As superfícies de cobre niqueladas foram caracterizadas por medidas de potencial de circuito aberto, polarização anódica, cronoamperometria, impedância eletroquímica e por MEV / EDS. Os resultados obtidos, empregando as diferentes técnicas, indicaram que a deposição de níquel sobre cobre em meio de NaC1 0,1 mol.L-1, pH = 3, contendo 1,0X10-3 mol.L-1 de SDS foi a apresentou melhores características tanto em relação ao rendimento quanto à qualidade do depósito formado. / The effect of anionic (sodium dodecylsulphate - SDS and sodium dodecylbenzenesulphonate - SDBS) and cationic (dodecylammonium chloride - DAC) surfactants has been studied in different metal / sodium chloride interfaces, at pH = 5.8 and pH = 3.0 . Platinum, copper and nickel have been used as substracts. Electrochemical (anodic and cathodic potentiostatic polarisation, cyclic voltammetry, chronoamperometry, and electrochemical impedance, using stationary and rotating disk electrodes - RDE) and non-electrochemical techniques (\"in situ\" Raman spectroscopy / SERS ; scanning electronic microscopy - SEM / energy dispersion spectroscopy - EDS) have been used to study the action of these surfactants on anodic and cathodic reactions that occur in the interfaces. DAC has shown strong -1 inhibitory action on reduction and oxidation water reactions, on Pt / 0.1 mol.L-1 NaCl interfhace, without electroactivity in all the potential range studied. Stationary electrode, has shown that DAC is more effective as inhibitor for the anodic processes than for the cathodic one. Using rotating disc electrode (RDE), surfactant presents about 90 % of inhibitory efficiency in both processes, suggesting that mass transport favours DAC adsorption on Pt. Furthermore the inhibitory action is the same when using copper and nickel as substract , at pH = 5.8. The three surfactants (SDS, SDBS and DAC) were studied on cathodic potential range, in order to verify their action on hydrogen evolution reaction, in Cu / NaCl 0.1 mol.L-1 , pH = 3.0, using RDE. Anionic surfactants have not shown inhibitory action on the mentioned reaction, increasing its rate at more negative potentials than -1.0 V / ECS. On the other hand, DAC inhibits the same reaction, showing 50 % inhibitory efficiency. Surfactants adsorption on copper have been studied by Raman Spectroscopy (SERS) \"in situ\". These studies have shown the adsorption of DAC, SDS and SDBS through carbonic chain (hydrophobic) at corrosion potential (Ecorr) and at more negative and more positive potentials. The presence of the polar head at the interface have been confirmed for SDS and SDBS. For DAC, however, it was not possible to characterize the ammonium group adsorption from Raman spectra. The effect of these surfactants have also been studied for nickel electrodeposition process on copper. SDS increased the process yield (28 % to 43 %, at E = -1.1 V / ECS), when compared to the results obtained without surfactant. Deposits were brighter and more homogeneous than those obtained in the absence of SDS and SDBS surfactants, confirming the brightening action of these additives in commercial deposition baths. DAC also inhibits Ni /Ni2+ reduction, producing nickel deposit just on the edge of copper electrode. The results, obtained from different techniques, have shown that nickel deposition on copper, in 0.1 mol.L-1 NaC1, pH = 3, containing 1.0X10-3 mol.L-1 SDS, presented the best performance, if it is considered the yield values and the quality of the deposit.

Foram desenvolvidos sensores magnéticos tipo \\ita miniaturizados, paralelos planos e ortogonais, com os núcleos compostos por ligas ferromagnéticas eletrodepositadas. O foco no desenvolvimento dos sensores paralelos planos foi a redução da complexidade do processo de microfabricação, utilizando apenas uma camada de bobinas. Para isto foram propostos dois leiautes em que as bobinas de excitação e as coletoras foram posicionadas no mesmo plano. Foram então construídos sensores miniaturizados utilizando um processo de microfabricação simplificado com apenas quatro máscaras fotolitográficas e núcleos de NiFe eletrodepositando. Os dispositivos resultantes apresentaram boa linearidade para campos de até 200 ?T, com responsividades máximas de 16 V/T e 8 V/T quando operados com a excitação senoidal e frequência de 100 kHz. O ruído\\ita contidos na faixa de 0,1 a 10 Hz foi estimado em 40 nT e 59 nT. Também foram desenvolvidos sensores tipo \\ita ortogonais. Foi proposto e validado um modelo matemático para o sinal de saída quando este tipo de sensor é operado em constante saturação. Desta maneira a permeabilidade magnética é modulada pela rotação da magnetização, reduzindo os saltos de Barkhausen. Os sensores foram construídos a partir de fios de cobre com diâmetros de 45 e 120 ?m eletrodepositados com ligas de NiFe e NiFeP, e envoltos por um solenoide. Os melhores dispositivos, com núcleo de NiFe, operados no modo de rotação da magnetização apresentaram considerável redução do ruído em relação ao modo convencional. A amostra menos ruidosa foi de 8 nT para 0,55 nT \\ita contidos na faixa de 0,1 Hz a 10 Hz. O preço pago foi uma diminuição na responsividade, de 796 para 211 V/T e o aumento no efeito \\ita, de 2 para 4,5 ?T. / Two kinds of miniaturized fluxgate magnetic sensor have been developed, a planar parallel and an orthogonal one, with electroplated ferromagnetic alloy cores. The development of the parallel one had focus on the overall manufacture complexity reduction. Two planar layouts making use of only one layer of coils were proposed and constructed with a simplified micromachinig process that used only four photolithographic masks. The cores were obtained by electroplating NiFe thought molds. The sensors presented a maximum sensitivity of 16 V/T and 8 V/T, depending on the layout, for a 100 kHz sine excitation. Also the rms noise levels contained in the 0.1-10 Hz range were measured, resulting in 40 nT and 59 nT. It has been also developed some orthogonal fluxgate sensors. The output signal generated by this kind of sensor operated in constant saturation mode was mathematical modeled and experimentally validated. In this case, the core magnetic permeability is no longer modulated by the domain walls movement but rather by the magnetization rotation. The advantage being the suppression of Barkhausen jumps, one of the main sources of noise. The sensors were build using cooper wires with two diameter, 45 and 120 ?m, electroplated with NiFe and NiFeP alloys. The best devices, with NiFe cores, operated in the magnetization rotation mode had their noise levels reduced by a factor of about 10 when compared to the conventional mode. The less noisy sample went from 8 nT to 0.55 nT \\ita contained in the 0,1-10 Hz range. The drawback was a decrease in the sensitivity, from 796 to 211 V/T and an increase in the perming error, from 2 to 4,5 ?T.

by Chan To = 電鍍錫在銅質底材上晶鬚生長的硏究 / 陳濤. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / by Chan To = Dian du xi zai tong zhi di cai shang jing xu sheng chang de yan jiu / Chen Tao. / Abstract --- p.i / 論文摘要 --- p.ii / Acknowledgements --- p.iii / Table of Content --- p.v / Chapter Chapter 1 --- INTRODUCTION / Chapter 1.1 --- Lead-free movement and the problem of whisker --- p.1-1 / Chapter 1.2 --- Properties of tin and tin-copper intermetallics --- p.1-2 / Chapter ´Ø --- Tin --- p.1-2 / Chapter ´Ø --- Tin-copper intermetallics --- p.1-2 / Chapter 1.3 --- Literature Review of Whisker --- p.1-4 / Chapter 1.3.1 --- Feature of the whisker --- p.1-4 / Chapter 1.3.2 --- Conditions prone to whisker growth --- p.1-8 / Chapter 1.3.3 --- Growth mechanism of the whisker --- p.1-10 / Chapter 1.3.4 --- Methods to prevent or remove whisker --- p.1-11 / Chapter 1.4 --- Motivation & Aims of Studies --- p.1-12 / Chapter Chapter 2 --- EXPERIMENTAL & INSTRUMENTATION / Chapter 2.1 --- Sample Preparation --- p.2-1 / Chapter ´Ø --- Electroplating process --- p.2-1 / Chapter 2.2 --- Instrumentation --- p.2-6 / Chapter 2.2.1 --- Scanning Auger Microscope (SAM) analysis --- p.2-6 / Chapter ´Ø --- Experimental conditions --- p.2-9 / Chapter ´Ø --- Sample preparation for Auger analysis --- p.2-10 / Chapter ´Ø --- Depth profile analysis --- p.2-11 / Chapter ´Ø --- Mapping --- p.2-11 / Chapter ´Ø --- Line scan --- p.2-12 / Chapter 2.2.2 --- X-ray diffractometer (XRD) --- p.2-12 / Chapter 2.2.3 --- Scanning Electron Microscope (SEM) --- p.2-13 / Chapter Chapter 3 --- INFLUENCE OF CATHODIC/ANODIC ELECTROCHEMICAL CLEANING ON THE WHISKER GROWTH / Chapter 3.1 --- Introduction --- p.3-1 / Chapter 3.2 --- Theory --- p.3-2 / Chapter ´Ø --- Reactions occurring at the anode/cathode --- p.3-3 / Chapter 3.3 --- Sample description --- p.3-5 / Chapter 3.4 --- Results and discussion --- p.3-5 / Chapter ´Ø --- Surface morphology before electroplating --- p.3-5 / Chapter ´Ø --- Whisker observation --- p.3-7 / Chapter 3.5 --- Summary --- p.3-18 / Chapter Chapter 4 --- INFLUENCE OF COPPER CONCENTRATION IN THE PLATING BATH ON COPPER DIFFUSION AND WHISKER FORMATION / Chapter 4.1 --- Introduction --- p.4-1 / Chapter 4.2 --- Theory and Literature Review --- p.4-2 / Chapter ´Ø --- Diffusion kinetic --- p.4-2 / Chapter ´Ø --- Influence of solute atoms --- p.4-5 / Chapter 4.3 --- Sample description --- p.4-6 / Chapter 4.4 --- Results and discussion --- p.4-6 / Chapter ´Ø --- SEM observations --- p.4-6 / Chapter ´Ø --- Cross-sectional analysis --- p.4-8 / Chapter ´Ø --- Surface and depth profile analysis --- p.4-15 / Chapter ´Ø --- XRD analysis --- p.4-21 / Chapter 4.5 --- Summary --- p.4_24 / Chapter Chapter 5 --- ANNEALING EFFECT ON THE WHISKER GROWTH / Chapter 5.1 --- Introduction --- p.5-1 / Chapter 5.2 --- Theory and Literature Review --- p.5-2 / Chapter 5.3 --- Sample description --- p.5-3 / Chapter 5.4 --- Results and discussion --- p.5-4 / Chapter ´Ø --- SEM whisker observation --- p.5-4 / Chapter ´Ø --- Cross-sectional Auger analysis --- p.5-4 / Chapter ´Ø --- Surface and depth profile analysis --- p.5-16 / Chapter 5.5 --- Summary --- p.5-27 / Chapter Chapter 6 --- FORMATION MECHANISM OF THE STRIATION ON WHISKER / Chapter 6.1 --- Introduction --- p.6-1 / Chapter 6.2 --- Results and discussion --- p.6-2 / Chapter ´Ø --- Texture of the striation --- p.6-2 / Chapter ´Ø --- Time evolution in the surface morphology --- p.6-6 / Chapter ´Ø --- Stage of whisker growth --- p.6-6 / Chapter 6.3 --- Summary --- p.6-12 / Chapter Chapter 7 --- CONCLUSIONS & FUTURE STUDIES / Chapter 7.1 --- Conclusions --- p.7-1 / Chapter 7.2 --- Future studies --- p.7-3 / Reference

This dissertation describes experimental studies of the superconducting proximity effect in single-crystal Pb, Sn, and Zn nanowires of lengths up to 60 um, with both ends of the nanowires in contact with macroscopic electrodes that are either superconducting (Sn or Pb) or non-superconducting (Au). The Pb, Sn, and Zn nanowires are fabricated using a template-based electrochemical deposition method. Electric contacts to the nanowires are formed in situ during electrochemical growth. This method produces high transparency contacts between a pair of macroscopic electrodes and a single nanowire, circumventing the formation of oxide or other poorly conducting interface layers. Extensive analyses of the structure and the composition of the nanowire samples are presented to demonstrate that (1) the nanowires are single crystalline and (2) the nanowires are clean without any observable mixing of the materials from the electrodes. The nanowires being investigated are significantly longer than the nanowires with which electrode-induced superconductivity was previously investigated by other groups. We have observed that in relatively short (~6 um) Sn and Zn nanowires, robust superconductivity is induced at the superconducting transition temperatures of the electrodes. When Sn and Pb nanowires are in contact with a pair of Au electrodes, superconductivity is suppressed completely. For nanowires of 60 um in length, although the suppression of superconductivity by Au electrodes is only partial, the induced superconductivity at the higher transition temperatures of the electrodes remains full and robust. Therefore, an anomalous superconducting proximity effect has been observed on a length scale which far exceeds the expected length based on the existing theories of the proximity effect. The measured current-voltage characteristic of the nanowires reveals more details such as hysteresis, multiple Andreev reflection, and phase-slip centers. An interesting relation between the proximity effect and the residual-resistance-ratio of the nanowires has also been observed. Possible mechanisms for this proximity effect are discussed based on these experimental observations.