STM analiza površine srebrnog ogledala

In this work, the structure of a silver mirror surface was examined by the STM technique. It was shown that the structural characteristics which enable a high degree of mirror reflection from this surface, which is very close to the ideal reflectivity of silver, are: flat and mutually parallel parts of the surface which are smooth on the atomic level, and distances between adjacent flat parts which state several atomic diameters.STM tehnikom je ispitana struktura površine srebrnog ogledala. Pokazano je da su strukturne karakteristike koje su omogućile visok stepen ogledalske refleksije koji je bio veoma blizak idealnoj refleksivnosti srebra: ravni i međusobno paralelni delovi površine koji su glatki na atomskom nivou, i rastojanja između susednih ravnih delova koja iznose nekoliko atomskih prečnika

Social Problems as Constructs of Social Reality

Social problems are perceived situations incompatible with the values of a significant number of people, which lead to negative social and economic consequences. Their basic characteristics are: that they are predominantly caused by social factors, mass, awareness of their existence and that they can be eliminated by social measures and interventions. The paper analyzes whether social problems are objective social facts that are not questionable or whether social constructs are based on perception, interiorization and cultural diversity. In particular, the influence of social constructivism on the relation of social workers and users, i.e. understanding of the nature of social needs, is pointed out. Social problems, become part of human reality through the processes of externalization, objectification and internalization, which indicates that they can to a significant extent be considered social constructs. This can explain why some of the phenomena, which from the point of view of objective criteria represent social problems in some societies and they are perceived as such, unlike others. In this sense, social problems are not only “objective social facts”, but also social artifacts, products of cultural, value and historical exchanges among people. By rejecting a linear approach in interpreting unsatisfied social needs and introducing the approach of “ignorance” of social workers, i.e. “subjectivity” expressed in the user’s perception of the problem, social constructivism em phasizes the approaches to empowerment, participation and involvement. Language as a social construction in the understanding and explanation of reality and processes in social work introduces terms of strength, resources, assessment and reflection

99mTc-hexakis-(2-metoxy-isobutyl-isonitrile) ( 99mTc-MIBI) a new myocardial imaging agent: synthesis of MIBI, optimising conditions for radiolabelling with 99mTc at high radiochemical purity and in vivo behavior

99mTc-MIBI is a promising radiopharmaceutical for myocardial perfusion imaging agent, but it has also shown good results in identifying several types of tumors, such as breast, lung and thyroid cancers. It is a lipophilic, cationic technetium (1) complex. In this paper a complete study on the synthesis of 2-metohy-isobutyl-isonitrile (MIBI) as well as a formulation of a lyophilized kit for labeling with 99mTc is presented. Investigation on effective factors as well as finding out the optimum parameters to obtain the highest labelling efficiency and radiochemical purity of 99mTc-MIBI complex were performed. The radiochemical purity of the labelled preparation was high (>95%). Biodistribution study performed in health male Wistar rats showed satisfactory biokinetics results. 99mTc-MIBI was accumulated in sufficient amount into the hearth tissue for myocardial perfusion imaging. MIBI in kit formulation was found to be stable and also safe for administration.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Electrodeposition of iron powder particles of different characteristics

Iron deposits obtained at high current densities and overpotentials are very important from a technological point of view. It has been stated that the open and porous structures of copper or iron deposits obtained at high current densities were ideally suited for use as electrodes in electrochemical devices such as fuel cells, batteries and chemical sensors, while the extremely high surface area is relevant for evaluating some electrochemical reactions. Mainly two types of electrolytes were investigated and these were based on sulfate and chloride electrolytes. With increasing duration of electrolysis, dendrites merge, which is unacceptable for the case of further application. These deposits must be grinded in order to obtain powders. However, in the range of lower acidity the deposits become powdery and, in some cases, may be spongy and sticky. Generally, up to now research indicates that electrodeposition of Fe powders have two steps, deposition of fragile film and grinding. It must be emphasized that we tried and succeeded to obtain Fe powders without grinding process. The aim of this work was to investigate electrodeposition processes of Fe powders from sulfate and chloride electrolytes and morphologies of powder as a function of type of electrolyte and current density.Belgrade, Serbia, June 6-10, 201

Electrodeposition of iron powder particles of different characteristics

Iron deposits obtained at high current densities and overpotentials are very important from a technological point of view. It has been stated that the open and porous structures of copper or iron deposits obtained at high current densities were ideally suited for use as electrodes in electrochemical devices such as fuel cells, batteries and chemical sensors, while the extremely high surface area is relevant for evaluating some electrochemical reactions. Mainly two types of electrolytes were investigated and these were based on sulfate and chloride electrolytes. With increasing duration of electrolysis, dendrites merge, which is unacceptable for the case of further application. These deposits must be grinded in order to obtain powders. However, in the range of lower acidity the deposits become powdery and, in some cases, may be spongy and sticky. Generally, up to now research indicates that electrodeposition of Fe powders have two steps, deposition of fragile film and grinding. It must be emphasized that we tried and succeeded to obtain Fe powders without grinding process. The aim of this work was to investigate electrodeposition processes of Fe powders from sulfate and chloride electrolytes and morphologies of powder as a function of type of electrolyte and current density.Belgrade, Serbia, June 6-10, 201

ELECTRODEPOSITION AND MORPHOLOGY OF COPPER POWDER PARTICLES OBTAINED AT DIFFERENT CURRENT REGIMES

The effect different deposition regimes (constant and reversing currents), on the powdered copper electrodeposits morphology were investigated. The morphology of electrodeposited copper powder was investigated using a scanning electron microscope (SEM). The effect of the current amplitude, cathodic to anodic time ratio and period of the current wave are discussed. It is shown that the parameters determining the reversing current wave determine the micro-morphology of the copper powder particles deposited

Electrodeposition of Fe Powder from Citrate Containing Electrolytes

Polarization characteristics of the electrodeposition processes of Fe powders from different citrate electrolytes and the morphology of the obtained powders were investigated. The effect of complexing agents on the cathodic polarization, the current efficiency and morphology of electrodeposited Fe powders were investigated. The morphology of obtained powders depends on the kind of supporting electrolyte, but not on the current density in investigated range. A characteristic feature of powders deposited from citrate-chloride supporting electrolyte is cauliflower-like compressed structure. On the other side, Fe powders electrodeposited from citrate-sulfate supporting electrolyte appeared in the form of spongy-like agglomerates. Possibility of Fe powders protection from corrosion in the process of production and during long-term storing has been shown

Influence of the phase composition of refractory materials on creep

In this paper, the relationship between the creeping effect and mineralogical characteristics of the applied binding phase for various refractory materials (high-alumina materials, with high or low impurity content, tar bonded either magnesite or dolomite materials and silicate bonded chrom-magnesite materials) is presented. The mechanism of creeping is analyzed and the activation energy for creep for each investigated material is obtained and discussed. All investigated materials are creep sensitive under investigated conditions and have similar activation energies for creep except high-alumina refractories with a low impurity content.U radu je data veza puzanja vatrostalnih materijala i mineraloških karakteristika vezivnih faza za različite vatrostalne materijale (visokoaluminatne, katranom vezane magnezitne, katranom vezane dolomitne materijale i silikatno vezane hrommagnezitne materijale). Pored toga analiziran je mehanizam puzanja i proračunata je energija aktivacije procesa puzanja za svaki od ispitivanih materijala

The Effect of Periodically Changing Regimes on the Electrodeposition of Silver Powder

The effect of different deposition regimes (constant and reversing currents, constant and pulsating overpotential), on the powdered and dendritic silver electrodeposits morphology were investigated. The morphology of electrodeposited silver powder was studied utilizing a scanning electron microscope. The results obtained in constant regimes were compared with those obtained in pulsating and reversing regimes. The size of dendrites decreased strongly with increased overpotential or current. It was also shown that the agglomeration of silver dendrites in spongy-like agglomerates was strongly decreased by pulsating overpotential electrodeposition or reversing current. The possibility of obtaininig powder particles, with different properties, depending on conditions of electrolysis was demonstrated

Istraživanje organizacionih nauka u periodu postmoderne

Emergence of industrial society raises a number of important questions for researchers and organizational sciences. Existing theories of organizations (related to industrial engineering and business systems) are characterized by fragmentation and an absolute relativism. This position is a result of the continuous displacement of gravity between the organization processes and institutions and on the other hand, the interaction of man and organizations. Therefore, proper guidance can be difficult for other organizational science. The setting of this question and the search for answers has a stake in the philosophy of science. By accepting the facts in the life situations (dualism of determinism and phenomenology) is the basis of the philosophy of facticity in the science on business organization. Problems of the organization are present in all areas of human activity. This fact determines the issue of demarcation of organizational and other sciences. Determine the structure and abstraction some of organizational science, and special areas of research organizations in the social systems is a step that allows the intensification of research in the future.Nastajanje postindustrijskog društva postavlja brojna i značajna pitanja istraživačima organizacionih nauka. Postojeće teorije organizacija (koje se odnose na organizaciju preduzeća, odnosno poslovnih sistema) karakteriše fragmentarnost i apsolutni relativizam. Ovakav pristup ima rezultat u neprekidnom izmeštanju težišta između organizacije procesa i institucija i sa druge strane, interakcije čoveka i organizacija. Zato odgovarajući putokaz teško može biti za ostale organizacione nauke. Postavka ovog pitanja i traganje za odgovorom ima oslonac u filozofiji nauka. Prihvatanjem činjenica u okviru životnih situacija (dualizma determinizma i fenomenologije) je osnov filozofije fakticiteta u Nauci o organizaciji poslovanja. Problemi organizacije prisutni su u svim područjima ljudskog delovanja. Ova činjenica određuje pitanje razgraničenja organizacionih sa drugim naukama. Određivanje strukture i apstrahovanja pojedinih organizacionih nauka, odnosno posebnih područja istraživanja organizacije u društvenim sistemima predstavlja iskorak koji omogućava intenziviranje istraživanja u narednom periodu