Vlădescu, filosoful german

5 Răspunsuri la Vlădescu, filosoful german

1. de laurentiucat March 13, 2010 at 22:02
   

   cine-i oasama asta?

2. de mohamed March 13, 2010 at 21:04
   

   Introduction
   Some molecules absorb ultraviolet and visible light. The increase in absorbance of light as a solution to increase attenuation. Absorbance is directly proportional to the path length, b and concentration, C, species absorption. Beer’s law.
   is a years, and  A = constant of proportionality, called absorbtivity.
   Variable molecules absorb different wavelengths of radiation. An absorption spectrum will showcase some of the corresponding absorption peak within the group structure of molecules. For example, the absorption is observed in ultraviolet wavelength of the carbonyl acetone is the same as be included in the two ethyl ketone carbonyl.

   1. Background

   A clear differentiation of certain compounds is their color. Therefore, the p-benzoquinone is yellow; Chlorophyll is the green, in the 2,4 – dinitrophenylhydrazine derivatives of aldehydes, ketones, colors ranging from intense yellow to deep red, depending on the conjugated double bonds and the A Division for horses forest is colorless. In this admiration for the implementation of the human eye beam reflectance spectroscopy analysis of the surface of hard or instantaneous start by liquid. Although we see the light (or white) or standard consistent with the color, it is essentially emission wavelength from abroad range of ultraviolet (UV), observation and infrared (IR) part of the spectrum. As shown on the right to form the color, physical markets can be separated by daylight through the prism of its behavior bending beam in varying degrees according to wavelength. Electromagnetic radiation, such as observations of light often seen as a wave phenomenon, characterized by wavelength or the occurrence. Wavelength refers to the bottom of the left, as the distance involved adjacent peak (or trough), and may designate meters, centimeters or nanometers (10-9 meters). Frequency is the number of wave cycles, in the past fixed unit of time travel, usually grant Hz, or Hertz (Hz). Visible wavelength range from about 400 to 800 nm. The longest wavelength of visible light is red and the shortest is violet. Other general color of the spectrum in order to reduce the wavelength, you can remember the memory of: Roy ġ different sources. Wavelength we recognize the color, especially in the visible part of the spectrum display and are listed below. Diagram in a row, such as the one in the bottom left corner, the wavelength will increase moving from left to right.
   • Purple: 400 – 420 nm
   • Indigo: 420 – 440 nm
   • Blue: 440 – 490 nm
   • Green: 490 – 570 nm
   • Yellow: 570 – 585 nm
   • Orange: 585 – 620 nm
   • Red: 620 – 780 nm

   When the light reflects through the whole white or colored material, part of a feature of various types of wavelengths are absorbed. The remaining light will then assume the color of the corresponding wavelength (twist) absorption. The Association was founded in the color wheel shown on the right. Here, the matching color is sharply conflicting. Therefore, included in 420-430 nm light yellow material, and absorb 500-520 nm light to red. Green is unique, it can create absoption near 400 nm and absorption near800nm.
   The value of early human colored pigments, and use them attractive purpose. Many of inorganic minerals, but some important organic dye, also known as. These include deep red pigment, kermesic acid, a blue dye, indigo, safflower, yellow pigments, Saffron. Rare Dibromo-indigo derivatives, punicin, with the royal robes, and rich color. Oil and gas deep orange carotene is widely distributed in plants, but not stable enough, as a permanent pigment, in addition to food coloring. A common feature of the compounds, all of these colors to show below is a broad classification of conjugated π electrons.

   2. Electromagnetic spectrum
   Observed spectral composition, but a small part of the total radiation spectrum. Most of the radiation environment, we can not see, but can be detected by special testing instruments. This electromagnetic spectrum ranging from very short wavelengths (including gamma rays and X-rays) to very long wavelengths (including microwaves and broadcast radio waves). The following chart shows the number of major areas of this spectrum, and show the link between anti-wavelength and occurrence (shown at the top of the following formula chart).

   Energy in connection with a given spectrum allocation in proportion to frequency. The relationship between the bottom of the equation illstrate, which provides the energy of a photon by a specific wavelength of radiation.
   The visible and ultraviolet spectrum
   UV spectrum of photons involved in the UV-visible areas. In this way, it uses the visible and near (near ultraviolet (UV) and near-infrared (NIR)) ranges. Absorption in the visible range of chemicals directly affect the color of the occupation. In this area of the electromagnetic spectrum, through molecular electronic transitions. The system is balanced fluorescence spectra, fluorescence in this transition from the excited state to deal with the ground state, while absorbing a transitional measure, from the ground state to the excited state.
   Electronic transition absorption of ultraviolet and visible radiation corresponds to the outer electron excitation. There are three types of electronic transitions can be taken into account;
   1. , and, Line of sight involves n e
   2. Transition involving charge transfer electronic
   3. Transition involving d and f e (not included in this group)
   When an atom or molecule absorbs energy, electrons are promoted to the ground state of the excited state. In the molecules, atoms can rotate and vibration of mutual respect, seek common ground. The vibration and rotation have different energy levels, can be seen as crowded at the summit meeting in each electronic level.

   ,, Absorbing species contain and n e
   Absorption of ultraviolet and visible light radiation of organic molecules are limited to certain functional groups (chromophores), including the low-valence electron excitation energy. Spectrum a molecular chromophores containing these compounds. This is because the superposition of rotational and vibrational transitions of the electronic transitions gives a mixture of overlapping lines. This seems to be a permanent absorption band.
   ,, Electronic transition may and the n electrons;

   * transitions    
   an electronic bonding orbital are very pleased to equivalent anti-bonding orbital. The energy required for large. For example, methane (CH bond of * transition) shows the maximum absorption    which only can only accept wavelength of 125.  The maximum absorption due to * transition did not see the typical UV-visible.   Spectrum (200 – 700 nm)
   *   ñ transitions
   Saturated compound atoms and lone * transition.   pairs (non-bonding electron) the ability of n These changes often require less * transition.     energy than They can initiate the wavelength range 150 – 250 nm. The number of organic functional * a small peak in the ultraviolet region.   groups and n
   *     * and    ñ transitions
   Most of the absorption spectra of * electronic excited organic compounds is based on the transition n or state. This is because the absorption peak for these experiments to facilitate the transition region, a decline in the spectrum (200 – 700 nm). These changes require an e.unsaturated group of elements,
     Moore absorbtivities from n * transitions low, ranging from 10 to 100 sting Moore – 1 cm – 1 Chu. * transitions, usually     with Moore absorbtivities sting 10 million -1 – 1 cm – 1 Chu.
   Dissolved in the solvent in the absorption of species also have an impact on the spectrum of species. The corresponding peak from the n * transition shifted to a shorter wavelength (blue shift) solvent    polarity increases. This is due to increase in solvent lone pairs, thus reducing the energy of the n tracks. Usually (but not always), reverse * transitions.    (ie, redshift) is seen This is due to attractive forces between the solvent polarization and absorption, thus lowering the energy levels are excited and flat state. This effect is more excited state, they are able to distinguish excited state declined slightly dull – led to a small red shift.   This result also affects ñ * transition, but to cover up the blue shift, resulting in solvent lone pair.

   Charge – Transfer Absorption
   Many inorganic species, studies have shown that charge-transfer absorption, known as charge-transfer complex. For a proof of the charge transfer complex behavior, one of its components must have a donation of property and other electronic components must be able to accept electronic. Absorption of radiative transfer, and then related to the orbit of an electron from the donor and receptor-related.
   Moore absorbtivities the charge-transfer absorption is large (10,000 big sting Moore – 1 cm – 1 Office).
   3. UV-Vis absorption spectra:
   To understand why some compounds, color and others not, and determines the color of the conjugate relations, we have an accurate measurement of light absorption of different wavelengths and near the visible part of the spectrum. Optical spectroscopy of business, so that these experiments easily, and often are investigating the near-ultraviolet and visible part of the spectrum.
   In the visible photon energy range of the region, including 36-72 kcal / mole, and near ultraviolet region, out of 200 nautical miles, will this energy range of 143 kcal / mole. Ultraviolet radiation with wavelengths less than 200 nanometers, is difficult to handle, but is rarely used as a routine tool for structural analysis.
   Mentioned above, the energy is sufficient to promote or molecular electronic excitation to a higher energy orbit. Therefore, the absorption spectra of the region is sometimes referred to as “electronic spectrum.” A diagram shows a variety of electronic excitation may occur in organic molecules, is displayed on the left. 6, an overview of the transition, only the two lowest energy (the most left, the color blue) is achieved by the energy in the 200-800 nm spectrum. As a rule, strongly

   Advocates the promotion of electronic will be the highest occupied molecular orbital (the HOMO) and the lowest unoccupied molecular orbital (LUMO), the resulting species are known as the excited state. When the sample molecules are exposed to light with energy matching the molecular electronic transitions may be some light energy is absorbed by electrons are elevated to a higher energy orbit. Optical absorption wavelength spectrometer records occurs, together with the extent of absorption at each wavelength. The resulting spectrum is a graph of the absorbance (A) and wavelength, as shown in the spectrum of isoprene. Since isoprene is a colorless, it does not absorb the visible part of the spectrum and the countries of the region does not display graphics. Absorbance usually range from 0 (no absorption) 2 (99% absorption), it is also in the context of the definition of spectrometer operation.
   Due to the absorption is proportional to the number of samples, molecular absorption spectrometer in the beam (such as the molar concentration of the sample tube), which must be corrected absorbance value for this and other business factors, if different spectrum of compounds is more meaningful way. Corrected absorption value is the so-called “molar absorption coefficient,” is particularly useful for spectral comparison of different compounds to determine the relative intensity of optical absorption features (hair color). Molar absorption coefficient (ε) is defined as:
   Molar absorption coefficient, ε = A / Cl (where A = absorption points, C = molar concentration of sample / l, and L = optical path length through the sample cm.)
   If the isoprene spectrum on the right to obtain a dilute hexane solution (C = 4 × 10-5 mole per liter) in 1 cm cuvette in the sample, a simple calculation, using the above formula shows that the molar absorptivity is 20,000, the maximum absorption wavelength . In fact, the whole scale of the vertical absorption may be changed to a molar absorptivity of the scale, once the sample is at hand. Click the spectrum will show this change units.

   From the K-line diagram should be very clear that the only group of molecules may absorb light in the 200-800 nm region Pi electronics and miscellaneous non-bonded atoms have a valence shell electron pair. This group is known as optical absorption chromophores. A list of some simple hair color and light absorption characteristics is to provide more than the left. Oxygen non-bonding electron alcohol, ether, without causing absorption of 160 nm or more. Thus, pure alcohol and ether solvents can be used for spectroscopy.
   The presence of chromophores the best record in the molecular UV-visible spectrum, but most of the instruments failed to provide data to absorb at wavelengths below 200 nm so that hair color detection to isolate the problem. Fortunately, there is a general move conjugate maximum absorption wavelength is longer, such as in the case of isoprene, the conjugate to become a major structural features identified this technology.
   Molar absorption coefficient may be very large strongly absorbing chromophores ( “10,000) and very small, if the absorption of weak (10 to 100). On the Richter ofε not only reflects the size of the hair color and light, the probability of a given wavelength will be absorption when the strike flourish.

   4. The importance of the conjugate
   A Comparison of absorption spectra of 1 – pentene, the maximum absorption wavelength = 178 nm, with the isoprene (above) clearly shows the importance of conjugated chromophores. Further evidence of this effect is shown below. Spectrum on the left shows that conjugated double and triple bond also makes the maximum absorption wavelength longer. From the spectra shown in Figure Polyene center, it is clear that each additional double bond in conjugated π electronic system changes in the maximum absorption wavelength of about 30 in the same direction. In addition, the molar absorption coefficient (ε) roughly doubled, each new conjugated double bonds. Terms of Use Spectroscopists defined in the table on the right describe the changes in the absorption. Thus, the expansion results, the universal red shift and hyperchromic conjugate changes in absorption.
   The appearance of several absorption peaks or shoulders for a given hair color is a very common highly conjugated system, and often depends on the solvent. This reflects not only the fine structure of different conformations can be assumed that such a system, but electronic transitions of different vibrational levels is possible for each electronic state. Vibrational fine structure of the gas phase spectrum of this is the most obvious, and growing, fuzzy solution changed as solvent n-hexane, methanol.
   Displacement of the absorption term

   In order to understand why the red shift caused by changes in the conjugate should be the maximum absorption of hair color, we need to study the relative energy levels of the Bi-track. When the two conjugated double bonds, 4 P – atomic orbitals combine to produce four will molecular orbital (two keys and two anti-bonding). This is described in the preceding section diene chemistry. In the same way, the three double bonds in conjugated trienes molecular orbital must be the establishment of six, semi-bonding and a half anti-bonding. The most favorable energetically π__ “π * excited when the energy from the highest π-bond orbital (the HOMO) to the lowest energy of the π anti-bonding orbital (LUMO).
   The following diagram illustrates this point has stimulated an isolated double bond (only two will orbit), and click the map, a conjugated diene and triene. In each case, the HOMO and LUMO orbital blue color magenta flowers. Increased conjugate bring the relationship between the HOMO and LUMO orbital closer. Energy (ΔE) required to e-marketing, so the low, while the wavelength of energy to provide a corresponding increase in (remember λ = ħ • dirty / ΔE).

   Examples of __ π “* π incentives
   Click on the map of the research

   Many other types of conjugated π electron system as a chromophore to absorb light in 200-800 nm region. These include and unsaturated aldehydes and ketones, and aromatic ring compounds. Some examples shown below. Spectrum of the unsaturated ketone (at left) illustrates the use of logarithms shows molar absorption coefficient. In the π__ “π * absorption at 242 strong, ε = 1.8 million people. Weak ñ __” π * absorption of nearly 300 sea miles there is a ε = 100.

   Benzene exhibits very strong absorption near 180 nm (ε “65,000), the weak absorption of 200 nm (ε = 8000) and a group with a much weaker for the 254 nm (ε = 240). Only the last of a group of absorption peaks of fully show that because the cut-off characteristics of 200 nautical miles, the most spectrophotometers. newly added conjugated naphthalene, anthracene, and four changes of benzene redshift reasons, these absorption bands, the chart shown on the left below. All the absorption peaks would not be the same amount , which for the anthracene (green shaded box) and four benzene (blue shaded box) and weak absorption of shielding strong band experienced a larger redshift. As one can expect that their spectra, naphthalene, anthracene are colorless, but the four benzene is orange.

   Spectrum of the bicyclic diene (above right) shows some vibrational fine structure, but are generally similar in appearance to that of isoprene, as shown above. Double-check revealed that the maximum absorption of the more high-replace-diene has been transferred to a longer wavelength of about 15 nm. This “substituent effect” is the general olefins and LTs, and the more obvious enone chromophore.

   Application of UV-visible spectrum
   UV-visible spectroscopy is a very flexible technology for almost every lab is a fast, non-interference analysis of the contents of multi-component samples. Quality assurance / quality control department to use instruments to make the rapid analysis of products.
   Apply

   An example of the UV-visible readout
   UV / visible spectrum, is frequently used to solve quantitative determination of transition metal ions and highly conjugated organic compounds.
   • Solutions of transition metal ions can be colored (that is, absorption of visible light) because d electrons in metal atoms from an excited electronic state toanother. Its color metal ions in solution strongly influenced by the presence of other species, such as certain anions or ligands. For example, the color of the dilute solution of copper sulfate is a very light blue; adding ammonia and changes color increased the maximum absorption wavelength (maximum absorption wavelength).
   • organic compounds, especially those with a high degree of conjugation, also absorb light in the ultraviolet and visible region of the electromagnetic spectrum. Solvent for these decisions are often water-soluble compounds, or ethanol as the organic water-soluble compounds. (Organic solvents may have a significant UV absorption, is not suitable for all solvents used in UV spectra. Ethanol, the wavelength of maximum absorption is very weak.) Solvent polarity, pH, can affect the absorption spectra of organic compounds. Tyrosine, for example, increase the maximum absorption, molar extinction coefficient increases, pH value from 6 to 13 or lower solvent polarity.
   • While the charge-transfer complex will also produce a color, the color is often too heavy for the quantitative measurement.
   Beer Lambert law, absorbed a solution is directly proportional to the concentration of absorbing kinds of solutions and the path length. Therefore, for a fixed path length, UV / visible spectrum can be used to determine the concentration of the absorption in a solution. Want to know how quickly the changes in absorbance and concentration. This can be said that from the reference (in the table molar extinction coefficient), or more precisely, the decision from the calibration curve.
   Azi outside / VIS spectrophotometer can be used as detection of high-performance liquid chromatography. The existence provides an analyte reaction can be assumed to be proportional to the concentration. For accurate results, the instrument response to analyte in the unknown should be better than to respond to the standard, which is very similar to the use of calibration curve. Response (for example, peak height) for a particular concentration is known as response factors.

3. de Mihai March 11, 2010 at 20:23
   

   Domnule Guran, domnul Vladescu parca a promis ca scoate “forfetarul” dar sintem la jumatatea lui martie si nimic.Cu alte cuvinte mergem inchis si mai jupuim fraierii care nu protesteaza pina cad in cap.Pacat ca nimeni nu ii ia la intrebari pt ce au promis.
   Ne e dor de Bizbazar poate reusiti sa reluati emisiunea.

4. de Mihai March 11, 2010 at 20:21
   

   Domnule Guran, domnul Vladescu parca a promis ca scoate “forfetarul” dat sintem la jumatatea lui martie si nimic.Cu alte cuvinte mergem inchis si mai jupuim fraierii care nu protesteaza pina cad in cap.Pacat ca nimeni nu ii ia la intrebari pt ce au promis.
   Ne e dor de Bizbazar poate reusiti sa reluati emisiunea.

5. de laurentiucat February 25, 2010 at 23:59
   

   vladescu un liberal cu fixatii taxiste,un plasirist cu inclinatii germane..care nu e in stare sa faca o simulare pe computer..un ministru care se crede la simpozioane,o apa de ploaie..pai o filozofie germana vedem la johannis..nu la vladescu.asta e un fel de bitman nitel mai bagat in cifre nu in note…inafara faptului ca-l ia gura repede pe dinainte si si-a tras niste divertisment la minister prin niste purtatori de vorbe muti pana acu..n-am vazut nici masuri,nici tedinte..sa nu zic de filozofeli..