Size Distribution Of Nanoparticles Research Articles

Synthesis of ZnO Nanoparticles by Chemical Method and its Structural and Optical Characterization

In this report, ZnO nanoparticles (NPs) was synthesized by chemical method using Zinc Acetate dehydrate [Zn(CH3COO)2.2H2O)] as precursors and Ethanol and distilled water as solvent. Sodium hydroxide (NaOH) was used to maintain the pH and helps to establish the NPs. The NPs are characterized by XRD, UV-visible spectroscopy and SEM image analysis. The XRD characterization gives the polycrystalline nature of ZnO NPs with the size ~23 nm and ~27 nm calculated by Scherrer’s method and Williamson–Hall method respectively. The crystalline size of these NPs calculated using XRD pattern is validated by SEM image analysis. Using the UV-Visible spectrophotometer and Tauc plot method, the optical band gap of ZnO is found to be 3.35 eV. The uniform size distribution of NPs shown in SEM image and strong UV absorption shown in UV-Visible spectra indicate that thus prepared NPs are highly desirable for photo-catalytic activity and detection applications. BIBECHANA 19 (2022) 90-96

Investigations on Mode Transition Mechanisms and Discharge Characteristics of Electrically Exploding Aluminum Wires in Argon Gas

Electrically exploding wires (EEWs) are a promising method for nanoparticle preparation, and the size distribution of nanoparticles is significantly affected by ambient pressure. However, the influence of ambient pressure on EEW characteristics is still unclear, which brings incredible difficulties in parameter optimization for nanoparticle preparation. In this article, mode transition mechanisms and discharge characteristics of EEWs in argon gas were experimentally investigated. A mode transition of EEWs, from the shunting to the internal as ambient pressure increases, was demonstrated through electrical measurement. The ohmic heating duration, maximum power, and breakdown electric field increase with ambient pressure in shunting mode and show a saturated trend in internal mode. Through laser imaging and framing imaging, two typical structures of EEWs, that is, the “core-corona” structure ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$p &lt; 50$ </tex-math></inline-formula> kPa) and the “discharge channel-vapor” structure ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$p &gt;200$ </tex-math></inline-formula> kPa), were observed and analyzed. By reconstructing evolutionary trajectories of coronal plasmas and high-density cores, we have found that increased ambient pressure inhibits the diffusion processes of EEWs. According to ambient pressure, EEW in argon gas was divided into four regions: shunting, transitional, internal, and saturated.

Synthesis and characterization of titanium nitride nanoparticles

Titanium nitride (TiN) materials have gained an interest over the past years due to their unique characteristics, such as thermal stability, extreme hardness, low production cost, and comparable optical properties to gold. In the present study, TiN nanoparticles were synthesized via a thermal benzene route to obtain black nanoparticles. Scanning electron microscopy (SEM) was carried out to examine the morphology. Further microscopic characterization was done where the final product was drop cast onto double-sided conductive carbon tape and sputter-coated with gold/palladium at a thickness of 4 nm for characterization by field emission scanning electron microscopy (FE-SEM) with energy dispersive X-Ray spectroscopy (EDS) that revealed they are spherical. ImageJ software was used to measure the average size of the particles to be 79 nm in diameter. EDS was used to determine the elements present in the sample and concluded that there were no impurities. Further characterization by Fourier Transform infrared (FTIR) spectroscopy was carried out to identify the characteristic peaks of TiN. X-ray diffraction (XRD) revealed typical peaks of cubic phase titanium nitride, and crystallite size was determined to be 14 nm using the Debye-Scherrer method. Dynamic light scattering (DLS) analysis revealed the size distribution of the TiN nanoparticles, with nanoparticles averaging at 154 nm in diameter. Zeta potential concluded the surface of the TiN nanoparticles is negatively charged.

Influence of Laser Energies on the Generation of Cobalt Oxide Nanoparticles via Laser Ablation in Liquid

Nanoparticles fabrication using pulsed laser synthesis is considered a straightforward, reliable, and green approach for the fabrication of nanomaterials. In this study, cobalt oxide (CoO) nanoparticles were synthesized from cobalt targets using pulsed laser ablation inside a 10% v/v ethanol solution. This study examined the effect of the laser energies on the size and morphology of CoO nanoparticles. The size, morphology of the fabricated nanomaterials were studied using transmission electron microscopy (TEM), and their optical properties were obtained using ultraviolet-visible (UV-Vis) spectroscopy. Uniform size distribution of nanoparticles with diameters less than 60 nm was observed at 30, 45, and 60 mJ. The optimum condition at which the CoO nanoparticles are fabricated with a narrower size distribution was reported, which would be helpful in several applications such as electronic thin film, pigments and dyes, capacitors, gas sensors, and lithium-ion batteries.

Insight into the role of ultrasound, morphology and crystal structure for enhancing the recycling and catalytic performance of Au-MoS2 nanocomposite catalyst in reduction of nitro-compounds

The chemical intercalation exfoliation of commercial MoS2 and the hydrothermal synthesis within their multi-step procedures and high cost have been reported as the prevalent approaches to produce 2D-MoS2 nanosheet, so far. In this study, the high-intensity ultrasound, as a novel straightforward sonochemical approach was utilized for the synthesis of 1 T-MoS2 nanosheets which were then decorated with small sizes of Au nanoparticles (~10 nm) giving rise to the uniform dispersion. When reference materials of the same composition were synthesized in a classic hydrothermal medium, flower-like morphology with a 2-H structure was obtained with a broad and big size distribution of Au nanoparticles (≥50 nm). The prepared materials were thoroughly characterized using XRD, SEM/TEM/EDS mapping, N2-BET adsorption-desorption, and XPS. The nanocomposite morphology and structure were found to have a great effect on the catalytic reduction of hazardous chemicals (nitrobenzene and 3-nitroacetophenone), revealing the benefits of the sonochemically produced catalysts. Notably, the obtained catalytic results revealed that among the produced catalysts, the sonochemically synthesized Au/MoS2 NSs exhibited the highest aniline selectivity of 99 % at conversion ratio of 95 %, and 3-aminoacetophenone selectivity of 99 % at conversion ratio of 98 %. Moreover, the as-prepared sonochemically catalyst displayed high stability for at least 8 cycles of reaction while maintaining high reducing efficiency. The superior activity is discussed in terms of higher surface area and pore diameter, the sulfur deficient surface and the synergistic effect between Au0 and Au+ species. The developed new sonochemical route opens up new opportunities for the facile production of the versatile MoS2 NSs-based core/satellite nanostructures with high catalytic activity. The fulfillment of the green chemistry principle of the ultrasonic technique (eliminating any toxic reducing agents, stabilizers, or organic surfactants) is emphasized.

Controlling the Particle Size and Absorption Spectra of Honey Mediated Green Synthesis of Silver Nanoparticles for Antibacterial Application

Silver nanoparticles were synthesized using locally purchased honey and silver nitrate solution. This method provides a simplistic and straightforward approach to the formation of silver nanoparticles. The silver nanoparticles with varying amounts of silver nitrate solution were characterized using ultraviolet-visible spectroscopy and Fourier transform infrared spectroscopy. In addition, dynamic light scattering characterization was used to determine the average size and size distribution of silver nanoparticles. Experimental results revealed that varying the amount of silver nitrate solution can control the size and absorption spectra of silver nanoparticles. A large amount of silver nitrate solution will exhibit a peak in the higher wavelength. The shifting of the absorption peaks at 401, 406, 407, 408, and 409 nm are believed to be related to the wavelength of the surface plasmon resonance. Moreover, a larger amount of silver nitrate solution also results in an increasing size with 27.2, 57.9, and 63.4 nm as revealed in the size distribution via dynamic light scattering. This green synthesis method of silver nanoparticles will provide a cost-effective production as an alternative to commercial antibacterial agents.

Influence of the TiO2 nanoparticles on upconversion luminescence of Er3+-doped and Er3+/Yb3+-codoped GeO2-PbO glasses

We report the effect of TiO2 nanoparticles (NPs) on the optical properties of Er3+-doped and Er3+/Yb3+-codoped GeO2-PbO glasses. The present investigation demonstrates the adequate experimental procedure to produce TiO2 NPs in anatase structure (size distribution of TiO2 NPs centered at ∼ 50 nm) that favors the infrared-to-visible frequency upconversion (UC) process in Er3+-doped and Er3+/Yb3+ codoped GeO2-PbO. The samples were produced with the melt-quenching technique; phase transformation from amorphous phase to anatase crystalline structure takes place during the annealing that was performed at 420 °C. The feasibility of obtaining GeO2-PbO glasses with improved UC, due to Er3+ ions located in low symmetry sites promoted by the anatase structure of TiO2 NPs and the UC mechanisms from Yb3+ to Er3+ ions is presented. Photoluminescence growth of about 40% (at ∼ 525 and 545 nm) was observed for the samples doped with Er3+ and TiO2 NPs in comparison with the one doped with Er3+ and without TiO2 NPs. Furthermore, an enhancement of ∼25% (525, 545 e 655 nm) was estimated for the UC intensity of samples codoped with Er3+/Yb3+ and with TiO2 NPs when compared with those without TiO2 NPs. The present investigation covers the lack of the literature related to the investigation of anatase structure of TiO2 NPs in Er3+-doped and Er3+/Yb3+ codoped GeO2-PbO glasses and can be extended to different hosts for different photonics applications.

Biosynthesis of silver nanoparticles using nanocurcumin extracted from fresh turmeric of Vietnam

Abstract This study presents a novel process to synthesize curcumin nanoparticles from fresh turmeric. An ultrasonic-assisted cajeput oil in water emulsion technique was used to synthesize nanocurcumin. The prepared nanocurcumin was spherical with an average size of 47 nm and size distribution of 5–80 nm. The synthesized nanocurcumin showed improved aqueous-phase solubility, and it was used as a reducing agent and stabilizer for biosynthesizing silver nanoparticles. Furthermore, the X-ray diffraction pattern of the silver nanoparticles showed four distinct diffraction peaks at 38.3°, 44.6°, 65.1°, and 78.1° corresponding to the lattice planes of face-centered cubic silver ((111), (200), (220), and (311)). Transmission electron microscopy analysis indicated the average size and maximum size distribution (80 %) of the silver nanoparticles were 10.9 nm and 5–15 nm, respectively. UV–visible spectroscopy measurement of samples indicated the localized surface plasmon resonance absorbance of an aqueous dispersion of silver nanoparticles at 406 nm. Zeta potential analysis revealed a negative charge with a magnitude of −27.2 mV, which indicated higher aqueous dispersion stability of the silver nanoparticles prepared from nanocurcumin. The nanoparticles showed antibacterial activity against Vibrio parahaemolyticus.

A simple formula for determining nanoparticle size distribution by combining small-angle X-ray scattering and diffraction results.

X-ray scattering and diffraction phenomena are widely used as analytical tools in nanoscience. Size discrepancies between the two phenomena are commonly observed in crystalline nanoparticle systems. The root of the problem is that each phenomenon is affected by size distribution differently, causing contrasting shifts between the two methods. Once understood, the previously discrepant results lead to a simple formula for obtaining the nanoparticle size distribution.

Dependence of size distribution of nanoparticles on hole size uniformity in membrane emulsification

Metal oxide nanoparticles were fabricated by membrane emulsification using alumina through-hole membranes with different hole size uniformity. Hole size of alumina through-hole membrane used for membrane emulsification and the size of obtained nanoparticles were evaluated by SEM observation, and the relationship between the uniformity of hole size and the size distribution of the obtained nanoparticles was investigated. As a result, nanoparticles with higher size uniformity were obtained when the RSD (relative standard deviation) of hole size was 3.8%. This indicates that the hole size uniformity of the emulsification membrane is important for the fabrication of droplets and nanoparticles of uniform size by membrane emulsification.

Anti-melanogenic activity of vanadium incorporated PVA chitosan electrospun fibers: An in vitro model

Designing a powerful in vitro cell culture platform to support precision medicine can help predict cancer treatment success. Our work reports the fabrication of chitosan/polyvinyl alcohol electrospun fibers with eclectic concentrations of vanadium-loaded chitosam nanoparticles against A375 human skin cancer cells. Vanadium is an active compound against A375 that causes apoptosis and cell cycle block. Distribution of nanoparticle size categorized using Dynamics light scattering (DLS) method. This experimental study shows that the cell cycle stops at different stages for the analyzed species (checkpoint G2 and G0/G1), which raises the significance of the chemical shape of the nanoparticles in the scaffolds and its composition with shows the impact on their mechanism of action. The Results suggest that this biomimetic model may provide a vastly applicable 3D culture system to study the effect of anti-cancer drugs on tumor malignancy in vitro and in vivo. These results give more intelligence into the application of vanadium nanoparticles in biological systems and their role as a potential therapeutic agent in various types of cancer.

How to trust size distributions obtained by single particle inductively coupled plasma mass spectrometry analysis

Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) is a technique widely used to obtain direct information about the number concentration and the size distribution of nanoparticles in liquid suspensions. However, its methods still lack clear quality control strategies to confirm the validity of the information derived from them. Only the detection of the complete size distribution of the nanoparticles in a sample over the size critical value ensures obtaining unbiased quantitative information, otherwise information should be restricted to report the presence of nanoparticles over a certain size and number concentration since their actual total number concentration is underestimated and the size overestimated. Under the latter conditions, data processing produces histograms showing the tails of the incomplete size distributions, although apparently, complete distributions can also be obtained when particle events are recorded as peaks, as reported here for the first time. The occurrence of these misleading situations must be critically evaluated for each SP-ICP-MS analysis. An approach, based on estimation of size critical values and successive dilutions, is proposed for the assessment of the validity of the quantitative information obtained, together with specific criteria for reconsidering the information that can be derived from those measurements. The approach was verified with different case studies and applied to the analysis of complex nanomaterials, confirming the validity of the reported information by comparison with other techniques. A calculation tool is also included to facilitate the estimation of size critical values under experimental conditions.Graphical abstract

Nanoscale Control of Hydrated Portland Cement Structure

The durability of cement-containing building materials, like the cement stone itself, depends on their moisture resistance, frost resistance, and corrosion resistance. All these properties are determined not only by the composition of the initial clinker, but also by the structural organization at the micro-and nanoscale of hydrated Portland cement. In this work, the structural parameters of hydrated Portland cement compositions at the nanoscale level were determined by the method of small-angle neutron scattering: the size distribution of nanoparticles of calcium silicate hydrate, the average radius of nanoparticles, and fractal dimension. It is shown that the introduction of modifying nanoadditives into Portland cement affects the structural parameters of the cement stone. The following nanoadditives were used: of artificial (alpha aluminium oxide, gamma aluminum oxide) and of technogenic (carbonate and alumo-alkaline sludges) origin, as well as complex nanoadditives containing surfactants. Changes in structural parameters of Portland cement with nanoadditives in the process of hydration are traced. It is shown that the use of nanoadditives makes it possible to control the process of formation of the structure of hydrated Portland cement on the nanoscale level, to directly influence the values of structural parameters and, ultimately, to the properties of cement stone.

In Situ Laser Light Scattering for Temporally and Locally Resolved Studies on Nanoparticle Trapping in a Gas Aggregation Source

AbstractGas phase synthesis of nanoparticles (NPs) via magnetron sputtering in a gas aggregation source (GAS) has become a well‐established method since its conceptualization three decades ago. NP formation is commonly described in terms of nucleation, growth, and transport alongside the gas stream. However, the NP formation and transport involve complex non‐equilibrium processes, which are still the subject of investigation. The development of in situ investigation techniques such as UV–Vis spectroscopy and small angle X‐ray scattering enabled further insights into the dynamic processes inside the GAS and have recently revealed NP trapping at different distances from the magnetron source. The main drawback of these techniques is their limited spatial resolution. To understand the spatio‐temporal behavior of NP trapping, an in situ laser light scattering technique is applied in this study. By this approach, silver NPs are made visible inside the GAS with good spatial and temporal resolution. It is found that the argon gas pressure, as well as different gas inlet configurations, have a strong impact on the trapping behavior of NPs inside the GAS. The different gas inlet configurations not only affect the trapping of NPs, but also the size distribution and deposition rate of NPs.

Biosynthesis of Silver Chloride Nanoparticles (AgCl-NPs) fromExtreme Halophiles and Evaluation of Their Biological Applications.

The biosynthesis of nanoparticles (NPs) has gained an overwhelming interest due to their biological applications. However, NPs synthesis by pigmented extreme halophiles remains underexplored. The NPs synthesis using pigmented halophiles is inexpensive and less toxic than other processes. In this study, pigmented halophilic microorganisms (n = 77) were screened to synthesize silver chloride nanoparticles (AgCl-NPs) with silver nitrate as metal precursors, and their biological applications were assessed. The synthesis of AgCl-NPs was possible using the crude extract from cellular lysis (CECL) of six extreme halophiles. Two of the AgCl-NPs viz. AK2-NPs and MY6-NPs synthesized by the CECL of Haloferax alexandrinus RK_AK2 and Haloferax lucentense RK_MY6, respectively, exhibited antimicrobial, antioxidative, and anti-inflammatory activities. The surface plasmon resonance of the AgCl-NPs was determined with UV spectroscopy. XRD analysis of AK2-NPs and MY6-NPs confirmed the presence of silver in the form of chlorargyrite (silver chloride) having a cubic structure. The crystallite size of AK2-NPs and MY6-NPs, estimated with the Scherrer formula, was 115.81nm and 137.50nm. FTIR analysis verified the presence of diverse functional groups. Dynamic light-scattering analysis confirmed that the average size distribution of NPs was 71.02nm and 117.36nm for AK2-NPs and MY6-NPs, respectively, with monodisperse nature. The functional group in 1623-1641cm-1 indicated the presence of protein β-sheet structure and shifting of amino and hydroxyl groups from the pigmented CECL, which helps in capping and stabilizing nanoparticles. The study provides evidence that CECL of Haloferax species can rapidly synthesize NPs with unique characteristics and biological applications.

SpICP-MS characterisation of released silver nanoparticles from (nano)textile products

The low limits of detection and information regarding the concentration and size distribution of nanoparticles provided by single particle inductively coupled plasma mass spectrometry (spICP-MS) has been taken in advance for assessing released silver nanoparticles from (nano)textiles (nanosilver textiles). The releasing procedure consisted of using orbital-horizontal shaking (100 rpm, 20 °C, 30 min) and ultrapure water (10 mL) as an extractant, and it was found to guarantee silver nanoparticles stability (silver nanoparticle concentration and size distribution). Stability of released silver nanoparticles was further investigated at several filtration (0.22, 0.45 and 5.0 μm) and centrifugation conditions, stages required for fluff removal after extraction and just before spICP-MS determinations. Filtration using 5.0 μm filters was found to not affect silver nanoparticles concentrations and size distributions. The extractive procedure plus spICP-MS has shown a limit of detection and a limit of quantification for silver nanoparticle number concentration of 4.59 × 104 and 1.53 × 105 silver nanoparticles per gram of textile, respectively, whereas a limit of detection in size of 12 nm was obtained. Repeatability of the overall procedure was 14% (silver nanoparticle concentration) and 6% (mean silver nanoparticle size). Similarly, analytical recovery assays using standard silver nanoparticles of 20, 40, and 60 nm led to recoveries within the 102–113% range. The high degree of fixation of the AgNPs to the fabric and the softness of the extraction process to guarantee the integrity of the nanoparticles has led to a non-quantitative extraction (extraction percentages between 0.3 and 9.0% depending on the textile sample). However, the methodology developed has proven to be highly efficient for the characterization of the extracted AgNPs, and robust since the stability of the released AgNPs during the extraction procedure.

Metal-doped TiO2 photocatalyst as antibacterial - A Review

Photocatalyst nanomaterials are developing as new materials for many applications. Titanium dioxide (TiO2) is a photocatalyst nanomaterial widely applied to solar cells, chemical sensors, health products and paint pigmentation. In this review article, we aim to provide a comprehensive overview of the development of the metal as a TiO2 doping material and its application as an antibacterial. TiO2 as an antimicrobial photocatalyst has been widely reported. Sol-gel synthesis method on semiconductors can make nanoparticle size, not agglomerate, homogeneous, pure and control mass distribution. Metal-doped TiO2 can activate the performance of TiO2 to work on visible light, thereby increasing the performance of TiO2 in its application as an antibacterial. Nickel (Ni), copper (Cu), manganese (Mn) and sulfur (S) have been shown to affect increasing the performance of TiO2 to inhibit bacteria in visible light. TiO2/Ni has antibacterial activity against Staphylococcus aureus (S. aureus) bacteria. TiO2/Cu has antibacterial activity against Escherichia coli (E.coli), S. aureus, Klebsiella pneumonia (K. Pneumonia) and Saccharomyces sp.. TiO2/Mn/S has antibacterial activity against Bacillus coagulans (B. Coagulans) and (K. Pneumonia). This review can add to the knowledge and the latest developments of metaldoped TiO2 photocatalysts based on antibacterial properties to be applied to water-purifying membranes, skin health and self-cleaning paints.

Microreactor technology in experimental and modelling study of alcohol oxidation on nanogold

Selective oxidation of methanol, ethanol, 1-propanol and 1-butanol to corresponding aldehydes was performed in a microreactor in the presence of a Au/γ-Al2O3 coated catalyst. Nanoparticle size distribution, acidity, specific surface area and the average pore size as well as uniformity and thickness of the coating layer were evaluated with relevant characterization techniques. The experiments were designed to reveal the effect of temperature, residence time and oxygen-to-alcohol ratio on both alcohol conversion and product distribution. Stability and repeatability of the coating procedure was successfully demonstrated. To describe the reaction kinetics, plausible kinetic equations were implemented in a pseudo-homogeneous plug flow model, which turned out to be an adequate approximation to describe the flow pattern in the microreactor. Non-linear regression analysis enabled the determination of the rate and adsorption parameters included in the kinetic model. An advanced kinetic and mass transfer model was developed to reveal the impact of the diffusion inside the catalytic washcoat layer, confirming that molecular diffusion is not a limiting factor for alcohol oxidation in the microreactor.

Alpha Tocopherol Loaded Polymeric Nanoparticles: Preparation, Characterizations, and In Vitro Assessments Against Oxidative Stress in Spinal Cord Injury Treatment.

Spinal cord injury (SCI) is characterized by mechanical injury or trauma to the spinal cord. Currently, SCI treatment requires extremely high doses of neuroprotective agents, which in turn, causes several adverse effects. To overcome these limitations, the present study focuses on delivery of a low but effective dose of a naturally occurring antioxidant, α-tocopherol (α-TP). Calcium alginate nanoparticles (CA-NP) and poly D,L-lactic-co-glycolic acid nanoparticles (PLGA-NP) prepared by ionotropic gelation and solvent evaporation technique had particle size of 21.9 ± 11.19 and 152.4 ± 10.6nm, respectively. Surface morphology, surface charge, as well as particle size distribution of both nanoparticles were evaluated. Entrapment of α-TP into CA-NP and PLGA-NP quantified by UPLC showed entrapment efficiency of 4.00 ± 1.63% and 76.6 ± 11.4%, respectively. In vitro cytotoxicity profiles on human astrocyte-spinal cord (HA-sp) showed that blank CA-NP at high concentrations reduced the cell viability whereas blank PLGA-NP showed relatively safer cytotoxic profiles. In addition, PLGA nanoparticles encapsulated with α-TP (α-TP-PLGA-NP) in comparison to α-TP alone at high concentrations were less toxic. Pretreatment of HA-sp cells with α-TP-PLGA-NP showed two-fold higher anti-oxidative protection as compared to α-TP alone, when oxidative stress was induced by H2O2. In conclusion, CA-NP were found to be unsuitable for treatment of SCI due to their cytotoxicity. Comparatively, α-TP-PLGA-NP were safer and showed high degree of protection against oxidative stress than α-TP alone.

Advanced quantitative analysis of colloidal solution of metal nanoparticles produced by laser ablation in liquids

The diameter of laser synthesized colloidal nanoparticles can be derived from a volume of ablated material and absorbance at surface plasmon resonance wavelength. The origin of such nanoparticles’ diameter is studied in this work. The study is based on Beer-Lambert law where nanoparticle size-distribution and UV-Vis photoabsorbance data are used. Theoretically modeled diameter is verified by independent integral approach proving that simple model derived in our previous work is by most means usable for determination of diameter of laser synthesized nanoparticles in colloidal solution with sizes less than SPR wavelength. Here is also presented the mathematical proof which indicates that in monodisperse limit, under assumption that size-distribution of synthesized nanoparticles can be described by log-normal function, diameter obtained by simple analytical model is in fact mode diameter (most frequent diameter) of size-distribution. Furthermore, it is shown that mode diameter of size-distributions can be obtained from volume average diameter of nanoparticles over experimentally determined diameter distribution as well as from number average diameter of nanoparticles over the same diameter distribution by multiplication of those diameters with shift factors depended only on standard deviation of log-normal distribution. This is verified for size-distributions obtained independently by AFM, TEM and DLS techniques and is proposed to be universal property of log-normal distribution function.