Local Structure of Pd1 Single Sites on the Surface of PdIn Intermetallic Nanoparticles: A Combined DFT and CO-DRIFTS Study

Local structure of Pd1 single sites on the surface of Pd1In1 intermetallic nanoparticles supported on α-Al2O3 was investigated by the combination of CO-DRIFTS spectroscopy and DFT. CO-DRIFTS spectra of PdIn/Al2O3 catalyst exhibit only one asymmetric absorption band of linearly adsorbed CO comprising two peaks at 2065 and 2055 cm−1 attributable to CO molecules coordinated to Pd1 sites located at (110) and (111) facets of PdIn nanoparticles. The absence of bridged or hollow-bonded CO bands indicates that multipoint adsorption on PdIn nanoparticles is significantly hindered or impossible. DFT results show that on (110) facet multipoint CO adsorption is hindered due to large distance between neighboring Pd atoms (3.35 Å). On (111) facet multipoint CO adsorption on surface palladium atoms is impossible, since adjacent Pd atoms are located below the surface plane.

Perencanaan Sistem Pemasaran Online Produk Pertanian Melalui E-Marketplace

Angka pengguna internet semakin berkembang pada era revolusi industry 4.0. Hal ini dapat dimanfaatkan untuk mengembangkan bisnis secara lebih luas, salah satunya dapat memanfaatkan berbagai media pemasaran online yang tersedia seperti marketplace. Sektor pertanian berpotensi untuk diterapkan pemasaran produk secara online yang mengadopsi konsep marketplace. Namun, berbagai tantangan muncul seiring dengan lahirnya berbagai marketplace di Indonesia, khususnya berkaitan dengan kemudahan penggunaan marketplace produk pertanian, mengingat pengguna internet di Indonesia beranjak dari berbagai rentang usia dan latar belakang. Artikel ini bertujuan membangun perancangan marketplace pertanian dengan menerapkan kualitas pelayanan marketplace yang baik dengan memperhatikan nilai user experience (UX), tingkat efektivitas serta tingkat efisiensi untuk pengguna. Metode yang digunakan dalam perancangan marketplace ini adalah metode five plane user experience elements yang terdiri dari lima tahapan antaralain Strategy Plane, Scope Plane, Structure Plane, Skeleton Plane, Surface Plane yang memiliki keterkaitan antar lapisnya. Adapun hasil penelitian ini menunjukkan bahwa responden membutuhkan suatu aplikasi yang lebih menarik dalam segi tampilan seperti memberikan detail produk yang lengkap dengan hasil gambar yang nyata, juga menampilkan gambar dari sudut pandang yang berbeda – beda serta pemilihan huruf (font) dan tema warna yang sesuai. Sedangkan perancangan prototipe HiTani sebagai hasil dari adaptasi terhadap karakteristik dan kebutuhan konsumen menunjukkan hasil perhitungan Success Rate yang diperoleh pada pengujian tingkat efektifitas sebesar 85,6% dengan tingkat pencapaian sangat efektif, dan pengukuran terhadap tingkat efisiensi pada prototype ini nilai efisiensinya dalah 84,74% maka dapat disimpulkan bahwa prototype marketplace HiTani ini sudah efisien dari segi efisiensi waktu penggunaannya.

Effect of oxidation on cellulose and water structure: a molecular dynamics simulation study

Enzymatic cleavage of glycocidic bonds is an important, green and biocompatible means to refine lignocellulosic biomass. Here, the effect of the resulting oxidation point defects on the structural and water interactions of crystalline cellulose {100} surface are explored using classical molecular dynamics simulations. We show that even single oxidations reduce the connections within cellulose crystal significantly, mostly via local interactions between the chains along the surface plane but also via the oxidation defects changing the structure of the crystal in direction perpendicular to the surface. Hydrogen bonding on the surface plane of cellulose is analyzed to identify onset of desorption of glucose chains, and the desorption probed. To assess the actual soluble product profile and their fractions resulting from lytic polysaccharide monooxygenase (LPMO) enzyme oxidation on real cellulose crystal samples, we employ High-Performance Anion-Exchange Chromatography with Pulsed Amperometric-Detection (HPAEC-PAD) technique. The findings demonstrate the LPMO oxidation results in soluble glucose fragments ranging from 2 to 8 glucose units in length. Additionally, significantly more oxidized oligosaccharides were released in LPMO treatment of AaltoCell than Avicel, the two studied microcrystalline cellulose species. This is likely to result from the large reactive surface area preserved in AaltoCell due to manufacturing process. Furthermore, as can be expected, the oxidation defects at the surfaces lead to the surfaces binding a larger amount of water both via direct influence by the defect but also the defect induced protrusions and fluctuations of the glucose chain. We quantify the enhancement of water interactions of cellulose crystals due to the oxidation defects, even when no desorption takes place. The molecular simulations indicate that the effect is most pronounced for the C1-acid oxidation (carboxylic acid formation) but present also for the other defects resulting from oxidation. The findings bear significance in understanding the effects of enzymatic oxidation on cellulose nanocrystals, the difference between cellulose species, and cleavage of soluble products from the cellulosic material.

Первопринципные расчеты магнитной анизотропии пленок Fe и Co, разделенных прослойкой немагнитных металлов

This paper presents the results of numerical calculations of the magnetic characteristics of Co and Fe monolayer films on Cu and Pt surfaces using the VASP software package. The values ​​of the difference between the total energies of the antiferromagnetic and ferromagnetic configurations are calculated depending on the convergence parameters and the thickness of the nonmagnetic material. The values ​​of the magnetic anisotropy and magnetic moment of atoms in the structures of Co / Cu / Co, Fe / Pt / Fe, Co / Pt / Co, Pt / Co / Cu / Co / Pt are determined depending on the orientation of the surface face. For the (110) and (111) faces, the phenomenon of reorientation in the Co / Cu / Co structure is confirmed, when the anisotropy of the cobalt films parallel to the surface plane is replaced by the perpendicular anisotropy due to the introduction of an ultrathin platinum film into the structure.

LARGE VALUES OF THE TRANSVERSE M UES OF THE TRANSVERSE MAGNETIC RESISTANCEOF SINGLE CRYSTAL NICKEL FILMS

Background. The anisotropy of the transverse magnetoresistance of single-crystal nickel films was studied in this work. The measurements were carried out on samples whose surface plane coincided with the [001] plane. Studies of the magnetoresistance in a single-crystal nickel film have shown the effect of tensile stresses acting on it from the side of magnesium oxide. The modification of the anisotropy of magnetoreflection of a film on a substrate as compared to a free sample is apparently associated with a change in the shape of the Fermi surface of carriers.

QM/MM Molecular Dynamics Investigation of the Binding of Organic Phosphates to the 100 Diaspore Surface

<div><div><div><p>The fate of phosphorus (P) in the eco-system is strongly affected by the interaction of phos- phates with soil components and especially reactive soil mineral surfaces. As a consequence, P immobilization could occur which eventually leads to P inefficiency and thus unavailability to plants with strong implications on the global food system. A molecular level understanding of the mechanisms of the P binding to soil mineral surfaces could be a key for the development of novel strategies for more efficient P application. Much experimental work has been done to understand P binding to several reactive and abundant minerals especially goethite (α-FeOOH). On the other hand, atomistic modeling of the P-mineral molecular systems using molecular dynamics (MD) simulations is emerging as a new tool which provides more detailed information regarding the mechanisms, nature, and strength of these binding processes. The present study characterize the binding of the most abundant organic phosphates in forest soils, inositol hexaphosphate (IHP) and glycerolphosphate (GP), to the 100 diaspore (α-AlOOH) surface plane. Here, different molecular models have been introduced to simulate typical situations for the P-binding at the diaspore/water interface. For all models, quantum mechanics/molecular mechanics (QM/MM) based MD simulations have been performed to explore the diaspore–IHP/GP–water interactions. The results provide evidence for the formation of monodentate (M) and bidentate (B) motifs for GP and M and as well as two monodentate (2M) motifs for IHP with the surface. The calculated interaction energies suggest that GP and IHP prefer to form the B and 2M motif, respectively. Moreover, IHP exhibited stronger binding than GP with diaspore and water. Further, the role of water in controlling binding strengths via promoting of specific binding motifs, formation of H-bonds, adsorption and dissociation at the surface, as well as proton transfer processes is demonstrated. Finally, the P-binding at the 100 diaspore surface plane is weaker than that at the 010 plane highlighting the influential role of the coordination number of Al atoms at the top surface of diaspore.</p></div></div></div>

QM/MM Molecular Dynamics Investigation of the Binding of Organic Phosphates to the 100 Diaspore Surface

<div><div><div><p>The fate of phosphorus (P) in the eco-system is strongly affected by the interaction of phos- phates with soil components and especially reactive soil mineral surfaces. As a consequence, P immobilization could occur which eventually leads to P inefficiency and thus unavailability to plants with strong implications on the global food system. A molecular level understanding of the mechanisms of the P binding to soil mineral surfaces could be a key for the development of novel strategies for more efficient P application. Much experimental work has been done to understand P binding to several reactive and abundant minerals especially goethite (α-FeOOH). On the other hand, atomistic modeling of the P-mineral molecular systems using molecular dynamics (MD) simulations is emerging as a new tool which provides more detailed information regarding the mechanisms, nature, and strength of these binding processes. The present study characterize the binding of the most abundant organic phosphates in forest soils, inositol hexaphosphate (IHP) and glycerolphosphate (GP), to the 100 diaspore (α-AlOOH) surface plane. Here, different molecular models have been introduced to simulate typical situations for the P-binding at the diaspore/water interface. For all models, quantum mechanics/molecular mechanics (QM/MM) based MD simulations have been performed to explore the diaspore–IHP/GP–water interactions. The results provide evidence for the formation of monodentate (M) and bidentate (B) motifs for GP and M and as well as two monodentate (2M) motifs for IHP with the surface. The calculated interaction energies suggest that GP and IHP prefer to form the B and 2M motif, respectively. Moreover, IHP exhibited stronger binding than GP with diaspore and water. Further, the role of water in controlling binding strengths via promoting of specific binding motifs, formation of H-bonds, adsorption and dissociation at the surface, as well as proton transfer processes is demonstrated. Finally, the P-binding at the 100 diaspore surface plane is weaker than that at the 010 plane highlighting the influential role of the coordination number of Al atoms at the top surface of diaspore.</p></div></div></div>