Pillar Formation Research Articles

Отработка угольных целиков унифицированными выемочными модулями локальными забоями

Almost all of the applied technologies of underground coal mining are associated with formation of coal pillars within the limits of the operating mines. These pillars have different purposes, geometrical parameters, occurrence conditions and the functions they perform. Significant coal reserves suitable for excavation are located in the pillars. Improvement of the mining process of the coal pillars that are in favourable conditions and have already fulfilled their main and subsidiary designated functions, is urgent because these reserves are unrecoverable. Most processes in mining technologies are structured and interconnected. The system approach to identification of these relationships allows to form requirements to the process of pillar mining by local faces and controlled coal breaking. The article considers the structure and parameters of the coal pillars as mining objects; it analyses the mechanical method of their mining with coal breaking using the heading-and-bench technology. The main competing methods of coal breaking are analysed, instead of cutting, shearing of coal off the pillars using structural blocks of the given sizes is accepted. The concept of the ‘local face’ for coal pillars extraction is defined. A scheme of the local face is proposed and described. The structure of the technological process and technical means in the form of a unified excavation module for extraction of pillars with coal breaking using structural blocks is described based on the analysis of the pillar mining process using local faces. There proposed the ‘a’ multiplication parameter that reflects the significance and correlation between the strength, technological and technical factors and the size of the separated blocks. The ‘a’ parameter characterises the correlation between the sizes of the coal lumps separated from the coal mass and the parameters of the local face, namely the technological process and technical means.

Cu Pillar Wafer Pretreatment for Enhancing Wettability and Cleaning Cu Seed Layer

Semiconductor packaging serves the dual purpose of shielding semiconductor devices from external elements and facilitating electrical connections between chips and substrates. This intricate process, integral to transforming semiconductor devices into fully functional products, directly impacts the stability, reliability, and performance of electronic devices. With the semiconductor industry grappling with the physical constraints of miniaturization in recent years, the significance of packaging technology has surged. Modern packaging focuses not only on safeguarding devices but also on efficiently establishing electrical connectivity between chips and substrates or among different chips, transcending its conventional role.In semiconductor packaging, the establishment of interconnections holds paramount importance in enabling electrical pathways between internal and external components of semiconductor devices. Various interconnection methods, including Redistribution Layers (RDL), Through Silicon Vias (TSV), microbumps, and microvias, are employed, linking different layers or integrating multiple chips into complex three-dimensional configurations. As the demand for higher integrity mounts, the density of interconnections within semiconductor packages undergoes a notable surge, necessitating structural adaptations in these connections. Notably, the adoption of copper pillars with solder caps has supplanted conventional bonding techniques reliant on solder balls to enhance performance. This transition stems from the risks associated with traditional solder balls, such as potential damage to component chips due to their high melting temperatures. In contrast, copper pillars with solder caps offer superior electrical conductivity while mitigating the drawbacks inherent in solder balls.In contrast to methods like Damascene and TSV processes, the formation of copper micro pillars involves infusing copper into via holes created within a photoresist (PR) layer. However, PR patterning may inadvertently introduce organic impurities that hinder the adhesion of the copper seed layer. Moreover, PR exhibits relative hydrophobicity compared to metallic copper, facilitating air entrapment within PR vias. These challenges can lead to irregularities in copper electrodeposition and the formation of defects within copper pillars. Additionally, organic residues at the interface between the copper seed layer and the pillars can compromise their mechanical and electrical reliability while elevating electrical resistance. Consequently, post-treatment measures following PR patterning are imperative to optimize the copper electrodeposition process.This presentation introduces pre-treatment procedures preceding significant copper electrodeposition to ensure the attainment of flawless copper pillars. Through this study, three distinct pre-treatment methods were explored to enhance the stacking properties of PR-patterned wafers, eliminate organic impurities from the copper seed layer, and regulate the hydrophobic nature of the PR layer while eradicating copper surface oxides. By fine-tuning parameters and evaluating the quality of copper electrodeposition resulting from these pre-treatments, an optimal pre-treatment protocol for achieving defect-free copper pillars is proposed. Figure 1

Generation of nano-to-microplastics from polypropylene surfaces via femtosecond laser ablation in liquids with different viscosities

Preparation of polypropylene (PP) nano and microparticles, crucial for investigating the effects of plastics on both human health and the environment, presents a significant and immediate challenge. Utilizing an fs laser system in different liquid mediums such as water, dodecane, and hexadecane, we have successfully generated PP particles with sizes ranging from 1.8 to 4911 nm. This outcome is partly attributed to the constraint on plasma expansion caused by the viscosity of the liquid media. We investigated the areas of material removal and observed a transition from ordered to disordered removal patterns during this process. The formation of filaments and pillars within the material removal cavity, along with the deposition layer at the cavity edge, primarily occurred due to insufficient plasma formation at low laser energy levels. Furthermore, we observed neck-shaped filaments and nano cracks on the deposition surface, which were attributed to the heat effect during laser interaction with the PP substrate. Moreover, we collected distinct nano-Fourier transform infrared spectroscopy (FTIR) signals from both the nanoparticle area and the deposition layer, revealing a 2 cm−1 wavenumber difference between the two regions. This discrepancy proved to be a valuable method for distinguishing between the nanoparticle area and the deposition layer.

Improvement of the transitional technology from open pit to underground mining of magnetite quartzite

The paper analyzes the disadvantages of the technology of iron ore open pit mining and current environmental problems of open pit mining. The paper also addresses problems of possible displacement and strains of rocks in the classical open pit mining method with extraction of minerals exclusively by open pit mining, studies current transitional technologies from open pit to integrated open pit-underground and subsequent underground mining, and presents an improved methodology for studying the stress-strain state of the massif during transition from open pit mining to integrated open pit-underground and subsequent underground mining. There are studied, developed and proposed options of environmentally friendly technologies of integrated open pit-underground mining with mining waste disposal in the worked-out space of underground mines and open pits, highly efficient calculation schemes for studying the stress-strain state of a rock massif during transition from open pit to underground mining with formation of protective barrier pillars, an option with the development of the lower room of stage II under protection of an ore pillar left within the contours of the upper room of stage I, and an option with the development of the lower room of stage II under protection of an artificial pillar made of the consolidating backfill in the upper room of stage I. The stress-strain state of the massif and possibilities of forming internal waste rock dumps when applying integrated open pit-underground mining technologies are studied and substantiated. Transition technologies from open pit to underground mining of iron ore raw materials under the bottom of an operating open pit are developed and proposed on the example of Kryvyi Rih iron ore basin.

Characterization of laser-induced surface structures of aluminum in an oxygen-free atmosphere

Brazing of materials with high oxygen affinity, such as aluminum alloys, requires the removal of surface oxides. This is commonly achieved using chemical fluxes. The approach described here utilizes IR-pulsed laser radiation at a pulse duration of 45 ns to remove the oxide layer. To prevent reoxidation, an oxygen-free atmosphere is used by introducing monosilane (SiH4) into the process chamber, which binds the oxygen molecules. The laser-induced surface structuring that occurs during oxide removal of aluminum alloy EN AW-6082 was investigated. Pulse energies between 60 – 300 µJ and different pulse overlaps between 0 – 90 % were analyzed for topography and roughness based on the process atmosphere. The results suggest that the roughness increases significantly only at 90 % overlap. Additionally, laser structuring with high energy and overlap in the presence of O2 results in a porous surface layer, while in the absence of O2, it leads to pillar formation with higher roughness.

Pillar Growth by Focused Electron Beam-Induced Deposition Using a Bimetallic Precursor as Model System: High-Energy Fragmentation vs. Low-Energy Decomposition.

Electron-induced fragmentation of the HFeCo3(CO)12 precursor allows direct-write fabrication of 3D nanostructures with metallic contents of up to >95 at %. While microstructure and composition determine the physical and functional properties of focused electron beam-induced deposits, they also provide fundamental insights into the decomposition process of precursors, as elaborated in this study based on EDX and TEM. The results provide solid information suggesting that different dominant fragmentation channels are active in single-spot growth processes for pillar formation. The use of the single source precursor provides a unique insight into high- and low-energy fragmentation channels being active in the same deposit formation process.

Into the Mystic: ALMA ACA observations of the Mystic Mountains in Carina

ABSTRACT We present new observations of the Mystic Mountains cloud complex in the Carina Nebula using the ALMA Atacama Compact Array (ACA) to quantify the impact of strong UV radiation on the structure and kinematics of the gas. Our Band 6 observations target CO, 13CO, and C18O; we also detect DCN J=3–2 and 13CS J=5–4. A dendrogram analysis reveals that the Mystic Mountains are a coherent structure, with continuous emission over −10.5 km s−1 < v < −2 km s−1. We perform multiple analyses to isolate non-thermal motions in the Mystic Mountains including computing the turbulent driving parameter, b, which indicates whether compressive or solenoidal modes dominate. Each analysis yields values similar to other pillars in Carina that have been observed in a similar way but are subject to an order of magnitude less intense ionizing radiation. We find no clear correlation between the velocity or turbulent structure of the gas and the incident radiation, in contrast to other studies targeting different regions of Carina. This may reflect differences in the initial densities of regions that go on to collapse into pillars and those that still look like clouds or walls in the present day. Pre-existing over-densities that enable pillar formation may also explain why star formation in the pillars appears more evolved (from the presence of jets) than in other heavily irradiated but non-pillar-like regions. High resolution observations of regions subject to an array of incident radiation are required to test this hypothesis.

Deuterium retention in tungsten, tungsten carbide and tungsten-ditungsten carbide composites

The selection of the most suitable material for the EU DEMO divertor is still underway. Current research focuses on the development of tungsten-based materials for plasma-facing applications. In addition to other requirements, the candidate material must also exhibit low intrinsic hydrogen isotope retention. To verify the suitability of the tungsten carbide-containing materials, we examined the effect of carbon in the form of carbide or free carbon on deuterium (D) retention.The samples were consolidated by Field Assisted Sintering (FAST) and examined in terms of phase composition and microstructure before the d-retention studies. The Nuclear Reaction Analysis (NRA) technique was used to determine the depth distribution of D after the exposure to D plasma (fluence of 1.3 × 1024 D/m2 and 1.3 × 1025 D/m2 and an exposure temperature of 370 K and 523 K, respectively). Thermal Desorption Spectroscopy (TDS) was used to measure the D desorption spectra. The surfaces of samples exposed to D plasma were also examined in terms of microstructure by scanning electron microscopy. The study has shown that apart from the d-fluence and exposure temperature, the materials’ composition plays a vital role in d-retention, accompanied by blisters and pillar formation. The lowest d-retention was observed for tungsten and the highest in the W-W2C composite. The blisters and pillars were formed in these two materials but not in the WC, which also contains free carbon. At higher D fluence, approximately 15 to 20-times more blisters and pillars were formed in the W-W2C composite than in the tungsten prepared by the same method. The results suggest that the number of defects causing higher d-retention is the highest in W-W2C. On the other hand, the absence of surface irregularities in the WC-C sample after D retention studies indicates that the cause for higher D retention does not lie in the carbides, but, presumably, the microstructural and crystal lattice defects govern the D retention in tungsten-tungsten carbide systems.

Thermal stress-assisted formation of submicron pillars from a thin film of CoCrCuFeNi high entropy alloy: experiments and simulations.

In this work, for the first time, the thermal stress-assisted formation of submicron pillars (SPs) from a high entropy alloy (HEA) thin film is made possible, and novel molecular dynamics (MD) simulations are proposed to assess the underlying mechanisms. In a series of experiments, the growth of quasi-equiatomic HEA SPs from CoCrCuFeNi HEA thin films was demonstrated under different heating and cooling conditions. Atomistic simulations are performed to probe possible formation mechanisms in two ways. One is to first obtain surface elastic constants and then conduct surface stability analysis with the consideration of size-dependent surface stress. The other is to effectively apply large compressive stress while simplifying the molecular dynamics (MD) model by using the Stoney equation to perform long-term MD simulations. From the former, it is suggested that surface diffusion is likely not the dominant cause for the observed pillar formation. From the latter, it is revealed that the level of compressive stress plays a much greater role than the crystalline structure of the film sample. Light has been shed on the stress-assisted formation of submicron pillars from CoCrCuFeNi HEA films by both experimental and simulation approaches.

Cryogenic Temperature Growth of Sn Thin Films on Ferromagnetic Co(0001)

AbstractTopological electronic materials hold great promise for revolutionizing spintronics, owing to their topological protected, spin‐polarized conduction edge or surface state. One of the key bottlenecks for the practical use of common binary and ternary topological insulator materials is the large defect concentration that leads to a high background carrier concentration. Elemental tin in its α‐phase is a room temperature topological semimetal, which is intrinsically less prone to defect‐related shortcomings. Recently, the growth of ultrathin α‐Sn films on ferromagnetic Co surfaces has been achieved; however, thicker films are needed to reach the 3D topological Dirac semimetallic state. Here, the growth of α‐Sn films on Co at cryogenic temperatures was explored. Very low‐temperature growth holds the promise of suppressing undesired phases, alloying across the interfaces, as well as the formation of Sn pillars or hillocks. Nevertheless, the critical Sn layer thickness of ≈3 atomic layers, above which the film partially transforms into the undesired b‐phase, remains the same as for room‐temperature growth. From ferromagnetic resonance studies, and supported by electron microscopy, it can be concluded that for cryogenic Sn layer growth, the interface between Sn and Co remains sharp and the magnetic properties of the Co layer stay intact.

Thermocapillary patterning of non-Newtonian thin films

Deformation of thin viscous liquid films exposed to a transverse thermal gradient results in Bénard–Marangoni instability, which would lead to the formation of micro- and nano-sized features. Linear and nonlinear analyses are performed to investigate the thermally induced pattern formation in shear thinning and shear thickening liquid films. The so-called thin film (TF) equation is re-derived to include viscosity variations using the power-law (PL) model. The characteristic wavelength for the growth of instabilities is found using a linear stability analysis of the PL-TF equation. A finite-difference-based discretization scheme and adaptive time step solver are used to solve the PL-TF equation for the nonlinear numerical model. The results show that the rheological property affects the timescale of the process and the size and final shape of the formed features. The fastest growth pillar reaching the top substrate in a shear thickening fluid is shorter than both the shear thinning and the Newtonian fluid cases. Moreover, morphological changes between patterns of shear thinning and shear thickening fluids are correlated with local viscosity variations. The number of formed pillars considerably increases with the increasing flow behavior index. The existing model also predicts the formation of pillars and bicontinuous structures at very low and high filling ratios.

A Study of Ta2O5 Nanopillars with Ni Tips Prepared by Porous Anodic Alumina Through-Mask Anodization.

The paper discusses the formation of Ta2O5 pillars with Ni tips during thin porous anodic alumina through-mask anodization on Si/SiO2 substrates. The tantalum nanopillars were formed through porous masks in electrolytes of phosphoric and oxalic acid. The Ni tips on the Ta2O5 pillars were formed via vacuum evaporation through the porous mask. The morphology, structure, and magnetic properties at 4.2 and 300 K of the Ta2O5 nanopillars with Ni tips have been studied using scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometry. The main mechanism of the formation of the Ta2O5 pillars during through-mask anodization was revealed. The superparamagnetic behavior of the magnetic hysteresis loop of the Ta2O5 nanopillars with Ni tips was observed. Such nanostructures can be used to develop novel functional nanomaterials for magnetic, electronic, biomedical, and optical nano-scale devices.

Improving single-lap joint load bearing by bioinspired interlocking patterns on substrates

This study aims to evaluate the effect of adding a pattern of conical holes on the substrate surface to improve mechanical interlocking of the bonded joint. The holes allowed the formation of micro pillars in the adhesive layer, promoting mechanical interlocking and considerably increasing the resistance of the joints. The single-lap shear tests were performed according to the ASTM D1002 standard. The results showed that the proposed solution presents a viable alternative to improve the resistance of bonded joints, promoting an increase of up to 99.84% in the final displacement and final resistance of the tested specimens. The finite element analysis also showed a reduction up to 18.11% in the stress peaks in the singularity point of the adhesive layer. Significant changes in the stress distribution around the micro pillars also was observed. Failures also have changed from an almost entirely adhesive condition to extremely fragmented cohesive failures.

Sub-micrometer pillar formation in fused silica using double-pulse back-surface laser ablation

This work presents an investigation into the characteristics of double-pulse, back-surface ablation of fused silica via the use of a picosecond pulse laser with a wavelength of 532 nm.The processing depth of back-surface ablation was found to be greater than that of front-surface ablation for a given laser power. The processing depth of back-surface ablation was further increased via the use of double-pulse ablation using an appropriate laser fluence combination for the first and second pulse relative to the single-pulse ablation threshold, Fth. Setting the laser fluence of pulses in ascending order (where the first pulse is below Fth and the second pulse is greater than Fth) is found to increase the processing depth. Furthermore, non-trivial features of the processing trace were found; an axisymmetric circular trench with a sub-micrometer scale protrusion at its center was observed in the case of double-pulse, back-surface ablation using laser pulses in an ascending order of laser fluence under certain conditions. The protrusion has a pillar-like shape with a diameter of several hundred nanometers; the pillar-like structure has a height of about 1.3 µm from the trench bottom, and protruded 0.7 µm from the back-surface plane. When the first pulse had a laser fluence of greater than Fth, the protrusion was not present and the shape was similar to that obtained when using a single-pulse ablation.The results of this work show the superiority of double-pulse, back-surface ablation of fused silica compared with the equivalent single-pulse technique in terms of enhanced throughput and the capability to create unique sub-micrometer structures.

Thermal expansion of free volume in "classic" and regulated dimethacrylates: photocured directly and via a mask to study pillar formation.

The temperature dependence of free volume in dimethacrylates (poly2M), cured by direct irradiation (poly2M-A) or via a mask (poly2M-B), and in a thiol-based 2M sample (poly2M-co-EDDT), was investigated by positron annihilation lifetime spectroscopy (PALS) and dilatometry (DIL) to study the influence of thiol regulation on the microstructure via free volume characteristics. It was found that the free volume fraction as determined from experimental data by using the standard spherical approach for the hole shapes showed systematic differences from the analogous quantity as evaluated from the lattice-hole theory. Much better results were obtained for cylindrical holes, which expand 'anisotropically' in poly2M samples and 'isotropically' in the poly2M-co-EDDT resin. In addition, the hydrogen bond changes and the conversion of monomers in cured samples studied by near infra-red spectroscopy (NIR) revealed spectrum-structure correlations for the final cured thermosets.

Frame mine structure for underground mining of thick ore bodies

The article describes the research results on the convergent technology for underground mining of thick ore bodies using a frame mine structure. The brand-new concept of the stability evaluation in anthropogenically altered rock mass uses the inter-disciplinary design solutions developed within the scope of nature-like convergent technologies. The nature-like convergent framing technology based on the modern deformation concepts ensures the highest stability of the load-bearing structures in mines. For the quantitative evaluation of the in-situ stress field variation in the course of mining, a new index is proposed – the influence factor. This index-based estimate shows that the strongest effect on the size of induced tensile strain zones in thick ore body mining is exerted by the mining systems with caving. The authors present the stress–strain analysis of the frame mine structure, the mechanism of tensile strain zones, and the level of deformation in enclosing rocks, ore and various-purpose pillars. The design and construction sequence of the new mine structure, as well as the related safety, eco-friendliness and efficiency of mining are demonstrated. A casestudy of stage-wise preparation and extraction of an ore site is presented, including the first stage of formation of artificial separation and protection pillars and the second stage of open stoping with borehole blasting by sections and using VRC.The study was supported by the Russian Science Foundation, Project No. 19-17-00034.The authors highly appreciate participation of N. G. Vysotin, A. M. Yanbekov, S. S. Shermatova, M. A. Kosyreva, Ch. V. Khazhyylai, V. I. Leizer and E. D. Yakusheva from the Research Center for Applied Geomechanics and Convergent Technologies in Mining at the NUST MISIS College of Mining in this study.

Intussusceptive Angiogenesis in Human Metastatic Malignant Melanoma

Angiogenesis supplies oxygen and nutrients to growing tumors. Inhibiting angiogenesis may stop tumor growth, but vascular endothelial growth factor inhibitors have limited effect in most tumors. This limited effect may be explained by an additional, less vascular endothelial growth factor-driven form of angiogenesis known as intussusceptive angiogenesis. The importance of intussusceptive angiogenesis in human tumors is not known. Epifluorescence and confocal microscopy was used to visualize intravascular pillars, the hallmark structure of intussusceptive angiogenesis, in tumors. Human malignant melanoma metastases, patient-derived melanoma xenografts in mice (PDX), and genetically engineered v-raf murine sarcoma viral oncogene homolog B1 (BRAF)-induced, phosphatase and TENsin homolog deleted on chromosome 10 (PTEN)-deficient (BPT) mice (BrafCA/+Ptenf/fTyr-Cre+/0-mice) were analyzed for pillars. Gene expression in human melanoma metastases and PDXs was analyzed by RNA sequencing. Matrix metalloproteinase 9 (MMP9) protein expression and T-cell and macrophage infiltration in tumor sections were determined with multiplex immunostaining. Intravascular pillars were detected in human metastases but rarely in PDXs and not in BPT mice. The expression of MMP9 mRNA was higher in human metastases compared with PDXs. High expression of MMP9 protein as well as infiltration of macrophages and T-cells were detected in proximity to intravascular pillars. MMP inhibition blocked formation of pillars, but not tubes or tip cells, invitro. In conclusion, intussusceptive angiogenesis may contribute to the growth of human melanoma metastases. MMP inhibition blocked pillar formation invitro and should be further investigated as a potential anti-angiogenic drug target in metastatic melanoma.

Gateless and Capacitorless Germanium Biristor with a Vertical Pillar Structure

For the first time, a novel germanium (Ge) bi-stable resistor (biristor) with a vertical pillar structure was implemented on a bulk substrate. The basic structure of the Ge pillar-typed biristor is a p-n-p bipolar junction transistor (BJT) with an open base (floating), which is equivalent to a gateless p-channel metal oxide semiconductor field-effect transistor (MOSFET). In the pillar formation, we adopted an amorphous carbon layer to protect the Ge surface from both physical and chemical damage by subsequent processes. A hysteric current-voltage (I-V) characteristic, which results in a sustainable binary state, i.e., high current and low current at the same voltage, can be utilized for a memory device. A lower operating voltage with high current was achieved, compared to a Si biristor, due to the low energy bandgap of pure Ge.

Pulsed laser deposited stoichiometric GaSb films for optoelectronic and phase change memory applications

Phase-change memory (PCM) holds great potential in realizing the combination of DRAM-like speeds with non-volatility and large storage capacity for future electronic devices including in-memory computing. However, various (reliability) issues related to e.g. too high programming current (power consumption), resistance drift, data retention (low crystallization temperature), phase separation and density change upon switching stand in the way to make PCM really attractive. GaSb thin films have interesting optical and electrical properties which are attractive for optoelectronic and PCM applications but so far reported stoichiometric GaSb compositions are Sb-rich which produced reliability issues in PCM devices. In this study, we managed to deposit stoichiometric GaSb thin films using pulsed laser deposition (PLD) by varying deposition parameters and conditions. Using electron microscopy, the morphology of deposited films and target surface and the compositional deviation from exact stoichiometry have been investigated. We show that the directional nature of laser-target interaction is directly responsible for film quality in PLD in which particulates with high number density are generated due to directional pillar formation. Suppressing this pillar formation, by a simple 180° target rotation, showed an increase in deposition yield by 60%, exact stoichiometric transfer from target to substrate, and large reduction in particulate density. Moreover, from XRD analysis, we show that exact stoichiometric transfer from target to substrate is crucial for structural integrity of the produced films. Temperature induced structural transformation from resistivity vs. temperature measurements show a high crystallization temperature of 250 °C for stoichiometric GaSb thin film. We believe the exact stoichiometric GaSb thin films with reduced particulate densities and favorable structural and (opto)electronic properties are attractive for future PCM devices.

A Study of Microvascular Density in Carcinoma of Breast with CD34 Immunostaining

Introduction: Tumor agiogenesis is generally classified in to two types, namely, sprouting and intussusceptive angiogenesis. The formation of new blood vessels from the already existing is termed as sprouting angiogenesis. Many growth factors including endothelial growth factor (VEGF) contribute the formation of new vessels at the tumor sites. On other hand, the tumor able to split the existing blood vessels, this type is termed as intussuscepted angiogenesis and discovered in human colon adenocarcinoma xenograft. In intussuscepted angiogenesis, an existing blood vessel splits into two new blood vessels by formation of trans vascular pillars.
 Objective: The present study aimed to analyse the nicrovascular density on breast cancer patients using CD 34 immunostaining method.
 Results: This mis-regulation may lead to the development of cancers. Histological grading with Grade II were more with 19 (63.3%) cases followed by Grade I with 4 (13.3%) and Grade III with 3 (10%) cases. There was increase in mean vascular density in Grade II when compared with Grade I and Grade III. However no significant correlation was observed statistically with a P value of 0.176. Using different antibodies such as CD34, CD31, Factor VIII and CD105 to microvessels differentiation was highlighted.
 Conclusion: The results showed that the anti-CD34 monoclonal antibody is more sensitive than the anti- CD31 antibody in calculation of MVD in breast cancer as mentioned in previous studies.