• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.1062-1070
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• 2022

In the present communication, pure and stable α-Bismuth Oxide (Bi₂O₃) nanoparticles (NPs) were synthesized by low temperature solution combustion method using urea as a fuel and calcined at 500℃. The synthesized sample was characterized by using powder X-ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), Energy dispersive X-ray analysis (EDAX), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR) and UV-Visible absorption spectroscopy. The PXRD pattern confirms the formation of mono-clinic, stable and low temperature phase α-Bi₂O₃. The direct optical energy band gap was estimated by using Wood and Tauc's relation which was found to be 2.81 eV. The characterized sample was studied for X-ray/gamma ray shielding properties in the energy range 0.081-1.332 MeV using NaI (Tl) detector and multi channel analyzer (MCA). The measured shielding parameters agrees well with the theory, whereas, slight deviation up to 20% is observed below 356 keV. This deviation is mainly due to the influence of atomic size of the target medium. Furthermore an accurate theory is necessary to explain the interaction of X-ray/gamma ray with the NPs.The present work opens new window to use this facile, economical, efficient, low temperature method to synthesize nanomaterials for X-ray/gamma ray shielding purpose.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2000.05a
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• pp.1-1
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• 2000

The results of the modification of metal materials treated by high temperature pulst:d plasma fluxes (HTlPPF) with a specific power of incident flux changing in the $(3...100)10^5{]\;}W/cm^2$ range and a pulse duration lying from 15 to $50{\;}\mu\textrm{s}$ have been presented. The results of HTPPF action were studied on the stainless steels of 18Cr-l0Ni, 16Cr- 15Ni, 13Cr-2Mo types; on the structural carbon steels of (13...35)Cr, St. 3, St. 20, St. 45 types; on the tool steels of U8, 65G, ShHI5 types, and others; on nickel and high nickel alloy of 20Cr-45Ni type; on zirconium- and vanadium-base alloys and other materials. The microstructure and properties (mechanical, tribological, erosion, and other properties) of modified materials and surface alloying of metals exposed to HTPPF action have been investigated. It was found that the modification of materials by HTPPF resulted in a simultaneous increase of several properties of the treated articles: microhardness of the surface and layers of 40...60 $\mu\textrm{m}$ in depth, tribological characteristics (friction coefficient, wear resistance), mechanical properties ({\sigma_y}, {\;}{\sigma_{0.2}}.{\;}{\sigma_r}) on retention of the initial plasticity ($\delta$), corrosion resistance, radistanation erosion under ion irradiation, and others. The determining factor of the changes observed is the structural-phase modification of the near-surface layers, in particular, the formation of the fine cellular structure in the near-surface layers at a depth of $20{\;}{\mu\textrm{m}}$ with dimension of cells changing in the range from 0.1 to $1., 5{\;}\mu\textrm{m}$, depending on the kind of material, its preliminary treatment, and the parameters of plasma fluxes. The remits obtained have shown the possibility of purposeful surface alloying of metals exposed to HTPPF action over a depth up to 20...45 $\mu\textrm{m}$ and the concentration of alloying element (Ni, Cr, V) up to 20 wt.%. Possible industrial brunches for using the treatment have been also considered, as well as some results on modifying the serial industrial articles by HTPPF.

• Structural Engineering and Mechanics
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• v.86 no.5
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• pp.673-686
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• 2023

Determining the properties of pile from cone penetration test (CPT) is costly, and need several in-situ tests. At the present study, two novel hybrid learning models, namely PSO-RF and HHO-RF, which are an amalgamation of random forest (RF) with particle swarm optimization (PSO) and Harris hawks optimization (HHO) were developed and applied to predict the pile set-up parameter "A" from CPT for the design aim of the projects. To forecast the "A," CPT data along were collected from different sites in Louisiana, where the selected variables as input were plasticity index (PI), undrained shear strength (S_u), and over consolidation ratio (OCR). Results show that both PSO-RF and HHO-RF models have acceptable performance in predicting the set-up parameter "A," with R² larger than 0.9094, representing the admissible correlation between observed and predicted values. HHO-RF has better proficiency than the PSO-RF model, with R² and RMSE equal to 0.9328 and 0.0292 for the training phase and 0.9729 and 0.024 for testing data, respectively. Moreover, PI and OBJ indices are considered, in which the HHO-RF model has lower results which leads to outperforming this hybrid algorithm with respect to PSO-RF for predicting the pile set-up parameter "A," consequently being specified as the proposed model. Therefore, the results demonstrate the ability of the HHO algorithm in determining the optimal value of RF hyperparameters than PSO.

• Journal of English Language & Literature
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• v.55 no.5
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• pp.907-936
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• 2009

Quite arguably, W. E. B. Du Bois is the first figure in the history of black nationalism who engaged most persistently and systematically with the dominant ideology of racism and white supremacy. It is not too much to say that, by contending with the Eurocentric but taken-for-granted concept of the 'Negro' in the turn of the century, Du bois has laid the theoretical and ideological cornerstone of postcolonialism today. But his concept of race varied over time and was even contradictory in the same writings. The early Du Bois defined race as something historically made rather than biologically given and determined. Yet he didn't utterly deny the significance of physical traits and skin color in constructing racial identity. His notion of the 'Negro' was not unambiguous, either. While drawing on the 'soul' of 'black folk' to undermine the Eurocentric dichotomy of white/mind and black/body, Du Bois argued that there is some kind of 'spiritual' differences between whites and blacks, differences that are essentially inherent and hereditary in the 'Negro.' Such essentialist notion of race and the 'Negro' was on the wane in the later Du Bois, especially after his encounter with Marxism. He came to think of race merely as a discourse of racism that can be subverted and even appropriated for anti-racist practices. Following the Marxist assumption that 'the color line' is a class conflict on the international level, Du Bois contended that the 'Negro' is an outcome of slavery which is in turn a subsystem of Western capitalism. He also argued that, since the 'Negro' is not a biological essence but a sociocultural formation, the identity of the 'Negro' can and must be reconstructed according to historical change. For Du Bois, therefore, the resistance against colonialism and capitalism became a resistance against racism. This is why his Pan-African movement shifted its gear from the American program in the initial phase to a truly 'Afrocentric' and socialist one.

• CELLMED
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• v.13 no.14
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• pp.17.1-17.23
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• 2023

Menopause is a physiological phase experienced by all women as part of normal aging known as menopause. Per se, menopause is not a disease, but hormonal imbalance may lead to menopausal symptoms in some women. The unani physician described that in Sinn-i-Inḥiṭāṭ/ Sinn al-Yās, Burūdat (coldness) increases lead to Ihtibās al-Tamth (amenorrhea) that can occur naturally. Besides, Khilt Dam (blood) production decreases from the liver, slight production occurs, tends towards Burūdat. Therefore, at this age, Ihtibās al-Tamth is associated with Alāmāt Sinn al-Yās(menopausalsymptoms) including weight gain, loss of appetite, hirsutism, fatigue, headache, backache, arthralgia, neck pain, general myalgia, nervousness, anxiety, depression, and insomnia. The traditional Unani manuscripts are enriched with knowledge for the management of Alāmāt Sinn al-Yās. Consequently, an extensive exploration of classical texts concerning the management of Alāmāt Sinn al-Yās was undertaken. Moreover, PubMed, Scopus, Google Scholar, and other indexing databases were thoroughly explored for evidence-based approaches to managing menopausalsymptoms. The principle management as per Unani texts is to treat the cause of Alāmāt Sinn al-Yās. Unani medicines with emmenagogue, anti-inflammatory, analgesic, cardioprotective, and neuroprotective properties are beneficial for the amelioration of Alāmāt Sinn al-Yās. Unani Herbs such as Asgandh, Aslusūs, Khārkhasak, Tagar, Shuneez, Ustukhuddus, Zafran, and Majūn Najāh possess properties and are proven scientifically for their efficacy in Alāmāt Sinn al-Yās. Hence, the substantiation and preservation of traditional knowledge assume paramount importance in facilitating prospective research and proving invaluable in the modern era. Moreover, the conduct of randomized controlled trials, systematic reviews, and meta-analyses becomes imperative.

• Journal of the Korea Institute of Building Construction
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• v.24 no.4
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• pp.507-515
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• 2024

Recent advancements in Building Information Modeling(BIM) have significantly impacted the construction industry, driving competitiveness and innovation. However, rebar construction, a critical component influencing project quality and cost, has lagged behind in BIM adoption. Traditional methods relying heavily on 2D drawings for rebar detailing have hindered efficiency and introduced potential errors. This paper presents a novel system designed to automate the detailed modeling of rebar, thereby promoting BIM integration within rebar construction and optimizing construction management processes. The system leverages confirmed structural drawings from the post-structural design phase to automatically generate intricate rebar models for columns and beams. To ensure adherence to domestic structural design standards, the system is developed using C# programming language and the Revit API. By automating rebar modeling, this system aims to minimize human error, reduce labor-intensive tasks, and enhance overall rebar construction efficiency through the effective utilization of generated rebar model data.

• The korean journal of orthodontics
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• v.40 no.2
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• pp.106-114
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• 2010

Objective: The aim of this experimental study was to evaluate the effects of direct electrical current stimulation (DECS) on bone regeneration in response to an expansion of the inter-premaxillary suture in the rat. Methods: Sixteen 50 - 60 days old Wistar male rats were separated into two equal groups (control and experimental). Both groups were subjected to expansion, and 30-gram of force was applied to the maxillary incisors with helical-spring. In the experimental group, two metallic-screws were placed at lateral parts of the maxillary segments. Electrodes were connected to the screws. The device was activated with current adjustment to measure $10{\mu}A$ continuously and the current was monitored daily during the expansion and early-retention phase. Bone regeneration in the sutural area was histomorphometrically evaluated including new-bone area (${\mu}m^2$), bone perimeter (${\mu}m$), feret's diameter (${\mu}m$) and newly formed bone (%) parameters. Kruskal-Wallis rank and Mann-Whitney U tests were used for statistical evaluation at p < 0.05 level. Results: Statistical analysis showed significant differences between groups for all investigated histomorphometric parameters. New bone area (p = 0.002), bone perimeter (p = 0.004), feret's diameter (p = 0.002) and newly formed bone percentage (p = 0.002) measurements were significantly higher in the experimental group than the control group. Bone histomorphometric measurements revealed that bone architecture in the DECS group was improved. Conclusions: The application of DECS to an orthopedically expanded inter-premaxillary suture area during the early retention phase stimulated the formation of new bone.

• Tuberculosis and Respiratory Diseases
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• v.43 no.5
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• pp.683-692
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• 1996

Background: Although most of the patients with tuberculous pleural effusions completely reabsorbed their effusions and became asymptomatic within 2 to 4 months, later surgical procedures such as decortication is needed in some patients because of dyspnea caused by pleural loculations and thickening despite anti-tuberculous chemotherapy. It is obligatory to secure adequate drainage to prevent the development of complications. But, the best methods for treating loculated tuberculous pleural effusions remain debatable. Recent several reports revealed that intrapleural instillation of fibrinolytic agents is an effective adjunct in the management of complicated empyema and may reduce the need of surgery. Purpose : The effects of catheterization with intrapleural urokinase instillation were prospectively evaluated in the patients with septated tuberculous pleural effusion, and compared with other therapeutic effects of different modalities of therapy such as repeated thoracentesis and small-bored catheterization. Methods : Forty-eight patients diagnosed with tuberculous pleurisy were randomly separated into three groups; control group(n=13), catheter group(n=12), urokinase group(n=22). In urokinase group, dose of 100.000U urokinase was instilled into the pleural cavity via a percutaneous drainage catheter for complete drainage or total dose of 700,000U of urokinase. After two hours clamping, the catheter was opened and intermittently irrigated. The early and late effectiveness of therapies was assessed by radiographically and by measuring the volume of fluid drained from the catheter. Results : There was statistically significantly better result in the urokinase group in respect of frequency of catheterization, frequency of catheter obstruction and the duration of catheterization in early effectiveness(p < 0.05). There were no difference in radiologic improvement of follow-up in later phase chest X-ray between urokinase group and catheter group in later phase(p > 0.05). But there were more failure rates in control group especially honeycomb septa in pleural effusion sonographically than former two groups. And there were no complications of urokinase such as fever or hemorrhage. Conclusion : In the treatment of septated tuberculous pleurisy, there were better results in urokinase than those of catheterization alone in early effectiveness. And there was no difference in radiographic improvement between urokinase group and catheter group. Intrapleural instillation of urokinase is an effective and safe mode of treatment for septated tuberculous pleural effusions and alleviates the need for thoracotomy.

• Korea journal of population studies
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• v.20 no.1
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• pp.97-128
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• 1997

This paper was set out to study the structure of the career occupational mobility in the early and rapid phase of industrialization in Korea. By analyzing the individual life histories regarding occupational mobility and achievement, I propose a model of yearly career mobility of Korean men and Women during the period of 30 years between 1954 and 1983. With the occupational classification scheme of 5 groups - Upper Nonmanual, Lower Nonmanual, Self Employed, Manual, Farm - the mobility pattern in the person-year mobility table analyzed can be characterized primarily by the strong influence of immobility. The degree of immobility, however, is different by the occupational groups. The absolute amount of immobility can be summarized as being U-shaped. Overall, the pattern of mobility can be explained best by the concept of occupational distance. I then propose a model of relative career occupational mobility pattern that combines the conceptual and theoretical basis and the methodological rigor. The model is based on the notion of the reproduction of inequality, the labor market context, and the life history perspective. The model encompasses the 6 conceptual explanatory factors such as persistence effect, ceiling effect, traditional sector effect, nonmanual occupation effect, alternative mobility channel effect, and occupational distance effect, as well as the effects of both origin and destination occupations. The relative pattern of career mobiliity in Korea can be characterized by the following six findings. First, the persistence effect on the diagonal cells of the mobility table is dominant. Second, a clear evidence of the negative effect of occupational distance between nonmanual occupations and manual and farm occupations is found. Third, the out-mobility from farming took place regardless of the destination occupations. Fourth, the internal mobility within the nonmanual occupation block is high and bi-directional, and is exclusive against other occupations. Fifth, the 'self employed' occupation is serving a peculiar function in both inflow and outflow pattern. Last, the relative pattern of career occupation mobility is asymmetrical in terms of the upward and downward mobility.

• Journal of the Korean Magnetics Society
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• v.16 no.1
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• pp.6-10
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• 2006

The sulphur spinel $FeCr_{2-x}M_xS_4$(M=Ga, In) have been studied with Mossbauer spectroscopy, x-ray diffraction (XRD), and vibrating sample magnetometer. The XRB patterns for samples $FeCr_{2-x}M_xS_4$(M=Ga, In: x=0.1, 0.3) reveal a single phase, which the Ga and In ions are partially occupied to the tetrahedral (A) site. The Neel temperature for the Ga substituted samples increases from 180 to 188 K, with increase from x=0.1 to 0.3. While, it decreases from 173 to 160 K, for the In substituted samples of the x=0.1 and 0.3, respectively. The Mossbauer spectra were collected from 4.2 K to room temperature. We have analyzed the Mossbauer spectra using eight Lorentzian lines fitting method for the $FeCr_{2-x}In_xS_4$(x=0.1) at 4.2 K, yielding the 1311owing results; $H_{hf}=146.0kOe,\;{\Delta}E_Q=1.88mm/s,\;\theta=36^{\circ},\;\phi=0^{\circ},\;\eta=0.6$, and R=1.9. The Ga ions enter into the both sites octahedral (B) and tetrahedral (A), simultaneously the same amounts of Fe ions migrate from the A to the B site, this result is an agreement with XRD results, too. The ${\Delta}E_Q$ of the A and B site in Mossbauer spectra of the samples $FeCr_{2-x}Ga_xS_4$(x=0.3) are 0.83 and 2.94mm/s, respectively. While they are 0.56 and 2.36mm/s for the $FeCr_{2-x}In_xS_4$(x=0.3). It is noticeable that the ${\Delta}E_Q$ for the Ga doped samples are larger than that of the corresponding In doped samples, in spite of the larger ionic radius for In ions. The bond lengths of Cr-S, for the Ga and In doped samples (x=0.3) are found to be 2.41 and $2.43\;{\AA}$, respectively. We interpret that the larger covalence effect from the smaller bond length induces a large asymmetric charge distribution. Finally, it gives a large quadrupole interaction.