• The Korean Journal of Ecology
• /
• v.22 no.3
• /
• pp.119-129
• /
• 1999

The bryophyte communities on the forest floor of the mixed coniferous and deciduous broad-leaf forest and the evergreen coniferous forest of cool temperate and subalpine zones in Mts. Taebaek, Odae and Sulak of Tabaek Range were investigated from. the numerical and phytosociological viewpoints. As a result, four bryophyte communities were recognized there, considering the species composition of vascular vegetation; A. Thuja koraiensis-Abies nephrolepis/Taxus caespitosa-Pinus pumila/Hylocomium splendens-Pleurozium schreberi community, B: Sasamorpha borealis-Abies nephrolepis/Plagiomnium cuspidatum- Aulacomnium heterostichum community, C. Abies holophylla-Abies nephrolepis/Thuidium recognitum-Trachycystis immarginata cristatus community, D. Meehania urticifolia-Abies nephrolepis/Hylocomiopsis ovicarpa-Taxiphyllum aomoriense community. Among these, the community A was distributed in higher altitudes and characterized by the species group of the holarctic elements, e.g. Hylocomium splendens, Pleurozium schreberi, Dicranum majus, etc. limited in subarctic; subalpine and arctic; alpine zones and was confirmed as synusies of the Thujo-Abietetum nephrolepidis Song 1991 and Taxo-Pinetum pumilae Song 1985 belonging the Vaccinio-Piceetea Br.-Bl. 1939. In contrast the communities B, C and D were distributed in the mixed coniferous and deciduous broad-leaf forest of lower altitudes and characterized by the elements of the cool temperate; montane zone. They were confirmed as synusies belonging to the Corylo-Quercetum mongolicae Song 1988. By the result of the numerical syntaxonomical analysis such as cluster analysis, interspecific association, PCA, the communities were largely divided into the two types. The two types coincided with the community units or the diagnostic species of the bryophyte communities of the subalpine zone and the montane zone, respectively. Also the analysis revealed that the division of the above two forest zones are justifiable. Up to date many investigator have described the coniferous forest distibuted above 1000m in Taebaek mountains as the forest vegetation of subalpine zone. However, from the results of the present study, the boundary of the mixed forest and the true subalpine coniferous forest was elucidated to be ca. 1,500 m phytosociologically. Species richness was the highest in the community A, and the other four communities showed a similar species richness.

• Proceedings of the Korea Crystallographic Association Conference
• /
• 2002.11a
• /
• pp.5-6
• /
• 2002

The new spectrometer for X-ray Induced Electron Emission Spectroscopy (XIEES) .has been recently developed in KRISS in collaboration with PTI (Russia). The spectrometer allows to perform research using the XAFS, SXAFS, XANES techniques (D.C.Koningsberger and R.Prins, 1988) as well as the number of techniques from XIEES field(L.A.Bakaleinikov et all, 1992). The experiments may be carried out with registration of transmitted through the sample x-rays (to investigate bulk samples) or/and total electron yield (TEY) from the sample surface that gives the high (down to several atomic mono-layers in soft x-ray region) near surface sensitivity. The combination of these methods together give the possibility to obtain a quantitative information on elemental composition, chemical state, atomic structure for powder samples and solids, including non-crystalline materials (the long range order is not required). The optical design of spectrometer is made according to Johannesson true focusing schematics and presented on the Fig.1. Five stepping motors are used to maintain the focusing condition during the photon energy scan (crystal angle, crystal position along rail, sample goniometer rail angle, sample goniometer position along rail and sample goniometer angle relatively of rail). All movements can be done independently and simultaneously that speeds up the setting of photon energy and allows the using of crystals with different Rowland radil. At present six curved crystals with different d-values and one flat synthetic multilayer are installed on revolver-type monochromator. This arrangement allows the wide range of x-rays from 100 eV up to 25 keV to be obtained. Another 4 stepping motors set exit slit width, sample angle, channeltron position and x-ray detector position. The differential pumping allows to unite vacuum chambers of spectrometer and x-ray generator avoiding the absorption of soft x-rays on Be foil of a window and in atmosphere. Another feature of vacuum system is separation of walls of vacuum chamber (which are deformed by the atmospheric pressure) from optical elements of spectrometer. This warrantees that the optical elements are precisely positioned. The detecting system of the spectrometer consists of two proportional counters, one scintillating detector and one channeltron detector. First proportional counter can be used as I/sub 0/-detector in transmission mode or by measuring the fluorescence from exit slit edge. The last installation can be used to measure the reference data (that is necessary in XANES measurements), in this case the reference sample is installed on slit knife edge. The second proportional counter measures the intensity of x-rays transmitted through the sample. The scintillating detector is used in the same way but on the air for the hard x-rays and for alignment purposes. Total electron yield from the sample is measured by channeltron. The spectrometer is fully controlled by special software that gives the high flexibility and reliability in carrying out of the experiments. Fig.2 and fig.3 present the typical XAFS spectra measured with spectrometer.

• Journal of the Korean Magnetics Society
• /
• v.21 no.2
• /
• pp.77-82
• /
• 2011

The use of soft magnetic materials have been increasing in the various industrial fields according to the increasing demand for high performance, automatic, miniaturing equipments in the recent our life. In this study, we investigated the effect of factors on the core loss and magnetic properties of electrical steel and soft magnetic composites. Furthermore, we reviewed the major efforts to reduce the core loss and improve the soft magnetic properties in the two main soft magnetic materials. Domain purification which results from reduced density of defects in cleaner electrical steels is combined with large grains to reduce hysteresis loss. The reduced thickness and the high electrical conductivity reduce the eddy current component of loss. Furthermore, the coating applied to the surface of electrical steel and texture control lead to improve high permeability and low core loss. There is an increasing interest in soft magnetic composite materials because of the demand for miniaturization of cores for power electronic applications. The SMC materials have a broad range of potential applications due to the possibility of true 3-D electromagnetic design and higher frequency operation. Grain size, sintering temperature, and the degree of porosity need to be carefully controlled in order to optimize structure-sensitive properties such as maximum permeability and low coercive force. The insulating coating on the powder particles in SMCs eliminates particle-to-particle eddy current paths hence minimizing eddy current losses, but it reduces the permeability and to a small extent the saturation magnetization. The combination of new chemical composition with optimum powder manufacturing processes will be able to result in improving the magnetic properties in soft magnetic composite materials, too.

• Imaging Science in Dentistry
• /
• v.47 no.3
• /
• pp.165-174
• /
• 2017

Purpose: This study was performed to investigate the influence of object shape and distance from the center of the image on the volumetric accuracy of cone-beam computed tomography (CBCT) scans, according to different parameters of tube voltage and current. Materials and Methods: Four geometric objects(cylinder, cube, pyramid, and hexagon) with predefined dimensions were fabricated. The objects consisted of Teflon-perfluoroalkoxy embedded in a hydrocolloid matrix (Dupli-Coe-Loid TM; GC America Inc., Alsip, IL, USA), encased in an acrylic resin cylinder assembly. An Alphard Vega Dental CT system (Asahi Roentgen Ind. Co., Ltd, Kyoto, Japan) was used to acquire CBCT images. OnDemand 3D (CyberMed Inc., Seoul, Korea) software was used for object segmentation and image analysis. The accuracy was expressed by the volume error (VE). The VE was calculated under 3 different exposure settings. The measured volumes of the objects were compared to the true volumes for statistical analysis. Results: The mean VE ranged from -4.47% to 2.35%. There was no significant relationship between an object's shape and the VE. A significant correlation was found between the distance of the object to the center of the image and the VE. Tube voltage affected the volume measurements and the VE, but tube current did not. Conclusion: The evaluated CBCT device provided satisfactory volume measurements. To assess volume measurements, it might be sufficient to use serial scans with a high resolution, but a low dose. This information may provide useful guidance for assessing volume measurements.

• The Journal of Korean Society for Radiation Therapy
• /
• v.32
• /
• pp.17-29
• /
• 2020

Purpose: The purpose of this work was to investigate the dosimetric impact of mixed energy partial arc technique on prostate cancer VMAT. Materials and Methods: This study involved prostate only patients planned with 70Gy in 30 fractions to the planning target volume (PTV). Femoral heads, Bladder and Rectum were considered as oragan at risk (OARs). For this study, mixed energy partial arcs (MEPA) were generated with gantry angle set to 180°~230°, 310°~50° for 6MV arc and 130°~50°, 310°~230° for 15MV arc. Each arc set the avoidance sector which is gantry angle 230°~310°, 50°~130° at first arc and 50°~310° at second arc. After that, two plans were summed and were analyzed the dosimetry parameter of each structure such as Maximum dose, Mean dose, D2%, Homogeneity index (HI) and Conformity Index (CI) for PTV and Maximum dose, Mean dose, V70Gy, V50Gy, V30Gy, and V20Gy for OARs and Monitor Unit (MU) with 6MV 1 ARC, 6MV, 10MV, 15MV 2 ARC plan. Results: In MEPA, the maximum dose, mean dose and D2% were lower than 6MV 1 ARC plan(p<0.0005). However, the average difference of maximum dose was 0.24%, 0.39%, 0.60% (p<0.450, 0.321, 0.139) higher than 6MV, 10MV, 15MV 2 ARC plan, respectively and D2% was 0.42%, 0.49%, 0.59% (p<0.073, 0.087, 0.033) higher than compared plans. The average difference of mean dose was 0.09% lower than 10MV 2 ARC plan, but it is 0.27%, 0.12% (p<0.184, 0.521) higher than 6MV 2 ARC, 15MV 2 ARC plan, respectively. HI was 0.064±0.006 which is the lowest value (p<0.005, 0.357, 0.273, 0.801) among the all plans. For CI, there was no significant differences which were 1.12±0.038 in MEPA, 1.12±0.036, 1.11±0.024, 1.11±0.030, 1.12±0.027 in 6MV 1 ARC, 6MV, 10MV, 15MV 2 ARC, respectively. MEPA produced significantly lower rectum dose. Especially, V70Gy, V50Gy, V30Gy, V20Gy were 3.40, 16.79, 37.86, 48.09 that were lower than other plans. For bladder dose, V30Gy, V20Gy were lower than other plans. However, the mean dose of both femoral head were 9.69±2.93, 9.88±2.5 which were 2.8Gy~3.28Gy higher than other plans. The mean MU of MEPA were 19.53% lower than 6MV 1 ARC, 5.7% lower than 10MV 2 ARC respectively. Conclusion: This study for prostate radiotherapy demonstrated that a choice of MEPA VMAT has the potential to minimize doses to OARs and improve homogeneity to PTV at the expense of a moderate increase in maximum and mean dose to the femoral heads.

• Korean Journal of Environmental Biology
• /
• v.22 no.2
• /
• pp.247-258
• /
• 2004

Climatological, hydrological and planktonical research studies, measurements of primary production and photosynthetic efficiency from December 1976 to December 1978 have been carried out in two brackish lakes: Lake Etang de Berre and Lake Etang de Vaine located in the French Mediterranean coast, in the region of Carry-le-Rouet located on the north-west Mediterranean near Marseilles, and in fresh water inflows from 4 Rivers (Touloubre, Durance, Arc, Durancole) to Lake Etang de Berre. Physico-chemical parameters were measured for this study: water temperature, salinity, density, pH, alcalinity, dissolved oxygen (% saturation), phosphate, nitrate, nitrite, silicate etc. Diverse biological parameters were also studied: photosynthetic pigments, phaeopigments, specific composition and biomass of phytoplankton, primary pelagic production etc. Climatical factors were studied: air-temperature, solar-radiation, evaporation, direction (including strength) of winds, precipitation and freshwater volume of the four rivers. The changes in Lake ‘Etang de Berre’ ecosystem depend on the quality of the water in the Durance River, and on the effects of seawater near the entrance of the Caronte Canal. The water quality of the lake varies horizontally and vertically as a result of atmospheric phenomena, maritime currents and tides. The distribution of water temperatures is generally heterogeneous. Southeasterly winds and the Northeasterly Mistral wind are important in the origins of circulated and mixed water masses. These winds are both frequent and strong. They have, as a result, a great effect on the water environment of Lake Etang de Berre. In theory, the annual precipitation in this region is well over eight times the water mass of the lake. The water of the Durance River flows into Lake Etang de Berre through the EDF Canal, amounting to 90% of the precipitation. However, reduction of rainfall in dry seasons has a serious effect on the hydrological characteristics of the lake. The temperature in the winter is partially caused by the low temperature of fresh water, particularly that of the Durance River. The hydrological season of fresh and brackish water is about one month ahead of the hydrological season of sea water in its vicinity. The salinity of Lake Etang de Berre runs approximately 3$\textperthousand$, except at lower levels and near the entrance to the Caronte Canal. However, when the volume of the Durance River water is reduced in the summer and fall, the salinity rises to 15$\textperthousand$. In the lake, the ratio of fresh water to sea water is six to one (6:1). The large quantities of seston conveyed by rivers, particularly the Durance diversion, strongly reduce the transparency in the brackish waters. Although the amount of sunshine is also notable, transparency is slight because of the large amount of seston, carried chiefly by Tripton in the fresh water of the Durance River. Therefore, photosynthesis generally occurs only in the surface layer. The transparency progressively increases from freshwater to open seawater, as mineral particles sink to the bottom (about 1.7kg $m^{-2}a^{-1}$ on the average in brackish lakes). The concentration of dissolved oxygen and the rate of oxygen saturation in seawater (Carry-le-Rouet) ranged from 5.0 to 6.0 $m\ell$ㆍ.$1^{-1}$, and from 95 to 105%, respectively. The amount of dissolved oxygen in Etang de Berre oscillated between 2.9 and 268.3%. The monographs of phosphate, nitrate, nitrite and silicate were published as a part of a study on the ecology of phytoplankton in these environments. Horizontal and vertical distributions of these nutriments were studied in detail. The recent diversion of the Durance River into Lake Etang de Berre has effected a fundamental change in this formerly marine environment, which has had a great impact in its plankton populations. A total of 182 taxa were identified, including 111 Bacillariophyceae, 44 Chlorophyceae, and 15 Cyanophyceae. The most abundant species are small freshwater algae, mainly Chlorophyceae. The average density is about $10^{8}$ cells $1^{-1}$ in Lake Etang de Berre, and about double that amount in Lake Etang de Vaine. Differences in phytoplankton abundance and composition at the various stations or at various depths are slight. Cell biovolume V (equivalent to true biomass), plasma volume VP (‘useful’ biomass) and, simultaneously. the cell surface area S and S/V ratio through the measurement of cell dimensions were computed as the parameters of phytoplankton productivity and metabolism. Pigment concentrations are generally very high on account of phytoplankton blooms by Cyanophyceae, Chlorophyceae and Cryptophyceae. On the other hand, in freshwaters and marine waters, pigment concentrations are comparatively low and stable, showing slight annual variation. The variations of ATP concentration were closely related to those of chlorophyll a and phytoplankton blooms only in marine waters. The carbon uptake rates ranged between 38 and 1091 mg$Cm^{-2}d^{-1}$, with an average surface value of 256 mg; water-column carbon-uptake rates ranged between 240 and 2310 mg$Cm^{-2}d^{-1}$, with an average of 810, representing 290 mg$Cm^{-2}$, per year 45 000 tons per year of photosynthetized carbon for the whole lake. Gross photosynthetic production measured by the method of Ryther was studied over a 2-year period. The values obtained from marine water(Carry-le-Rouet) ranged from 23 to 2 337 mg$Cm^{-2}d^{-1}$, with a weighted average of 319, representing about 110 gCm$^{-2}$ per year. The values in brakish water (Etang de Berre) ranged from 14 to 1778 mg$Cm^{-2}d^{-1}$, with a weighted average of 682, representing 250 mg$Cm^{-2}$ per year and 38 400 tons per year of photosynthesized carbon for the whole lake.

• Journal of Preventive Medicine and Public Health
• /
• v.23 no.4 s.32
• /
• pp.416-427
• /
• 1990

Unfortunately, we have poor knowledge of medical technology in North Korea. This study has thus attempted to identify the level and status of medical technology development through analyzing the contents of medical textbooks currently in use. This study has assumed that three factors are influencing the level and status of medical technology in a society ; the level of socio-economic development in general, the level of scientific technology revolution and health policy. Forty textbooks are collected for this purpose. The main findings are summarized as follows : 1) North Korea s strengths in that (1) its herb drugs, which are in a broad use, are cheaper, more safe and more attainable than bio-equivalent chemical ones, and (2) the development of its medical technology was carried out with emphasis on the practical and basic health needs. 2) North Korea has weaknesses in that (1) its medical diagnostic method largely depends on manual procedures, (2) the R & D investment in the development of chemical drugs, especially antibiotics, is very small, (3) the amount of medical equipments is in a absolute shortage, and (4) the medical technology is destitute of specialty, caused mainly by the overemphasis on Juche-Uihak or herb medicine. 3) Medical technology has two faces, positive and negative so that it cannot be successfully evaluated by one. It eventually acts a positive function for public health through developments of drug, equipment and new medical treatment method. But it is also true that it has negative effects such as the dehumanization of high cost medical technology, cost hike due to over-investments in expensive equipment and the absence of wholistic care from overspecialization. 4) We have to consider economic status and the social needs of medical care in order to evaluate the medical technology of a society. It is also the case with North Korea. A whole picture of the North Korean medical technology could be understood only if further comprehensive studies of medical technology are to be carried out for North Korea.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.7 no.4
• /
• pp.15-22
• /
• 2003

Seismic design codes developed taking into account the strong earthquakes may result in unnecessary economical loss in the low seismic area, and the importance of the performance based design considering the soil-structure interaction is recognized for the reasonable seismic design. In this study. elastic and inelastic seismic response analyses of a single degree of freedom system on the soft soil layer were performed considering the nonlinearity of the soil for the 1 weak earthquakes scaled to the nominal peak accelerations of 0.07g and 0.11g. The seismic response analyses were performed in one step applying the earthquake motions to the bedrock, utilizing a pseudo 3-D dynamic analysis software of the soil-structure system. The study results indicated that seismic response spectra of a system assuming the rigid base or the linear soil layer does not represent the true behavior of a structure-soil system, and it is necessary to take into account the nonlinear soil-structure interaction effects and to perform the performance based seismic design for the various soil layers, having different characteristics, rather than to follow the routine design procedures specified in the design codes for the reasonable seismic design. The nonlinearity of the soft soil excited with the weak seismic motions also affected significantly on the elastic and inelastic seismic response spectra of a system due to the nonlinear soil amplification of the earthquake motions, and it was pronounced especially for the elastic response spectra.

• Journal of Korean Academy of Nursing
• /
• v.3 no.2
• /
• pp.121-132
• /
• 1973

Introduction : Nursing as a profession is gelling wide acceptance today, especially among independent -minded women with necessary physical, mental and academic qualifications. This is particularly true of "comprehensive nursing", which requires to total dedication on the part if the nurse herself-physical, mental and sociocultural. Such comprehensive approach is like-wise called for in the institutional training of professional nurses. Undergraduate nursing courses nowadays place an increasing emphasis on the microscopic approach of training a nurse as an intelligent and well-balanced human being with an optimum degree of cultural sophistication. Greater attention then ever before is now paid to close observation of the individual traits and aptitude of nursing students, so as to permit full development of individual capabilities, interests and propensities within the concept of "comprehensive human education. " Purpose of study 1. To determine the degree of understanding of the part of nursing students of the various aspects of the subject taught in undergraduate nursing course. 2. To determine the motivation of nursing students in choosing the profession and possible subsequent change or attitude and outlook in the course of under graduated studies, as a means of presenting a new practical approach in nursing training based on the concept of "comprehensive human education. " Problems of study 1. The environments of nursing training will impinge on individual nursing students with different psychological impacts from lower to upper classes of under graduated studies. 2. Educational environments will have varying psychological impacts on students: a. Difference in religious faith among students. b. Difference in campus environments. c. Difference in domestic (family) circumstances. d. Difference in innate capabilities of students, 3. The understanding and attitude of individual nursing students towards the science of nursing will Have a close correlation with their respective motivations in choosing-nursing as a profession, and will also be closely influenced by the peculiarities of the subject taught, tile campus environments, etc, Delimitations of the study 1. Two universities offering 4-year nursing courses were selected. Due to the limited number of potential subjects, the optimum conditions of sample collection could not be fulfilled. 2. Subjects were confined to two classes in each university (sophomores and seniors) but without regard to the ages or scholastic achievements of individual students. 3. The conclusions derived from this study should be limited in application to the subject groups covered by the present study: they should not in any event be extended or applied to other groups. Procedures 1. Subjects: 40 nursing students each from the sophomore and senior classes of the "Y" and "K" universities situated in Seoul, aggregating 160 students altogether. 2. Instruments: Use has been made of questionnaires on (1) family backgrounds and (2) general information concerning. 3. Statistical Method: The findings of the present survey have been subjected to critical analysis as to the means, percentages, Cgi squares (X), standard deviations and the significance of the difference in means. Findings 1. Nursing students have chosen their subject of study with a confident outlook towards their future in society. 2. Horsing students have the necessary abilities to complete the prescribed courses of study. 3. The campus life of nursing students has been judged as very constructive, not with-standing certain in adequacies in the available educational facilities and the shortages of teaching staff. 4. The achievement levels of nursing trainees varied greatly according to their respective educational environments as well as their school years. 5. Clear and definite distinctions were discernible between the two universities as regards certain aspects of this survey, while no signifiant difference was observed in other: a. Sophomores and seniors in both universities gave nearly identical answers to questions concerning (1) motivation in choosing nursing as a profession, and (2) the way of spending leisure hours. b. Both universities revealed similar respective differences between sophomores and seniors as regards the abilities of fulfilling academic requirements ill the basic subjects. c. Educational environments have been found to be somewhat superior in the "Y"university to those of the "K" university, particularly as regard general campus and dormitory conditions. d. The high degree of dissatisfaction with the faculty, found in both universities, was considered to be a consequence of the universal phenomenon of "brain drain" and the relative neglect of the "comprehensive approach"in education.

• Restorative Dentistry and Endodontics
• /
• v.24 no.2
• /
• pp.299-309
• /
• 1999

The composite resin, due to its esthetic qualities, is considered the material of choice for restoration of anterior teeth. With respect to shade control, the direct-placement resin composites offer some distinct advantages over indirect restorative procedures. Visible-light-cured (VLC) composites allow dentists to match existing tooth shades or to create new shades and to evaluate them immediately at the time of restoration placement. Optimal intraoral color control can be achieved if optical changes occurring during application are minimized. An ideal VLC composite, then, would be one which is optically stable throughout the polymerization process. The shade guides of the resin composites are generally made of plastic, rather than the actual composite material, and do not accurately depict the true shade, translucency, or opacity of the resin composite after polymerization. So the numerous problems associated with these shade guides lead to varied and sometimes unpredictable results. The aim of this study was to assess the color changes of current resin composite restorative materials which occur as a result of the polymerization process and to compare the color differences between the shade guides provided with the products and the actual resin composites before- and after-polymerization. The results obtained from this investigation should provide the clinician with information which may aid in improved color match of esthetic restoration. Five light activated, resin-based materials (${\AE}$litefil, Amelogen Universal, Spectrum TPH VeridonFil-Photo, and Z100) and shade guides were used in this study. Three specimens of each material and shade combination were made. Each material was condensed inside a 1.5mm thick metal mold with 10mm diameter and pressed between glass plates. Each material was measured immediately before polymerization, and polymerized with Curing Light XL 3000 (3M Dental products, USA) visible light-activation unit for 60 seconds at each side. The specimens were then polished sequentially on wet sandpaper. Shade guides were ground with polishing stones and rubber points (Shofu) to a thickness of approximately 1.5mm. Color characteristics were performed with a spectrophotometer (CM-3500d, Minolta Co., LTD). A computer-controlled spectrophotometer was used to determine CIELAB coordinates ($L^*$, $a^*$ and $b^*$) of each specimen and shade guide. The CIELAB measurements made it possible to evaluate the amount of the color difference values (${\Delta}E{^*}ab$) of resin composites before the polymerization process and shade guides using the post-polishing color of the composite as a control, CIE standard D65 was used as the light source. The results were as follows. 1. Each of the resin composites evaluated showed significant color changes during light-curing process. All the resin composites evaluated except all the tested shades of 2100 showed unacceptable level of color changes (${\Delta}E{^*}ab$ greater than 3.3) between pre-polymerization and post-polishing state. 2. Color differences between most of the resin composites tested and their corresponding shade guides were acceptable but those between C2 shade of ${\AE}$litefil and IE shade of Amelogen Universal and their respective shade guides exceeded what is acceptable. 3. Comparison of the mean ${\Delta}E{^*}ab$ values of materials revealed that Z100 showed the least overall color change between pre-polymerization and post-polishing state followed by ${\AE}$litefil, VeridonFil-Photo, Spectrum TPH, and Amelogen Universal in the order of increasing change and Amelogen Universal. Spectrum TPH, 2100, VeridonFil-Photo and ${\AE}$litefil for the color differences between actual resin and shade guide. 4. In the clinical environment, the shade guide is the better choice than the shade of the actual resin before polymerization when matching colors. But, it is recommended that custom shade guides be made from resin material itself for better color matching.