This study investigated the growth behavior and characteristics of compounds formed at the interface between a liquid Al-Si-Cu alloy and solid cast iron. Through microstructural analyses, it was observed that various AlFe and AlFeSi phases are formed at the interface, and the relative proportion of each phase changes when small amounts of strontium are added to the Al alloy. The results of the microstructural analysis indicate that the primary phases of the interfacial compounds in the Al-Si-Cu base alloy are Al8Fe2Si and Al4.5FeSi. However, in the Sr-added alloys, significant amounts of binary AlFe intermetallic compounds such as Al5Fe2 and Al13Fe4 formed, in addition to the AlFeSi phases. The inclusion of Sr has a slight diminishing effect on the rate at which the interfacial compounds layer thickens during the time the liquid Al alloy is in contact with the cast iron. The study also discusses the nano-indentation hardness and micro-hardness of the interfacial phases.

This study examines the correlation between livestock odor civil petitions and the establishment of malodor control areas in Jeju Special Self-Governing Province, focusing on swine farms where numerous civil petitions regarding malodors have been received. After the designation of the malodor control areas, high odor concentrations occurred in Aewoleup and Jocheon-eup, and the odor concentration decreased in other areas. The number of civil petitions shows a consistent annual trend, with increased petitions from March, peaking during summer (July and August), and decreasing from September into winter. In Jeju-si, there were many civil petitions in Hallim-eup and Aewol-eup where there were many malodor control areas. However, in Seogwipo-si, there were also many civil petitions in Pyoseonmyeon, where there is no malodor control area. Additionally, we compared the average multiple of compound malodors and the rate of exceeding the maximum allowable emission level for compound malodors with the number of livestock malodor civil petitions to assess the actual state of malodors. The results reveal a stronger correlation between the number of civil petitions and the rate of exceeding the compound malodors allowable emission level than the average multiple for compound malodors. These findings provide valuable insights into addressing livestock odor concerns and enhancing malodor control measures in Jeju Island.

ATP luminescence measurements (using Relative Light Units, RLU) has been used to assess the levels of bacterial contamination on the surfaces of various materials. However, not much is known about their suitability in assessing bacterial contamination on paper surfaces. This study was conducted to evaluate the feasibility of using ATP luminometers in measuring levels of bacteria contamination on paper surfaces. The three ATP luminometers studied were Clean-Q, smart PD-30, and 3M™ Clean-Trace™ LM1 manufactured by different companies. There were some differences in RLU results among the three ATP luminometers when they were tested with different concentrations of Micrococcus luteus cell suspension. 106 - 107 cells were required in order to effectively detect Bacillus subtilis, Escherichia coli, and Micrococcus luteus on the surfaces of A4 printing sheets (100 cm2) when using the three ATP luminometers. The sizes and physical properties of surface areas varied slightly among the swabs used for the three ATP luminometers. Concentration-specific measurements (RLU) of M. luteus taken from the surfaces of six kinds of paper (fine print paper, medium print paper, ground paper, newsprint paper, practice paper, tracing paper) were possible using the smart PD-30 and LM1 ATP luminometers. ATP detection values of M. luteus varied among the six types of paper. The highest ATP detection values were found on the surfaces of tracing paper. If the RLU value is recorded at the level of 1000, this could indicate a very high bacterial contamination level of 105 to 106 CFU/4 cm2.

The air dilution olfactory method to measure complex odors needs to store and carry odor samples from the field sampling until the analysis in laboratories. Until the analysis of sample in the laboratory, odor dilution factor (odor sensitivity) in the sample bag may decrease over time depending on the characteristics of each odor substances. This is one of the limitation for the air dilution olfactory method. Thus, the air dilution device enable to measure without loss in complex odors of samples. Recently, many studies on the performance test of on-site air dilution devices, i.e., field olfactometer, has been conducted to figure out the feasibility of the field olfactometers. In this study, seven odor samples were collected from five odor emission source sites. And comparative analysis with the air dilution olfactory method was carried out to assess the field applicability of the olfactometer. As results, the performance of the field olfactometer used in this study is regared as the affordable method. The dilution factors from between two methods showed the similar values, indicating low values of standard deviations. In order to ensure the accuracy and precision of measurement data using the field olfactometer, methodology minimized variables (that may affect measurement) needs to establish.

In this study, we analyzed the changes in concentrations of volatile fatty acids (VFA), phenols, and indoles, as well as odor contribution in pig slurry. The pig slurry was stored for approximately two months after the manure excretion of pigs which had been fed 3% level of peat moss additive. The investigation was carried out through lab-scale experiments simulating slurry pit conditions within pig house. Throughout the storage period, the concentration of VFA exhibited a tendency to be 11%-32% higher in the pig manure treated with peat moss as compared to the control group. From a concentration perspective, phenol and acetic acid accounted for the majority of the total odor compounds produced during the pig slurry storage period. However, their significance diminished when the concentration of odoros compounds are converted into odor activity value and odor contribution. Despite the odor reduction effect of the ammonia (NH3) adsorption by peat moss, if it cannot effectively reduce the high odor-contributing compounds such as indoles and p-cresol, the sole use of peat moss may not be considered an effective means of mitigating odors produced by pig slurry. According to this study, indoles, p-cresol, skatole, and valeric acid were consistently revealed as major odor-contributing substances during the two-month storage of pig slurry. Therefore, a comprehensive odor mitigation methodology should be proposed, taking into consideration the odor generation characteristics (including temporal concentration and odor contribution) of pig slurry-derived odors during storage.

The purpose of this study was to determine the conditions necessary for the total eradication of mite pests in indoor environments. The study involved the construction of a sterilization experimental setup. For this setup, various sterilization techniques, such as UV-C, ozone, ultrasound, and heat were applied, based on previous research. The experimental procedure consisted of placing mite pests in a chamber and subjecting them to different sterilization techniques. Observations were conducted immediately after the experiment and repeated five days later to assess the extent of eradication. The results showed that UVC, ozone, and ultrasound methods were not successful in completely eradicating the mite pests. In contrast, heat sterilization demonstrated effectiveness depending on the specific temperature and exposure time. To achieve the eradication of mite pests in indoor environments, it is necessary to maintain conditions of short-term high-temperature sterilization above 65°C or sustain temperatures above 50°C for a minimum duration of 90 minutes.

This study was carried out to develop a system to reduce ultrafine dust using hygroscopic materials such as glycerin and propylene glycol. Prior to the development of an ultrafine dust reduction system, the moisture condensation efficiency of glycerin and propylene glycol was investigated based on relative humidity (RH). The results showed that when no substances (glycerin and propylene glycol) were added to a tedlar bag, the relative humidity and temperature remained constant. The moisture condensation efficiency of glycerin was 60%, and the time it took to reach 50% of the initial relative humidity was about 40minutes. In the case of propylene glycol, the moisture condensation efficiency was 75%, and the time it took to reach 50% of the initial relative humidity was about 10 minutes. When glycerin and propylene glycol mixture was added, the moisture condensation efficiency was 68% and it took 20 minutes to reach 50% of the initial relative humidity. These results suggest that hygroscopic materials such as glycerin and propylene glycol can actually condense moisture in the atmosphere. In addition, considering actual atmospheric conditions, the relative humidity was set to 60% and 40% or less, and the moisture condensation efficiency was measured. The results showed that the mixture of glycerin and propylene glycol yielded the highest condensation efficiencies, at 69% and 62%, respectively. Therefore, it is preferable to use a mixture of glycerin and propylene glycol to condense moisture in the range of relative humidity in the actual atmosphere.

A 14-year-old castrated male Shih Tzu presented with acute hemorrhagic vomiting. The initial medical records indicated a probable diagnosis of acute gastritis due to inappropriate food intake. Although gastrointestinal (GI) endoscopy was the preferred diagnostic approach, the client declined anesthesia because of the dog’s underlying heart condition. Therefore, we opted for anesthesia-free capsule endoscopy. The procedure identified severe gastritis with no detectable abnormalities in the other GI regions. Following diagnosis, dietary modifications and omeprazole treatment were initiated, resulting in the resolution of clinical symptoms. Follow- up capsule endoscopy 3 weeks later verified a significant improvement in gastritis. This case highlights the potential of capsule endoscopy as a valuable diagnostic tool in patients presenting with acute vomiting.

A one-year-old, female, Maltese dog was presented with head tilting, horizontal nystagmus, and tetraparesis. Blindness was first identified, and magnetic resonance imaging (MRI) scanning revealed diffuse lesion which was hyperintense on T2-weighted image over the cerebellum and brainstem. The immunosuppressive therapy had been administered, but the patient had no improvement. Re-performed MRI revealed the progression of the pre-existed inflammatory lesions. Treatment with prednisolone, leflunomide, cyclosporine, and cytosine arabinoside was initiated. However, neurological signs had been progressive, and the patient was euthanized. The histopathological examination revealed the disseminated granulomatous meningoencephalomyelitis (GME). This GME case suggests the importance of initiation of treatment at the appropriate time.

Mucosa-associated lymphoid tissue (MALT) lymphoma (ML) is a type of non-Hodgkin’s lymphoma involving MALT, commonly the stomach or salivary glands, although virtually any mucosal site can be affected. ML originates from B cells in the marginal zone of MALT, and is also called extranodal marginal zone B cell lymphoma. It is a slow-growing cancer that usually responds well to treatment. A 59-year-old female presented with a 1-day history of quadriparesis and dysarthria. Up arrival at the hospital, motor power in the right upper and lower extremities was grade 3/5 according to the Medical Research Council scale, while that in the left leg was 4/5. The patient had been diagnosed with gastric ML 1 year prior, and had received antibiotics during the previous 2 weeks. The emergency magnetic resonance imaging of the brain performed at the time of presentation showed multifocal embolic infarction in the cerebral hemisphere bilaterally, which did not have a cardiac origin. Magnetic resonance angiography revealed no stenotic or occlusive lesions. Secondary prophylaxis with daily administration of 300 mg aspirin was prescribed. The patient was discharged with residual right hemiparesis 2 weeks after the onset of symptoms. Herein, we present a rare case of multifocal cerebral infarction in a gastric ML patient.

A 12-year-old intact female Schnauzer was referred for the evaluation of poorly controlled diabetes mellitus: despite insulin therapy, blood glucose concentration was consistently high, indicating a decreased insulin sensitivity. Laboratory analyses revealed persistent hyperglycemia, glucosuria, and ketonuria. Diagnostic approaches were performed to identify concurrent disorders that can cause insulin resistance. The dog was found to have concurrent hyperadrenocorticism, hyperlipidemia, pancreatitis, and vaginal cytology indicating diestrus in the estrus cycle. Trilostane administration for hyperadrenocorticism improved the insulin response; however, the dog remained hyperglycemic. Eventually, the dog showed complete remission without insulin administration 1 week after the ovariohysterectomy. The dog remained in remission for approximately 4 months, but eventually relapsed and the condition was permanent. Diestrus in intact females and hyperadrenocorticism are known to be the two main causes of insulin resistance in dogs. After the management of these conditions, the dog achieved diabetes remission, which rarely achieves in dogs. In cases of insulin resistance, such as hormonal imbalances or inflammatory conditions, remission can be achieved by addressing the underlying cause. Hence, it is important to assess the presence of comorbidities associated with insulin resistance in dogs with poorly controlled diabetes mellitus and to treat each condition as soon as possible.

Collagen peptides have garnered significant attention as functional foods across multiple fields due to their capacity to regulate physiological and hormonal processes, offering numerous advantages. However, despite their broad range of applications, comprehensive research on the potential toxicity of these substances remains lacking. Therefore, this study sought to assess the acute oral toxicity of a collagen peptide derived from skate (Raja kenojei) skin (CPSS) in both rats and dogs. In the rat model, CPSS was orally administered at doses of 300 and 2,000 mg/kg to Sprague-Dawley rats. An escalating single-dose oral toxicity assessment at doses of 500, 1,000, and 2,000 mg/kg was carried out in beagle dogs with 3-day intervals between doses. Throughout the 14-day post-administration assessment period, clinical signs, mortality rates, changes in body weight, and necropsy observations were closely monitored. After oral administration, no signs of toxicity associated with CPSS were observed in either rats or dogs. Therefore, the oral LD50 (approximate lethal dose for 50% mortality) for CPSS in rats was determined to exceed 5,000 mg/kg, and the maximum tolerated dose for dogs was estimated to be above 2,000 mg/kg. Consequently, this study offers safety data on the use of CPSS in functional foods and medicinal applications.

본 연구의 목적은 미국, 영국, 독일, 일본의 학교안전 법제를 살펴봄으로 써, 국내 학교안전에 시사하는 바를 논하고 제시하는 데에 있다. 외국사례를 통해 우리나라 학교안전사고 예방 및 학교안전관리시스템이 보다 실효성 있 게 작동하도록 몇 가지 적용 및 시사점을 제시하였다. 첫째, 학교 안전관리 책임을 명확히 하고 학교안전교육을 지원하는 법제의 명문화와 「학교폭력예 방법」, 「학교안전법」, 「학교보건법」을 「학교안전보건법」으로 통합할 필요가 있다. 둘째, 국가 책임을 강화하는 차원에서 충분한 예산 지원과 인력 확보 및 교직원의 안전 전문성 향상을 위한 제도 마련, 그리고 일원화된 전문기관 등이 필요하다. 셋째, 「학교안전법」을 「산업안전보건법」 수준으로 업그레이 드할 필요가 있고, 독일의 사회보험 수준으로 학교안전공제회의 역량을 제고 할 필요가 있다. 넷째, 체계적인 시스템과 실효성 있는 매뉴얼에 의해 작동되 도록 학교안전망을 촘촘하게 구축할 필요가 있다. 다섯째, 예방활동과 안전 교육의 패러다임을 전환할 필요가 있다. 여섯째, 평소 지역 유관기관·단체 등 과 안전시스템을 긴밀하게 공유, 연계할 필요가 있다. 일곱째, 실효성 있는 학교안전 위험성 평가를 실시하여 사고 발생률을 낮출 필요가 있다. 여덟째, 학교 보안을 더욱 강화할 필요가 있다. 아홉째, 학생안전 법제에 학생의 권리 와 의무를 함께 명시할 필요가 있다. 열 번째, 우리나라도 ‘갭 이어(Gap Ye ar)’ 제도 도입을 검토할 필요가 있다. 이상의 논의와 제시를 통해, 국내 학 교안전 및 학교안전 법제의 긍정적 변화를 기대한다.

1,2-Dichlorobenzene (1,2-DCB) is in various industries as solvents in herbicides, pesticides, and wax, and as degreasers or in the production of dyes. Studies on the hazards and risks of 1,2-DCB showed that this substance can cause skin corrosion, skin irritability, respiratory irritability, and certain target organ toxicity. Industrial workers are exposed to 1,2-DCB by inhalation or skin exposure and there is a lack of information on human hazards even though they can be exposed to organic compounds such as benzene or other DCB complexes rather than a single substance. In this study, we investigated the specific organ toxicity of 1,2- DCB and sex differences using whole-body inhalation in laboratory mice. Male and female mice were exposed to 0–120 ppm of the test substance for 13 weeks. After euthanization, the organs were collected, histopathological assessments and immunohistochemistry (IHC) were performed, and lipid peroxidation was analyzed. Macro and microscopic lesions were observed in the livers of male mice exposed to the test substance, and microscopic alterations were observed in the nasal cavities of male and female mice. IHC analysis of the liver confirmed a greater increase in cytochrome P450 induction in males than in female mice, and malondialdehyde and 4-hydroxynonenal were increased in both sexes by 1,2-DCB inhalation. Based on the relevant literature and experimental results, 1,2-DCB is believed to cause specific organ toxicity in the livers of male mice and the nasal cavities of both sexes of mice, which is supposed to be related to sex differences in cytochrome P450 induction and changes in lipid and oxidative products associated with the early metabolites of the test substance.

헌법은 종교의 자유를 보장한다. 종교의 자유의 보호대상에 명상은 포함되 는지 의문이다. 전통적으로 명상은 종교의 목적을 달성하기 위한 수단으로 활용되었다. 하지만 현대의 명상은 종교성에서 세속화·대중화·산업화로 변천 되었다. 명상의 세속화는 종교의 개념에 대한 재해석을 요청한다. 명상의 개 념은 더 이상 종교에 국한하지 않는다. 명상은 종교적 차원과 세속적 차원이 조응 혹은 분리된 개방적 개념으로 확장된 것이다. 그렇다면 명상을 종교로 포섭하여 일률적인 종교의 자유의 보호영역으로 설정할 수 없다. 국가는 종 교의 자유를 보호할 수 있도록 종교의 범위에 대하여 고민하여야 한다. 합의 된 헌법적 정의는 부재하다. 이에 대한 헌법적 대답을 부과한다. 헌법질서 아 래 상이해진 두 개념 간에 평화적 공존을 위해서는 새로운 정립이 필요하기 때문이다. 명상에 관한 헌법적 문제는 크게 세 가지로 정리된다. 첫째, 명상 은 종교인가? 둘째, 헌법상 명상의 개념은 무엇인가? 셋째, 종교의 자유와 명 상은 어떠한 관계를 갖는가? 종교적 명상과 세속적 명상으로 구분하여 종교 의 자유에 대한 실효성 있는 헌법해석을 시도해 볼 수 있다. 종교적 명상의 경우 종교가 추구하는 유일한 목적에 이르기 위한 수단이다. 이와 달리, 세속 적 명상의 경우 각인의 다양한 목적을 내적으로 경험하기 위한 생활의 실천 이란 점에서 합리적인 헌법적 해석이 전제되어야 한다. 본고는 종교성을 갖 는 명상의 경우 종교의 자유의 영역이지만, 세속성을 갖는 명상의 경우에는 무종교의 자유의 영역으로 보는 것은 정당한지 여부에 대하여 고찰한다. 이 를 논증하기 위하여 헌법상 종교와 명상의 개념, 종교의 자유와 무종교의 자 유를 구분하여 탐색한다. 그리고 무종교의 자유의 구체적인 내용으로 무신앙 의 자유, 무종교적 행위의 자유, 무종교적 집회·결자의 자유, 무종교의 자유 제한의 한계를 명상의 개념을 접목하여 살펴보고, 이어서 종교의 자유와 무 종교의 자유에서 각기 파생되는 가칭 ‘종교적 명상의 자유’와 ‘세속적 명상의 자유’에 대하여 제언한다. 본 연구의 목적은 헌법상 종교와 명상의 개념을 살 펴보고, 헌법해석을 통해 상충할 수 있는 종교적 명상과 세속적 명상의 기본 권 보호의 범위를 법익형량 할 수 있는 방향성을 제시함에 있다.

근자에 헌법기관인 중앙선거관리위원회를 둘러싸고 2가지 쟁점이 문제가 되고 있다. 중앙선거관리위원회를 비롯한 선거관리위원회의 정치적 편향성 문 제 그리고 친인척 특혜채용과 관련한 내부 비위 문제에 대하여 감사원이 선 거관리위원회를 직무감찰할 수 있는지 여부가 바로 그것이다. 민주적 선거제도의 구현과 국민의 참정권의 완전한 실현을 위해서는 선 거관리를 담당하는 선거관리위원회의 정치적 중립성 유지가 무엇보다 중요 하다. 현행 헌법 시행 이후 비교적 정치적 중립성 유지를 잘 해왔던 선거 관리위원회가 2010년 이후 공고화된 양당 체제에 따른 정치적 대립의 격 화 등 다양한 요인으로 인하여 정치적 중립성을 유지하지 못하고 정부와 여당에 우호적인 편향성을 빈번하게 드러냈었는데 2017년 문재인 정부 출 범 이후 이러한 편향적 경향은 짙어져 여러 차례 정치문제로 비화되었다. 이러한 정치적 편향성 문제에 더하여 2023년에는 선거관리위원회 전·현직 공무원의 친인척 특혜채용 의혹이 불거져 사회적으로 큰 문제가 되었다. 그리하여 선거관리위원회의 친인척 특혜채용 의혹에 대하여 감사원이 직무 감찰에 나서야 한다는 여론이 강하게 제기되어 중앙선거관리위원회가 감사 원 직무감찰 대상기관에 해당되는지 여부가 법적 쟁점으로 부각되었다. 본 논문에서는 중앙선거관리위원회가 정치적 편향성을 드러내는 구조적 원 인이 중앙선거관리위원회 위원 9인 중 8인을 비상임으로 하고 대통령이 임명 하는 위원 중 1인을 상임위원으로 호선하는데 있음을 논증하였고 여기에 현직 대법관이 위원장으로 호선되어 중앙선거관리위원회 위원장을 겸직하는 오랜 관행도 중앙선거관리위원회 정치적 편향성에 간접적으로 원인제공을 한다는 점을 살펴보았다. 그리하여 중앙선거관리위원회 위원 전원을 상임직으로 전환 하는 동시에 대법원장이 대법관을 역임한 자를 중앙선거관리위원회 위원으로 지명하고 해당 피지명자를 위원장으로 호선하는 개선방안을 제시하였다. 한 편, 중앙선거관리위원회가 감사원의 직무감찰 대상기관에 해당하는지는 헌법의 문리적 해석, 역사적 배경, 선거관리위원회가 담당하는 사무의 법적 성격, 기능적 권력분립주의 등을 고려할 때 직무감찰 대상기관으로 볼 수 없음을 논 증하였으며 선거관리위원회의 내부적 비위나 직무태만 등에 대하여는 중앙선 거관리위원회의 내부적 감찰 활동에 우선 맡기고 내부적 통제가 미흡한 경우 국회나 수사기관 등에 의한 외부적 통제를 고려해야 함을 개선방안으로 제시 하였다.

Cesium lead iodide (CsPbI3) with a bandgap of ~1.7 eV is an attractive material for use as a wide-gap perovskite in tandem perovskite solar cells due to its single halide component, which is capable of inhibiting halide segregation. However, phase transition into a photo inactive δ-CsPbI3 at room temperature significantly hinders performance and stability. Thus, maintaining the photo-active phase is a key challenge because it determines the reliability of the tandem device. The dimethylammonium (DMA)-facilitated CsPbI3, widely used to fabricate CsPbI3, exhibits different phase transition behaviors than pure CsPbI3. Here, we experimentally investigated the phase behavior of DMA-facilitated CsPbI3 when exposed to external factors, such as heat and moisture. In DMA-facilitated CsPbI3 films, the phase transition involving degradation was observed to begin at a temperature of 150 °C and a relative humidity of 65 %, which is presumed to be related to the sublimation of DMA. Forming a closed system to inhibit the sublimation of DMA significantly improved the phase transition under the same conditions. These results indicate that management of DMA is a crucial factor in maintaining the photo-active phase and implies that when employing DMA designs are necessary to ensure phase stability in DMA-facilitated CsPbI3 devices.

3Y-TZP (3 mol% yttria-stabilized tetragonal zirconia polycrystals) ceramics have excellent mechanical properties including high fracture toughness, good abrasion resistance as well as chemical and biological stability. As a result, they are widely used in mechanical and medical components such as bearings, grinding balls, and hip implants. In addition, they provide excellent light transmittance, biocompatibility, and can match tooth color when used as a dental implant. Recently, given the materials’ resemblance to human teeth, these ceramics have emerged as an alternative to titanium implants. Since the introduction of CAD/CAM in the manufacture of ceramic implants, they’ve been increasingly used for prosthetic restoration where aesthetics and strength are required. In this study, to improve the surface roughness of zirconia implants, we modified the 3YTZP surface with a biocomposite of hydroxyapatite and forsterite using room temperature spray coating methods, and investigated the mixed effect of the two powders on the evolution of surface microstructure, i.e., coating thickness and roughness, and biological interaction during the in vitro test in SBF solution. We compared improvement in bioactivity by observing dissolution and re-precipitation on the specimen surface. From the results of in vitro testing in SBF solution, we confirmed improvement in the bioactivity of the 3Y-TZP substrate after surface modification with a biocomposite of hydroxyapatite and forsterite. Surface dissolution of the coating layer and the precipitation of new hydroxyapatite particles was observed on the modified surface, indicating the improvement in bioactivity of the zirconia substrate.

The effects of Ni2+ substitution for Mg2+-sites on the microwave dielectric properties of (Mg1-xNix)(Ti0.95(Mg1/3 Ta2/3)0.05)O3 (0.01 ≤ x ≤ 0.05) (MNTMT) ceramics were investigated. MNTMT ceramics were prepared by conventional solid-state reaction. When the MgO / TiO2 ratio was changed from 1.00 to 1.02, MgTi2O5 was detected as a secondary phase along with the MgTiO3 main phase in the MNTMT specimens sintered at 1,400 °C for 4h. For the MNTMT specimens with MgO / TiO2 = 1.07 sintered at 1,400 °C for 4h, a single phase of MgTiO3 with an ilmenite structure was obtained from the entire range of compositions. The relative density of all the specimens sintered at 1,400 °C for 4h was higher than 95 %. The quality factor (Qf) of the sintered specimens depended strongly on the degree of covalency of the specimens, and the sintered specimens with x = 0.01 showed the maximum Qf value of 489,400 GHz. The dielectric constant (K) decreased with increasing Ni2+ content because Ni2+ had a lower dielectric polarizability (1.23Å3) than Mg2+ (1.32Å3). As Ni2+ content increased, the temperature coefficient of resonant frequency (TCF) improved, from -55.56 to -21.85 ppm/°C, due to the increase in tolerance factor (t) and the lower dielectric constant (K)