Charge Structure of the Combined System (La0.6Sr0.4MnO₃)0.7(La0.6Sr0.4FeO₃)0.3 as Investigated by Mossbauer Spectroscopy

Young Rang Uhm,Sam Jin Kim,Chul Sung Kim 한국자기학회 2002 Journal of Magnetics Vol.7 No.1

The charge structures of La_(0.6)Sr_(0.4)FeO₃ (LSMO) and of the combined system (La_(0.6)Sr_(0.4)MnO₃)_(0.7)(La_(0.6)Sr_(0.4)FeO₃)_(0.3) are investigated by using Mossbauer spectroscopy. The antiferromagnetically ordered La_(0.6)Sr_(0.4)FeO₃(LSFO) has possible charges of Fe³+ and Fe⁴+, which include a low-spin Fe⁴+ state at and above 230 K. The temperature dependences of the Mossbauer spectra for the La_(0.6)Sr_(0.4)FeO₃ system and for the combined (LSMO)_(0.7)(LSFO)_(0.3) system are fitted as three sets of Zeeman patterns corresponding to Fe³+ and Fe⁴+ below 230 K. At and above 230 K, the fitted Mossbauer spectra for the combined system are the same in all temperature ranges. Above 230 K, La_(0.6)Sr_(0.4)FeO₃ spectrum consists of two sets of six Lorentzians for Fe³+ and one line for low spin Fe⁴+. It is worth noting that large fields are induced in the combined system.

골프장연습장 이용 고객의 전환장벽 요인에 따른 시장세분화

김애랑(Ae Rang Kim),전호문(Ho Moon Jun),조우정(Woo Jeong Cho) 한국사회체육학회 2013 한국사회체육학회지 Vol.0 No.53

The purpose of this study was to segment the customers of driving range by clustering them based on switching barriers. The second purpose was to identify the characteristics of each cluster. The third purpose was to examine the differences of satisfaction and switching intentions of each cluster. In order to measure the switching barriers, 13 items divided into 3 factors, which were 7 items for switching cost (Cronbach`s α = .875), 3 items for interpersonal relationship (Cronbach`s α = .686), and 3 items for attraction of alternatives (Cronbach`s α = .764) were used. A total of 431 responses were analyzed with the statistical methods such as frequency analysis, exploratory factor analysis, K-mean cluster analysis, Chi-square analysis, One-way ANOVA, and multiple regression analysis. The findings for this study were as follows. First, the three clusters were identified based on switching barriers. Second, each cluster was explained by the personal characteristics of the customers of driving range. Third, statistically significant differences in switching intentions and satisfactions were found among clusters.

Effect of Accelerated Aging on the Color Stability of Dual-Cured Self-Adhesive Resin Cements

Kim, Ah-Rang,Jeon, Yong-Chan,Jeong, Chang-Mo,Yun, Mi-Jung,Huh, Jung-Bo Korean Academy of Dental Science 2015 Journal of korean dental science Vol.8 No.2

Purpose: The effect of accelerated aging on color stability of various dual-cured self-adhesive resin cements were evaluated in this study. Materials and Methods: Color stability was examined using three different brands of dual-cured self-adhesive resin cements: G-CEM LinkAce (GC America), MaxCem Elite (Kerr), and PermaCem 2.0 (DMG) with the equivalent color shade. Each resin cement was filled with Teflon mold which has 6 mm diameter and 2 mm thickness. Each specimen was light cured for 20 seconds using light emitting diode (LED) light curing unit. In order to evaluate the effect of accelerated aging on color stability, color parameters (Commission Internationale de l'Eclairage, CIE $L^*$, $a^*$, $b^*$) and color differences (${\Delta}E^*$) were measured at three times: immediately, after 24 hours, and after thermocycling. The $L^*$, $a^*$, $b^*$ values were analyzed using Friedman test and ${\Delta}E^*$ values on the effect of 24 hours and accelerated aging were analyzed using t-test. These values were compared with the limit value of color difference (${\Delta}E^*=3.7$) for dental restoration. One-way ANOVA and Scheff's test (P<0.05) were performed to analyze each ${\Delta}E^*$ values between cements at each test period. Result: There was statistically significant difference in comparison of color specification ($L^*$, $a^*$, $b^*$) values after accelerated aging except $L^*$ value of G-CEM LinkAce (P<0.05). After 24 hours, color difference (${\Delta}E^*$) values were ranged from 2.47 to 3.48 and $L^*$ values decreased and $b^*$ values increased in all types of cement and MaxCem Elite had high color stability (P<0.05). After thermocycling, color change's tendency of cement was varied and color difference (${\Delta}E^*$) values were ranged from 0.82 to 2.87 and G-CEM LinkAce had high color stability (P<0.05). Conclusion: Color stability of dual-cured self-adhesive resin cements after accelerated aging was evaluated and statistically significant color changes occurred within clinically acceptable range.

최인훈 소설 연구 : 주인공 독고준의 욕망과 심리 세계를 중심으로

박해랑(Park Hae Rang) 한국문학회 2014 韓國文學論叢 Vol.67 No.-

최인훈 소설 는 그의 여러 소설 중 가장 난해한 작품에 속한다. 비사실주의 소설로 기존의 소설과는 다른 중층구조를 이루고 있다. 그는 소설에서 인물에 대한 심리 세계를 매우 치밀하게 서술하고 있다. 특히 주인공의 심리는 그의 행동에 중요한 원인으로 작용하고 있다. 최인훈 소설에서 인물들의 성향은 여러 작품에서 반복되거나 연속되어 나타나고 있으며, 작가는 인물들의 사유 세계를 섬세히 묘사하고 있다. 소설에서 주인공은 시대적 가치관과 개인적 가치관의 혼돈 속에서 이성에 대한 욕망을 다양하게 표출하고 있다. 그에 비해 지금까지 인물에 대한 심리 연구는 거의 없는 편이다. 이에 최인훈 소설에서 인물의 심리 연구를 새로운 논의 방법으로 제시하고, 그 소설의 난해성 해소와 연구 범위 의 확대에 기여하고자 한다. 본 연구는 에서 주인공 독고준을 중심으로 그의 욕망과 심리 세계를 연구하는 것에 목적을 둔다. 문학에서 심리적 상태를 표현하고, 문학연구에 있어 심리를 연구하는 것은 지금까지 중요한 과제가 되 어 왔다. 인물의 복잡한 심리를 연구하는 과정은 그 인물 행위의 동기를 분석하여 그 의미를 설명하는데 매우 유용한 방법이다. 에서 독고준은 이유정의 방에서 나와 자신의 방으로 들어가는 복도의 끝에서 환상 여행을 떠난다. 환상적인 공간 이동을 통하여 독고준은 기억에 잠재된 무의식 세계를 여행한다. 독고준의 여행 목적은 과거'W시의 그 여름날을 기억하는 그녀'를 만나기 위한 욕망의 실현이다. 그녀를 만나기 위해 여행을 강행하면서 그가 깨달은 것은 가족에 대한 그리움이며, 어머니에 대한 사랑이다. 또한 어린 시절 경험한 자아비판의 상흔은 그 시절의 교실로 돌아가 지도원 선생과 대면함으로써 치유한다. 독고준은 여행내내 자아와 세계의 대립으로 균열이 심화되어 간다. 이러한 균열은 그를 내면세계로 침잠하게 한다. 그러나 반복적인 여행을 통해 내면의 상흔을 치유하고, 현실을 인식하여 자아의 성장을 이룬다. 독고준은 여행하는 동안 부끄러움을 느끼고, 여행이 끝난 후에도 자신의 행동에 부끄러움을 느낀다. 자신이 한 행동에 대해 반성하고 부끄러움을 느끼는 것은 자아가 성장하고, 정체성을 확립해가는 과정이다. 인간은 끊임없이 자아와 세계의 갈등을 빚는다. 자아와 세계가 투쟁과 충돌을 통해 화해의 결실을 이루기도 하지만 다수의 인간은 투쟁과 충 돌을 회피하고 내면으로 침잠하여 세계로부터 스스로를 소외시키는 경향을 가지기도 한다. 현실과 당면하지 않고 사회에 대해 스스로 소외시키는 것을 성장의 한 방편으로 보는 것이 불편한 사실이지만, 이렇게 밖에 할 수 없는 현실이 냉정하다. 독고준은 이러한 현실에 살고 있는 회색(灰色)인이다. 그러나 무의식의 환상 여행을 마친 후 자신의 방에서 비오는 창밖을 바라보는 그의 모습은 현실을 직시하고 받아들이려는 노력의 자세로 보인다. 에서 독고준의 욕망과 심리 묘사는 주인공을 매개로 한 행동의 의미와 심리 체계를 구조화한 것으로 평가할 수 있다. 독고준이 혼돈된 세계에서 자아의 성장과 가치관을 정립해가는 과정을 살펴봄으로 작품에 대한 이해의 폭을 넓히고, 최인훈 소설의 다양한 분석과 연속성 있는 연구의 틀을 마련할 수 있을 것이다. Choi In-Hoon's novel Seo-Yu-Gi belongs to one of the most abstruse novels. As an unrealistic novel, it consists of multi-layered structures. He narrates psychological realm of the characters very closely. Especially, the state of mind of the protagonist in his behavior works as an important element. The personality of characters in various Choi's novels appear repeatedly and continuously, and he describes their psyche delicately. Reduced to a chaotic state, the protagonist in the novel expresses his desire for the other sex variously. However, until now, studies on the mentality and psychology of the character have been rare. Therefore, I will present the study on the character's mentality and psychology as a new argument method, and I'd like to contribute to reduction of abstruseness and expand the study range. This study aims at studying on the desire and psychological realm of the protagonist, Dok Go-Joon in Seo-Yu-Gi. It becomes important task to express metal state and to study the mentality in literary researches. A course of study on the complex mentality of the character is very useful to analyze the motivation of the behavior and to explain the meaning. Dok Go-Joon in Seo-Yu-Gi. takes a fantasy journey at the end of hall stepping out of the Lee You-Jung's room. Through moving space, Dok Go-Joon travels the world of unconsciousness embedded in his memory. The purpose of his travel is to fulfill his desire to meet her. She remembers the summer day of W city. What he realizes is longing for his family and loving for his mother. Also, the scar caused by self criticism in his childhood is healed up by facing instructor in the classroom of the time. The rupture between his ego and world becomes worse through the entire trip. This rupture begins to withdraw to his inner world. However, he heals the scar through the repetitive travel, recognize the reality, and accomplish selfdevelopment. Dok Go-Joon feel abashed during the trip and still he does after the trip. It is the process of establishing his own identity for him to reflect on his behavior and have shyness. Humans always come into conflict between ego and world. Ego and world can bear a fruit of reconciliation, but most humans tend to avoid the struggle, conflict withdraw into the inner world, and isolate themselves from the world. From the perspective of growth and maturity, it is uncomfortable fact that humans do not face the reality and isolate themselves from the society, but the reality is quite cold and different because people can not do any other things. Dok Go-Joon is “A Gray man” who lives in this reality. However, his image, which looks out the window for rainy days after unconscious fantasy journey, can be seen as an effort to face and embrace the reality. Description of Dok Go-Joon's desire and state of mind in Seo-Yu-Gi can be appraised as structurization of behavioral meaning and psychological system. By looking for the process for Dok Go-Joon to establish self-development and values, I can broaden and deepen the understanding of this work and provide a framework for various and continuous study on Choi's novels.

A Study on the Screening of Children at Risk for Developmental Disabilities Using Facial Landmarks Derived From a Mobile-Based Application

Sang Ho Hwang,Yeonsoo Yu,Jichul Kim,Taeyeop Lee,Yu Rang Park,Hyo-Won Kim 대한신경정신의학회 2024 PSYCHIATRY INVESTIGATION Vol.21 No.5

Objective : Early detection and intervention of developmental disabilities (DDs) are critical to improving the long-term outcomes of af-flicted children. In this study, our objective was to utilize facial landmark features from mobile application to distinguish between children with DDs and typically developing (TD) children. Methods : The present study recruited 89 children, including 33 diagnosed with DD, and 56 TD children. The aim was to examine the effectiveness of a deep learning classification model using facial video collected from children through mobile-based application. The study participants underwent comprehensive developmental assessments, which included the child completion of the Korean Psychoedu-cational Profile-Revised and caregiver completing the Korean versions of Vineland Adaptive Behavior Scale, Korean version of the Child-hood Autism Rating Scale, Social Responsiveness Scale, and Child Behavior Checklist. We extracted facial landmarks from recorded vid-eos using mobile application and performed DDs classification using long short-term memory with stratified 5-fold cross-validation. Results : The classification model shows an average accuracy of 0.88 (range: 0.78–1.00), an average precision of 0.91 (range: 0.75–1.00), and an average F1-score of 0.80 (range: 0.60–1.00). Upon interpreting prediction results using SHapley Additive exPlanations (SHAP), we verified that the most crucial variable was the nodding head angle variable, with a median SHAP score of 2.6. All the top 10 contributing variables exhibited significant differences in distribution between children with DD and TD (p<0.05). Conclusion : The results of this study provide evidence that facial landmarks, utilizing readily available mobile-based video data, can be used to detect DD at an early stage.

FTIR을 이용한 브라질 Itabira 지역 에메랄드의 분광학적 특성 연구

임예원 ( Ye Won Lim ),장윤득 ( Yun Deuk Jang ),김종랑 ( Jong Rang Kim ),김형수 ( Hyeong Soo Kim ),김종근 ( Jong Gun Kim ),김정진 ( Jeong Jin Kim ) 한국광물학회 2008 광물과 암석 (J.Miner.Soc.Korea) Vol.21 No.4

현재 에메랄드의 중요한 산지로 자리 잡아가고 있는 Itabira 지역 에메랄드의 분광학적 특성을 연구하기 위하여 에메랄드를 C-축에 수직, 수평인 방향으로 각각 절단하였으며, H2O 관련 범위의 좀 더 세부적인 피크 관찰을 위하여 KBr로 압축한 pellet시료를 만들어 적외선 분광분석(FTIR) 실험을 수행 하였다. H2O 관련 범위에서 5,271cm-1, 1,638cm-1 피크가 나타나는 것으로 보아 본 시료는 Type-Ⅱ에 해당함을 관찰할 수 있었으며, H2O-Na-H2O 배열 형태를 가지는 Type-Ⅱa에 해당하는 피크가 아주 강하게 나타나고 있다. H2O 관련 범위를 제외한 특정 범위에서는 CO2, Cl 피크 등이 관찰 되었으며, 적외선 분광분석법을 이용하여 타입의 분류뿐만 아니라 상대적인 피크 강도 비교를 통하여 Na2O 함량 또한 예측 가능한 것으로 사료된다. Emerald deposit located on Itabira, Brazil is one of the major one in the world. We applied three different analytical approaches on Itabira emerald samples, (1) perpendicular to the c-axis, (2) parallel to the c-axis, (3) emerald pallet mixed with KBr, using Fourier Transform Infrared (FTIR) spectroscopy, to understand and compare spectroscopic characteristics of three Itabira emerald samples. Occurrence of 5,271 cm-1 and 1,638 cm-1 absorption peaks within H2O-related range indicates that the samples belong to Type-II emerald. These emerald samples also display strong absorption peak generated from Type-IIa emerald preserving H2O-Na-H2O sequence. CO2- and Cl-related absorption peaks observed within specific range except for H2O-related range. These observations and results suggest that FTIR analysis can be used for not only classification of emerald types, but also prediction of Na2O content within the emerald through comparison of relative peak intensity.

청소년을 위한 영양지수 개발과 타당도 검증

김혜영(Kim, Hye-Young),이정숙(Lee, Jung-Sug),황지윤(Hwang, Ji-Yun),권세혁(Kwon, Sehyug),정해랑(Chung, Hae Rang5),곽동경(Kwak, Tong-Kyung),강명희(Kang, Myung-Hee),최영선(Choi, Young-Sun) 한국영양학회 2017 Journal of Nutrition and Health Vol.50 No.2

본 연구는 생애주기별 영양지수 중 청소년을 위한 영양지수 (Nutrition Quotient for Adolescents, NQ-A) 모형을 개발하고자 수행되었다. 영양지수 평가항목 선정을 위해 식품섭취영역에서 20개 문항, 식행동·식습관 영역에서 21개 문항의 총 41개 문항으로 구성된 파일럿 조사용 체크리스트를 개발하였다. 청소년 213명을 대상으로 1일의 식사 섭취실태 조사를 포함한 파일럿 조사를 수행하고, 체크리스트 항목 점수와 식사섭취실태 관련 변수들 간의 상관관계가 높은 24개의 평가항목으로 구성된 전국단위 조사용 체크리스트를 개발하였다. 전국단위 조사는 시도별 집락별로 층화추출된 중고등학생 1,547명에 대해 구조화된 설문지로 면대면 조사를 수행하였고, 탐색적 요인분석을 수행하여 청소년 영양지수의 평가 항목을 19개 항목의 5개 요인으로 분류하고, 구조방정식 모형을 이용해 평가 항목의 구성타당도를 검증하고 추정된 경로계수를 가중치로 적용하였다. 청소년 영양지수를 위한 5개의 요인과 가중치는 각각 균형 0.25, 다양 0.15, 절제 0.25, 환경 0.15, 실천 0.20이었다. 균형 영역에는 과일 섭취 빈도, 흰 우유 섭취 빈도, 콩류 섭취 빈도, 생선 섭취 빈도의 4개 항목이 포함되었고, 다양 영역은 채소 반찬 섭취 빈도, 반찬 골고루 먹는 정도, 편식 정도의 3개 항목, 절제 영역은 과자 또는 달거나 기름진 빵 섭취 빈도, 가공 음료 섭취 빈도, 라면 섭취 빈도, 카페인 음료섭취 빈도, 야식 섭취 빈도, 길거리 음식 섭취 빈도의 6개 항목, 환경 영역은 아침식사 빈도, 식탁에 앉아서 식사하는 정도, TV·핸드폰·컴퓨터 사용 시간의 3개 항목, 그리고 실천 영역은 영양 표시 확인 정도, 음식 먹기 전 손 씻는 정도, 운동 빈도의 3개 항목이 포함되었다. 전국단위 조사대상자의 영양지수 (NQ-A) 평균 점수는 56.0점이었고, 세부 영역별로는 균형 58.6점, 다양 55.6점, 절제 48.1점, 환경 70.6점, 실천 52.1점이었다. 영양지수 점수와 각 영역별 등급은 전국 조사 결과의 백분위수 분포를 기준으로 75~100 백분위의 경우 ‘상’ 등급, 25 ~ <75 백분위의 경우 ‘중’ 등급, 0 ~ <25 백분위는 ‘하’ 등급으로 분류하였다. 영양지수의 경우 63.1~100점은 ‘상’ 등급, 49.0~63점은 ‘중’ 등급, 0~48.9점은 ‘하’ 등급으로 판정되었다. 본 연구에서 개발된 청소년을 위한 영양지수는 19개 항목으로 구성된 식행동 체크리스트를 통해 영양지수 점수와 균형, 다양, 절제, 환경, 실천 영역의 점수를 산출할 수 있으며, 상대적인 NQ 등급 부여를 통해 식사의 질과 식행동이 양호한 지를 판정할 수 있다. 본 연구에서 개발된 청소년용 영양지수 (NQ-A)가 청소년의 식사의 질과 식행동 평가 및 영양교육의 효과 평가 등에 많이 활용될 것으로 기대된다. Purpose: The purpose of this study was to develop a nutrition quotient for adolescents (NQ-A) to assess overall dietary quality and food behavior of Korean adolescents. Methods: Development of the NQ-A was undertaken in three steps: item generation, item reduction, and validation. Candidate items of the NQ-A checklist were selected based on literature reviews, results of the fifth Korea National Health and Nutrition Examination Survey data, dietary guidelines for Korean adolescents, expert in-depth interviews, and national nutrition policies and recommendations. A total of 213 middle and high school students participated in a one-day dietary record survey and responded to 41 items in the food behavior checklist. Pearson"s correlation coefficients between the responses to the checklist items along with nutritional status of the adolescents were calculated. Item reduction was performed, and 24 items were selected for the nation-wide survey. A total of 1,547 adolescents from 17 cities completed the checklist questionnaire. Exploratory factor and confirmatory factor analyses were performed to develop a final NQ-A model. Results: Nineteen items were finalized as the checklist items for the NQ-A. Checklist items were composed of five factors (balance, diversity, moderation, environment, and practice). The five-factor structure accounted for 47.2% of the total variance. Standardized path coefficients were used as weights of the items. The NQ-A and five-factor scores were calculated based on the obtained weights of the questionnaire items. Conclusion: Nutrition Quotient for adolescents (NQ-A) would be a useful instrument for evaluating dietary quality and food behavior of Korean adolescents. Further research on NQ-A is needed to reflect changes in adolescent"s food behavior and environment.

Selective ring opening of phenanthrene over NiW-supported mesoporous HY zeolite catalyst depending on their mesoporosity

Lee, Su-Un,Lee, You-Jin,Kim, Jeong-Rang,Kim, Eun-Sang,Kim, Tae-Wan,Kim, Hyung Ju,Kim, Chul-Ung,Jeong, Soon-Yong Elsevier 2017 Materials research bulletin Vol.96 No.3

<P><B>Abstract</B></P> <P>Selective ring opening of multi-ring aromatics is a potential route for the production of valuable middle distillates from heavy oil, but a bi-functional (acidic and metallic) catalyst is required. We report here the use of mesoporous HY zeolites with variation of their mesoporosity to overcome diffusion resistance for bulky aromatics. NiW was impregnated on acidic zeolites for the metallic function of the bi-functional catalyst. To investigate the mesoporosity effect on selective ring opening, phenanthrene was selected as a model compound for multi-ring aromatics, and its reaction was conducted in a batch reactor. The introduction of moderate mesoporosity into an HY zeolite resulted in a noticeable effect on the yields of desirable mono-ring aromatics due to the easier accessibility of bulky reactants into the inner active sites of the zeolite. The mesoporosity of the catalyst seems to play an important role in the selective ring opening of phenanthrene but the optimum level should be determined.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mesoporous HY zeolites were prepared by pseudomorphic synthesis using TMAOH and CTAB. </LI> <LI> The mesoporosity of the zeolites increased with the TMAOH concentration. </LI> <LI> Phenanthrene was selected as a model compound for multi-ring aromatics in heavy oil. </LI> <LI> NiW/mesoporous HY catalysts were used for selective ring opening of phenanthrene. </LI> <LI> The proper mesoporosity enhanced the catalytic performance due to ease accessibility. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Investigation for protection effect of CPV-2 vaccine against a Korean CPV-2c isolate

A-Rang Lee(A-Rang Lee),Kyoung-Ki Lee(Kyoung-Ki Lee),Hye-Young Jeoung(Hye-Young Jeoung),Bok-Kyung Ku(Bok-Kyung Ku),Ji-Young Park(Ji-Young Park) 한국예방수의학회 2022 한국예방수의학회 학술대회자료집 Vol.2022 No.-

Rational synthesis of silylated Beta zeolites and selective ring opening of 1-methylnaphthalene over the NiW-supported catalysts

Lee, Su-Un,Lee, You-Jin,Kim, Jeong-Rang,Jeong, Soon-Yong Elsevier 2017 Applied Catalysis B Vol.219 No.-

<P><B>Abstract</B></P> <P>Heavy oil has been by-produced from refinery and petrochemical processes, and its use as low-value fuels has been restricted by stricter environmental regulations due to heavy molecules, multi-ring aromatics, and high sulfur content. In a bi-functional catalyst system of metal and zeolitic acid, balancing metallic (from metal element) and acidic function (from zeolite elements) is essential for harnessing the selective ring opening (SRO) reaction with the aim of upgrading the heavy oil. Here, we report a synthetic strategy to control the acid site distribution of Beta zeolite through the silylation reaction with tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), and tetrabutyl orthosilicate (TBOS) as silylation agents. As the size of alkyl chain group in the silylation agents gets larger, the silylation agents were suppressed to spread into the channels and thus the formation of SiO<SUB>2</SUB> layer was intentionally occurred on the external surface of the zeolite. Resulting from the selectively deposited SiO<SUB>2</SUB> layer, NiW metals supported on each silylated Beta zeolite altered the metal distribution and further the balance of metallic and acidic function. NiW catalyst supported on TBOS-silylated Beta zeolite exhibited the best catalytic performance toward the SRO reaction of 1-methylnaphthalene in a fix-bed reaction system, proving the optimal balance of metallic and acidic functions. We expect that this study will benefit the control over the selective silylation reaction in order to optimize the balance of metallic and acidic functions in the bi-functional catalysts, and, hence, to promote properly aromatic saturation (hydrogenation) and ring opening (hydrocracking) for selective ring opening products.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The distribution of acid sites in zeolites was modified by silylation with various alkyl chains. </LI> <LI> Large silylation agents induce to deposit SiO<SUB>2</SUB> on the external surface of zeolites. </LI> <LI> NiW/silylated zeolite alters the balance of metallic and acidic functions. </LI> <LI> Selective ring opening of 1-methylnaphthalene by NiW/silylated zeolite was tested. </LI> <LI> The optimal balance of bi-functional catalysts improve conversion and selectivity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>