• 제목/요약/키워드: V-Band

검색결과 2,057건 처리시간 0.031초

Cloning and Characterization of Monofunctional Catalase from Photosynthetic Bacterium Rhodospirillum rubrum S1

  • Lee, Dong-Heon;Oh, Duck-Chul;Oh, You-Sung;Malinverni, Juliana C.;Kukor, Jerome J.;Kahng, Hyung-Yeel
    • Journal of Microbiology and Biotechnology
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    • 제17권9호
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    • pp.1460-1468
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    • 2007
  • In this study, an approx. 2.5-kb gene fragment including the catalase gene from Rhodospirillum rubrum S1 was cloned and characterized. The determination of the complete nucleotide sequence revealed that the cloned DNA fragment was organized into three open reading frames, designated as ORF1, catalase, and ORF3 in that order. The catalase gene consisted of 1,455 nucleotides and 484 amino acids, including the initiation and stop codons, and was located 326 bp upstream in the opposite direction of ORF1. The catalase was overproduced in Escherichia coli UM255, a catalase-deficient mutant, and then purified for the biochemical characterization of the enzyme. The purified catalase had an estimated molecular mass of 189 kDa, consisting of four identical subunits of 61 kDa. The enzyme exhibited activity over a broad pH range from pH 5.0 to pH 11.0 and temperature range from $20^{\circ}C$ to $60^{\circ}C$C. The catalase activity was inhibited by 3-amino-1,2,4-triazole, cyanide, azide, and hydroxylamine. The enzyme's $K_m$ value and $V_{max}$ of the catalase for $H_2O_2$ were 21.8 mM and 39,960 U/mg, respectively. Spectrophotometric analysis revealed that the ratio of $A_{406}$ to $A_{280}$ for the catalase was 0.97, indicating the presence of a ferric component. The absorption spectrum of catalase-4 exhibited a Soret band at 406 nm, which is typical of a heme-containing catalase. Treatment of the enzyme with dithionite did not alter the spectral shape and revealed no peroxidase activity. The combined results of the gene sequence and biochemical characterization proved that the catalase cloned from strain S1 in this study was a typical monofunctional catalase, which differed from the other types of catalases found in strain S1.

서양 예술작품에 나타난 넥타이의 역사적 고찰 (A Development of Necktie Design in Western Art)

  • 이의정;정세희
    • 한국의상디자인학회지
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    • 제8권1호
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    • pp.81-96
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    • 2006
  • This study aimed to investigate the sociocultural phenomena which affected to clothing change in 1650-1900 and to examine the features of men's necktie in the western art. For this study, information about historic neckwear is obtained from the visual evidence of painted or engraved portraits, contemporary written sources. The covered area of this study was Europe mainly England and France. For this process, research steps were as follows : 1. Investigating the sociocultural phenomena which affect to clothing change through 1650-1900 and analysis of men's clothing and appearance. 2. Finding the changing characteristics of neckties including it's different types, shapes, knots, colors and materials and analyzing similarities and differences of neckties by the times. 3. Examining necktie as one of important and representative icons of male gender identity. The results of the study was as follows: 1. In 1660-1900, men's fashion was simplified in color and detail due to the influence of practical Puritanism and matured civil culture. And British men's fashion spreaded throughout whole European countries and get popularity. 2. In 1650-1720, there were band, cravat and steinkirk. And expecially cravatier, a expert custodian of cravats, was appeared in that period. In 1720-1800, there were stock, solitaire and cravat. In 1800-1850, neckwear were popularized and got various sizes and types up to shape and size of chemise collars. Black stock, scarf cravat and shawl cravat were popular and terms of 'necktie' were used for an certain neckcloth shape. And abundant literature for necktie were published thanks to the development of printing technology in that period. In 1851-1900, the leady-made neckties were spreaded and there were changes in shape, length, knot of necktie up to V-zone formed with shirt's collars and vest types. Neckwear was gradually evolving through four distinct styles, bow tie, scarf or neckerchief, Ascot and four-in-hand. 3. After the mid-l7th Century, as civil culture matured and splendid and extravagant colorful men's wear disappeared, British men's fashion spreaded throughout whole European countries and got popularity. The necktie become an essential ornamental accessory of men's fashion and one of important and representative icons of male gender identity.

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Optical Diagnostics of Nanopowder Processed in Liquid Plasmas

  • Bratescu, M.A.;Saito, N.;Takai, O.
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제40회 동계학술대회 초록집
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    • pp.17-18
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    • 2011
  • Plasma in liquid phase has attracted great attention in the last few years by the wide domain of applications in material processing, decomposition of organic and inorganic chemical compounds and sterilization of water. The plasma in liquid is characterized by three main regions which interact each - other during the plasma operation: the liquid phase, which supply the plasma gas phase with various chemical compounds and ions, the plasma in the gas phase at atmospheric pressure and the interface between these two regions. The most complex region, but extremely interesting from the fundamental, chemical and physical processes which occur here, is the boundary between the liquid phase and the plasma gas phase. In our laboratory, plasma in liquid which behaves as a glow discharge type, is generated by using a bipolar pulsed power supply, with variable pulse width, in the range of 0.5~10 ${\mu}s$ and 10 to 30 kHz repetition rate. Plasma in water and other different solutions was characterized by electrical and optical measurements. Strong emissions of OH and H radicals dominate the optical spectra. Generally water with 500 ${\mu}S/cm$ conductivity has a breakdown voltage around 2 kV, depending on the pulse width and the repetition rate of the power supply. The characteristics of the plasma initiated in ultrapure water between pairs of different materials used for electrodes (W and Ta) were investigated by the time-resolved optical emission and the broad-band absorption spectroscopy. The deexcitation processes of the reactive species formed in the water plasma depend on the electrode material, but have been independent on the polarity of the applied voltage pulses. Recently, Coherent anti-Stokes Raman Spectroscopy method was employed to investigate the chemistry in the liquid phase and at the interface between the gas and the liquid phases of the solution plasma system. The use of the solution plasma allows rapid fabrication of the metal nanoparticles without being necessary the addition of different reducing agents, because plasma in the liquid phase provides a reaction field with a highly excited energy radicals. We successfully synthesized gold nanoparticles using a glow discharge in aqueous solution. Nanoparticles with an average size of less than 10 nm were obtained using chlorauric acid solutions as the metal source. Carbon/Pt hybrid nanostructures have been obtained by treating carbon balls, synthesized in a CVD chamber, with hexachloro- platinum acid in a solution plasma system. The solution plasma was successfully used to remove the template remained after the mesoporous silica synthesis. Surface functionalization of the carbon structures and the silica surface with different chemical groups and nanoparticles, was also performed by processing these materials in the liquid plasma.

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생물방제균 Bacillus sp. YBL-7의 형질전환조건 (Genetic Transformation of Biocontrol Agent Bacillus sp, YBL-7 by Plasmid pE194)

  • 한길환;정병곤;김상달
    • 한국미생물·생명공학회지
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    • 제20권4호
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    • pp.384-389
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    • 1992
  • 식물근부균 Fusarium solani의 생육을 강력히 길항하는 Bacillus sp. YBL-7을 토양으로부터 분리하였으며 그 길항기작이 항생물질임을 이미 보고하였다. 분리된 생물방제균 Bacillus sp. YBL-7 균주들 siderophore, 가수분해능 등의 타 방제기능을 도입할 수 있는 다기능적인 방제균으로 육종하기 위해 plasmid vector pE194를 이용하여 효율적인 형질전환 system을 확립하고자 하였으며, 이때 필요한 여러가지 조건을 조사하였다. 생물방제균 Bacillus sp. YBL-7 원형질체 형성의 최적조건은 5시간 배양된 균체를 사용함으로써, 최종농도가 200${\mu}g$/ml인 lysozyme을 $37^{\circ}C$에서 90분간 처리함으로써 원형질체 생성율이 가장 높았다. 삼투압안정 완충제인 SMM bufferso의 sucrose 농도는 0.5M에서 안정하였고, mannitol 재생 배지에서 원형질체를 재생시켰을 경우 첨가된 agar의 농도가 1.2%에서, mannitol은 0.7M의 농도에서 가장 재생율이 높았다. 형질전환율은 polyethylene glycol 농도가 40%(w/v)일 때 가장 높았으며, plasmid DNA와의 접촉시간과 발현배양시간은 각각 10분, 120분에서 가장 효과가 좋았다. 또한 plasmid DNA의 농도는 5$\mu$g/ml 첨가에서 가장 높았으며, 형질전환된 숙주균주 Bacillus sp. YBL-7내에서의 pE194는 매우 안정하게 유지되었으며, 외붕 전자가 도입된 전환체와 숙주균주가 동일한 억제력을 갖는 것으로 확인되었으며, agarose gel 상에서도 고유의 plasmid pE194의 band를 확인 할 수 있었다.

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사군자탕(四君子湯) 및 사물탕(四物湯) 약침(藥鍼)이 면역반응(免疫反應)에 미치는 영향(影響) (The effects of Sakunjatang and Samultang Aqua-acupuncture on immune response)

  • 이병렬;안병철
    • 대한한의학회지
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    • 제18권1호
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    • pp.357-374
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    • 1997
  • In order to investigate the effects of Sakunjatang(四君子湯) and Samultang(四物湯) aqua-acupuncture on immune response, Sprague-Dawley male rats were used and randomly divided into four group. Normal group was normal control, Control group was injected i.v. with 2mg/kg MTX on 9th and 11th day after sensitization with SRBC on 5th day, Sakunjatang aqua-acupunctured group(Sample A) was aqua-acupunctured daily for 18 days into the locus corresponding Bisu(B20) locus of the human body to Rat and MTX was administered 9th and 11th experimental day, Samultang aqua-acupunctured group(Sample B) was aqua-acupunctured daily for 18 days into the locus coresponding Bisu(B20) locus of the human body to Rat and MTX was administered 9th and 11th experimental day. In the 9th day and the 11th day after aqua-acupuncture, MTX was injected to reduce immune function in the tail of rat. leukocyte count, lymphocyte ratio, lymphocyte count of spleen, lymphocyte count of bonemarrow, contact hypersensitivity to DNFB, morphologic change of thymus cell, and electropherogram of serum protein. The result were summarized as follows: 1. Before MTX injection, leukocyte count had no significant difference in Sakunjatang aqua-acupunctured group and Samultang aqua-acupunctured group compared to control group and after MTX injection, leukocyte count had no significant difference Sakunjatang aqua-acupunctured group and Samultang aqua-acupunctured group. 2. Before MTX injection, lymphocyte ratio was decreased significantly Sakunjatang aqua-acupunctured group and Samultang aqua-acupunctured group compared to control group. 3. After MTX injection, lymphocyte ratio was increased significantly Sakunjatang aqua-acupunctured group, Samultang aqua-acupunctured group had no significant difference compared to control group. 4. The lymphocyte count of spleen was increased significantly Sakunjatang aqua-acupunctured group and Samultang aqua-acupunctured group compared to control group. 5. The lymphocyte count of bonemarrow was increased significantly Sakunjatang aqua-acupunctured group, Samultang aqua-acupunctured group had no significant difference compared to control group. 6. Contact hypersensitivity was no significant difference in Sakunjatang aqua-acupunctured group and Samultang aqua-acupunctured group compared to control group. 7. In the morphologic change of thymus cell, control group compared to normal group had a indistinct boundary between cortex and medulla, and lymphocyte cell density of thymus was low, Sakunjatang aqua-acupuryctured group had a distinct boundary between cortex and medulla, and lymphocyte cell density of thymus was high. 8. In the SDS-PAGE electrophorogram of serum protein, Sakunjatang aqua-acupunctured group and Samultang aqua-acupunctured group had a wide band of nearby 50,000 and 25,000 Dalton which meant IgG generate more activity.

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Solution-Processed Nontoxic and Abundant $Cu_2ZnSnS_4$ for Thin-Film Solar Cells

  • 문주호
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2012년도 춘계학술발표대회
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    • pp.65-65
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    • 2012
  • Copper zinc tin sulfide ($Cu_2ZnSnS_4$, CZTS) is a very promising material as a low cost absorber alternative to other chalcopyrite-type semiconductors based on Ga or In because of the abundant and economical elements. In addition, CZTS has a band-gap energy of 1.4~1.5eV and large absorption coefficient over ${\sim}10^4cm^{-1}$, which is similar to those of $Cu(In,Ga)Se_2$(CIGS) regarded as one of the most successful absorber materials for high efficient solar cell. Most previous works on the fabrication of CZTS thin films were based on the vacuum deposition such as thermal evaporation and RF magnetron sputtering. Although the vacuum deposition has been widely adopted, it is quite expensive and complicated. In this regard, the solution processes such as sol-gel method, nanocrystal dispersion and hybrid slurry method have been developed for easy and cost-effective fabrication of CZTS film. Among these methods, the hybrid slurry method is favorable to make high crystalline and dense absorber layer. However, this method has the demerit using the toxic and explosive hydrazine solvent, which has severe limitation for common use. With these considerations, it is highly desirable to develop a robust, easily scalable and relatively safe solution-based process for the fabrication of a high quality CZTS absorber layer. Here, we demonstrate the fabrication of a high quality CZTS absorber layer with a thickness of 1.5~2.0 ${\mu}m$ and micrometer-scaled grains using two different non-vacuum approaches. The first solution-processing approach includes air-stable non-toxic solvent-based inks in which the commercially available precursor nanoparticles are dispersed in ethanol. Our readily achievable air-stable precursor ink, without the involvement of complex particle synthesis, high toxic solvents, or organic additives, facilitates a convenient method to fabricate a high quality CZTS absorber layer with uniform surface composition and across the film depth when annealed at $530^{\circ}C$. The conversion efficiency and fill factor for the non-toxic ink based solar cells are 5.14% and 52.8%, respectively. The other method is based on the nanocrystal dispersions that are a key ingredient in the deposition of thermally annealed absorber layers. We report a facile synthetic method to produce phase-pure CZTS nanocrystals capped with less toxic and more easily removable ligands. The resulting CZTS nanoparticle dispersion enables us to fabricate uniform, crack-free absorber layer onto Mo-coated soda-lime glass at $500^{\circ}C$, which exhibits a robust and reproducible photovoltaic response. Our simple and less-toxic approach for the fabrication of CZTS layer, reported here, will be the first step in realizing the low-cost solution-processed CZTS solar cell with high efficiency.

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폐기종실(廢棄種實)의 식량자원화(食糧資源化)에 관(關)하여 제(第)5보(報) : 수박씨의 화학적(化學的) 조성(組成) (Studies on the Development of Food Resources from Waste Seeds V. Chemical Composition of Water-melon Seed)

  • 윤형식;권중호;황주호;배만종
    • 한국식품영양과학회지
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    • 제12권3호
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    • pp.207-211
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    • 1983
  • 수박씨를 효율적(效率的)으로 이용(利用)할 목적(目的)에서 지질(脂質) 및 단백질(蛋白質)의 특성(特性)을 검토(檢討)한 결과(結果)는 다음과 같다. 1. 수박씨의 일반(一般) 성분(成分) 중(中) 조지방(粗脂肪)과 조단백질(粗蛋白質)은 각각(各各) 40.40% 및 28.36%였다. 2. 수박씨의 지질(脂質)은 중성지질(中性脂質)이 97.35%였으며, 중성지질(中性脂質)의 성분(成分)으로는 triglyceride(50.40%) diglyceride(21.84%) 및 sterol(11.48%)이 대부분(大部分)을 차지하고 있었다. 3. 지방산(脂肪酸) 조성(組成)은 linoleic acid(55.30~67.85%) palmitic acid(12.07~28.12%) 및 oleic acid(9.06~16.40%)가 주(主) 지방산(脂肪酸)이었으며, 그밖에 stearic acid와 linolenic acid가 소량(少量)씩 함유(含有)되어 있었다. 4. 염(鹽)(0.7M $MgSO_4$)용해성(溶解性) 단백질(蛋白質)의 추출율(抽出率)은 약(約) 27%, 아미노산(酸) 조성(組成)은 glutamic acid와 arginine이 높은 함량(含量)이었고, lysine, threonine, valine, methionine, isoleucine, leucine 및 phenylalanine과 같은 필수(必須) 아미노산(酸)이 검출(檢出)되었다. 5. 호박씨 단백질(蛋白質)의 전기영동(電氣泳動) band는 6개로 나타났고, 분획(分劃)된 주(主) 단백질(蛋白質)의 수율(收率)은 52.4%였으며, 아미노산(酸) 조성(組成)은 전체 단백질(蛋白質)에서와 같이 glutamic acid와 arginine이 높게 나타났다. 6. 염용해성(鹽溶解性) 단백질(蛋白質)에서 분획(分劃)된 주(主) 단백질(蛋白質) 분자량(分子量)은 약(約) 120,000이었다.

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$O_2$RTA 방법으로 제조된 $Ta_2O_{5-x}$ 박막의 전기적 특성 (A Study on Electrical Properties of $Ta_2O_{5-x}$ Thin-films Obtained by $O_2$ RTA)

  • 김인성;송재성;윤문수;박정후
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제51권8호
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    • pp.340-346
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    • 2002
  • Capacitor material utilized in the downsizing passive devices and integration of passive devices requires the physical and electrical properties at given area such as capacitor thickness reduction, relative dielectric constant increase, low leakage current and thermal stability. common capacitor materials, $Al_2O_3$, $SiO_2$, $Si_3N_4$, $SiO_2$/$Si_3N_4$, TaN and et al., used until recently have reached their physical limits in their application to integration of passive devices. $Ta_2O_{5}$ is known to be a good alternative to the existing materials for the capacitor application because of its high dielectric constant (25~35), low leakage current and high breakdown strength. Despite the numerous investigations of $Ta_2O_{5}$ material, there have little been established the clear understanding of the annealing effect on capacitance characteristic and conduction mechanism. This study presents the dielectric properties $Ta_2O_{5}$ MIM capacitor structure Processed by $O_2$ RTA oxidation. X-ray diffraction patterns showed the existence of amorphous phase in $600^{\circ}C$ annealing under the $O_2$ RTA and the formation of preferentially oriented-$Ta_2O_{5}$ in 650, $700^{\circ}C$ annealing and the AES depth profile showed $O_2$ RTA oxidation effect gives rise to the $O_2$ deficientd into the new layer. The leakage current density respectively, at 3~1l$\times$$10_{-2}$(kV/cm) were $10_{-3}$~$10_{-6}$(A/$\textrm{cm}^2$). In addition, behavior is stable irrespective of applied electric field. the frequency vs capacitance characteristic enhanced stability more then $Ta_2O_{5}$ thin films obtained by $O_2$ reactive sputtering. The capacitance vs voltage measurement that, Vfb(flat-band voltage) was increase dependance on the $O_2$ RTA oxidation temperature.

UV 기반 백색 LED용 청색 형광체의 발광특성 및 백색 LED 제조 (Luminescence Characteristics of Blue Phosphor and Fabrication of a UV-based White LED)

  • 정형식;박성우;김태훈;김종수
    • 한국광학회지
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    • 제25권4호
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    • pp.216-220
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    • 2014
  • UV용 청색 형광체 $CaMgSi_2O_6:Eu^{2+}$를 환원 분위기 속에서 고상반응법(Solid-state reaction)으로 합성하였다. 합성된 형광체의 결정성을 확인하기 위해 X-선 회절(X-ray diffraction) 패턴 측정결과 C2/c(15)의 공간군과 단사정계(Monoclinic) 구조를 가지는 JCPDS No.75-1092와 일치하는 단일상임을 확인하였다. 광 여기 및 발광 스펙트럼을 통하여 350 nm 부근에서 최대 흡수치가 나타나며, 450 nm의 청색 발광을 보인다. 이는 $Eu^{2+}$이온의 $4f^7-4f^65d$의 천이에 기인한다. 온도에 따른 형광체의 발광 스펙트럼을 확인한 결과 $100^{\circ}C$에서 54%의 휘도 유지율을 보였다. 상기 합성된 $CaMgSi_2O_6:Eu^{2+}$와 400 nm의 Ultra Violet 발광 다이오드를 이용하여 상용 녹색, 적색 형광체와 혼합하여 백색 LED를 구현 하였다. 구현된 백색 LED는 구동 전류 350 mA, 구동 전압 3.45 V에서 색좌표 x=0.3936, y=0.3605, 색온도(CCT) 3500 K, 연색성(CRI) 87, 발광 효율 18 lm/w로 나왔다. 또한 400시간 기준 수명 시험 결과 초기광도 대비 97%의 유지율을 보였다. 따라서 본 연구를 통해 합성한 청색 형광체 $CaMgSi_2O_6:Eu^{2+}$는 UV LED기반의 백색 조명용 형광체로서의 가치가 있는 것으로 생각된다.

Visible Light Driven ZnFe2Ta2O9 Catalyzed Decomposition of H2S for Solar Hydrogen Production

  • Subramanian, Esakkiappan;Baeg, Jin-Ook;Kale, Bharat B.;Lee, Sang-Mi;Moon, Sang-Jin;Kong, Ki-Jeong
    • Bulletin of the Korean Chemical Society
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    • 제28권11호
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    • pp.2089-2092
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    • 2007
  • Tantalum-containing metal oxides, well known for their efficiency in water splitting and H2 production, have never been used in visible light driven photodecomposition of H2S and H2 production. The present work is an attempt in this direction and investigates their efficiency. A mixed metal oxide, ZnFe2Ta2O9, with the inclusion of Fe2O3 to impart color, was prepared by the conventional ceramic route in single- and double-calcinations (represented as ZnFe2Ta2O9-SC and ZnFe2Ta2O9-DC respectively). The XRD characterization shows that both have identical patterns and reveals tetragonal structure to a major extent and a minor contribution of orthorhombic crystalline system. The UV-visible diffuse reflection spectra demonstrate the intense, coherent and wide absorption of visible light by both the catalysts, with absorption edge at 650 nm, giving rise to a band gap of 1.9 eV. Between the two catalysts, however, ZnFe2Ta2O9-DC has greater absorption in almost the entire wavelength region, which accounts for its strong brown coloration than ZnFe2Ta2O9-SC when viewed by the naked eye. In photocatalysis, both catalysts decompose H2S under visible light irradiation (λ ≥ 420 nm) and produce solar H2 at a much higher rate than previously reported catalysts. Nevertheless, ZnFe2Ta2O9-DC distinguishes itself from ZnFe2Ta2O9-SC by exhibiting a higher efficiency because of its greater light absorption. Altogether, the tantalum-containing mixed metal oxide proves its efficient catalytic role in H2S decomposition and H2 production process also.