Browsing by Author "Yogesh Kumar"

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A novel ground bounce reduction technique using four step power gating
(2013) Yogesh Kumar; Shubham Paliwal; Chandan Kr. Rai; S.K. Balasubramanian
The power gating is a technique to reduce leakage power in standby mode by using Sleep switch. In power gating, the circuit suffers the ground bouncing due to the switching of the Sleep Transistor from standby mode to active mode. In this paper, we have presented a four step power gating technique for further reducing the Ground/Power bouncing. This technique not only controls the bouncing but also controls the wake-up time and transition energy overheads in transition period. To control the wakeup time, pre-boosting and post-boosting current technique is applied by using two MOS transistors, limiting the discharge current and voltage swing in noise limiting stage. Application of proposed technique reduces 73% and 20% bounce noise as compared to conventional power gating and three step power gating techniques respectively. Simulations are carried out using 4-bit Ripple Carry Adder as low Vth logic circuit in Cadence Virtuoso simulation environment and UMC 0.18μm technology. © 2013 IEEE.
AIE active quinazoline based probes for selective detection of Fe3+ and acidochromism
(Elsevier B.V., 2023) Yogesh Kumar; Nikhil Kumar Singh; Sujay Mukhopadhyay; Daya Shankar Pandey
Synthesis and thorough characterizations of two A-D-π-A’ type asymmetric donor–acceptor constructs 6-(4-(4-(pyridin-2-yl)piperazin-1-yl)-phenyl)-5,6-dihydrobenzo-[4,5]-imidazo[1,2–c]-quinazoline (P1) and 6-(4-(4-(pyrimidin-2-yl)-piperazin-1-yl)phenyl)-5,6-dihydro-benzo[4,5]-imidazo[1,2–c] quinazoline (P2) have been described. The formation and composition of these compounds have been ascertained by spectroscopic studies (IR, 1H, 13C, ESI–MS, UV/Vis and fluorescence). Quinazoline unit in P1 and P2 acts as acceptor whereas piperazine as donor moiety and their properties has further been tuned by incorporating pyridyl and pyrimidyl group. AIE behaviour of P1 and P2 have been studied in THF/water by absorption and emission spectroscopy by varrying water fraction. Prominent role of the restriction of intra-molecular rotation on (RIR) in AIE for these compounds has been supported by viscosity measurements. Photophysical behaviour and morphology of the aggregates have been investigated by UV/Vis, fluorescence, and scanning electron microscopy (SEM). Owing to asymmetric donor–acceptor (A-D- π -A’) nature these display (twisted intramolecular charge transfer) TICT via D-A unit. In addition, P1 and P2 serve as highly selective and sensitive fluorescence sensor for Fe3+ and Job's plot analysis suggested 2:1 binding stoichiometry between the metal centre Fe3+ and probes. As well, P1 and P2 display promising reversible acidochromism. © 2022
An AIE active BODIPY based fluorescent probe for selective sensing of Hg 2 + via dual mechanism PET and CHEF
(World Scientific, 2021) Vishwa Deepak Singh; Rajendra Prasad Paitandi; Yogesh Kumar; Daya Shankar Pandey
A pyrazole appended BODIPY ligand (L) is synthesized and thoroughly characterized by various spectroscopic studies (1H, 13C, 11B, 19F, ESI-MS, UV-vis and fluorescence). The ligand (L) displays aggregation induced emission (AIE) in solution (a mixture of CH3OH and water) and solid state. The vital role of the restriction of intramolecular rotation (RIR) in AIE is supported by viscosity experiments and fluorescence lifetime studies. Photophysical behaviour and aggregate morphology is investigated by UV-vis, emission and scanning electron microscopy (SEM). Multiple strong intermolecular hydrogen bonds (C-H ··· N and C-H ···F) play a significant role in the AIE response. In addition, L shows strong sensitivity toward Hg2+ion via chelation induced enhanced fluorescence (CHEF) mechanism. Job's plot analysis suggested a 1:1 binding stoichiometry between L and Hg2+, which has been further supported by electrospray ionization mass spectrometry and density functional theory. © 2021 World Scientific Publishing Company.
Artificial light-harvesting systems (LHSs) based on boron-difluoride (BF2) hydrazone complexes (BODIHYs)
(Royal Society of Chemistry, 2021) Vishwa Deepak Singh; Bhupendra Kumar Dwivedi; Yogesh Kumar; Daya Shankar Pandey
In the quest to develop artificial light-harvesting systems (LHSs) with high energy transfer efficiency, hydrazone ligands L1-L2 and their -BF2 complexes (BODIHYs; B1 and B2) have been synthesized. Ligands L1 and L2 and the BODIHYs have been thoroughly characterized by various techniques (1H, 13C, 11B, and 19F NMR, ESI-MS, UV-vis and fluorescence). Further, the BODIHYs (B1 and B2) have been utilized as a new platform for artificial LHSs. It has been categorically shown that efficient artificial LHSs can be achieved by combining AIEgens B1 and B2 with rhodamine B (RhB) under aqueous conditions. In these systems B1 and B2 serve as a donor while RhB as an acceptor. The calculated energy transfer efficiency and antenna effect for the BODIHYs in combination with RhB came out to be appreciably high (B1 = 68%, 28.7; B2 = 80%, 35.5) at a donor/acceptor ratio of 25 : 1. This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
BODIHY based novel AIEgens and directive role of σ–spacers on their reversible mechanochromism
(Elsevier Ltd, 2021) Vishwa Deepak Singh; Bhupendra Kumar Dwivedi; Yogesh Kumar; Daya Shankar Pandey
Synthesis of the novel hydrazone based ligands (L1–L3) and their borondifluoride (BF2) complexes (BODIHYs; B1–B3) have been described. The ligands and BODIHYs have been thoroughly characterized by spectroscopic studies (1H NMR, 13C NMR, 11B NMR, 19F NMR, ESI–MS, UV–vis and fluorescence) and structures of L1, L2 and B1–B3 determined by X–ray single crystal analyses. Emission behaviour of these compounds in solution and solid state have been fine tuned by varying the σ–spacers (–O, –S and –SO2). Vital role of various interactions in aggregation induced emission (AIE; B1 and B2), aggregation caused quenching (ACQ; B3) and reversible mechanochromism (B1–B3) have been rationalized by X-ray single crystal analyses. Dual emission band (~484 and 550 nm) for B3 have been attributed to the involvement of the intra-/and intermolecular charge transfer processes. The observed hypsochromic shift in these luminophores (upon grinding) successfully reverted back upon exposure to dichloromethane (CH2Cl2). An analysis of the powder X–ray diffraction (PXRD) pattern, before and after grinding advocated alteration of prevailing crystal packing by the external force as it rescinds the weak intra-/and intermolecular interactions of the molecule. © 2020 Elsevier Ltd
Clinical and metabolic markers based study of Swas Kasa Chintamani Rasa (An Ayurvedic herbo-metallic preparation) in childhood bronchial asthma (Tamak Swas)
(BRNSS Publication Hub, 2014) Yogesh Kumar; Brij Mohan Singh; Prashant Gupta
Background: Asthma is a problem worldwide, with an estimated 300 million affected individuals. It is a disease of the respiratory system, characterised by intermittent inflammation, constriction or obstruction of the airways leading to a temporary reduction in airflow, and associated shortness of breath. Aims: In Ayurveda, there are lots of drugs to treat the bronchial asthma (Tamak Swas), among them Swas-Kasa-Chintamani Rasa (SKCR) is considered a good drug to cure. Materials and Methods: A total of consented 23 children of both sex under 12 years of age were included in the study and divided into three groups, blood samples were collected before treatment and after the completion of therapy for the metabolic markers like Hb gm%, TLC, AEC, S. Protein, S. Albumin, SGOT, SGPT, alkaline phosphatase and S. Bilirubin. SKCR was given for a total of 45 days in a dose of 4 mg/kg/dose × 12 hourly with garlic, ginger and honey in ratio of 1:2:4. Statistical Analysis Used: In the present study, SPSS software was used to get statistical data such as Mean (X-), Mean Difference (d′), Standard Deviation (SD) and Student′s "t" test, etc. Results and Conclusions: The findings suggest that the drug is more effective in those cases who are not receiving corticosteroid with bronchodilator in comparison to children receiving corticosteroids with/without bronchodilator. No specific adverse effect of drug SKCR was observed.
Competitive ICT in asymmetric D−A Scaffolds showing visible solvatochromism, temperature-induced emission enhancement and AIE based acidochromism
(Elsevier B.V., 2022) Ashish Kumar Kushwaha; Yogesh Kumar; Surendra Kumar; Roop Shikha Singh
Meticulous attention to details of intramolecular charge transfer (ICT) has proved to be an effective strategy to design donor-acceptor fluorophores equipped with multichromic behaviour. Herein, we report three asymmetric donor-acceptor fluorophores bearing A′−D−A−D−A′ and D′−D−A−D−D′ scaffolds. The D−A−D core has been modified by appending pyridine/pyrimidine as additional acceptor and phenyl as additional donor and piperazine as flexible spacers. The asymmetric scaffold has equipped them with naked-eye solvatochromism even under daylight which further authenticated the effective charge separation in ground as well as excited state. The comparative account of photophysical behaviour displays the varying extent of twisted intramolecular charge transfer (TICT) owing to asymmetry. The interplay of restricted intramolecular rotation (RIR) and TICT leads to AIE induced H+ sensing and reversible acidochromism in PC1 which can be visualized by a comparatively uncommon acid induced emission enhancement. The activation of vibrational bands at higher temperature leads to a rare temperature induced emission enhancement in PC1−PC3. PC1 has been developed as the very first ‘turn-on’ thermochromic sensor based on β-diketone-boron difluoride (BF2bdk) complexes. © 2022 Elsevier B.V.
Design and synthesis of heteroleptic Ni(II) dipyrrin complexes for electrochemical proton reduction reactions: Cyclic voltammetric and theoretical studies
(Elsevier B.V., 2024) Rajendra Prasad Paitandi; Indranil Mondal; Yogesh Kumar; Nikhil Kumar Singh; Daya Shankar Pandey
The effect of nuclearity on electrochemical hydrogen generation using new heteroleptic Ni(II) complexes containing redox-active dipyrrin and dithiocarbamate ligands has been described. Complexes 1–2 have been meticulously characterized by spectroscopic studies (ESI-MS, IR, 1H, 13C NMR, UV–vis) and their structures unambiguously confirmed by X-ray single crystal analyses. Electrocatalytic properties of the complexes toward hydrogen evolution reaction have been investigated by cyclic voltammetric studies in an organic medium in the presence of acetic acid as a weak proton source. Notably, complexes 1 and 2 produce H2 via doubly reduced Ni(II) species i.e. Ni(0) in the presence of acetic acid. Further, these complexes exhibited significant electrocatalytic activity (TOF: 264 (1) and 650 s−1 (2). Controlled potential electrolysis established a minimum Faradaic efficiency of 92 (1) and 96 % (2). Complex 2 exhibited higher turnover frequency relative to 1, while 1 showed lower overpotential (0.35 V) in comparison to 2 (0.45 V). The stability of the complexes and the amount of produced H2 has been investigated by bulk electrolysis study. A tentative mechanism (ECEC; E, electrons and C, chemical steps) and involved intermediate species for the proton reduction reaction for 1 has been established by theoretical studies. © 2024 Elsevier B.V.
DNA/protein binding and anticancer activity of ruthenium (II) arene complexes based on quinoline dipyrrin
(Elsevier B.V., 2023) Nikhil Kumar Singh; Yogesh Kumar; Rajendra Prasad Paitandi; Rajan Kumar Tiwari; Ajay Kumar; Daya Shankar Pandey
Arene ruthenium complexes [(η6–arene)Ru(L)Cl] (η6–arene = benzene, R1; p-cymene, R2) containing the chelating ligand (2–chloro–3–(di(1H–pyrrol–2–yl)methyl)quinoline) (L) have been synthesized and carefully characterized by various studies (1H and 13C NMR, IR, ESI–MS, UV–vis). The structure of R1 has been verified by X-ray single crystal analyses. Binding of the complexes with calf thymus DNA (CT–DNA) has been investigated by absorption titration, ethidium bromide (EB) displacement and viscosity measurements. Experimental binding constants (5.1 × 104 M−1, R1; 5.7 × 104 M−1, R2) suggested appreciable bonding of the complexes with CT–DNA. Fluorescence, synchronous and 3D fluorescence spectroscopic studies showed that complexes strongly bind with bovine serum albumin. Intercalative interaction of the complexes with DNA has been further supported by DFT studies. Our studies have shown potential anticancer activity of both the complexes R1 and R2 against T cell lymphoma. Among these complexes R2 showed better anticancer activity relative to R1 (IC50, R1, 30 μM and R2, 20 μM). © 2022
DNA/Protein binding and anticancer activity of Zn(II) complexes based on azo-Schiff base ligands
(Elsevier B.V., 2022) Yogesh Kumar; Nikhil Kumar Singh; Vishwa Deepak Singh; Irshad Ali; Rajan Kumar Tiwari; Ajay Kumar; Daya Shankar Pandey
Synthesis of the azo–Schiff base ligands 2-((E)-((4-(diethylamino)phenyl)imino)methyl)-4-((E)-(2-(phenylthio)phenyl)diazenyl)phenol (L1) and-((E)-((4-(diethylamino)phenyl)-imino)methyl)-4-((E)-(2-phenoxyphenyl)diazenyl)phenol (L2) and Zn(II) complexes (C1-C2) containing these ligands have been described. Characterization of the ligands and complexes has been achieved by spectral studies (IR, 1H, 13C, ESI–MS, UV/vis., emission) and structures of C1 and C2 verified by X-ray single crystal analyses. Absorption titration studies on the complexes revealed that these strongly interact with calf thymus DNA (CT-DNA). Calculated equilibrium binding constants (Kb) for C1 and C2 converged to 4.51 × 104 and 3.74 × 104. Protein binding studies of the complexes with BSA have been performed by UV/vis, fluorescence, synchronous and 3D fluorescence spectroscopy. MTT assay toward Hut-78 cell line suggested high cytotoxicity for C1 (IC50: 70 μM) relative to C2 (IC50: 110 µM). Upon irradiation (UV light; λ, 365 nm) the complexes C1 and C2 exhibited cis–trans photo isomerization and after withdrawal of the light these settled back to more stable trans form. Rate constant (k) for photo isomerization of C1 and C2 has been worked out using electronic absorption data (2.29 × 10−2, C1; 2.12 × 10−2 s−1, C2) and supported by theoretical studies (DFT). © 2022 Elsevier B.V.
Effect of substituents on photophysical and aggregation behaviour in quinoline based bis-terpyridine Zn(II) complexes
(Elsevier S.A., 2019) Vishwa Deepak Singh; Bhupendra Kumar Dwivedi; Rajendra Prasad Paitandi; Yogesh Kumar; Daya Shankar Pandey
Synthesis of the terpyridine based novel Zn(II) complexes (C1–C3) have been described. Characterization of these complexes has been achieved by spectroscopic studies (IR, 1H, 13C, 19F, HRMS, UV/Vis and fluorescence) and structure of C1 determined by X-ray single crystal analyses. Cautious tuning by incorporating appropriate substituents (–H; C1, –CH3; C2 and –OCH3; C3) enabled the complexes to exhibit solvent dependent emission indicative of more polarized excited state probably due to enhanced intramolecular charge transfer (ICT). Occurrence of aggregation induced emission (AIE) in C3 has been validated by solid state emission and vital role of RIR in inducing AIE upon aggregation by fluorescence lifetime experiments. The role of solvent and substituents on photophysical behaviour and morphology of the complexes has been investigated by UV/Vis, emission and scanning electron microscopy (SEM). As well, lowering of the energy gap between HOMO and LUMO by electron donating substituents –CH3 (C2) and –OCH3 (C3) has been supported by DFT studies. © 2018 Elsevier B.V.
Elaborative Studies on Non-Porous Carbon Material for Super Capacitor Application
(Wiley-VCH Verlag, 2019) Pawan S. Dhapola; Nanda G. Sahoo; Bhaskar Bhattacharya; Yogesh Kumar; Pramod K. Singh; Meenal Gupta
This study demonstrates a simplistic and effectual approach to prepare non-porous carbon for which nitrogen is doped in poly(vinyl chloride) (PVC) in presence of catalyst cobalt chloride (COCl2). Characterization of the prepared non-porous carbon is carried out using Raman, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, and Brunauer–Emmett–Teller. The calculated surface area of the prepared carbon is 15.78 m2 g−1. To compare the performance of prepared non-porous carbon with pure PVC as an electrode material for supercapacitor application, two EDLC cells are prepared. In both the cells, 1-ethyl-3-methylimidazolium thiocyanate (ionic liquid) is used as an electrolyte and filter paper is used as a separator. Six times increment is found in the specific capacitance value of EDLC prepared using nitrogen-doped carbon (NC-CO) than prepared using pure PVC. The calculated specific capacitance values using low-frequency impedance spectroscopy are 62.28 and 7 F g−1, respectively, for NC-CO and pure PVC. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Impact of cropping systems on pedogenic distribution and transformations of micronutrients, plant accumulation and microbial community composition in soils: a review
(Springer, 2023) S.S. Dhaliwal; Raj Gupta; A.K. Singh; R.K. Naresh; Agniva Mandal; U.P. Singh; Yogesh Kumar; S.K. Tomar; N.C. Mahajan
Different types of agricultural cropping systems involving wheat coupled with rice, maize and cotton are adapted by most of the farmers around the world. In order to increase the production of food grains with the adaptation of these cropping systems, intensive cultivation is required which eventually needs more quantity of macro as well as micronutrients. The availability of micronutrients to plants is majorly affected by cropping patterns and their profile distribution and the chemical pools. For instance, rice–wheat (R-W) cropping system depletes the available micronutrients status in soil. Many crops have a deep root system that allows them to fulfill their micronutrients requirement from deeper soil layers. In pedon, the surface layer of soil is richer in micronutrients than sub-surface soils. Thus, the knowledge of all the forms or fractions of micronutrient in soil and conditions that help in converting them to their available forms is essential. Excessive use of macronutrient fertilizers in soil with alkaline pH, results in an upsurge accumulation of micronutrients under R-W system. Consequently, it is essential to understand the relationship between accumulation of micronutrients by plants and different chemical pools of micronutrients and their distribution in the pedon. Also, the incorporation of different crops in various cropping systems has a marked influence on microbial communities in soil which play a crucial role in nutrient cycling, gaseous exchanges, aggregation and soil biochemical processes that ultimately influences crop productivity and soil health. Thus, imaging the extent of micronutrient availability to plants, various fractions of micronutrients and microbial community in soil under different cropping systems is necessary. © 2022, International Society for Tropical Ecology.
Improving Chickpea Genetic Gain Under Rising Drought and Heat Stress Using Breeding Approaches and Modern Technologies
(Springer Nature, 2022) Uday C. Jha; Harsh Nayyar; Rintu Jha; Prasant Kumar Singh; Girish Prasad Dixit; Yogesh Kumar; Biswajit Mondal; Avinash Kumar Srivastava; Eric J. B. von Wettberg; Pronob J. Paul; Ajaz A. Lone; Srinivasan Samineni; Sailesh K. Tripathi; Kadambot H. M. Siddique
Increasing grain legume production, particularly for chickpea, will provide essential “plant-based dietary protein” and other micronutrients under the changing global climate. Drought and terminal heat stress limit plant growth and negatively affect various phenological events, causing severe yield losses. Among various strategies for improving stress tolerance, the judicious utilization of available genetic variation in the chickpea gene pool could minimize the adverse effects of drought and heat stress, sustaining chickpea yields. In addition, advancements in chickpea genomic resources, from molecular markers, namely, SSR, SNP, and INDELs and tools for association genetics, RNA-seq, to the availability of chickpea genome sequences and efforts of global chickpea germplasm resequencing allow us to identify loci and haplotypes contributing to drought and heat tolerance across the whole genome. Thus, molecular markers have enabled the successful transfer of drought-tolerant traits to elite chickpea cultivars using marker-assisted and haplotype-based breeding approaches. Likewise, the role of drought- and heat-responsive proteins and metabolites could significantly improve our understanding of the molecular mechanisms of drought and heat tolerance in chickpea via proteomics and metabolomics. Moreover, emerging novel breeding technologies (e.g., genomic selection, speed breeding, and genome editing) could enhance the necessary genetic gain to feed the increasing global population under an abruptly changing global climate. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022.
Long-term application of agronomic management strategies effects on soil organic carbon, energy budgeting, and carbon footprint under rice–wheat cropping system
(Nature Research, 2024) R.K. Naresh; P.K. Singh; Rajan Bhatt; Mandapelli Sharath Chandra; Yogesh Kumar; N.C. Mahajan; S.K. Gupta; Nadhir Al-Ansari; Mohamed A. Mattar
In the plains of western North India, traditional rice and wheat cropping systems (RWCS) consume a significant amount of energy and carbon. In order to assess the long-term energy budgets, ecological footprint, and greenhouse gas (GHG) pollutants from RWCS with residual management techniques, field research was conducted which consisted of fourteen treatments that combined various tillage techniques, fertilization methods, and whether or not straw return was present in randomized block design. By altering the formation of aggregates and the distribution of carbon within them, tillage techniques can affect the dynamics of organic carbon in soil and soil microbial activity. The stability of large macro-aggregates (> 2 mm), small macro-aggregates (2.0–2.25 mm), and micro-aggregates in the topsoil were improved by 35.18%, 33.52%, and 25.10%, respectively, over conventional tillage (0–20 cm) using tillage strategies for conservation methods (no-till in conjunction with straw return and organic fertilizers). The subsoil (20–40 cm) displayed the same pattern. In contrast to conventional tilling with no straw returns, macro-aggregates of all sizes and micro-aggregates increased by 24.52%, 28.48%, and 18.12%, respectively, when conservation tillage with organic and chemical fertilizers was used. The straw return (aggregate-associated C) also resulted in a significant increase in aggregate-associated carbon. When zero tillage was paired with straw return, chemical, and organic fertilizers, the topsoil's overall aggregate-associated C across all aggregate proportions increased. Conversely, conventional tillage, in contrast to conservation tillage, included straw return as well as chemical and organic fertilizers and had high aggregate-associated C in the subsurface. This study finds that tillage techniques could change the dynamics of microbial biomass in soils and organic soil carbon by altering the aggregate and distribution of C therein. © 2024, The Author(s).
Photophysical properties of some novel tetraphenylimidazole derived BODIPY based fluorescent molecular rotors
(Royal Society of Chemistry, 2020) Bhupendra Kumar Dwivedi; Vishwa Deepak Singh; Yogesh Kumar; Daya Shankar Pandey
The strategic design, synthesis and thorough characterization of four novel hydroxyl-substituted tetraphenylimidazole (HPI) based boron dipyrromethene (BODIPY) fluorophores (HPIB1-HPIB4) have been reported. Single crystal X-ray structure determination unveiled non-planar twisted orientations for these molecules. The non-planar orientations entirely restrict detrimental π-π interactions and avoid the non-radiative relaxation pathway for excited states in the solid/aggregated state and make them AIE active. The AIE characteristics of these compounds have been related to fine J-aggregation (evident from their crystal structures) along with restricted intra-molecular rotations (RIRs). These compounds display significant sensitivity toward viscosity and can serve as fluorescent molecular rotors due to multiple phenyl groups around the imidazole ring, which has been confirmed by measuring fluorescence quantum yields and lifetimes. © 2020 The Royal Society of Chemistry.
Publisher Correction: Long-term application of agronomic management strategies effects on soil organic carbon, energy budgeting, and carbon footprint under rice–wheat cropping system (Scientific Reports, (2024), 14, 1, (337), 10.1038/s41598-023-48785-z)
(Nature Research, 2024) R.K. Naresh; P.K. Singh; Rajan Bhatt; Mandapelli Sharath Chandra; Yogesh Kumar; N.C. Mahajan; S.K. Gupta; Nadhir Al-Ansari; Mohamed A. Mattar
In the original version of this Article, Mohamed Mattar was omitted as a corresponding author. Correspondence and requests for materials should also be addressed to mmattar@ksu.edu.sa. © The Author(s) 2024.
Sensitivity Analysis of DSSAT CERESWheat Model for Uttar Pradesh for Variations
(Apple Academic Press, 2024) Yogesh Kumar; Shivam Sharma; Sushan Rungta; Anil Kumar Singh; Ganesh B. Gohain; Mahfooz Alam
Plant growth is impacted by variation in atmospheric conditions. The impacts of changes in the climate on the growth and maturation of the plant body may be estimated and assessed using crop simulation models (CSMs). In order to assess the model’s sensitivity to alterations in a variety of climatic parameters, including rainfall, minimum and maximum temperature, DSSAT CSM integrated with a wheat model – CERES (crop environment resource synthesis) was used over four growing seasons (2015-2016 to 2018-2019) for Meerut district of Uttar Pradesh state on three different dates of sowing (DOS) 15th Nov (D1), 22nd Nov (D2) and 29th Nov (D3) with a variety HD2967 (V1). The Sensitivity analysis study showed yield variation due to changes in meteorological parameters. The actual maximum temperature increased by 1.0 °C, 2.0 °C, and 3.0 °C, and decreased by 1.0 °C, 2.0 °C, and 3.0 °C for the whole crop season using the environmental modification field to check the impact on crop yield. The observed yield and crop simulation yield results have less percent deviation on 22nd Nov (D2) as compare the results with 15th Nov (D1) and 29th Nov (D3) for study area and the simulated yield increases with successive increase of maximum temperature and decreases by successive decrease of maximum temperature of wheat crop for Meerut district. © 2025 by Apple Academic Press, Inc.
Single quantum dot rectifying diode with tunable threshold voltage
(Royal Society of Chemistry, 2017) Gopal S. Kenath; Piyali Maity; Yogesh Kumar; Hemant Kumar; Vinod K. Gangwar; Sandip Chaterjee; Satyabrata Jit; Anup K. Ghosh; Bhola N. Pal
An ambient atmosphere single quantum dot (QDs) rectifying diode with tunable threshold voltage has been fabricated using cobalt (Co) doped CdS QDs with a device structure of ITO/ZnO/QDs. Current-voltage (I-V) characterization of this device has been tested using ambient atmosphere scanning tunnelling microscope (STM). The scanning tunnelling spectra (STS) shows a very high rectification behavior of this single dot based device with a ratio of 103. The threshold voltage of this device decreases with increase in doping concentration of QDs. Reduction of this turn-on voltage occurs due to the formation of additional energy band of Co impurity within the band gap of QDs that exist closer to the valance band (VB) of CdS. Existence of this additional energy band has also been observed in the UV-VIS absorption data of Co doped CdS, which introduces an additional absorption peak in the near infrared region. This impurity band is fully populated at room temperature and the width of this band increases with doping concentration, which is the key for the tunability of threshold voltage. This finding has been explained with one empirical model of relative band shifting of semiconductor-QDs-tip interfaces with positive and negative substrate bias. © 2017 The Royal Society of Chemistry.
Solid state emissive azo-Schiff base ligands and their Zn(ii) complexes: Acidochromism and photoswitching behaviour
(Royal Society of Chemistry, 2021) Yogesh Kumar; Vishwa Deepak Singh; Bhupendra Kumar Dwivedi; Nikhil Kumar Singh; Daya Shankar Pandey
The synthesis of Zn(ii) complexes (C1-C2) based on azo-Schiff base ligands 2-((E)-(phenyl-imino)methyl)-4-((E)-(2-(phenylthio)phenyl)diazenyl)phenol (L1) and 4-((E)-(2-(phenyl-thio)phenyl)diazenyl)-2-((E)-(p-tolylimino)methyl)phenol (L2) has been described. These have been thoroughly characterized by spectroscopic studies (IR, 1H, 13C, ESI-MS, electronic absorption, emission) and the structures of C1 and C2 have been determined by X-ray single crystal analyses. The ligands L1 and L2 exhibit reversible acid/base induced "ON-OFF-ON"switching in solution and solid state. Upon exposure to UV light (λ, 365 nm) C1 and C2 display cis-trans photoisomerisation and after removal of light they transform to more stable trans-form. Electronic absorption and 1H NMR studies on C1 and C2 revealed rather rapid (1.27 × 10-1 s-1) photoisomerization for C2 relative to C1 (2.7 × 10-2 s-1) which has also been supported by theoretical studies (DFT). The rather fast photoisomerization for C2 compared to C1 may be related to a small energy gap between HOMO and LUMO levels for the respective isomers. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.