Template Transformation Research Articles

Self-sacrificing MOF-74 to amorphous CoMoS4 hollow tube with nanosheet surface for high stability supercapacitors

Designing high-performance electrodes and elucidating their energy storage mechanisms are crucial for supercapacitors. In this study, an in situ conversion method is firstly employed to transform CoCH (Co(CO3)0.5(OH)·0.11 H2O) into Co-MOF-74 nanorods, which serves as a self-sacrificial template. Subsequently, the amorphous CoMoS4 hollow tube arrays with self-assembled nanosheet surfaces are obtained through MoO42- etching and S2- exchange. Benefiting from the nanosheets-coated hollow tubular structure and amorphous characteristics, CoMoS4 exhibits a high areal capacitance of 7.01 F·cm−2 at 2 mA·cm−2 and 91.81 % retention after 5000 cycles. When further assembled into a hybrid supercapacitor, the CoMoS4//AC device exhibits excellent performance with the energy density of 0.684 mWh·cm−2 at 1.876 mW·cm−2 and 91.39 % retention after 10000 cycles. Furthermore, the mechanism study reveals that Mo- and S-doped amorphous CoOOH is a genuine energy storage material. This work provides valuable insights into the preparation of amorphous materials using the self-sacrificial template transformation method and the understand of their energy storage mechanisms.

Study of binder effect on the lithium storage kinetics of copper phosphide nanotube anode

Copper phosphide (CP) stands out as a promising anode material for lithium-ion batteries due to its high theoretical capacity (1281 mAh g−1). However, the fast capacity decay of copper phosphide poses a significant challenge due to its huge volume change. Optimization of binder selection presents an effective way to harness the high lithium storage capacity of copper phosphide. In this study, copper phosphide nanotubes were synthesized using a hard template transformation method. The following investigation delved into the impact of different binders on the electrode structure and the lithium-ion storage performance of copper phosphide. Notably, employing polyacrylic acid (PAA) as a binder resulted in a stable capacity of 526.8 mAh g−1 over 400 cycles at 100 mA g−1 for the copper phosphide electrode. The remarkable lithium-ion storage property of the CP-PAA electrode is ascribed to the robust interaction between PAA and the P–O bond on the copper phosphide surface. This interaction not only mitigated volume expansion but also enhanced the kinetics of electrochemical reactions.

Extraction of intersecting palm‐vein and palmprint features for cancellable identity verification

AbstractA novel method based on the cross‐modality intersecting features of the palm‐vein and the palmprint is proposed for identity verification. Capitalising on the unique geometrical relationship between the two biometric modalities, the cross‐modality intersecting points provides a stable set of features for identity verification. To facilitate flexibility in template changes, a template transformation is proposed. While maintaining non‐invertibility, the template transformation allows transformation sizes beyond that offered by the conventional means. Extensive experiments using three public palm databases are conducted to verify the effectiveness the proposed system for identity recognition.

The reversibility of cancelable biometric templates based on iterative perturbation stochastic approximation strategy

Researchers have been proposing different matching frameworks for cancelable template design to improve the matching performance and security of biometric authentication systems. Despite the advantages provided by these systems, they are often vulnerable to different attacks due to their templates' invertible nature. This study utilized an iterative perturbation stochastic approximation procedure to analyze the irreversible order-based encoding approach used in cancelable biometric template transformation. The strategy begins by exploiting the scores corresponding to the encoded words, then a mixed variable-based iterative perturbation is used to generate independent random elements and consequently the corresponding template from the scores. The strategy exploits the vulnerability of three different cancelable systems it has tested, demonstrating that other techniques of similar nature fall short of the security standard for attack mitigation that cancelable biometric systems require. After analyzing the reasons that exploit the system's vulnerability, we use a parameterized thresholding non-uniform quantization as a countermeasure to boost the system's robustness while maintaining a balanced performance-security trade-off. As a result, the system can evade attacks without significantly hindering its matching performance. Finally, generality and computational complexity evaluations on different modalities and strategies validate the attack's efficacy and realism, respectively.

Crystalline-amorphous core-shell copper vanadate coralline as anode material for high-performance lithium-ion battery

Constructing electrode materials with core-shell structures is considered an effective strategy to enhance the electrochemical performance of lithium-ion batteries (LIBs) anode. Herein, a novel amorphous copper vanadium oxide coated crystalline copper vanadates was designed and synthesized through a template transformation route. The copper vanadates showed a three-dimension coralline morphology assembled by nanoparticles. When applied to the LIBs anode, the as-prepared electrode exhibited a large reversible capacity (967 mAh g−1), superior rate performance (390 mAh g−1 at 5 A g−1), and cycle stability (98.2% retention after 200 cycles). This enhanced lithium storage was related to the synergistic effect of the amorphous buffer layer and abundant oxygen vacancies that could buffer volume expansion and promote the pseudo-capacitance behavior.

Multimodal Biometric Template Transformation Approach using a List Ranking Algorithm

User authentication has become vital with the advancement in technologies that comes with an increased threat to security. Biometrics is typically used to secure the data of individuals based on their unique features, such as fingerprints, retinas, and hand geometry. Template transformation is a technique in which the original feature vectors are transformed into modified feature vectors. When these templates are transformed and stored, it becomes difficult for imposters to hack the system. Existing systems store and secure these templates based on key generation. When the key information is compromised, the system can be easily hacked. Hence, in the proposed system, the templates are transformed using a modified list ranking algorithm and then stored for verification. Also, in order to improve security, instead of using a single biometric, the proposed system obtains biometric data from left fingerprints, right fingerprints and palm prints and fuses them into a single feature vector set. Thus, even when the repository is attacked, it would be very difficult to break into the system. The proposed system provides a 2.9 % equal error rate compared with existing systems.

Establishment of Parallel Text Corpus of Equipment Manufacturing Industry Based on Data Mining Technology

In the era of language big data, traditional data analysis methods can’t analyze semi-structured or unstructured data such as text, but all the contents in the equipment manufacturing corpus belong to text data. The equipment manufacturing corpus is a linguistic information base for legal activities and equipment manufacturing research, which aims to study equipment manufacturing and collect equipment manufacturing cases. At present, the construction of legal database in China is not perfect, and there are still many problems. In this paper, a method based on template transformation is proposed to automatically acquire parallel corpus on the Internet, and a method based on the number of transformation patterns and the retrieval and sorting of transformation patterns is adopted to verify bilingual parallel texts. This system can build a large-scale parallel corpus of equipment manufacturing industry by automatically acquiring a large number of parallel texts from the Internet.

A Complete User Authentication and Key Agreement Scheme Using Cancelable Biometrics and PUF in Multi-Server Environment

With the current development and popularization of biometrics recognition technology, our biometrics and other identity information may be illegal bulk scalping, and there is the possibility of being used for false enrolment, network fraud and other illegal criminal activities. Although some network platforms based on biometrics recognition adopt multi-identity authentication, network hacking technology is also improving constantly. Therefore, we must not ignore the importance of biometrics data protection. To this end, we propose a complete user authentication protocol and key agreement scheme based on cancelable biometrics and physical unclonable function (PUF). Firstly, cancelable biometrics are generated by efficient biometrics fusion processing which called “PUF-TTM” (Template Transformation Method) using a PUF embedded into the device. Then based on Biometrics-as-a-Service (BaaS) model and secret sharing technology, a complete authentication protocol in multi-server environment is designed, and the robustness, effectiveness and security of our proposed scheme are ensured from the perspective of performance and security analysis.

In Situ Pyrolysis Tracking and Real‐Time Phase Evolution: From a Binary Zinc Cluster to Supercapacitive Porous Carbon

The in situ tracking of the pyrolysis of a binary molecular cluster [Zn7 (μ3 -CH3 O)6 (L)6 ][ZnLCl2 ]2 is presented with one brucite disk and two mononuclear fragments (L=mmimp: 2-methoxy-6-((methylimino)-methyl)phenolate) to porous carbon using TG-MS from 30 to 900 °C. Following up the spilled gas product during the decomposed reaction of zinc cluster along the temperature rising, and in conjunction with XRD, SEM, BET and other materials characterization, where three key steps were observed: 1) cleavage of the bulky external ligand; 2) reduction of ZnO and 3) volatilization of Zn. The real-time-dependent phase-sequential evolution of the remaining products and the processing of pore forming template transformation are proposed simultaneously. The porous carbon structure featuring a uniform nano-sized pore distribution synthesized at 900 °C with the highest surface area of 1644 m2 g-1 and pore volume of 0.926 cm3 g-1 exhibits the best known capacitance of 662 F g-1 at 0.5 A g-1 .

In Situ Pyrolysis Tracking and Real‐Time Phase Evolution: From a Binary Zinc Cluster to Supercapacitive Porous Carbon

AbstractThe in situ tracking of the pyrolysis of a binary molecular cluster [Zn7(μ3‐CH3O)6(L)6][ZnLCl2]2 is presented with one brucite disk and two mononuclear fragments (L=mmimp: 2‐methoxy‐6‐((methylimino)‐methyl)phenolate) to porous carbon using TG‐MS from 30 to 900 °C. Following up the spilled gas product during the decomposed reaction of zinc cluster along the temperature rising, and in conjunction with XRD, SEM, BET and other materials characterization, where three key steps were observed: 1) cleavage of the bulky external ligand; 2) reduction of ZnO and 3) volatilization of Zn. The real‐time‐dependent phase‐sequential evolution of the remaining products and the processing of pore forming template transformation are proposed simultaneously. The porous carbon structure featuring a uniform nano‐sized pore distribution synthesized at 900 °C with the highest surface area of 1644 m2 g−1 and pore volume of 0.926 cm3 g−1 exhibits the best known capacitance of 662 F g−1 at 0.5 A g−1.

PolyCodes: generating cancelable biometric features using polynomial transformation

Cancelable biometrics is a template protection technique proposed to bridge the growing gap between ‘biometrics for security’ and ‘security for biometrics’. Various approaches have been reported in literature, yet transforming a biometric template for privacy preservation is a challenging task. The manuscript proposes a random polynomial based template transformation technique to generate protected biometric templates named as ‘PolyCodes’. These protected versions are privacy and discriminability preserving, revocable, and provide significant dimensionality reduction. Several polynomial functions with dimensionality reduction factor ranging from 65% to 90% are designed and evaluated for security and performance. Further, applicability of the proposed ‘PolyCodes’ is experimentally verified for many biometric modalities such as visible and thermal face, palmprint, palmvein, and fingervein.

Random Distance Method for Generating Unimodal and Multimodal Cancelable Biometric Features

The cancelable biometric-based template protection method proposed in this paper addresses security and privacy concerns emerging from the phenomenal usage of biometric systems. Cancelable biometric transforms the original biometric identity of a user to a pseudo-biometric identity that is used for storage and matching purposes. The use of pseudo-identity mitigates privacy risks and allows revocability in case of compromise. This paper proposes a novel template transformation technique named random distance method which not only generates discriminative and privacy preserving revocable pseudo-biometric identities, but also reduces their size by 50%. Extensive experimentation is performed to analyze recognition and protection performance on unimodal and multimodal pseudo-identities generated with various biometric modalities such as face, thermal face, palmprint, palmvein, and fingervein. It is observed that the matching performance obtained with the proposed cancelable templates in the worst-case is closer to the performance achieved in the original domain. Also, multimodal cancelable biometric templates generated with the proposed method are observed for improved performance. Furthermore, the proposed approach is successfully analyzed for non-invertibilty, unlinkability, as well as its resistance for various types of attacks like attacks via record multiplicity, dictionary, false accepts, and brute force.

Multi‐Anion Intercalated Layered Double Hydroxide Nanosheet‐Assembled Hollow Nanoprisms with Improved Pseudocapacitive and Electrocatalytic Properties

Electrochemically active hollow nanostructured materials hold great promise in diverse energy conversion and storage applications, however, intricate synthesis steps and poor control over compositions and morphologies have limited the realization of delicate hollow structures with advanced functional properties. In this study, we demonstrate a one-step wet-chemical strategy for co-engineering the hollow nanostructure and anion intercalation of nickel cobalt layered double hydroxide (NiCo-LDH) to attain highly electrochemical active energy conversion and storage functionalities. Self-templated pseudomorphic transformation of cobalt acetate hydroxide solid nanoprisms using nickel nitrate leads to the construction of well-defined NiCo-LDH hollow nanoprisms (HNPs) with multi-anion intercalation. The unique hierarchical nanosheet-assembled hollow structure and efficiently expanded interlayer spacing offer an increased surface area and exposure of active sites, reduced mass and charge transfer resistance, and enhanced stability of the materials. This leads to a significant improvement in the pseudocapacitive and electrocatalytic properties of NiCo-LDH HNP with respect to specific capacitance, rate and cycling performance, and OER overpotential, outperforming most of the recently reported NiCo-based materials. This work establishes the potential of manipulating sacrificial template transformation for the design and fabrication of novel classes of functional materials with well-defined nanostructures for electrochemical applications and beyond.

Random Slope method for generation of cancelable biometric features

Cancelable biometric templates are transformed versions of original biometric templates used for authentication purposes. The transformation functions should fulfill the important template protection criteria of diversity, revocability, non-invertibility, and performance. Although there exists a number of transformation techniques, yet many of these techniques fail to meet security and privacy requirements in the stolen token scenario and tend to become invertible with degraded performance. The work proposes a novel cancelable biometric technique named as ‘Random Slope’ method for generating secure, revocable, and non-invertible templates. Two approaches (RS-V1 and RS-V2) developed using the proposed concept not only fulfill the important cancelability criteria, but also provide dimensionality reduction upto 75%. The performances of the proposed approaches are experimentally verified for various biometric modalities such as visible and thermal face, palmprint, palmvein, and fingervein. As compared to some state of the art template transformation schemes, the proposed RS-V1 and RS-V2 approaches establish their reliability and effectiveness by performing better than these existing techniques with significant reduction in dimensions.

Ratiometric Catalyzed-Assembly of NanoCluster Beacons: A Nonenzymatic Approach for Amplified DNA Detection.

In this work, a novel fluorescent transformation phenomenon of oligonucleotide-encapsulated silver nanoclusters (AgNCs) was demonstrated, in which green-emissive AgNCs effectively transformed to red-emissive AgNCs when placed in close proximity to a special DNA fragment (denoted as convertor here). Taking advantage of a catalyzed-hairpin-assembly (CHA) amplification strategy, we rationally and compatibly engineered a simple and sensitive AgNC-based fluorescent signal amplification strategy through the ratiometric catalyzed-assembly (RCA) of green-emissive NanoCluster Beacon (NCB) with a convertor modified DNA hairpin to induce the template transformation circularly. The proposed ratiometric fluorescent biosensing platform based on RCA-amplified NCB (RCA-NCB) emits intense green fluorescence in the absence of target DNA and will undergo consecutively fluorescent signal transformation from green emission to red emission upon exposure to its target DNA. The ratiometric adaptation of the NCB to CHA circuit advances their general usability as biosensing platform with great improvements in detection sensitivity. By measuring the fluorescence intensity ratio of the red emission and green emission, the proposed RCA-NCB platform exhibits sensitive and accurate analytical performance toward Werner Syndrome-relevant gene, the proof-of-concept target in this work. A low detection limit down to the pM level was achieved, which is lower than most of the reported AgNC-based fluorescent DNA biosensors, making the proposed RCA-NCB biosensing strategy appealing in amplifying the ratiometric fluorescent signal for sensitive DNA detection. Moreover, our proposed RCA-NCB platform shows good recovery toward the target DNA in real human serum samples, illustrating their potential promise for clinical and imaging applications in the future.

Random Projection-based Cancelable Template Generation for Sparsely Distributed Biometric Patterns

Cancelable biometrics, a template transformation approach, attempts to provide robustness for authentication services based on biometrics. Several biometric template protection techniques represent the biometric information in binary form as it provides benefits in matching and storage. In this context, it becomes clear that often such transformed binary representations can be easily compromised and breached. In this paper, we propose an efficient non-invertible template transformation approach using random projection technique and Discrete Fourier transformation to shield the binary biometric representations. The cancelable fingerprint templates designed by the proposed technique meets the requirements of revocability, diversity, non-invertibility and performance. The matching performance of the cancelable fingerprint templates generated using proposed technique, have improved when compared with the state-of-art methods.

Ionothermal Carbon Nanochemistry and Its Use in Energy Conversion

Nanoporous carbon materials are known for their applicability in important areas such as sorption, catalysis and electrochemistry (e.g. fuel cell catalysts, supercapacitor or battery electrodes) It was shown that mesoporous nitrogen doped carbons (NDCs) act as an inexpensive and highly active non-metal catalyst in the oxygen reduction reaction (ORR), with the potential to reach performances of practical need one day.1More importantly nitrogen doped carbons are acting as solid-state ligand and support material for non-noble catalysts using low cost transition metals like iron or cobalt. This class of materials has the potential for a disruptive technology in fuel cells e.g. for automotive applications. A key strategy towards improvement for this aim comprises the generation of carbons with advantageous porosity, which typically means high surface area and mass transport pores. My group is developing a novel nanochemistry strategy that is using inorganic salt melts as unconventional reaction medium for the porogenesis, thereby revisiting classic activation techniques.2 Carbon materials with extra high surface area and pore volumes, four times as high as in commercial activated carbons, are obtained.3 In our most recent work we introduce an in-situ template transformation as a new tool to develop anisotropic tubular porosity towards highly porous NDCs. While we previously observed that residual solid salt can introduce additional macroporosity, we herein purposely in-situ crystallize nanoscopic fibrous salt crystals acting as anisotropic templates for mass transport nanopores.4 The utilization of magnesium chloride in contrast to the more commonly used zinc chloride supports the scalability and shows the more general applicability of the salt templating strategy. The obtained NDCs show very high specific surface areas up to 2780 m2 g 1 and outstanding total pore volumes up to 3.86 cm3 g-1, because of the present unique nanochannel pores. In a next step, we exploit the unique porosity for the development of a mild low temperature formation of non-noble oxygen reduction catalysts with the conservation of the doped carbon chemistry. Very active catalysts with a half wave potential of up to 0.76 V vs. RHE in 0.05 M H2SO4 are obtained after metalation with iron. The catalyst shows four electron selectivity and exceptional stability with only a very low performance degradation of down to ∆E1/2 = 5 mV after 1000 cycles between 0.4-1.0 V at 50 mV s-1 in O2-saturated electrolyte. The Fe K-edge fourier transform EXAFS profile of the most active catalyst is almost completely matching that of the iron(II) phthalocyanine, indicating the possibility to create active and stable FeN4 sites for advanced non-noble oxygen reduction electrocatalysts at chemically non-destructive low temperatures.

Advanced fingerprinting of high-quality cocoa: Challenges in transferring methods from thermal to differential-flow modulated comprehensive two dimensional gas chromatography

The possibility to transfer methods from thermal to differential-flow modulated comprehensive two-dimensional gas chromatographic (GC×GC) platforms opens interesting perspectives for routine analysis of complex samples. Flow modulated platforms avoid the use of cryogenics, thereby simplifying laboratory operations and analyst supervision during intensive analytical sessions.This study evaluates the feasibility of transferring a fingerprinting method capable of classifying and discriminating cocoa samples based on the volatiles fraction composition according to their origin and processing steps. Previously developed principles of GC×GC method translation are applied to an original fingerprinting method, developed for a loop-type thermal modulated GC×GC–MS system, to engineer a method for a reverse-injection differential flow modulated platform (GC×2GC–MS/FID) with a dual-parallel secondary column and dual detection. Effective method translation preserves analytes elution order, 1D resolution, and 2D pattern coherence.The experimental results confirm the feasibility of translating fingerprinting method conditions while preserving the informative power of 2D peak patterns for sample classification and discrimination. Correct translation enables effective transfer of metadata (e.g., compound names and MS fragmentation patterns) by automatic template transformation and matching from the original/reference method to its translated counterpart. Although the adoption of a narrow bore (i.e. 0.1mm dc) column in the first-dimension enabled operation under close-to-optimal conditions with the differential-flow modulation platform, due to the dual-parallel columns in the second-dimension, it resulted in lower overall method sensitivity. Nevertheless, fingerprinting accuracy was preserved and most of the key-aroma compounds and technological markers were effectively mapped, thus limiting the loss of fingerprinting information.

Ratiometric NanoCluster Beacon: A Label-Free and Sensitive Fluorescent DNA Detection Platform.

Although researches until now have emphasized the influence of an oligonucleotide sequence on the fluorescence of oligonucleotide-stabilized silver nanoclusters (AgNCs), this influence has been explored as a novel ratiometric fluorescent signal transduction in this work. This study builds on our original discovery of a template-transformation phenomenon, which demonstrated that the connection of a special DNA fragment (5'-CACCGCTTT-3') with a green-emitting AgNC nucleation sequence (GNuS, 5'-TGCCTTTTGGGGACGGATA-3') creates a red-emitting AgNC nucleation sequence (RNuS, 5'-CACCGCTTTTGCCTTTTGGGGACGGATA-3'). Attempts to expand this idea and construct elegant ratiometric NanoCluster Beacons (NCBs) for DNA sequence detection are not straightforward, and, thus, we carried out a series of investigations with the goal of understanding the mechanism of this template-transformation phenomenon. Experimental results showed that the six-nucleotide fragment (5'-CACCGC-3') at the 5'-end of RNuS acts as a template convertor and takes full responsibility for the template transformation from GNuS to RNuS. Moreover, we found that the appropriate proximity of the convertor to GNuS also plays a significant role in the template transformation. We then show that the insights gained here for the template-transformation mechanism allow us to construct ratiometric NCBs by simply appending the convertor and the GNuS onto a rationally designed stem-loop probe. This new type of NCB emits intense red fluorescence without the addition of a target DNA and emerges as a new, bright green emission only when hybridized to its target DNA. By measuring the distinct variation in the fluorescence intensity ratios of green and red emission, this ratiometric NCB was demonstrated to sensitively detect Hepatitis-A virus gene sequences, a proof-of-concept target in this work, with good selectivity.

Irreversible Biometric Template Protection by Trigonometric Function

A protection against biometrics fraud operations will never end because of the continuously occurring computer systems hacking attempts, in particular, the attempts to steal templates from databases related to biometrics. The objective of this paper is to propose a new technique for a biometric template protection, which is characterized as non-invertible (irreversible) template transformation for the reference biometric template inside the database. The proposed technique is based on cosine or sine trigonometric functions to exploit the periodicity property that leads to one-to-many solutions in mathematics, which is well explained in this paper, as well as tested with many attempts to revert the original template. Moreover, security analysis has been discussed in terms of several kinds of attacks such as multiplicity and brute force attacks. The analysis has given promising and fruitful results regarding the security and easiness in involving it inside the commercial work.