Geological Borehole Video Image Stitching Method Based on Local Homography Matrix Offset Optimization.

Due to the influence of the shooting environment and inherent image characteristics, there is a large amount of interference in the process of image stitching a geological borehole video. To accurately match the acquired image sequences in the inner part of a borehole, this paper presents a new method of stitching an unfolded borehole image, which uses the image generated from the video to construct a large-scale panorama. Firstly, the speeded-up robust feathers (SURF) algorithm is used to extract the image feature points and complete the rough matching. Then, the M-estimator sample consensus (MSAC) algorithm is introduced to remove the mismatched point pairs and obtain the homography matrix. Subsequently, we propose a local homography matrix offset optimization (LHOO) algorithm to obtain the optimal offset. Finally, the above process is cycled frame by frame, and the image sequence is continuously stitched to complete the construction of a cylindrical borehole panorama. The experimental results show that compared with those of the SIFT, Harris, ORB and SURF algorithms, the matching accuracy of our algorithm has been greatly improved. The final test is carried out on 225 consecutive video frames, and the panorama has a good visual effect, and the average time of each frame is 100 ms, which basically meets the requirements of the project.

An Efficient LiDAR Point Cloud Map Coding Scheme Based on Segmentation and Frame-Inserting Network.

In this article, we present an efficient coding scheme for LiDAR point cloud maps. As a point cloud map consists of numerous single scans spliced together, by recording the time stamp and quaternion matrix of each scan during map building, we cast the point cloud map compression into the point cloud sequence compression problem. The coding architecture includes two techniques: intra-coding and inter-coding. For intra-frames, a segmentation-based intra-prediction technique is developed. For inter-frames, an interpolation-based inter-frame coding network is explored to remove temporal redundancy by generating virtual point clouds based on the decoded frames. We only need to code the difference between the original LiDAR data and the intra/inter-predicted point cloud data. The point cloud map can be reconstructed according to the decoded point cloud sequence and quaternion matrices. Experiments on the KITTI dataset show that the proposed coding scheme can largely eliminate the temporal and spatial redundancies. The point cloud map can be encoded to 1/24 of its original size with 2 mm-level precision. Our algorithm also obtains better coding performance compared with the octree and Google Draco algorithms.

Adaptive Fixed-Time Neural Networks Control for Pure-Feedback Non-Affine Nonlinear Systems with State Constraints.

A new fixed-time adaptive neural network control strategy is designed for pure-feedback non-affine nonlinear systems with state constraints according to the feedback signal of the error system. Based on the adaptive backstepping technology, the Lyapunov function is designed for each subsystem. The neural network is used to identify the unknown parameters of the system in a fixed-time, and the designed control strategy makes the output signal of the system track the expected signal in a fixed-time. Through the stability analysis, it is proved that the tracking error converges in a fixed-time, and the design of the upper bound of the setting time of the error system only needs to modify the parameters and adaptive law of the controlled system controller, which does not depend on the initial conditions.

Porous Cr2O3 Architecture Assembled by Nano-Sized Cylinders/Ellipsoids for Enhanced Sensing to Trace H2S Gas.

How to achieve high sensing of Cr2O3-based sensors for harmful inorganic gases is still a challenge. To this end, Cr2O3 nanomaterials assembled from different building blocks were simply prepared by chromium salt immersion and air calcination with waste scallion roots as the biomass template. The hierarchical architecture calcined at 600 °C is constructed from nanocylinders and nanoellipsoids (named as Cr2O3-600), and also possesses multistage pore distribution for target gas accessibility. Interestingly, the synergism of two shapes of nanocrystals enables the Cr2O3-based sensor to realize highly sensitive detection of trace H2S gas. At 170 °C, Cr2O3-600 exhibits a high response of 42.8 to 100 ppm H2S gas, which is 3.45 times larger than that of Cr2O3-500 assembled from nanocylinders. Meanwhile, this sensor has a low detection limit of 1.0 ppb (S = 1.4), good selectivity, stability, and moisture resistance. These results show that the combination of nanosized cylinders/ellipsoids together with exposed (104) facet can effectively improve the sensing performance of the p-type Cr2O3 material. In addition, the Cr2O3-600 sensor shows satisfactory results for actual monitoring of the corruption process of fresh chicken.

Bimetallic MOFs-derived coral-like Ag-Mo2C/C interwoven nanorods for amperometric detection of hydrogen peroxide.

Coral-like Ag-Mo2C/C-I and blocky Ag-Mo2C/C-II composites were obtained from one-step in situ calcination of [Ag(HL)3(Mo8O26)]n·nH2O [L: N-(pyridin-3-ylmethyl) pyridine-2-amine] under N2/H2 and N2 atmospheres, respectively. The coral-like morphology of Ag-Mo2C/C-I is composed of interwoven nanorods embedded with small particles, and the nano-aggregate of Ag-Mo2C/C-II is formed by cross-linkage of irregular nanoparticles. The above composites are decorated on glassy carbon electrode (GCE) drop by drop to generate two enzyme-free electrochemical sensors (Ag-Mo2C/C/GCE) for amperometric detection of H2O2. In particular, the coral-like Ag-Mo2C/C-I/GCE sensor possesses rapid response (1.2 s), high sensitivity (466.2 µA·mM-1·cm-2), and low detection limit (25 nM) towards trace H2O2 and has wide linear range (0.08 µM~4.67 mM) and good stability. All these sensing performances are superior to Ag-Mo2C/C-II/GCE, indicating that the calcining atmosphere has an important influence on microstructure and electrochemical properties. The excellent electrochemical H2O2 sensing performance of Ag-Mo2C/C-I/GCE sensor is mainly attributed to the synergism of unique microstructure, platinum-like electron structure of Mo2C, strong interaction between Mo and Ag, as well as the increased active sites and conductivity caused by co-doped Ag and carbon. Furthermore, this sensor has been successfully applied to the detection of H2O2 in human serum sample, contact lens solution, and commercial disinfector, demonstrating the potential in related fields of environment and biology. Graphical abstract.

A rational design of layered metal-organic framework towards high-performance adsorption of hazardous organic dye.

Water pollution originating from organic dyes is endangering the survival and development of society; however, adsorbents with high capacity (>5000 mg g-1) for the fast removal (≤30 min) of Congo Red (CR) in aqueous solution have been not reported to date. In the present work, an acid-base stably layered MOF, [Cd(H2L)(BS)2]n·2nH2O (L-MOF-1, H2L = N1,N2-bis(pyridin-3-ylmethyl)ethane-1,2-diamine, BS = benzenesulfonate), was hydrothermally prepared. L-MOF-1 exhibited high-performance adsorption of CR in aqueous solution at room temperature. The experimental adsorption capacity of the L-MOF-1 adsorbent towards CR reached up to about 12 000 mg g-1 in 20 min in the pH range of 2.2-4.7, which is the best adsorbent with the highest capacity and fastest adsorption of CR to date. The spontaneous adsorption process can be described by the pseudo-second-order kinetic and Langmuir isotherm models. Meanwhile, the L-MOF-1 absorbent possessed a highly positive zeta potential in acid condition (even at pH = 2.2, zeta potential = 36.2 mV). Its good adsorption performance mainly originates from its strong electrostatic attraction with CR in acidic condition, together with diverse hydrogen bonds and ππ stacking interactions. Furthermore, the L-MOF-1 absorbent exhibited good selectivity and could be reused five times through simply washing, where its adsorption efficiency was hardly affected. Therefore, L-MOF-1 is a potential absorbent for effectively removing CR from dye wastewater.

Novel neuron-network-like Cu-MoO2/C composite derived from bimetallic organic framework for highly efficient detection of hydrogen peroxide.

Fabrication of non-enzymatic electrochemical sensors based on metal oxides with low valence-state for nanomolar detection of H2O2 has been a great challenge. In this work, a novel neuron-network-like Cu-MoO2/C hierarchical structure was simply prepared by in-situ pyrolysis of 3D bimetallic-organic framework [Cu(Mo2O7)L]n [L: N-(pyridin-3-ylmethyl)pyridine-2-amine] crystals. Meanwhile, the MoO2/C nano-aggregates were also obtained by liquid phase copper etching. Subsequently, two non-enzymatic electrochemical sensors were fabricated by simple drop-coating of the above two materials on the surface of glassy carbon electrode (GCE). Electrochemical measurements indicate that the Cu-MoO2/C/GCE possesses highly efficient electrocatalytic H2O2 property during wider linear range of 0.24 µM-3.27 mM. At room temperature, the Cu-MoO2/C composite displays higher sensitivity (233.4 µA mM-1 cm-2) and lower limit of detection (LOD = 85 nM), which are 1 and 2.5 times larger than those of MoO2/C material, respectively. Such excellent ability for trace H2O2 detection mainly originates from the synergism of neuron-network-like structure, enhanced electrical conductivity and increased active sites caused by low valence-state MoO2 and co-doping of Cu and carbon, and even the interaction between Cu and Mo. In addition, the H2O2 detection in spiked human serum and commercially real samples indicates that the Cu-MoO2/C/GCE sensor has certain potential application in the fields of environment and biology.

Potential Anti-Tumor Drug: Co-Crystal 5-Fluorouracil-nicotinamide.

5-Fluorouracil-nicotinamide (5-FU-NCM), a co-crystal with a 2D layer structure formed by hydrogen bonds, was synthesized by solvent evaporation and liquid phase-assisted grinding at room temperature. Compared to 5-FU alone, the results of solubility, oil-water partition coefficient, anti-tumor effect in vivo and vitro, acute toxicity, and pharmacokinetic parameters indicate that the co-crystal is a potential anti-tumor drug.

Cd(ii) coordination polymers constructed from bis(pyridyl) ligands with an asymmetric spacer in chelating mode and diverse organic dicarboxylates: syntheses, structural evolutions and properties.

Self-assembly of diverse Cd(ii) metal salts, four organic dicarboxylic acids, and two flexible bis(pyridyl) ligands leads to the formation of thirteen complexes, namely, [Cd(L1)(C4H4O4)]n (1), [Cd(L2)(C4H4O4)0.5]n·nOH·8nH2O (2), [Cd(L1)(C4H2O4)]n (3), [Cd(L1)(C4H2O4)]n (4), [Cd2(L2)(C4H2O4)2(H2O)2]n·nH2O (5), [Cd2(L1)(m-BDC)2(H2O)2]n (6), [Cd2(L2)(m-BDC)2(H2O)2]n (7), [Cd3(L1)2(p-BDC)3(H2O)4]n·2nH2O (8), [Cd(L2)(p-BDC)0.5Cl]n (9), [Cd(L2)(p-BDC)0.5(H2O)]n·n(ClO4)·nH2O (10), [Cd3(L2)2(p-BDC)(SO4)2(H2O)6]n·4nH2O (11), [Cd(L2)(p-BDC)]n·nH2O (12) and [Cd(L2)(p-BDC)]n·nMeOH (13) (L1 = N,N'-bis(pyridin-4-ylmethyl)propane-1,2-diamine, L2 = N,N'-bis(pyridin-3-ylmethyl)propane-1,2-diamine, m-BDC2- = m-benzene dicarboxylate dianion, p-BDC2- = p-benzene dicarboxylate dianion), which have been characterized by elemental analysis, IR, TG, PL, and powder and single-crystal X-ray diffraction. The influence of different Cd(ii) salts on the structure variations and properties has also been investigated. Complexes 1 and 3 present a (4,4) layer motif accomplished by the interconnection of adjacent Cd(ii) cations through L1 molecules and trans-conformational succinates or fumarates. In contrast, the cis-conformational succinates in complex 2 only afford the formation of a chain structure. The L1 and L2 molecules in complexes 4 and 5 adopt the same coordination and join adjacent Cd(ii) cations together with fumarates, giving rise to different 3D networks with vma and irl topologies. The same coordination mode of L1 and L2 in complexes 6-8 joins adjacent Cd(ii) cations together with aromatic dicarboxylates, leading to different (63)(65·8), 2-periodic (6·3) and (4·4) layer motifs. The L2 molecules in complexes 9-13 present different coordination modes and join adjacent Cd(ii) cations together with p-BDC2- dianions to form diverse (6·3) layer motifs, and different 3D networks with cds and eca topologies. Therefore, the diverse coordination modes of the bis(pyridyl) ligand and the feature of different organic dicarboxylate anions can effectively influence the topological structures of these complexes. Luminescence investigation reveals that the emission maximum of these complexes varies from 403 to 433 nm in the solid state at room temperature.

Ladder chain Cd-based polymer as a highly effective adsorbent for removal of Congo red.

Developing of high effective and fast-rate adsorbent materials has been recently attracted intensive attentions all over the world due to organic dye polluted water treatment. However, few studies have been reported on the ultrahigh-capacity and fast-rate removal of Congo red. In this work, a new stable Cd-based coordination polymer exhibits excellent adsorption performance towards Congo Red. This ladder chain [Cd4(H2L)4(H2O)8(NDS)]n·3n(NDS) (I) (H2L = N1,N2-bis(pyridin-3-ylmethyl) ethane-1,2-diamine, 1,5-H2NDS = 1,5-naphthalene disulfonic acid) has been successfully synthesized by the hydrothermal reaction. At room temperature, the experimental adsorption capacity of coordination polymer (I) towards Congo red can reach up to 16,880 mg g-1 in 20 min (pH = 2.0-3.2), and its higher capacity and faster rate are all better than those in reported inorganic and metal-organic frameworks absorbents. The adsorption process is spontaneous and endothermic reaction, and fits well with the second-order kinetics, Langmuir and Scatchard isotherm adsorption models. The excellent adsorption performance of (I) towards Congo red is related to the strong electrostatic, various hydrogen bonding and π-π stacking interactions under acidic conditions.

Large-Scale Synthesis of Hierarchically Porous ZnO Hollow Tubule for Fast Response to ppb-Level H2S Gas.

Response and recovery time to toxic and inflammable hydrogen sulfide (H2S) gas are important indexes for metal oxide sensors in real-time environmental monitoring. However, large-scale production of ZnO-based sensing materials for fast response to ppb-level H2S has been rarely reported. In this work, hierarchically porous hexagonal ZnO hollow tubule was simply fabricated by zinc salt impregnation and subsequently calcination using absorbent cotton as the template. The influence of calcination temperature on the corresponding morphology and sensing properties is also explored. The hollow tubules calcined at 600 °C are constructed from abundant cross-linked nanoparticles (∼20 nm). Its Brunauer-Emmett-Teller surface area is 31 m2·g-1 and the meso- and macroporous sizes are centered at 35 and 115 nm, respectively. The sensor with a lower detection limit of 10 ppb exhibits a fast response speed of 29 s toward the 50 ppb H2S rather than those of the reported intrinsic and doped ZnO-based sensing materials. Furthermore, the sensor shows a wide linear range (10-1000 ppb), good reproducibility, and stability. Such excellent trace ppb-level H2S performances are mainly related to the inherent characteristics of hierarchically porous hollow tubular structure and the surface-adsorbed oxygen control type mechanism.

Enhanced H2S gas-sensing performance of Zn2SnO4 hierarchical quasi-microspheres constructed from nanosheets and octahedra.

Most of the reported ternary oxides based sensors have not been realized to detect ppb-level H2S till now. In this work, Zn2SnO4 hierarchical quasi-microspheres were prepared through a facile surfactant-free hydrothermal method followed by calcination in air atmosphere. The quasi-microspheres are composed of nanosheets with the thickness of 100 nm and octahedra with the average size of 0.63 µm, respectively. The sensor fabricated from such Zn2SnO4 hierarchical quasi-microspheres shows excellent selective response to H2S at 133 °C with the lowest detection limit of 1 ppb. The gas response exhibits good linear relationship in the concentration range of 1-1000 ppb. Such outstanding H2S sensing property might be attributed to its porous structure, the synergistic effect of the two typical building blocks and the surface adsorbed oxygen, and the possible sensing mechanism is also discussed.

A two-stage classification method for borehole-wall images with support vector machine.

Analyzing geological drilling hole images acquired by Axial View Panoramic Borehole Televiewer (APBT) is a key step to explore the geological structure in a geological exploration. Conventionally, the borehole images are examined by technicians, which is inefficient and subjective. In this paper, three dominant types of borehole-wall images on coal-rock mass structure, namely, border images, fracture images and intact rock mass images are mainly studied. The traditional image classification methods based on unified feature extraction algorithm and single classifier is not effect for the borehole images. Therefore, this paper proposes a novel two-stage classification approach to improve the classification performance of borehole images. In the first-stage classification, the border images are identified from three kinds of images based on texture features and gray-scale histograms features. For the remaining two types of images, in the second-stage classification, Gabor filter is first applied to segment the region of interest (ROI) (such as microfracture, absciss layer and horizontal cracks, etc.) and the central interference region. Then, using the same feature vector after eliminating the central interference region, fracture images are separated from intact rock mass images. We test our two-stage classification system with real borehole images. The results of experimental show that the two-stage classification method can effectively classify three major borehole-wall images with the correction rate of 95.55% in the first stage and 95% in the second stage.

Rare earth metal-organic complexes constructed from hydroxyl and carboxyl modified arenesulfonate: syntheses, structure evolutions, and ultraviolet, visible and near-infrared luminescence.

The reaction of 2-hydroxyl-4-carboxylbenzenesulfonic acid (H3L) and rare earth (RE) metal nitrates together with two N-heterocyclic ligands gives rise to the formation of 38 complexes, namely, [La(H2L)2(ox)0.5(H2O)4]n·2nH2O (1-La) (ox = oxalate), [RE2(H2L)2 (ox)(H2O)12]·2(H2L)·8H2O (2-RE) (RE = Nd, Sm, Eu, Gd, Tb, Dy), [RE(SO4)(H2O)7]·(H2L)·3H2O (3-RE) (RE = Ho, Er, Tm, Yb, Lu and Y), [RE(L)(H2O)3]n·nH2O (4-RE) (RE = Er, Tm, Yb and Lu), [RE(L)(2,2'-bipy)(H2O)]n (5-RE) (RE = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho and Y, 2,2'-bipy = 2,2'-bipyridine), [RE(L)(1,10-phen)(H2O)]n (6-RE) (RE = La, Pr, Nd, Sm, Eu, 1,10-phen = 1,10-phenanthroline), and [RE(L')(1,10-phen)2(H2O)]n (7-RE) (RE = Gd, Tb, Ho, Er, Yb and Lu, H3L' = 2-hydroxy-3-nitro-4-carboxybenzenesulfonic acid), which have been characterized by elemental analysis, IR, TG, PL, powder and single-crystal X-ray diffraction. Complexes 1-La, 2-RE and 3-RE present zigzag chain, di- and mono-nuclear structures, in which H2L- acts as a counterion and monodentate and µ2-bridging monoanions. For the three species, light RE metal cations tend to induce the formation of oxalate while heavy RE metal cations tend to induce the formation of sulfate. Complexes 4-RE and 5-RE exhibit layer structures incorporating helical chains, in which the L3- trianion presents µ3 and µ4 coordination modes. Complexes 6-RE containing light RE metal cations show layer structures incorporating helical chains, while complexes 7-RE containing heavy RE metal cations have helical chain structures supported by the bridging of in situ generated L'3-. Remarkably, the in situ generated oxalates in 1-La and 2-RE, as well as the in situ generated L'3- in 7-RE, also play a crucial role in determining the structures of these complexes. Structure evolutions make these complexes present various luminescent emissions. Complexes 3-Tm, 3-Yb, 3-Lu, 3-Y and 4-Lu exhibit ultraviolet emissions from 354 to 370 nm. Complexes 1-La and 6-La present blue emissions at 442 and 463 nm. Complexes 2-Eu, 2-Tb, 5-Tb and 7-Tb exhibit characteristic red and green emissions while the complex 5-Y presents a green emission at 501 nm. Meanwhile, complexes 2-Nd, 3-Yb, 4-Yb, 5-Nd, 6-Nd, and 7-Yb show near-infrared (NIR) emissions. Moreover, 2-Eu, 2-Tb, 5-Tb, 7-Tb and 5-Y show longer luminescence lifetimes from 390.47 to 1211.57 µs.

Phosphorus-Doped Carbon Nitride Tubes with a Layered Micro-nanostructure for Enhanced Visible-Light Photocatalytic Hydrogen Evolution.

Phosphorus-doped hexagonal tubular carbon nitride (P-TCN) with the layered stacking structure was obtained from a hexagonal rod-like single crystal supramolecular precursor (monoclinic, C2/m). The production process of P-TCN involves two steps: 1) the precursor was prepared by self-assembly of melamine with cyanuric acid from in situ hydrolysis of melamine under phosphorous acid-assisted hydrothermal conditions; 2) the pyrolysis was initiated at the center of precursor under heating, thus giving the hexagonal P-TCN. The tubular structure favors the enhancement of light scattering and active sites. Meanwhile, the introduction of phosphorus leads to a narrow band gap and increased electric conductivity. Thus, the P-TCN exhibited a high hydrogen evolution rate of 67 µmol h(-1) (0.1 g catalyst, λ >420 nm) in the presence of sacrificial agents, and an apparent quantum efficiency of 5.68 % at 420 nm, which is better than most of bulk g-C3 N4 reported.

Macrocyclic dinuclear, helical, layered and 3-D Ag(I) complexes constructed from AgX (X = NO3(-) and ClO4(-)) and flexible bis(pyridyl) ligands with a chelating spacer: syntheses, structures and photoluminescence properties.

Reaction of AgX (X = NO3− and ClO4−) and three flexible bis(pyridyl) ligands with a chelating spacer leads to the formation of eight novel Ag(I)-bis(pyridyl) coordination complexes: {[Ag2L1(NO3)2]n·2nH2O} (1), {[AgL1]n·nClO4} (2), {[AgL2]n·nNO3} (3), {[AgL2]n·nClO4} (4), [Ag2(H2L2)2]·6ClO4·9H2O (5), {[AgL3]n·nNO3·nH2O} (6), {[AgL3]n·nClO4·nH2O} (7), and {[Ag3(L3)2(ClO4)]n·2nClO4} (8) (L1 = N,N'-bis(pyridin-2-ylmethyl)propane-1,3-diamine, L2 = N,N'-bis(pyridin-3-ylmethyl)propane-1,3-diamine, L3 = N,N'-bis(pyridin-4-ylmethyl)propane-1,3-diamine), which have been characterized by elemental analysis, IR, TG, UV-Vis DRS, PL, powder and single-crystal X-ray diffraction. Complex 1 presents a (4,4) layered motif which is furnished by the bridging of L1 molecules and nitrate anions in µ4 (κ1N1:κ1N2:κ1N3:κ1N4) and µ2 (κ1O4:κ1O6) modes. With a different µ2 (κ1N1:κ1N2:κ1N3:κ1N4) mode, L1 molecules in complex 2 join the adjacent Ag(I) cations to form a helical chain structure. Complexes 3 and 4 also show helical chain structures with the L2 molecules displaying the same µ3 (κ1N1:κ1N2:κ1N3:κ1N4) mode. The protonation of ­NH­ groups in the chelating spacer leads to the formation of H2L22+ cations which further results in a macrocyclic dinuclear motif in complex 5. Complexes 6 and 7 are 3-D svi-x nets with the counter-anions and lattice water molecules being encapsulated in the 1-D channels. Complex 8 exhibits a snake-shaped chain with the L3 molecules presenting µ3 (κ1N:κ1N':κ1N″:κ1N) mode. The structural diversities of complexes 1­8 can be attributed to the coordination modes and conformations of L1­L3. The photoluminescence properties demonstrate that complexes 1, 2 and 5 exhibit ligand-based blue emission maxima from 455 to 462 nm at room temperature in the solid state.

Highly efficient multifluorenyl host materials with unsymmetrical molecular configurations and localized triplet States for green and red phosphorescent devices.

Highly efficient green and red electro-phosphorescence is achieved in devices with the host material DPESPODEF3. The multiple fluorenyl moieties of the host material are arranged such that it has an unsymmetrical molecular configuration, and its triplet-state location is tuned such that it has independent energy (ET) and charge transfer (CT) channels. As a result, DPESPODEF3 can suppress triplet-triplet annihilation and triplet-polaron quenching. In the resulting green and red phosphorescent devices, impressive external quantum efficiencies of ca. 20% and 16% and power efficiencies of ca. 75 and 20 lm W(-1) , respectively, are observed.

Suppressing triplet state extension for highly efficient ambipolar phosphine oxide host materials in blue PHOLEDs.

A series of phosphine oxide hosts were constructed to investigate the influence of the triplet state extension in hosts on electrophosphorescence, in which DPESPOPhCz with the carbazolyl-localized triplet state endowed its blue-emitting PHOLEDs with favourable performance, including an external quantum efficiency more than 13%.

Well-designed strategy to construct helical silver(I) coordination polymers from flexible unsymmetrical bis(pyridyl) ligands: syntheses, structures, and properties.

In this Article, self-assembly of AgX (X = NO3(-) and ClO4(-)) salts and four flexible unsymmetrical bis(pyridyl) ligands, namely, N-(pyridin-2-ylmethyl)pyridin-3-amine (L1), N-(pyridin-3-ylmethyl)pyridin-2-amine (L2), N-(pyridin-4-ylmethyl)pyridin-2-amine (L3), and N-(pyridin-4-ylmethyl)pyridin-3-amine (L4), results in the formation of eight helical silver(I) coordination polymers, [Ag(L)(NO3)]n [L = L1 (1), L2 (2), L3 (3), L4 (4)] and [Ag(L)(ClO4)]n [L = L1 (5), L2 (6), L3 (7), L4 (8)], which have been characterized by elemental analysis, IR, TG, PL, and powder and single-crystal X-ray diffraction. The alternating one-dimensional (1-D) left- and right-handed helical chains are included in achiral complexes 1-3 and 5-8. By contrast, the ligand L4 only alternately bridges Ag(I) cation to form the 1-D right-handed helical chain in complex 4. The pitches of these helical chains locate in the range 5.694(5)-17.016(6) Å. Meanwhile, the present four unsymmetrical bis(pyridyl) ligands in the eight complexes present diverse cis-trans and trans-trans conformation and facilitate the construction of helical structures. Moreover, the solid-state luminescent emission intensities of the perchlorate-containing complexes are stronger than those of nitrate-containing complexes at room temperature.