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BackgroundThe neutrophil to lymphocyte ratio (NLR) is a cost-effective and easily identifiable inflammatory biomarker that has been shown to be closely associated with tumor prognosis and predict survival in patients with multiple malignancies. However, the predictive value of NLR in patients with gastric cancer (GC) treated with immune checkpoint inhibitors (ICIs) has not been fully explored. Therefore, we conducted a meta-analysis to explore the potential of NLR as a predictor of survival in this population.MethodsWe systematically searched the PubMed, Cochrane Library, and EMBASE databases from inception to the present for observational researches on NLR and its relationship with progression or survival in GC patients receiving ICIs. To assess the prognostic significance of NLR on overall survival (OS) or progression-free survival (PFS), we used fixed or random-effect models to derive and combine hazard ratios (HRs) with 95% confidence intervals (CIs). We also examined the relationship between NLR and treatment efficacy by calculating relative risks (RRs) with 95% CIs for objective response rate (ORR) and disease control rate (DCR) in patients with GC receiving ICIs.ResultsNine studies of 806 patients were eligible. OS and PFS data were obtained from 9 and 5 studies, respectively. In nine studies, NLR was associated with poor survival, the pooled HR was 1.98 (95% CI 1.67- 2.35, p < 0.001), indicating a significant association between high NLR and worse OS. We conducted subgroup analyses based on study characteristics to confirm the robustness of our findings. A relationship between NLR and PFS were reported in five studies with a HR of 1.49 (95% CI 0.99- 2.23, p = 0.056), which was not significantly associated. Pooling four studies that examined the correlation between NLR and ORR/DCR in GC patients, we observed a significant correlation between NLR and ORR (RR = 0.51, p = 0.003), but no significant correlation between NLR and DCR (RR = 0.48, p = 0.111).ConclusionIn summary, this meta-analysis indicates that increased NLR is significantly linked to worse OS in patients with GC receiving ICIs. In addition, lowering NLR can improve ORR. Thus, NLR can serve as a predictor for prognosis and treatment response in GC patients treated with ICIs. Nevertheless, further high-quality prospective studies are required to verify our findings in the future.

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Porous metals are a class of cellular materials with lightweight and unique mechanical, electrical, thermal, physical and acoustic characteristics. Magnesium and magnesium alloy foams have exhibited excellent advantages. In particular, open-cell Mg-based foams (porous Mg/Mg alloy foams) have been used for bioresorbable implants, CO2 trapping systems, filters, heat exchangers, absorbent panels and many other applications. While significant progress has been taken in producing porous Mg-based foams with good structure–property relations, but with a large number of different processing parameters, different mechanical properties and pore morphologies of each porous Mg-based foam, it is essential to understand the individual effects of each aspect of the parameters. Therefore, the present article summarized the effects of available processing parameters on the structure and mechanical properties of the porous Mg-based foams. Finally, the future perspectives to enhance the structure and properties of porous Mg/Mg alloy foams were discussed.

A booster vaccination is called for constraining the evolving epidemic of SARS-CoV-2. However, the necessity of a new COVID-19 vaccine is currently unclear. To compare the effect of an Omicron-matched S DNA vaccine and an ancestral S DNA vaccine in boosting cross-reactive immunities, we firstly immunized mice with two-dose of a DNA vaccine encoding the spike protein of the ancestral Wuhan strain. Then the mice were boosted with DNA vaccines encoding spike proteins of either the Wuhan strain or the Omicron variant. Specific antibody and T cell responses were measured at 4 weeks post boost. Our data showed that the Omicron-matched vaccine efficiently boosted RBD binding antibody and neutralizing antibody responses against both the Delta and the Omicron variants. Of note, antibody responses against the Omicron variant elicited by the Omicron-matched vaccine were much stronger than those induced by the ancestral S DNA vaccine. Meanwhile, CD8+ T cell responses against both the ancestral Wuhan strain and the Omicron strain also tended to be higher in mice boosted by the Omicron-matched vaccine than those in mice boosted with the ancestral S DNA vaccine, albeit no significant difference was observed. Our findings suggest that an Omicron-matched vaccine is preferred for boosting cross-protective immunities.

Additional file 1. Table S1. GenBank accession numbers of Chinese rotavirus strains with G8 genotype. Table S2. Comparison of VP7 gene’s pairwise distances between Chinese G8 strains and closely related strains.

With the drive to create a decentralized digital economy, Web 3.0 has become a cornerstone of digital transformation, developed on the basis of computing-force networking, distributed data storage, and blockchain. With the rapid realization of quantum devices, Web 3.0 is being developed in parallel with the deployment of quantum cloud computing and quantum Internet. In this regard, quantum computing first disrupts the original cryptographic systems that protect data security while reshaping modern cryptography with the advantages of quantum computing and communication. Therefore, in this paper, we introduce a quantum blockchain-driven Web 3.0 framework that provides information-theoretic security for decentralized data transferring and payment transactions. First, we present the framework of quantum blockchain-driven Web 3.0 with future-proof security during the transmission of data and transaction information. Next, we discuss the potential applications and challenges of implementing quantum blockchain in Web 3.0. Finally, we describe a use case for quantum non-fungible tokens (NFTs) and propose a quantum deep learning-based optimal auction for NFT trading to maximize the achievable revenue for sufficient liquidity in Web 3.0. In this way, the proposed framework can achieve proven security and sustainability for the next-generation decentralized digital society.

Background Timely and precise etiology diagnosis is crucial for optimized medication regimens and better prognosis in central nervous system infections (CNS infections). We aimed to analyze the impact of mNGS tests on the management of patients with CNS infections. Methods We conducted a single-center retrospective cohort study to analyze the value of mNGS in clinical application. Three hundred sixty-nine patients with a specific CNS infection diagnosis were enrolled, and their clinical data were collected. CDI and DDI were defined in our study to describe the intensity of drug use in different groups. We also used LOH and mRS to evaluate whether the application of mNGS could benefit CNS infection patients. Results mNGS reported a 91.67% sensitivity in culture-positive patients and an 88.24% specificity compared with the final diagnoses. Patients performed with the mNGS test had less drug use, both total (58.77 vs. 81.18) and daily (22.6 vs. 28.12, p

With the development of power communication network, the service data carried by power communication network increases exponentially, which puts forward higher requirements for the processing capacity of power communication network. In order to guarantee the service quality of the communication network, a deep confidence-based power communication bandwidth prediction algorithm is proposed in this paper, which has good robustness for nonstationary sequences. The experimental results show that, compared with the traditional neural network algorithm, the proposed algorithm has more advantages in predicting accuracy and robustness, can improve the carrying capacity of the power communication network, and provide a strong guarantee for the safe and stable operation of the power system.

Stretchable and flexible sensing arrays can facilitate human-computer interaction and biofeedback, such as robots, medical devices, and human-computer interface devices. To meet the demand on perceiving the temperature distributions on varied surface areas with low cost, in this paper, we designed a stretchable and flexible thermal sensing cushion (SFTSC) based on the two-dimensional thermistor array with multi-arch structure. The $8 \times 8$ negative temperature coefficient resistors each with two pins were used as the thermistors. For good stretchability, every conductive textile electrode (CTE) in the SFTSC was fabricated by folding a conductive textile strip with multi-arch structure in an insulated elastic textile substrate. For decreasing the number of the test wires, all thermistors in the SFTSC were arrayed in the shared row-column fashion by inserting two pins of every thermistor into its row CTE and its column CTE, respectively. The performances of the SFTSC were evaluated by temperature sensing experiments of a cup, human hand and sitting posture, and the experimental results showed that the SFTSC with good flexibility and good stretchability could perceive its surface temperature well even its surface area was stretched larger 2.25 times.

An enantioselective oxidative C–H/N–H carbonylation process was developed in this work. A bimetallic Pd/Cu-based catalyst system was found to catalyze enantioselective C(sp2)–H carbonylation of prochiral arylsulfonamides via desymmetrization process in the presence of mono-N-protected amino acid ligands. This reaction provides a facile strategy to the stereoselective construction of the lactam-type products, such as isoindoline-1-ones and isoquinoline-1-ones, in good yields and enantioselectivities under balloon pressure with the mixture of CO/O2. The reaction mechanism was rationalized by using density functional theory (DFT) study.

An unprecedented and multiple C–H activation/N-dealkylative C–N bond activation provides a direct and facile access to indolo[1,2-a]quinoxalin-6-ones and phthalides., A novel Pd/Cu-cocatalyzed carbonylative cyclization by C–H activation and N-dealkylative C–N bond activation has been developed for the chemoselective construction of synthetically useful heterocycles. The N,N-dimethylamine group on o-indolyl-N,N-dimethylarylamines was found to act as both the directing group and reactive component in this C–H carbonylative cyclization reaction. Furthermore, a unique C–H oxidation/carbonylative lactonization of diarylmethylamines is firstly demonstrated under modified reaction conditions, which could be easily applicable to the one-step synthesis of multi-substituted phthalides bearing an N,O-ketal skeleton that is difficult to access by previously reported methods. Mechanistic studies implicate that Pd/Cu-cocatalyzed C–H oxidation/carbonylative lactonization is a sequential reaction system via Cu-catalyzed C(sp3)–H oxidation and Pd-catalyzed oxidative carbonylation of the C(sp2)–H bond. It was found that trace amounts of water are essential to promote the Cu-catalyzed C(sp3)–H oxidation of diarylmethylamine for the formation of the hydroxyl group, which could act as an in situ-formed directing group in the intramolecular carbonylative lactonization step.

The arbitrary ratio power splitter is widely used in photonic integrated circuits (PICs), for signal monitoring, power equalization, signal feedback, and so on. Here we designed a fabrication-tolerant, compact, broadband, and low-loss arbitrary ratio power splitter. The proposed arbitrary ratio power splitter was realized with an adiabatically tapered silicon rib waveguide with 70 nm shallow etches and an S i 3 N 4 waveguide. The fabrication analysis confirmed that both of them are robust to fabrication errors. 3D finite-difference time-domain simulations show a very low excess loss (less than 0.02 dB for S i 3 N 4 waveguide and 0.05 dB for Si rib waveguide), and a broadband operating wavelength range (100 nm). Good fabrication tolerance and standard critical dimensions make the arbitrary ratio power splitter compatible with the standard fabrication process of commercial silicon photonic foundries.

With the gradual realization of the goal of "full coverage, full collection and full cost control" of the power consumption information acquisition system established by the State Grid Corporation of China, the smart grid with the basic technical characteristics of informatization, automation and interaction has entered the stage of full completion. Therefore, the application of power big data technology has become an inevitable requirement for the intelligent development of the power industry, and power data anomaly detection has always been the top priority. Compared with traditional methods, this method is more able to collect the same feature relationship between data, and has strong generalization ability. After experimental comparison, the F1 score evaluation index of DSR-Net is 92.56, which is 9.33% higher than the traditional support vector machine algorithm.

Additional file 1: Table S1. Interrogated agents used in the TAC assay to test specimens from children with MSD in China.

A novel and unusual palladium-catalyzed [4+2] annulation of cyclopropenes with benzosilacyclobutanes is reported. This reaction occurred through chemoselective Si-C(sp2 ) bond activation in synergy with ring expansion/insertion of cyclopropenes to form new C(sp2 )-C(sp3 ) and Si-C(sp3 ) bonds. An array of previously elusive bicyclic skeleton with high strain, silabicyclo[4.1.0]heptanes, were formed in good yields with excellent diastereoselectivity under mild conditions. An asymmetric version of the reaction with a chiral phosphoramidite ligand furnished a variety of chiral bicyclic silaheterocycle derivatives with good enantioselectivity (up to 95.5:4.5 er). Owing to the mild reaction conditions, the good stereoselectivity profile, and the ready availability of the functionalized precursors, this process constitutes a useful and straightforward strategy for the synthesis of densely functionalized silacycles.

The direct olefination of aryl/alkyl halides with trimethylsilyldiazomethane (TMSD) as a C1- or C2-unit was achieved successfully via a metal carbene migratory insertion process, which offered a new access to afford (E)-vinyl silanes and (E)-silyl-substituted α,β-unsaturated amides in good yields and high chemoselectivity.

A silicon-on-insulator polarization diversity scheme is proposed. Based on an asymmetrical evanescent coupler, a broadband and compact polarization splitter–rotator comprising mode conversion tapers and mode sorting asymmetric Y junctions is optimized with silicon dioxide upper cladding and a silicon nitride waveguide. The simulation results show mode conversion loss is less than 0.2 dB, and the extinction ratio is lower than − 17 d B in the wavelength range of 1.48 µ m to 1.67 µ m .

Anti-icing is a technology urgently needed for human society to take production activities in high latitude and cold regions. Superhydrophobic coating is widely used to prevent important facilities from icing, such as power lines, building roof and aircraft skin. In this work, PTFE (PTFE, polytetrafluoroethylene) super hydrophobic coating was prepared on titanium alloy surface, a falling droplet impacted the PTFE super hydrophobic coating and froze on it. Then continuous freezing and thawing were carried out on the PTFE super hydrophobic coating. The result shows that the adhesion between PTFE super hydrophobic coating and droplet is extremely small. Droplet can bounce and roll along the surface, even at low temperatures. Freezing of droplet on PTFE super hydrophobic coating lasts 760 s, much longer than that of unmodified titanium alloy surface. Furthermore, the PTFE super hydrophobic coating has high wear resistance and can resist freezing and thawing permanently.

One-pot formation of 1,2,4-triazolo[1,5-b]pyridazine derivatives is presented in this manuscript, in which the targets are offered via cooperative Cu(i)/Zn(ii)-catalyzed tandem C–N addition and I2/KI-mediated intramolecular N–N bond formation.

Mg–Al–Zn alloy foam with a closed-cell structure was fabricated using CaCO3 as the blowing agent via a powder metallurgical approach. To ensure successful integral foaming, the following two principles should be used: the foamable precursor melting temperature should be lowered, the liquid fraction of the precursor should be higher than 30 wt% within 5 °C when the precursor starts to melt, and the melting temperature range should be less than 110 °C. The compression property of cellular Mg80Al19Zn1 alloy foam was examined, and the results showed that the foam possesses higher compressive strength than the other Mg/Mg alloy foams.

It is widely recognized that rolling Mg alloys is difficult due to their poor ductility. Conventional rolling of Mg alloys often needs to be conducted at high temperatures with multi-pass small thickness reduction, and the strong basal texture often leads to poor ductility and plate cracking. Herein, we conducted a single-pass high-reduction rolling (SPHRR) on AZ91 alloy after pre-homogenization (PH) and RD-ECAP pre-processing (PH + ECAP). Results shows that the AZ91 rolled plate processed by SPHRR (PH + ECAP + R) exhibits a good combination of high tensile strength (ultimate strength of ~420 MPa, yield strength of ~335 MPa) and high ductility (elongation-to-failure of ~19%), together with significantly reduced edge cracks. Microstructure examinations revealed that the improved mechanical property is mainly attributed to a typical bimodal grain structure featured with relatively high Schmidt factors of basal slips (SFbasal). The fine-grain structure produced by the high-pass RD-ECAP pre-processing contributes to the improvement of formability, provides favourable conditions for dynamic recrystallization (DRX) in further rolling and also promotes the formation of the bimodal structure. Overall, the high-pass RD-ECAP is applicable to improve plastic formability of hard-to-deform materials like Mg alloys, and thus has a promising prospect for industrial applications.

Multi-wavelength temperature measurement technology is an advanced radiation temperature measurement technology, which assumes a functional relationship between emissivity and spectrum. The measured multi-wavelength radiation signals and the function relationship between emissivity and spectral is used to obtain the true temperature and emissivity of the target. Multi-wavelength imaging temperature measurement technology detects the multi-wavelength radiation image information of the target and inversely calculates the temperature field distribution of the target. Aiming at the inadequacy of color CCD-based multi-wavelength imaging temperature measurement, such as adaptability of the nonlinear spectral emissivity model, and the narrow dynamic range of temperature measurement, and so on, a four-wavelength non-scanning imaging temperature measurement method based on non-equal ratio filter color splitting at the diaphragm was proposed. This method could effectively compress the band imaging bandwidth to form four narrow band imaging detections, and was suitable for wide dynamic range temperature field measurement of nonlinear spectral emissivity model targets. A four-wavelength imaging thermometer was developed according to the proposed temperature measurement method. The thermometer was mainly composed of a window, a neutral optical attenuator, a four-color filter, an optical objective lens, a visible/near infrared integrated sensor, a measurement control unit, and software. The real temperature distribution of the target was obtained according to the multi-wavelength warming algorithm by the thermometer software. The target high-temperature field (800-2500 ℃) was tested under laser heating conditions. The comparison between the measurement result and the thermocouple data shows that the error is less than 1%, and the method has higher accuracy and better dynamic range adaptability.

In this experiment, the synthesis of PHAs is studied by the microbial flora in the activated sludge, the aim is to reduce the production cost of PHAs and realize the reduction and resource recovery of residual sludge. The remaining sludge from this experiment was taken from the second sink of Lizhigou sewage purification plant, the PHAs was synthesized by using glucose and sodium acetate as carbon source culture and acclimatization sludge. Under normal temperature, the control PH was between 6.9 and 8.4, and COD was in the first stage: N: P=100:5:1, continuous cultivation of 7-15d, and the second stage controlled COD: N: P=200:10:2. By regulating COD, the accumulation of PHAs reached 7.24% when COD=1000. By controlling the time of N source and P source respectively, it is found that the synthesis quantity of PHAs increased with the control time, up to 4.03% and 5.01%. The experiment is also found that the higher the C/P ratio, the greater the synthesis amount of PHAs, which can reach to 6.53%, but the sludge is easy to expand at this time.

This paper made a in-depth research on the application of data mining in academic management system based on overall understanding of data mining, and selected the data sample of students in grade 2007 of Logistics Management major of Logistics School of Beijing Wuzi University, this paper used Clementine software to establish decision tree model and clustering model to analyze students’ cluster characteristics by taking students’ academic achievement, score of college entrance examination, CET 4 and CET 6 level, students’ family income and psychological health, the research can help school notice development features of students in order to improve way of students’ cultivation.

According to the application of ABC classification in goods location layout, this paper deals with its expansion and optimization. By using the coordinate curve and matrix model, we comprehensively consider the storage capacity, the output frequency, the characteristics of the product and the other dimensions, thus building a model of scientific distribution of stock on the basis of products characteristics, finally formed an improved classification of multidimensional variable combination. This improved classification plays an active role in increasing the efficiency of capacity utilization, decreasing the storage time, improving the use of inventory facility, it is suitable for all kinds of warehouse.

Many communities have researched the application of novel network architectures such as Content-Centric Networking (CCN) and Software-Defined Networking (SDN) to build the future Internet. Another emerging technology which is big data analysis has also won lots of attentions from academia to industry. Many splendid researches have been done on CCN, SDN, and big data, which all have addressed separately in the traditional literature. In this paper, we propose a novel network paradigm to jointly consider CCN, SDN, and big data, and provide the architecture internal data flow, big data processing and use cases which indicate the benefits and applicability. Simulation results are exhibited to show the potential benefits relating to the proposed network paradigm. We refer to this novel paradigm as Data-Driven Networking (DDN).

Additional file 1: Table S1. 1HNMR chemical shift of evodiamine and its inclusion complex in DMSO-d6.

In this paper, the viewpoint, which to use ANSYS software with programming ideas whatever the beginner, medium and advanced users, is put forward. This style of using ANSYS can make full use of ANSYS powerful functionality. There are many advantages, especially in modifying and deleting commands during an analysis, archiving and transferring your analysis documents, protecting your modeling and simulation intellectual property right, concurrent design and analysis, etc

In recent years, many sensors made of hard materials have been designed to detect human body movements in physical exercises. However, hard materials usually cause extra dyskinesia for body movements. To detect human limb motion with less dyskinesia in physical exercise, a novel flexible capacitive angle sensor (NFCAS) based on a conductive textile was designed in this paper. The NFCAS has two non-parallel plates, namely, an exciting plate and a sensing plate, which can be fixed onto the inner forearm and the inner upper arm. Thus, the angle between the two plates of the NFCAS can be used to represent the angle of medial elbow, and its variation can lead to changes in the sensor&rsquo, s capacitance at the same time. A push-ups experiment and pull-ups experiment were conducted to evaluate the designed NFCAS&rsquo, s performance. Experimental results showed that the NFCAS could detect the main processes of push-ups and pull-ups. Besides high measurement precision, the NFCAS is also soft, thin, lightweight, and easily made. Therefore, it can be widely applied for detecting human limb motion with less dyskinesia in physical exercises.

To compare the clinical efficacy on chronic pelvic inflammation between the acupoint embedding therapy and acupuncture, and to compare the efficacy of different patterns/syndroms in differentiation treated with acupoint embedding therapy.Two hundred and eighteen cases were randomized into an embedding therapy group (115 cases) and an acupuncture group (103 cases). In both groups, Shenshu (BL 23), Guanyuanshu (BL 26), Zigong (EX-CA 1), Yaoyangguan (GV 3), Guanyuan (CV 4) and Qihai (CV 6) were selected as the main points. For qi and blood stagnation pattern/syndrome, Zhongdu (LR 6), Diji (SP 8) and the others were added; for cold and damp stagnation pattern/syndrome, Diji (SP 8) and Sanyinjiao (SP 6) were added; for stasis and phlegm pattern/syndrome due to spleen deficiency, Sanyinjiao (SP 6) and Zusanli (ST 36) were added. In the embedding therapy group, the catgut was embedded at 7 - 13 acupoints each time, once every 10 days. In the acupuncture group, the conventional acupuncture therapy was applied, once a day. The symptom scores were assessed in the aspects of the lower abdominal pain severity and attack frequency, lumbosacral soreness and distention, abnormality of vaginal discharge and the others. The efficacy was compared between the two groups.The total effective rate was 93.0% (107/115) in the embedding therapy group, which was better than 83.5% (86/103) in the acupuncture group (P0.05). The symptom scores were all reduced after treatment in the two groups (all P0.05). In the embedding therapy group, the efficacies were not significantly different among different patterns/syndromes (all P0.05).The acupoint embedding therapy achieves the definite efficacy on chronic pelvic inflammation and obtains the similar efficacies among the different differentiated patterns/syndromes of the disease.

In this paper, we proposed an adaptive generalized displaced phased center antenna (AGDPCA) algorithm for clutter suppression in airborne radar from a viewpoint of a two-dimensional pulse-to-pulse canceller. First, the clutter model and signal model are given in matrix-vector form, and this leads naturally to the design of a two-dimensional (2-D) two-pulse (2-P) canceller and the GDPCA algorithm formulation. Second, the AGDPCA algorithm is developed by dynamically estimating the 2-D 2-P canceller from the received data. Third, the 2-D 2-P canceller is extended to 2-D multi-pulse canceller to improve the moving target detection performance in AGDPCA algorithm. The effectiveness of the proposed methods is tested via several experiments.

Research on cavitation is very significant for preventing cavitation erosion and for making use of bubbles effectively. Characteristics of cavitation in canonical ensemble are studied by molecular dynamics simulation. Effects of temperature and numerical density on cavitation are analyzed. Comparison with lattice Boltzmann method is also conducted. Simulation results indicate that the temperature and numerical density may affect cavitation remarkably. The formation of cavitation bubbles becomes unstable as the temperature increases, and even hard to occur. A lower numerical density makes cavitation bubble form easier. Moreover, as numerical density reduces, the temperature effect on cavitation becomes less.

We report a polarization dependent reflection phenomenon beyond the normal incidence with a subwavelength nanorod chain. Light waves of the transverse electric mode will be totally reflected while those of the transverse magnetic mode will transmit through. The total reflection or transmission phenomenon can be seen as a constructive or destructive interference of the incident field with the transverse mode field of the chain. With the low-loss feature and the ultra-compact characteristic, this structure may find applications in photonic circuits.

Grating couplers are widely investigated as coupling interfaces between silicon-on-insulator waveguides and optical fibers. In this work, a high-efficiency and complementary metal—oxide—semiconductor (CMOS) process compatible grating coupler is proposed. The poly-Si layer used as a gate in the CMOS metal—oxide—semiconductor field effect transistor (MOSFET) is combined with a normal fully etched grating coupler, which greatly enhances its coupling efficiency. With optimal structure parameters, a coupling efficiency can reach as high as ~ 70% at a wavelength of 1550 nm as indicated by simulation. From the angle of fabrication, all masks and etching steps are shared between MOSFETs and grating couplers, thereby making the high performance grating couplers easily integrated with CMOS circuits. Fabrication errors such as alignment shift are also simulated, showing that the device is quite tolerant in fabrication.

Lanthanum_doped intergrowth ferroelectrics: (Bi,La) 4 Ti 3 O 12 -Sr(Bi,La) 4 Ti 4 O 15 (SrBi 8-x La x Ti 7 O 27 ) (x＝0.00, 0.25, 0.50, 0.75, 1.00, 1.25, 1.50) ceramic samples have been prepared by solid_state reaction m ethod. Their structure was analyzed by x_ray diffraction, and their dielectricit y and ferroelectricity were measured. It is found that La doping does not change the crystal structure of Bi 4 Ti 3 O 12 -SrBi 4 Ti 4 O 15 . The coerciv e field (E C ) of SrBi 8-x La x Ti 7 O 2 7 increases slightly and the remnant polarization (2P r ) increases at first, then decreases with th e increas e of La content. The 2P r reaches a maximum value of 25.6 μC·cm -2 , whe n x is 0.50. The 2P r increases nearly 60%, but the E C incr eases only about 10%, compared with those of SrBi 8 Ti 7 O 27 . Their temperatures of phase t ransition (T C ) decrease with La doping. The T C of SrBi 7.5 La 0.50 Ti 7 O 27 is 556 ℃ and shows good thermal stability. As x becomes 1.50, the SrBi 7.5 La 0.50 Ti 7 O 27 exhibits a characteristic of relaxor ferroelectrics.

Ceramic samples SrBi 4-x La x Ti 4 O 15 (x =0.00, 0.10, 0.25, 0.50, 0.75, 1.00), have been prepared by solid-state reaction method. T heir structure was analyzed by x-ray diffraction, and their dielectricity and fe rroelectricity were measured. It is found that La-doping does not change the cry stal structure of SrBi 4 Ti 4 O 15 . The remnant pola rization (2P 4 ) in creases at first, then decreases with the increase of La content. The 2P 4 reaches a maximum value of 24.2 μC·cm -2 , when x is 0.25. The c oerc ive field of SrBi 3.75 La 0.25 Ti 4 O 15 is 60.8 kV·cm -1 . The 2P 4 increases by about 50% and the E c decrease s near 25%, compa red with these of SrBi 4 Ti 4 O 15 . Obviously, the f erroelectricity of SrBi 4 Ti 4 O 15 is improved by lanthanum doping. The te mperature of p hase transition (T c ) decreased with La cloping. The T c of SrBi 3.75 La 0.25 Ti 4 O 15 is 451 ℃. When x=0.75 and 1.00, the SrBi 4-x La x Ti 4 O 15 exhibit the typical characteristics of relaxor ferro electrics.