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Rapidly deactivation of Cu/SiO2 catalysts at high liquid hour space velocity (LHSV) has been an important obstacle for scale-up application. Herein, silver modified copper phyllosilicate nanotubes were fabricated by different strategies, and implemented to the selective hydrogenation of ethylene carbonate (EC) to methanol and ethylene glycol (EG) as alternative route for the indirect utilization of CO2. The CuPs Ag–copre catalyst synthesized by the co–ammonia evaporation hydrothermal process achieved 79% methanol and 99% EG yield within various ranges of EC LHSV, which was attributed to the balanced Cu+/Cu0 ratio and the enhanced H2 dissociation ability. Inlaid silver species over copper phyllosilicate promoted the interaction between the metal and the support, which substantially regulated the reducibility and dispersion of copper species, meanwhile, increased the stability for long-term running of the catalyst.

The hydrogenation of CO

MnO2/g-C3N4 nanocomposites were facilely synthesized by calcining the mixture of bulk g-C3N4 and MnO2 precursors. The effects of the morphology of MnO2 precursors and the mass ratio of MnO2 to g-C3...

Various Cu/CeO2 nanorod catalysts with different copper content were synthesized through a facile coprecipitation method for the hydrogenation of diethyl carbonate to methanol in a fixed-bed reactor. The methanol yield enhanced with increasing of copper loading, but excessive amount of copper would lead to the deactivation of catalyst at higher liquid hourly space velocity because of the active metal aggregation. The 20Cu/CeO2 and 30Cu/CeO2 catalyst displayed superior catalytic performance with the methanol space-time yield of 8.4 and 8.1 mmol·gcat−1·h−1, respectively. The remarkably enhanced catalytic performance was mainly ascribed to higher Cu0 surface area, appropriate ratio of Cu+/Cu0 and more surface oxygen vacancies associated with Ce3+, which stemmed from the strong interaction between Cu and the CeO2 support.

Objective The purpose of the study is to investigate the characteristics of prevalence and curve severity in patients with adolescent idiopathic scoliosis (AIS) and the body composition alterations between the patients with AIS and healthy controls. Methods Information on the study sample was obtained from a screening database. The AIS cohort was paired with an age- and gender-matched healthy cohort. The stratification of BMI and curve severity was conducted according to the criteria developed by the US Centers for Disease Control and Prevention and the Scoliosis Research Society. The prevalence and curve severity of the patients with AIS were investigated. Multigroup comparison of body composition parameters was conducted according to BMI between the patients with AIS and healthy controls. Results A total of 1,202 patients with AIS and an age- and gender-matched cohort were recruited from local schools. The underweight cases had the highest prevalence of AIS and significantly higher Cobb angle compared with the other three BMI subgroups. Although the patients with AIS had lower body weight, body fat mass, percentage of body fat, and fat-free mass compared with healthy controls, converse results were observed in the underweight cases after stratification according to BMI. Conclusion Based on the sporadic body composition of the patients with AIS observed in the current study, it is predictable that the pathophysiological alterations may be different before and after the onset of scoliosis. Well-designed human or animal studies for underweight patients would be helpful to reveal the mechanisms of pathophysiological alterations and better predict the development of AIS.

STUDY DESIGN A prospective randomized controlled trial. OBJECTIVE The aim of this study was to investigate the effectiveness of orthotic management versus exercise on spinal curvature, body symmetry, and quality of life. SUMMARY OF BACKGROUND DATA A number of well-designed studies comparing conservative treatment of adolescent idiopathic scoliosis (AIS) have been conducted and the evidence becomes stronger. However, there is a lack of the information on the effectiveness of orthotic management versus exercise. METHODS The inclusion criteria recommended by the Scoliosis Research Society (SRS) and the international Society on Scoliosis Orthopedic and Rehabilitation Treatment (SOSORT) were used during enrollment. Eligible patients were randomly assigned to either bracing group or exercise group. Patients in the bracing group were prescribed with a rigid thoracolumbosacral orthosis and requested to wear 23 h/day, while patients in the exercise group were treated with the protocol of the Scientific Exercise Approach to Scoliosis. Data regarding angle of trunk inclination, Cobb angle, shoulder balance, body image, and quality of life (QoL) were collected every 6 months. RESULTS Twenty-four patients in the bracing group and 29 patients in the exercise group participated in this study. For the intergroup comparison, the bracing group showed better results about the correction of spinal curvature (Cobb angle at the first 12 months of intervention, P = 0.039), scores concerning QoL, especially function (P

A plate-type Ru-doped anodic alumina-supported Ni catalyst was synthesized to investigate its activity and electrical-heating possibility in steam reforming of kerosene (SRK). The catalyst showed a favorable SRK durability, which was associated with a synergistic effect between Ru and Ni, referring to the formation of Ru–Ni alloy. Under an electrical-heating pattern, the SRK system could reach stability within ca. 15 min, and no deactivation was observed during the 10 h test. Therefore, this plate-type catalyst is very promising, because it is a multipurpose reforming catalyst for SRK as well as SRM and has a swift startup.

A plate-type anodic alumina support (γ-Al2O3/Fe–Cr–Ni alloy/γ-Al2O3) was used to prepare a series of Ru catalysts. The performance of these catalysts was investigated in the steam reforming of kerosene (SRK). Ethanol solution impregnation was used to enhance metal dispersion on the catalyst surface. The catalyst prepared by ethanol solution impregnation and dried at 120 °C (Ru/Al2O3-ED) gave a higher metal dispersion and more favorable activity and durability than that prepared in aqueous solution. However, owing to shrinking caused by the oxidation of ruthenium species, high temperature calcination in air after impregnation greatly decreased the metal dispersion on the catalyst surface, regardless of the impregnation solution type. In contrast to calcination in air, high temperature N2 treatment could decompose the reducible ruthenium species on the Ru/Al2O3-ED completely. This indicates that H2 pre-reduction is not an essential procedure for the SRK reactions over this catalyst. The experimental results also confirm this hypothesis. The effect of Ce addition was also investigated and was found to enhance significantly the catalyst tolerance to carbon deposition thereby improving the SRK durability of Ru/Al2O3-ED under a high space velocity. In addition, owing to the high electrical resistance of the Fe–Cr–Ni alloy, the anodic alumina catalyst itself can be used as a heater, when an electrical current is applied along the alloy layer. Under an electrical-heating pattern, the SRK reaction system reached stability within 15 min, offering a strong possibility for shortening the start-up time of conventional reformers from 1 to 2 h to a few minutes.

An anodic alumina supported silver catalyst (1.7 Ag/Al2O3) was synthesized to investigate the selective catalytic reduction (SCR) of NO under an electrically heating pattern. It was found that less than 1 min was required to heat the catalyst from room temperature to 450°C. Comparing with a common furnace heating pattern, similar de-NOx activity was achieved. According to the electrically heating tests, the NOx conversion of 1.7 Ag/Al2O3 remained above 80% for 15 h at 450°C (F/W = 65000 mL/(g · h)), which proved that it was commendable to apply this type of catalyst to C3H6-SCR of NO. Additionally, the promotional effect of hydrogen additive is also discussed under the electrically heating pattern. In the presence of 2000 ppm of hydrogen, the 1.7 Ag/Al2O3 reached 80% NOx conversion within a few seconds at 300°C, while the activity was very low at 300°C without hydrogen; such a high conversion was maintained for 15 h.

Two plate-type anodic alumina supported Ru catalysts, Ru/Al and Ru/Ce–Al, has been employed to investigate activities in the kerosene steam reforming reaction. H2 pre-reduction during the kerosene steam reforming was found not an essential procedure, in terms of activity and stability. In addition, the Ru/Ce–Al catalyst was more stable than Ru/Al without pre-reduction in the accelerated life test. In the 20 times of DSS operation over Ru/Ce–Al, no remarkable decline in kerosene conversion was observed, indicating that Ru/Ce–Al was tolerable to multiple cycles under such severe conditions without obvious deterioration. Under an electric heating pattern, the performance of catalyst Ru/Ce–Al was investigated. It showed that 100% of kerosene conversion would be obtained in just 15 min over the Ru/Ce–Al catalyst when the kerosene was introduced into the reactor. It also presented excellent stability during test and DSS operation, which indicates more promising lifetime for the Ru/Ce–Al catalyst in the wall-type reformer.

Plate-type metal monolithic anodic alumina supported Ru catalysts prepared by impregnation method has been employed for the kerosene steam reforming. The characteristics of the catalysts were analyzed by ICP, BET, TG and FESEM. We found that although plate-type Ru/Al2O3 catalyst displayed favorable activity in the long-term stability test, coke deposition resistance should be further improved. In order to inhibit the coking during the reforming reaction, ceria was added to Al2O3 support to synthesize Ru/Ceria-Al2O3 catalysts. The results showed that ceria addition to the Ru/Al2O3 catalyst enhanced the catalyst stability, resulting from the lower content of coke formation on the catalyst surface. Furthermore, it showed that the content of ceria had a greater impact on the content of coke formation on the catalyst surface. If more ceria were contained in Ru/Ceria-Al2O3 catalyst, less coke would be formed over the catalyst surface during the reaction.

A series of anodic alumina supported silver/titanium catalysts (Ag/Ti/Al2O3) were synthesized to investigate the effect of Ti on the selective catalytic reduction of NO with propene. In the low temperature region, the SCR activity was greatly enhanced on Ag/Ti/Al2O3 compared to Ag/Al2O3, and this promotion became more significant with increasing Ti loading. Adding Ti to an anodic alumina support did not cause obvious improvement of activity, indicating that the presence of Ti acted as a catalytic promoter of Ag, but did not directly participate in the SCR reaction. The result of NOx-TPD in flowing He showed that no obvious difference in the desorption performance of ads-NOx species was found between Ag/Al2O3 and Ag/Ti/Al2O3. However, in flowing O2/C3H6/He the desorption peak of nitrate species was decreased by about 50°C when Ti was present. The promoted partial oxidation of the reducing agent was believed to be a main reason. The result of H2-TPR suggested that besides Ag+ ion and metallic Ag another type of silver existed in Ag/Ti/Al2O3, possibly a moderately agglomerated Agnδ+ cluster. Additionally, in comparison with the SO2-aged Ag/Al2O3 catalyst, the SO2-aged Ag/Ti/Al2O3 catalyst provided a favorable tolerance to SO2 poisoning, and led to higher activity. A relatively lower SO2 adsorption amount and a faster reduction rate of sulfate species by propene were considered to be a reasonable interpretation.

A novel metal monolithic anodic γ-Al2O3 support was prepared by anodization using a clad aluminum plate. The catalytic combustion of methane on Pt/Al2O3/Alloy, Pd/Al2O3/Alloy and Pd–Pt/Al2O3/Alloy catalysts prepared by the impregnation method was studied. The catalysts were characterized by ICP, BET, and temperature-programmed oxidation (TPO). The results showed that at low temperatures ( 700°C), Pd–Pt/Al2O3/Alloy showed the best activity among these three catalysts, whereas the activity of Pd/Al2O3/Alloy decreased gradually. Therefore, it was concluded that the co-existence of Pd and Pt in the Al2O3/Alloy support in Pd–Pt/Al2O3/Alloy made its activity the best among that of all the catalysts studied over the entire temperature range (400–800°C) considered for methane combustion.

An anodic alumina supported 17.9 wt% Ni catalyst shows an excellent catalytic performance during steam reforming of methane at 700°C under W/F = 6.33 × 10–3 g-cat·h/L, even when compared with some commercial Ni and Ru reforming catalysts. This is considered to be the result of the existence of an interfacial NiAl2O4 layer, which could anchor the top metallic nickel particles to prevent them from reacting with the alumina support and sintering, thereby, effectively suppressing carbon deposition. Nevertheless, for the industrialization of anodic nickel catalysts, some effort should be made to alleviate the deterioration of anodic supports, because when subjected to a higher W/F as 1.27 × 10–3 g-cat·h/L, the catalyst shows irreversible deactivation, and little improvement is seen by increasing nickel spinel content and metal loading or modifying the impregnation solution pH.

A 17.9 wt.% Ni/Al 2 O 3 /alloy catalyst with porous anodic alumina support was subjected to steam reforming of methane after 700 °C steam purging and no reactivity was shown because of surface oxidation of sintered Ni particles. When 0.05 wt.% Ru doped on this catalyst, it exhibited self-activation and self-regenerative activity, resulted from the hydrogen spillover over Ru and/or Ru–Ni alloy. Moreover, a 97% CH 4 conversion was kept for 20 h over the catalyst under electrical heating pattern.

A series of plate-type metal-monolithic anodic alumina supported nickel catalysts were employed to investigate their reactivity in the steam reforming of methane reactions. After H2 reduction, a fresh 4.7 wt% Ni/γ-Al2O3/alloy catalyst provided only a short-term activity, and then deactivated quickly. By the temperature programmed reaction technologies, the oxidation of surface sintered metallic Ni particles in the SRM test was suggested to be the main reason for the catalyst deactivation. As a result, a 17.9 wt% Ni/NiAl2O4/γ-Al2O3/alloy catalyst with an interfacial NiAl2O4 layer was synthesized, which showed excellent SRM reactivity at 700 °C and this was believed to be resulted from the existence of interfacial NiAl2O4 layer which anchored the top metallic nickel particles and effectively suppressed catalyst sintering. Moreover, no unfavorable effect was evidenced over the SRM reactivity of anodic Ni catalysts when applying the electrically heated pattern. Nevertheless, for the industrialization of anodic nickel catalysts, some efforts should be made to alleviate the deterioration of anodic supports and the catalysts sintering under the SRM reactions.

The propagation and evolution model of botnet is the most common method to study the spreading features of bots, but current botnets' propagation and evolution models limited to describe active spread process based on worms, don't consider the passive spread process similar to """"plugged Trojan-horse into webpage"""", so these models can not exactly describe how the bots spread on the Internet. In this paper, a new botnet propagation and evolution model (WT-SIR) was proposed. This model carefully considers about the real situation of the Internet, especially probability of bots' status transformed from infected and immune to susceptible. Simulation result shows that the WT-SIR model more exactly satisfies the practical propagation laws and infection characteristics of bots on Internet.

Traditional hybrid P2P Bonnet control model divides nodes into super nodes and client nodes, which made proper compromise between connectivity and aggregation, but it has serious """"social-effect"""" problem. In this paper, an improved hybrid P2P control model (Shadow-Chord) based on chord is proposed, in which both super nodes and client nodes join a hidden structured Chord network in the usual, and they use backup communication channels to rejoin the network when all nodes in the routing table are unreachable. It is similar to construct a covert """"shadow network"""" for hybrid P2P network. Simulation result shows that the Shadow-Chord model effectively lowers the clustering coefficient and solves the """"social-effect"""" problem in traditional hybrid P2P network.

P2P botnets are a rapidly growing threat on the Internet. Having a decentralized control structure, a P2P botnet is very stealthy and robust to detect and defense. The paper studied the lifecycle of P2P botnets and developed a P2P botnet Steady-State Model, which helps understanding P2P botnets. The model can be used to study the behavior characteristics, which provide insight on possible defense or design tactics.

Botnets provide a botmaster infrastructure of management and use of cyber attack capabilities and have become one of the most significant threats to the Internet. The emergence of P2P botnets, which are more stealthy, robust and hazardous, has posed great challenges to botnet detection researches. The paper proposes a novel common P2P botnet detection approach that is able to identify unknown P2P botnets, even in the case that the target network had only a single bot. The traffic generated by a P2P bot has phased similar patterns, which occur at irregular intervals. This feature is called Irregular Phased Similarity (IPS) in the paper. The proposed approach detects P2P bots by identifying IPS characteristic. The experimental evaluation shows the efficiency of the approach on detecting the Storm and Waledac botnets.

Web service environment is characterized by its openness and distribution, in which the interacting entities usually have little knowledge about each other and may be in different domains, so the access control for web service has become a challenging problem that needs to be addressed properly. In this paper, an access control policy model based on context and role is proposed that can be appropriate for web service. The model takes context as the center to define and perform access control policies. It uses the contexts of user, environment and resource to execute dynamic roles assignment and constrain the authorization decision. Furthermore, Description Logic is adopted as the policy language to formalize the model. A series of access control policy axioms are defined and the reasoning method is proposed. Experiment result has proved the feasibility and validity of the presented method.

KNN is widely used in classification, but it could not gain good performance for multiattribute time series classifying. According to the characteristic of multiattribute time series and shortage of KNN, the attributes weighted sample reducing KNN classification approach—WRKNN is proposed. Two major aspects are improved for KNN classification, one is to give weight to the attributes of time series; the other one is to reduce the training set to relative equal density based on weighted distance. A equally distributed training data set is obtained by the improved KNN approach, and the number of training samples is decreased at the same time, hence the efficiency and accuracy is enhanced. At last, the feasible of WRKNN is tested by the experiment.