Two Essays on Value Co-Creation

In the past few decades, customer co-creation has received a significant amount of attention in both practice and academics. Prahalad and Ramaswamy (2000) advocated co-opting customer competence as a competitive strategy. The purpose of this dissertation is to investigate how to engage customers and employees into the value co-creation process. This dissertation is composed of two essays. Essay 1 focuses on customer co-creation behaviors and Essay 2 examines employee co-creation behaviors. Motivating customers to participate in the value co-creation process can help the firm achieve their long-term financial successes. However, the psychological mechanism underlying customer co-creation behavior is still not fully understood. Particularly, the goal-driven nature of customer co-creation is largely ignored in the literature. The objective of the first essay is to examine the dual role of goal self-concordance in customer co-creation behavior. Two studies will be conducted to examine each role respectively. Using four experiments, Study 1 examines the motivational power of goal self-concordance on customer co-creation behavior. Specifically, goal self-concordance is positively related to customers’ trying to participate in the co-creation process and anticipatory self-enhancement fully mediates the above relationship. Moreover, the results find that goal specificity weakens the relationship between goal self-concordance and anticipatory self-enhancement. In Study 2, three experiments are conducted to test the moderating effect of goal self-concordance on the relationship between co-creation goal achievement and customers’ perceived self-enhancement. The results find that customers’ perceived self-enhancement after co-creation goal achievement is positively related to customer satisfaction and their future co-creation behaviors and goal self-concordance mainly focuses on the direct effect to self-enhancement. Therefore, the moderating effect of goal self-concordance is not supported in this study. Theoretical and practical implications are also discussed. Essay 2 focuses on employee co-creation behaviors. Although customer co-creation has received a significant amount of attention in both practice and academics, most of the previous studies were conducted from the customer perspective while little is known about how employees are involved in the value co-creation process. To shed new light on employee co-creation behavior, a scale of employee co-creation behavior is developed first, and then a theoretical model that investigates the antecedents and consequences of employee co-creation behavior is tested. To test the hypothesized model, a self-administered survey of 225 employees from a major Auto 4S store chain in China was conducted. The results find that both customer orientation and perceived organizational support are positively associated with employee co-creation behavior, which in turn influences employees’ job satisfaction and job stress. Moreover, firm cross-functional cooperation strengthens the relationships between perceived organizational support and employee co-creation behavior. The findings of the study will provide implications to managers regarding how to measure employee co-creation behavior and how to engage employees into the value co-creation process

Uniformly Area Expanding Flows in Spacetimes

The central object of study of this thesis is inverse mean curvature vector flow of two-dimensional surfaces in four-dimensional spacetimes. Being a system of forward-backward parabolic PDEs, inverse mean curvature vector flow equation lacks a general existence theory. Our main contribution is proving that there exist infinitely many spacetimes, not necessarily spherically symmetric or static, that admit smooth global solutions to inverse mean curvature vector flow. Prior to our work, such solutions were only known in spherically symmetric and static spacetimes. The technique used in this thesis might be important to prove the Spacetime Penrose Conjecture, which remains open today. Given a spacetime $(N^{4}, \overline{g})$ and a spacelike hypersurface $M$. For any closed surface $\Sigma$ embedded in $M$ satisfying some natural conditions, one can "steer" the spacetime metric $\overline{g}$ such that the mean curvature vector field of $\Sigma$ becomes tangential to $M$ while keeping the induced metric on $M$. This can be used to construct more examples of smooth solutions to inverse mean curvature vector flow from smooth solutions to inverse mean curvature flow in a spacelike hypersurface.Comment: 134 pages, 12 figures. This is my Ph.D. thesis, department of mathematics, Duke University, April 201

Optimizing the design of nanostructures for improved thermal conduction within confined spaces

Maintaining constant temperature is of particular importance to the normal operation of electronic devices. Aiming at the question, this paper proposes an optimum design of nanostructures made of high thermal conductive nanomaterials to provide outstanding heat dissipation from the confined interior (possibly nanosized) to the micro-spaces of electronic devices. The design incorporates a carbon nanocone for conducting heat from the interior to the exterior of a miniature electronic device, with the optimum diameter, D0, of the nanocone satisfying the relationship: D02(x) ∝ x1/2 where x is the position along the length direction of the carbon nanocone. Branched structure made of single-walled carbon nanotubes (CNTs) are shown to be particularly suitable for the purpose. It was found that the total thermal resistance of a branched structure reaches a minimum when the diameter ratio, β* satisfies the relationship: β* = γ-0.25bN-1/k*, where γ is ratio of length, b = 0.3 to approximately 0.4 on the single-walled CNTs, b = 0.6 to approximately 0.8 on the multiwalled CNTs, k* = 2 and N is the bifurcation number (N = 2, 3, 4 ...). The findings of this research provide a blueprint in designing miniaturized electronic devices with outstanding heat dissipation

Design, Synthesis, Bioactivity Evaluation, Crystal Structures, and In Silico Studies of New α-Amino Amide Derivatives as Potential Histone Deacetylase 6 Inhibitors

Hydroxamate, as a zinc-binding group (ZBG), prevails in the design of histone deacetylase 6(HDAC6) inhibitors due to its remarkable zinc-chelating capability. However, hydroxamate-associated genotoxicity and mutagenicity have limited the widespread application of corresponding HDAC6 inhibitors in the treatment of human diseases. To avoid such side effects, researchers are searching for novel ZBGs that may be used for the synthesis of HDAC6 inhibitors. In this study, a series of stereoisomeric compounds were designed and synthesized to discover non-hydroxamate HDAC6 inhibitors using α-amino amide as zinc-ion-chelating groups, along with a pair of enantiomeric isomers with inverted L-shaped vertical structure as cap structures. The anti-proliferative activities were determined against HL-60, Hela, and RPMI 8226 cells, and 7a and its stereoisomer 13a exhibited excellent activities against Hela cells with IC50 = 0.31 µM and IC50 = 5.19 µM, respectively. Interestingly, there is a significant difference between the two stereoisomers. Moreover, an evaluation of cytotoxicity toward human normal liver cells HL-7702 indicated its safety for normal cells. X-ray single crystal diffraction was employed to increase insights into molecule structure and activities. It was found that the carbonyl of the amide bond is on the different side from the amino and pyridine nitrogen atoms. To identify possible protein targets to clarify the mechanism of action and biological activity of 7a, a small-scale virtual screen using reverse docking for HDAC isoforms (1–10) was performed and the results showed that HDAC6 was the best receptor for 7a, suggesting that HDAC6 may be a potential target for 7a. The interaction pattern analysis showed that the α-amino amide moiety of 7a coordinated with the zinc ion of HDAC6 in a bidentate chelate manner, which is similar to the chelation pattern of hydroxamic acid. Finally, the molecular dynamics simulation approaches were used to assess the docked complex’s conformational stability. In this work, we identified 7a as a potential HDAC6 inhibitor and provide some references for the discovery of non-hydroxamic acid HDAC6 inhibitors

Biomass-Derived 3D Interconnected Porous Carbon-Encapsulated Nano-FeS2 for High-Performance Lithium-Ion Batteries

The application of earth-abundant materials is strategically important for industrial manufacture. Utilizing the gelatinization and metallic complexation properties of lotus rhizome starch, a FeS2/lotus rhizome starch-derived carbon (LRSC) composite was prepared with ultrafine FeS2 particles encapsulated in hierarchically porous carbon. The abundant interconnected macropores and micropores in the LRSC can provide diffusion channels for ions and sufficient space for the volume change of FeS2. Besides, a continuous interconnected carbon matrix remarkably enhances the electrical conductivity of FeS2. Therefore, the hierarchically porous carbon-stabilized FeS2 exhibits significantly improved cycling performance compared to pristine FeS2 and FeS2 combined with glucose-pyrolyzed carbon. The electrochemical capacity of the FeS2/LRSC composite is 923.5 mA h g(-1) with a capacity retention of 90.2% after 100 cycles at 0.5 A g(-1), which is much higher than that of pristine FeS2 (54.6%) and FeS2/C (32.6%). This work offers an approach for designing cost-effective and high-performance electrodes for lithium-ion batteries

From Silica Sphere to Hollow Carbon Nitride-Based Sphere: Rational Design of Sulfur Host with Both Chemisorption and Physical Confinement

To suppress the shuttle effect and improve the sulfur utilization in lithium-sulfur battery, a novel hollow carbon nitride-based spheres material (HCNx) has been synthesized via polymerization of ethylenediamine and carbon tetrachloride on silica spheres and used as a sulfur host. The rational designed structure of HCNx retards diffusion of lithium polysulfides by both chemisorption and physical confinement. The enhanced conductivity of HCNx improves the utilization of the sulfur. As a result, the S/HCNx exhibits a discharge capacity of 579 mA h g(-1) after 500 cycles with a fade rate of 0.076% per cycle at 0.5 C. Even at 2 C, the S/HCNx cathode still exhibits a reversible discharge capacity of 658 mA h g(-1)

Optimizing the design of nanostructures for improved thermal conduction within confined spaces

<p>Abstract</p> <p>Maintaining constant temperature is of particular importance to the normal operation of electronic devices. Aiming at the question, this paper proposes an optimum design of nanostructures made of high thermal conductive nanomaterials to provide outstanding heat dissipation from the confined interior (possibly nanosized) to the micro-spaces of electronic devices. The design incorporates a carbon nanocone for conducting heat from the interior to the exterior of a miniature electronic device, with the optimum diameter, <it>D</it> ₀, of the nanocone satisfying the relationship: <it>D₀ ² </it>(<it>x</it>) &#8733; <it>x</it> ^1/2where <it>x </it>is the position along the length direction of the carbon nanocone. Branched structure made of single-walled carbon nanotubes (CNTs) are shown to be particularly suitable for the purpose. It was found that the total thermal resistance of a branched structure reaches a minimum when the diameter ratio, <it>&#946;* </it>satisfies the relationship: <it>&#946;* </it>= <it>&#947;</it> ^{-0.25<it>b</it>} <it>N</it> ^{-1<it>/k*</it>}, where <it>&#947; </it>is ratio of length, <it>b </it>= 0.3 to approximately 0.4 on the single-walled CNTs, <it>b </it>= 0.6 to approximately 0.8 on the multiwalled CNTs, <it>k</it>* = 2 and <it>N </it>is the bifurcation number (<it>N </it>= 2, 3, 4 ...). The findings of this research provide a blueprint in designing miniaturized electronic devices with outstanding heat dissipation.</p> <p>PACS numbers: 44.10.+i, 44.05.+e, 66.70.-f, 61.48.De</p